Unusual presentation of Sjogren's syndrome during pregnancy: a case report

BACKGROUND

Pregnancy imposes significant physiological changes, including alterations in electrolyte balance and renal function. This is especially important because certain disorders might worsen and make people more susceptible to electrolyte abnormalities. One such condition is Sjogren's syndrome (SS), an autoimmune disease that can cause distal renal tubular acidosis (dRTA). This case report offers a unique perspective on the intricate physiological interplay during pregnancy, emphasizing the critical importance of recognizing and managing electrolyte abnormalities, particularly in the context of autoimmune disorders such as Sjogren's syndrome.

CASE PRESENTATION

We report a case of a 31-year-old pregnant Indian woman at 24 weeks gestation presenting with fever, gastrointestinal symptoms, and progressive quadriparesis followed by altered sensorium. Severe hypokalaemia and respiratory acidosis necessitated immediate intubation and ventilatory support. Investigations revealed hypokalaemia, normal anion gap metabolic acidosis, and positive autoimmune markers for SS. Concurrently, she tested positive for IgM Leptospira. Management involved aggressive correction of electrolyte imbalances and addressing the underlying SS and leptospirosis.

CONCLUSION

This case underscores that prompt recognition and management are paramount to prevent life-threatening complications in pregnant patients with autoimmune disease. This report sheds light on the unique challenge of managing hypokalaemic quadriparesis in the context of Sjogren's syndrome during pregnancy.

The impact of kidney stone disease on quality of life in high-risk stone formers

OBJECTIVE

To assess the impact of kidney stone disease (KSD) and its treatment on the health-related quality of life (HRQOL) of high-risk stone formers with hyperparathyroidism, renal tubular acidosis, malabsorptive disease, and medullary sponge kidney.

PATIENTS AND METHODS

The Wisconsin Stone Quality of Life questionnaire was used to evaluate HRQOL in 3301 patients with a history of KSD from 16 institutions in North America between 2014 and 2020. Baseline characteristics and medical history were collected from patients, while active KSD was confirmed through radiological imaging. The high-risk group was compared to the remaining patients (control group) using the Wilcoxon rank-sum test.

RESULTS

Of 1499 patients with active KSD included in the study, the high-risk group included 120 patients. The high-risk group had significantly lower HRQOL scores compared to the control group (P < 0.01). In the multivariable analyses, medullary sponge kidney disease and renal tubular acidosis were independent predictors of poorer HRQOL, while alkali therapy was an independent predictor of better HRQOL (all P < 0.01).

CONCLUSIONS

Among patients with active KSD, high-risk stone formers had impaired HRQOL with medullary sponge kidney disease and renal tubular acidosis being independent predictors of poorer HRQOL. Clinicians should seek to identify these patients earlier as they would benefit from prompt treatment and prevention.

Nephrolithiasis and/or nephrocalcinosis is significantly related to renal dysfunction in patients with primary Sjögren's syndrome

OBJECTIVE

The present study compared the clinical features of patients with primary Sjögren's syndrome (pSS) with and without nephrolithiasis and/or nephrocalcinosis to determine factors related to renal dysfunction.

METHODS

The clinical features of 68 patients with anti-Sjogren's syndrome antigen A (SSA)/Ro-antibody-positive pSS with and without nephrolithiasis and/or nephrocalcinosis who underwent abdominal computed tomography and/or ultrasonography were retrospectively analysed.

RESULTS

Of the 68 patients with anti-SSA-antibody-positive pSS, 23 (33%) had renal nephrolithiasis and/or nephrocalcinosis, whereas 45 (67%) did not. Fourteen (20%) patients had renal dysfunction at diagnostic imaging. Among five patients who underwent renal biopsy, four patients with renal nephrolithiasis and/or nephrocalcinosis were diagnosed with tubulointerstitial nephritis, and one without nephrolithiasis and/or nephrocalcinosis was diagnosed with minimal change nephrotic syndrome. Estimated glomerular filtration rate at diagnostic imaging was significantly lower in patients with than without nephrolithiasis and/or nephrocalcinosis group (P = 0.010). In addition to nephrolithiasis and/or nephrocalcinosis (odds ratio [OR], 3.467; P = 0.045), the gap between serum sodium and chloride concentrations (OR, 10.400; P = 0.012) and increased urinary β2-microglobulin (OR, 5.444; P = 0.033) were associated with renal dysfunction at the time of diagnostic imaging.

CONCLUSION

Nephrolithiasis and/or nephrocalcinosis, normal anion gap metabolic acidosis, and tubulointerstitial damage are associated with renal dysfunction in patients with pSS.

Pembrolizumab-induced Acute Tubulointerstitial Nephritis Accompanying Fanconi Syndrome and Type 1 Renal Tubular Acidosis

Pembrolizumab, an immune checkpoint inhibitor, is used to treat a variety of refractory malignancies. However, these agents are sometimes associated with immune-related adverse events. A 71-year-old woman received pembrolizumab-integrated chemotherapy to treat her recurrent mandibular gingival cancer. Five months after stopping pembrolizumab, she developed acute tubulointerstitial nephritis associated with Fanconi syndrome and type 1 renal tubular acidosis, which resolved with steroid therapy. We experienced a case of pembrolizumab-induced Fanconi syndrome and type 1 renal acidosis. We recommend follow-up of the tubular function in addition to the renal function even after discontinuation of pembrolizumab.

An Infant Case of Transient Distal Renal Tubular Acidosis and Fanconi Syndrome Caused by Rotavirus Gastroenteritis

We report an infant case of transient distal renal tubular acidosis and Fanconi syndrome caused by rotavirus gastroenteritis. A 10-month-old boy was admitted to the hospital because of frequent vomiting, lack of vitality, and dehydration. He was diagnosed with rotavirus gastroenteritis on account of his positive stool rotavirus antigen test. Although he presented with acidemia and severe mixed metabolic acidosis, he also had a urine pH of 6.0, indicating impaired urinary acidification. Therefore, he was diagnosed with distal renal tubular acidosis. On the third day of hospitalization, a relatively low %tubular reabsorption of phosphate level with hypophosphatemia, increased fractional excretion of uric acid with hypouricemia, and high urinary β2-microglobulin levels were observed. Moreover, he was diagnosed with Fanconi syndrome on account of multiple proximal tubular dysfunctions. After remission of rotavirus gastroenteritis, the signs of renal tubular dysfunction improved. This was a case of rotavirus gastroenteritis-caused transient distal renal tubular acidosis and Fanconi syndrome. Severe metabolic acidosis resulted from anion-gap metabolic acidosis due to acute kidney injury by rotavirus gastroenteritis and normal anion-gap acidosis due to renal tubular acidosis. When renal tubular acidosis is associated with a disease that causes anion-gap metabolic acidosis, mixed metabolic acidosis occurs and becomes exacerbated. Furthermore, it is important to consider the complications of renal tubular acidosis in the case of severe metabolic acidosis.

Hypokalemia Related to Distal Renal Tubular Acidosis as an Initial Presentation of Primary Sjogren's Syndrome

Hypokalemia due to loss of potassium through the kidneys can be caused by distal Renal Tubular Acidosis (dRTA). The etiology of dRTA can be primary due to genetic defects or secondary to autoimmune diseases, especially Sjogren's syndrome (SS). The occurrence of dRTA in SS patients is low, at only 5% of cases. This case was interesting because dRTA was the initial clinical manifestation that led to the diagnosis of SS in the patient. A 48-year-old woman came with complaints of recurrent weakness. The patient was routinely hospitalized with severe hypokalemia and received potassium supplementation. The diagnosis of dRTA was based on repeated weakness, normal blood pressure, severe and recurrent hypokalemia, high urinary potassium, alkaline urine, low plasma bicarbonate, and standard anion gap metabolic acidosis. The diagnosis of SS in this patient was confirmed based on dry eyes, dry mouth, positive Schirmer's test, and positive autoantibodies to SS-A and Ro-52. There was a delay in the diagnosis of SS for two years in this patient because the complaints were initially subtle and non-specific. The hypokalemia in this patient was secondary to dRTA associated with primary SS. The possibility of an underlying autoimmune disorder should be considered in a patient presenting with recurrent severe hypokalemia. dRTA, as the etiology of hypokalemia, can be a gateway to the diagnosis of SS. In this patient, complaints related to dRTA appeared before the onset of sicca symptoms, and the diagnosis of SS was established.

Rickets in proximal renal tubular acidosis: a case series of six distinct etiologies

OBJECTIVES

Proximal renal tubular acidosis (pRTA) is characterized by a defect in the ability of the proximal convoluted tubule to reabsorb bicarbonate. The biochemical hallmark of pRTA is hyperchloremic metabolic acidosis with a normal anion gap, accompanied by appropriate acidification of the urine (simultaneous urine pH <5.3). Isolated defects in bicarbonate transport are rare, and pRTA is more often associated with Fanconi syndrome (FS), which is characterized by urinary loss of phosphate, uric acid, glucose, amino acids, low-molecular-weight proteins, and bicarbonate. Children with pRTA may present with rickets, but pRTA is often overlooked as an underlying cause of this condition.

CASE PRESENTATION

We report six children with rickets and short stature due to pRTA. One case was idiopathic, while the remaining five had a specific underlying condition: Fanconi-Bickel syndrome, Dent's disease, nephropathic cystinosis, type 1 tyrosinemia, and sodium-bicarbonate cotransporter 1-A (NBC1-A) defect.

CONCLUSIONS

Five of these six children had features of FS, while the one with NBC1-A defect had isolated pRTA.

Association of Familial Hyperkalemia and Hypertension with Proximal Renal Tubular Acidosis and Epileptic Seizures

INTRODUCTION

Familial hyperkalemic hypertension (FHHt) is an inherited disease characterized by hyperkalemia, hypertension, and hyperchloremic acidosis (HCA). The primary defect is a hyperactive sodium chloride co-transporter, expressed in the renal distal tubule. FHHt is caused by mutation in either WNK1, WNK4, KLHL3, or Cul3. The mechanism of HCA is not completely understood.

METHODS

Clinical and genetic data were collected from the largest family with FHHt described in the literature. Urine ammonia was measured in 26 family members. Epilepsy was diagnosed clinically.

RESULTS

Of the 85 family members, 44 are affected by the Q565E WNK4 mutation, and 28 are newly described. In genetically engineered mice, urinary ammonium was decreased. In our study, urine ammonium did not change. In 11 unaffected subjects, urine ammonia per creatinine was 8.013 ± 3.620 mm/mm, and in 15 subjects affected by FHHt, it was 8.990 ± 4.300 mm/mm (p = 0.546, not significant). Due to the large family size and prolonged follow-up, rare conditions can be identified. Indeed, two children have genetic generalized epilepsy and one child has migraine. The prevalence of epilepsy is 4.545% (2/44) much higher than in the general population (0.681%). This difference is statistically significant (χ2 with Yates correction = 5.127, p = 0.023).

CONCLUSIONS

We provide further evidence that the origin of HCA in FHHt lies in the proximal renal tubule. The association of FHHt with epilepsy leads us to speculate that the raised serum K in susceptible subjects may cause a rise in CSF K, and extracellular cerebral K, leading to epilepsy.

Hypokalemic Paralysis Revealing Primary Sjogren's Syndrome: A Case Report

Sjogren's syndrome is a rare chronic autoimmune disease characterised by dry eyes and dry mouth due to autoimmune destruction of the lacrimal and salivary glands, which can occur concurrently with other autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, or thyroiditis. It can lead to renal complications such as interstitial nephritis and glomerulonephritis, with distal/ type 1 renal tubular acidosis which may result in life-threatening electrolyte imbalance. We present a case of a 35-year-old female who presented with complaints of multiple episodes of muscle weakness. Type 1 renal tubular acidosis was discovered to be the cause of her symptoms which lead to the subsequent diagnosis of Sjogren's syndrome. This is rare presentation of Sjogren's syndrome, and it poses a challenge to diagnosis. Early detection and diagnosis of Sjogren's syndrome might be difficult due to existing diagnostic criteria, which contributes to a higher likelihood of missed diagnosis.

Keywords

case reports; hypokalemia; renal tubular acidosis; Sjogren's syndrome.

Renal tubular acidosis without interstitial nephritis in Sjögren's syndrome: a case report and review of the literature

BACKGROUND

Renal tubular acidosis is the principal clinical feature associated with tubulointerstitial nephritis in patients with primary Sjögren's syndrome. Renal tubular dysfunction due to interstitial nephritis has been considered the underlying pathophysiology connecting renal tubular acidosis and primary Sjögren's syndrome. However, the detailed mechanisms underlying the pathophysiology of renal tubular acidosis in primary Sjögren's syndrome is not fully understood.

CASE PRESENTATION

A 30-year-old woman was admitted with complaints of weakness in the extremities. The patient was hospitalized thirteen years earlier for similar issues and was diagnosed with hypokalemic paralysis due to distal renal tubular acidosis with primary Sjögren's syndrome. This diagnosis was based on a positive Schirmer's test. Besides, anti-Sjögren's syndrome-related antigen A was also detected. Laboratory tests indicated distal RTA; however, a renal biopsy showed no obvious interstitial nephritis. Laboratory tests conducted during the second admission indicated distal renal tubular acidosis. Therefore, a renal biopsy was performed again, which revealed interstitial nephritis. Histological analysis of acid-base transporters revealed the absence of vacuolar type H+-ATPases in the collecting duct. The vacuolar type H+-ATPase was also absent in the past renal biopsy, suggesting that the alteration in acid-base transporters is independent of interstitial nephritis.

CONCLUSIONS

This case study demonstrates that vacuolar-type H+-ATPases are associated with distal renal tubular acidosis, and distal renal tubular acidosis precedes interstitial nephritis in patients with primary Sjögren's syndrome.

Carbonic anhydrase II deficiency

Carbonic anhydrase II deficiency (OMIM # 259730), initially called "osteopetrosis with renal tubular acidosis and cerebral calcification syndrome", reveals an important role for the enzyme carbonic anhydrase II (CA II) in osteoclast and renal tubule function. Discovered in 1972 and subsequently given various names, CA II deficiency now describes >100 affected individuals encountered predominantly from the Middle East and Mediterranean region. In 1983, CA II deficiency emerged as the first osteopetrosis (OPT) understood metabolically, and in 1991 the first understood molecularly. CA II deficiency is the paradigm OPT featuring failure of osteoclasts to resorb bone due to inability to acidify their pericellular milieu. The disorder presents late in infancy or early in childhood with fracturing, developmental delay, weakness, short stature, and/or cranial nerve compression and palsy. Mental retardation is common. The skeletal findings may improve by adult life, and CA II deficiency can be associated with a normal life-span. Therefore, it has been considered an "intermediate" type of OPT. In CA II deficiency, OPT is uniquely accompanied by renal tubular acidosis (RTA) of proximal, distal, or combined type featuring hyperchloremic metabolic acidosis, rarely with hypokalemia and paralysis. Cerebral calcification uniquely appears in early childhood. The etiology is bi-allelic loss-of-function mutations of CA2 that encodes CA II. Prenatal diagnosis requires mutational analysis of CA2. Although this enzymopathy reveals how CA II is important for the skeleton and kidney tubule, the pathogenesis of the mental subnormality and cerebral calcification is less well understood. Several mouse models of CA II deficiency have shown growth hormone deficiency, yet currently there is no standard pharmacologic therapy for patients. Treatment of the systemic acidosis is often begun when growth is complete. Although CA II deficiency is an "osteoclast-rich" OPT, and therefore transplantation of healthy osteoclasts can improve the skeletal disease, the RTA and central nervous system difficulties persist.

Type 4 renal tubular acidosis and uric acid nephrolithiasis: two faces of the same coin?

PURPOSE OF REVIEW

The present review summarizes findings of recent studies examining the epidemiology, pathophysiology, and treatment of type 4 renal tubular acidosis (RTA) and uric acid nephrolithiasis, two conditions characterized by an abnormally acidic urine.

RECENT FINDINGS

Both type 4 RTA and uric acid nephrolithiasis disproportionately occur in patients with type 2 diabetes and/or chronic kidney disease. Biochemically, both conditions are associated with reduced renal ammonium excretion resulting in impaired urinary buffering and low urine pH. Reduced ammoniagenesis is postulated to result from hyperkalemia in type 4 RTA and from insulin resistance and fat accumulation in the renal proximal tubule in uric acid nephrolithiasis. The typical biochemical findings of hyperkalemia and systemic acidosis of type 4 RTA are rarely reported in uric acid stone formers. Additional clinical differences between the two conditions include findings of higher urinary uric acid excretion and consequent urinary uric acid supersaturation in uric acid stone formers but not in type 4 RTA.

SUMMARY

Type 4 RTA and uric acid nephrolithiasis share several epidemiological, clinical, and biochemical features. Although both conditions may be manifestations of diabetes mellitus and thus have a large at-risk population, the means to the shared biochemical finding of overly acidic urine are different. This difference in pathophysiology may explain the dissimilarity in the prevalence of kidney stone formation.

Fanconi syndrome in an elderly patient with membranous nephropathy during treatment with the immunosuppressant mizoribine

We report on an 80-year-old man diagnosed with Fanconi syndrome induced by mizoribine after 4 weeks of administration to treat membranous nephropathy. Mizoribine is an oral immunosuppressant that inhibits inosine monophosphate dehydrogenase and is widely used in Japan for the treatment of autoimmune diseases and nephrotic syndrome, as well as after renal transplantation. Acquired Fanconi syndrome is often caused by drugs (antibacterial, antiviral, anticancer, and anticonvulsant drugs) and is sometimes caused by autoimmune diseases, monoclonal light chain-associated diseases, or heavy metal poisoning. In our patient, hypokalemia, hypophosphatemia, glucosuria, hypouricemia, and severe proteinuria resolved gradually after discontinuation of mizoribine administration, despite oral administration of prednisolone followed by a single intravenous injection of rituximab. The patient was ultimately diagnosed with Fanconi syndrome induced by mizoribine based on his clinical course and his typical laboratory data with the absence of proximal tubular acidosis. To our knowledge, this is the first report of Fanconi syndrome possibly induced by mizoribine. Although the precise mechanism by which mizoribine induces proximal tubular dysfunction is unknown, we suggest that nephrologists should be aware of the onset of Fanconi syndrome, a rare complication during mizoribine treatment.

Severe Hypophosphatemia as the Initial Presentation of Renal Fanconi's Syndrome and Distal Renal Tubular Acidosis Related to Zoledronic Acid: A Case Report and Literature Review

INTRODUCTION

Zoledronic acid (ZA) is a widely used bisphosphonate compound for the prevention of skeletal metastasis-associated osteolysis and treatment of post-menopause osteoporosis. Acute kidney injury is one of the commonly described renal complications. Electrolyte disorder has also been reported relevant to ZA exposure and nephrotoxicity. Syndrome of persistent hypophosphatemia, hypokalemia, and metabolic acidosis is regarded as the initial signs of acute kidney injury.

CASE PRESENTATION

We reported a 64-year-old female with bone metastasis from lung adenocarcinoma who received a 5-year history of 4-week cycle of ZA infusion. She initially presented with symptomatic severe hypophosphatemia and was finally identified with ZA-induced generalized tubular dysfunction as Fanconi's syndrome and distal renal tubular acidosis. Renal pathological findings revealed toxic renal tubular necrosis. The ZA infusion was thus extended to an 8-week cycle with oral phosphate supplementation and alfacalcidol. Although periodic changes pre- and post-ZA infusion existed yet, hypophosphatemia was effectively improved, and the rapid decline of eGFR was partially delayed. We reviewed the literature and mainly summarized the characteristics of bisphosphonate-associated hypophosphatemia. Moderate hypophosphatemia was more frequently mentioned in contrast to severe cases being predisposed to be reported. Progressive hypophosphatemia serves as an early sign of kidney injury.

CONCLUSION

Progressive electrolyte disorders and CKD were the long-term renal outcomes of the current patient. We would like to arouse more attention to electrolyte imbalance related to early ZA-induced kidney injury and emphasize the significance of close monitoring.

Detailed Nephro-urological Management of a Case of Medullary Sponge Kidney with Distal Renal Tubular Acidosis and Obstructive Uropathy

Medullary sponge kidney (MSK) is a rare renal malformation characterized by precalyceal tubular ectasia of the renal collecting ducts that clinically manifests as recurrent renal stones, distal renal tubular acidosis (dRTA), osteoporosis, and nephrocalcinosis. In this case report, we present the case of a woman with a severe form of MSK associated with dRTA. She had extensive nephrocalcinosis and obstructive uropathy caused by a large upper ureteric stone in the left kidney. The stone was disintegrated by flexible ureteroscopic laser lithotripsy. Her initial biochemical derangements were identified and corrected with a Polycitra-K solution and hydrochlorothiazide, leading to reduced stone load and osteopenia 1 year later.

Type 1 Renal Tubular Acidosis with Hypokalemic Quadriparesis in Sjogren Syndrome

Sjogren syndrome is an autoimmune disease characterised by lymphocytic infiltration and inflammation of the exocrine glands resulting in decreased secretion of involved glands which manifests mostly as dry eye and dry mouth. The prevalence of the disease is reported to be about 10.3 per 10,000 population. It is more common in females with a male: female ratio of 16:1. Extra glandular manifestations are seen in up to 1/3rd of the cases. Renal involvement is seen in 4.9% of patients with Sjogren syndrome.

MATERIAL

Here we present three cases of Sjogren Syndrome who presented to our hospital with hypokalaemic quadriparesis.

OBSERVATION

On evaluation all three of the patients were found to have renal tubular acidosis type 1. None of these patients had any symptom of Sjogren syndrome before the onset of quadriparesis. All of these patients had acute onset progressive areflexic quadriparesis with involvement of facial muscles and drooping of eyelids without sensory or bladder bowel involvement. One of these patients had respiratory muscle paralysis severe enough to mandate mechanical ventilation. Arterial Blood Gas analysis and urine electrolyte analysis were suggestive of type 1 renal tubular acidosis. ANA positive in 2 of the 3 patients. Anti-SSA &amp; anti-SSB antibodies were positive in all three patients. Supportive measures and IV fluid and electrolyte correction was done. There was complete recovery of power in all three patients and were discharged on oral medications.Renal Tubular Acidosis is characterised by inability of the nephrons to maintain physiologic acid base balance. This usually results from a defect in the tubular transport mechanisms. Distal Renal tubular acidosis (as in these patients) is further defined by an alkalotic urinary pH(&gt;5.5) and profound hypokalemia due to impairment in H+ secretion in ditstal tubular alpha-intercalated cells. Owing to this imbalance of ionic transport in distal tubules there can be nephrocalcinosis, nephrolithiasis, rickets and severe muscle weakness. Sjogren syndrome is one of the etiologies leading to development of T1RTA.T1RTA can be the presenting feature of Sjogren Syndrome.

CONCLUSION

Though a rare manifestation of the disease if can be the presenting symptom. Work up for RTA (ABG, urine electrolytes, Urine PH and osmolarity etc) in patients with hypokalaemic paresis can help establish the etiological diagnosis(ANA, anti-SSA,anti-SSB) and help prevent future relapses of the disease.

Secondary distal renal tubular acidosis and sclerotic metabolic bone disease in seronegative spondyloarthropathy

Adults with distal renal tubular acidosis (dRTA) commonly present with hypokalaemia (with/without paralysis), nephrolithiasis/nephrocalcinosis and vague musculoskeletal symptoms. All adults with dRTA should be thoroughly evaluated for systemic diseases, certain medications and toxins. The leading cause of acquired or secondary dRTA in adults is primary Sjögren syndrome (SS); however, other collagen vascular diseases (CVDs) including seronegative spondyloarthropathy (SSpA) may at times give rise to secondary dRTA. Metabolic bone disease is often encountered in adults with dRTA, and the list includes osteomalacia and secondary osteoporosis; sclerotic metabolic bone disease is an extremely rare manifestation of dRTA. Coexistence of dRTA and sclerotic bone disease is seen in primary dRTA due to mutation in CA2 gene and acquired dRTA secondary to systemic fluorosis. Primary SS and SSpA, rarely if ever, may also lead to both secondary dRTA and osteosclerosis. Circulating autoantibodies against carbonic anhydrase II and possibly calcium sensing receptor may explain both these features in patients with CVD.

MELAS syndrome: an acute stroke-like episode complicated by renal tubular acidosis

MELAS, a mitochondrially inherited multisystem disorder, can present with acute stroke-like episodes. The literature thus far supports the use of L-arginine therapy in acute MELAS flares to alleviate and shorten the duration of symptoms. This is the case of a patient who presented with ataxia and worsening confusion on a background of genetically confirmed MELAS syndrome. In this instance, intravenous L-arginine therapy, along with corticosteroids, was administered in keeping with best practice. However, in a metabolically vulnerable patient, L-arginine therapy resulted in a further deterioration in his clinical status and the development of a non-anion gap metabolic acidosis.

Acute Flaccid Quadriparesis Because of a Rare Systemic Cause

Sjogren's syndrome is a chronic slowly progressive autoimmune disease characterized by lymphocytic infiltration of exocrine glands resulting in xerostomia and dry eyes. The syndrome has wide clinical spectrum from organ specific exocrionopathy to systemic manifestation. The disease can present alone or with other autoimmune diseases like RA, SLE, Scleroderma, autoimmune thyroid disease etc. Prevalence of primary Sjogren's is 0.5-1% and of secondary Sjogren's is 5-20%. Renal involvement is rare and can either be tubulointerstial or glomerular. Based on biopsy reports in the available literature, tubulointerstitial nephritis (TIN) is the most common histological abnormality, followed by glomerulonephritis as a distant second.1 Distal Renal tubular Acidosis is the most common manifestation of TIN. We report a case of a 35 year female with acute onset motor weakness (quadriparesis) with hypokalemia with NAGMA with distal RTA. Patient was diagnosed with Secondary Sjogren's and managed accordingly.

Distal renal tubular acidosis and nephrocalcinosis as initial manifestation of primary sjögren's syndrome

There is a well-established association between primary Sjögren's syndrome and distal renal tubular acidosis (dRTA). dRTA is a relatively infrequent manifestation of primary Sjögren's syndrome which can present with life-threatening electrolyte abnormalities while, in some patients, it could be the first manifestation of the syndrome. We report the case of a 35-year-old woman who presented with unexplained episodes of generalized weakness, severe hypokalemia, nephrocalcinosis, and normal anion gap metabolic acidosis. Subsequent evaluation revealed primary Sjögren's syndrome as her underlying condition. The patient responded well to potassium supplementation, sodium bicarbonate, and oral prednisolone. After four years of follow-up, there were no other extraglandular manifestations, the renal function remained stable and the acidosis was partially improved without the need for oral bicarbonate. This case demonstrates that dRTA could be the initial manifestation of primary Sjögren's syndrome and highlights the necessity for increased vigilance for patients presenting with persistent hypokalemia or nephrocalcinosis so that an early diagnosis can be made allowing for better control and prevention of disease progression.

A Nationwide Retrospective Study in Turkish Children With Nephrocalcinosis

BACKGROUND

Nephrocalcinosis (NC) is defined as calcium deposition in the kidney parenchyma and tubules. This study aims to determine the etiology, risk factors and follow-up results of patients with NC in Turkey.

MATERIALS AND METHODS

Patients diagnosed with NC in the Pediatric Nephrology Department Units of 19 centers from all geographical regions of Turkey over a 10-year period (2010?2019) were included in the study. The medical records from the centers were reviewed and demographic data, admission complaints, medical history, systemic and genetic disorders, risk factors for NC, treatment details and presence of NC after one year follow-up were recorded retrospectively.

RESULTS

The study sample included 195 patients (88 females, 107 males). The mean age at diagnosis was 39.44±47.25 (0.5?208) months; 82/190 patients (43.2%) were diagnosed incidentally; 46/195 patients (23.6%) had an underlying disease; idiopathic hypercalciuria was detected in 75/195 (38.4%) patients. The most common systemic diseases were distal renal tubular acidosis in 11/46 patients (23.9%), primary hyperoxaluria in 9/46 patients (19.6%) and Bartter syndrome in 7/46 patients (15.3%). After one year of follow-up, NC resolved in 56/159 patients (35.2%) and they all did not have an underlying systemic disease.

CONCLUSION

The most common presentation of NC was incidental. Distal renal tubular acidosis and primary hyperoxaluria were the main systemic diseases leading to NC, while hypercalciuria was the most common metabolic risk factor. Nephrocalcinosis was found to remain in most of the patients at a one year follow-up. It may resolve particularly in patients with no underlying systemic disease.

[Renal tubular distal acidosis: nephrocalcinosis as initial diagnosis.]

We present a case of a woman affected by Systemic Lupus Erythematosus (SLE) and distal renal tubular acidosis (DRTA) that during pregnancy presented an exacerbation of SLE together with a renal colic with spontaneous stone passage. Radiological exam revealed diffuse calcifications in both kidneys which suggests, in a context of DRTA, a nephrocalcinosis. With the stabilization of SLE and medical treatment directed to correct metabolic alterations we achieved radiological and clinical stability of lithiasic disease.

Relapsing Tubulointerstitial Nephritis with Antimitochondrial M2 Antibody Accompanied by Pulmonary Involvement

We herein report a 50-year-old woman who suffered from tubulointerstitial nephritis with antimitochondrial M2 antibody, distal renal tubular acidosis, and Fanconi syndrome. Our case also had interstitial pneumonia. After initially successful glucocorticoid therapy, tubulointerstitial nephritis and interstitial pneumonia relapsed. After the second successful round of glucocorticoid therapy, tubulointerstitial nephritis relapsed again and responded to glucocorticoid and azathioprine. This case might indicate (1) the association between pulmonary involvement and tubulointerstitial nephritis with antimitochondrial antibodies and (2) the need for a maintenance dose of glucocorticoid and immunosuppressants in tubulointerstitial nephritis with antimitochondrial antibodies.

Unusual Presentation of Polyautoimmunity and Renal Tubular Acidosis in an Adolescent With Hashimoto's Thyroiditis and Central Pontine Myelinolysis

Background: Hashimoto's thyroiditis is frequently associated with other autoimmune diseases and may include renal involvement. Case description: A 17-year-old female with previously diagnosed Hashimoto's thyroiditis and vitiligo was admitted to a pediatric intensive care unit with hypokalemic paralysis and acidosis, after having suffered from recurrent muscular weakness for approximately one year. A few days later she developed central pontine myelinolysis. After initial stabilization she was also diagnosed with distal renal tubular acidosis (dRTA) and tubular proteinuria which can occur in Sjögren's syndrome. Extended screening for autoimmune diseases additionally revealed celiac disease. Treatment with Prednisone and substitution of potassium quickly lead to the resolution of proteinuria and dRTA, but unilateral paralysis of the sixth nerve as a result of central pontine myelinolysis was irreversible. Conclusions: This is the rare case of polyautoimmunity including autoimmune thyroiditis, Sjögren's syndrome, vitiligo and celiac disease in an adolescent with few disease-specific symptoms. The diagnoses were made via a complicating nephritis causing dRTA and proteinuria. Delay in diagnosis lead to permanent neurological damage. This case highlights the need for pediatricians to be aware of rare accompanying diseases and their complications in "common" pediatric autoimmune diseases like Hashimoto's thyroiditis and celiac disease.

Association of urinary acidification function with the progression of diabetic kidney disease in patients with type 2 diabetes

OBJECTIVE

Although diabetic kidney disease (DKD) has been considered as a glomerulocentric disease in the past few decades, growing evidence demonstrated that tubular damage was indispensable in its pathogenesis and progression. This study was designed to investigate the association of urinary acidification dysfunction with the progression of DKD in type 2 diabetic patients.

METHODS

Here the urinary acidification functions were measured from 80 participants with renal biopsy-proven DKD. The different kinds of renal tubular transportation dysfunction were analyzed, including the dysfunction of bicarbonate reabsorption, titratable acid secretion, and ammonium secretion. In addition, patients were followed up for 17 (interquartile range, 11-32) months to evaluate the effect of urinary acidification dysfunction in the progression of DKD.

RESULTS

The most common urinary acidification dysfunction was the disorder of ammonium secretion, accounting for 53.75%. The more proteinuria excretion and the lower glomerular filtration rate (GFR) were observed in the urinary titratable acid disorder group than the normal group, and the same results were obtained for ammonium secretion disorder. Urine titratable acid was positively correlated with eGFR whereas it was inversely correlated with proteinuria, serum creatinine, and BUN. Moreover, 24 h urine protein, serum creatinine, BUN and cystatin C increased from DKD stage II to stage IV, whereas the eGFR and urine titratable acid decreased in the same way. Furthermore, Kaplan-Meier analysis and Cox regression showed that the disorder of titratable acid was an independent risk factor for DKD progression.

CONCLUSIONS

The dysfunction of urinary titratable acid is a potential biomarker for the severity of proteinuria, eGFR and glomerular lesions in patients with DKD. Moreover, the titratable acid disorder is an independent risk factor of the DKD progression.

AN UNUSUAL CASE OF FAMILIAL SYSTEMIC LUPUS ERYTHEMATOSUS WITH DISTAL RENAL TUBULAR ACIDOSIS AND HEMOLYTIC ANEMIA

Systemic lupus erythematosus (SLE) in children is associated with renal involvement in a majority. While glomerular involvement is a common manifestation, tubular involvement is rare. Tubular dysfunctions previously described with SLE are renal tubular acidosis (Type 1 and less commonly type 4). Isolated renal tubular acidosis without glomerular involvement has not been reported in childhood SLE. We report an adolescent girl with SLE, autoimmune thyroiditis and distal RTA who subsequently developed autoimmune hemolytic anemia. During a follow up of almost 7 years the girl never developed any proteinuria while the RTA persisted. Also during this period her mother was also diagnosed with SLE manifesting as thrombocytopenia.

A novel homozygous deletion in ATP6V0A4 causes distal renal tubular acidosis: A case report

RATIONALE

Autosomal recessive distal renal tubular acidosis (dRTA) is a rare condition, most cases of which are caused by genetic mutations. Several loss-of-function mutations in the ATP6V0A4 gene have been recently reported.

PATIENT CONCERNS

A 2-month, 24-day-old Chinese girl presenting with vomiting and diarrhea.

DIAGNOSIS

dRTA was established by metabolic acidosis and hypokalemia. Mutational analysis of the ATP6V0A4 gene revealed a homozygous deletion of exons 13 and 14. The father was found to have a heterozygous loss of both exons, whereas the mother was normal.

INTERVENTIONS

Patient was treated with potassium citrate.

OUTCOMES

The patient has shown normal pH and potassium levels.

LESSONS

This is the first case of a homozygous deletion in ATP6V0A4 reported in the literature. Although the initial auditory screening was normal in this case, this patient will nevertheless undergo long-term auditory testing.

Renal Tubular Acidosis Presenting as Nephrogenic Diabetes Insipidus

BACKGROUND

Nephrogenic diabetes insipidus (DI) can be primary or secondary to various causes.

CASE CHARACTERISTICS

One child with Fanconi syndrome with proximal renal tubular acidosis (RTA) due to nephropathic cystinosis, and other with Distal RTA with hearing loss.

OBSERVATION

Both cases showed features of nephrogenic DI, which resolved after treating the primary pathology.

MESSAGE

Renal Tubular acidosis may cause nephrogenic DI.

Transient distal renal tubular acidosis in a dog with gastric-dilatation-volvulus

A case of distal renal tubular acidosis occurring as a transient complication in a 13-year-old female greyhound dog with gastric-dilatation-volvulus was diagnosed. The acute renal ischemia and inflammatory condition associated with this syndrome could be considered the main underlying mechanisms responsible for the acute, severe, and complicating renal tubular dysfunction.

[A child with severe growth delay and renal cysts]

We describe the case of a 5-year-old who came to our attention for a growth delay. Among the investigations planned because of the child's short stature, we performed an abdominal ultrasound showing normal-sized kidneys with signs of cortico-medullar de-differentiation, diffuse medullary hyperechogenicity with reduction of cortical thickness and cortical-medullary cysts. The ultrasound findings, also confirmed in MRI, led us to suspect a genetically determined cystic nephropathy of the nephronophthisis or medullary cystic disease type. No mutation was identified in NPHP1, HNFb1 and UMOD genes. Interestingly, laboratory investigations revealed a severe metabolic acidosis with normal renal function and hypokalemia. These findings are not characteristics of a nephronophthisis. We therefore also performed molecular analysis for distal tubular acidosis (dRTA) that showed the association of two genetic variants of ATP6V1B1 and SLC4A genes. These "double mutations" have been inherited from the mother, which however does not have the classic dRTA phenotype. These variants do not currently meet the criteria for a conclusive molecular diagnosis of dRTA but represent variants of uncertain clinical significance. However, considering the clinical and laboratory data one can reasonably conclude that the child has a "probable" diagnosis of distal tubular acidosis. The rapid recovery of staturo-ponderal growth after the start of alkalizing treatment supports our diagnostic hypothesis. The association between distal tubular acidosis and renal cysts is well described in the literature. The hypothesis is that chronic hypokalemia may play a possible role in the formation of renal cysts.

Renal Tubular Acidosis: H+/Base and Ammonia Transport Abnormalities and Clinical Syndromes

Renal tubular acidosis (RTA) represents a group of diseases characterized by (1) a normal anion gap metabolic acidosis; (2) abnormalities in renal HCO3- absorption or new renal HCO3- generation; (3) changes in renal NH4+, Ca2+, K+, and H2O homeostasis; and (4) extrarenal manifestations that provide etiologic diagnostic clues. The focus of this review is to give a general overview of the pathogenesis of the various clinical syndromes causing RTA with a particular emphasis on type I (hypokalemic distal RTA) and type II (proximal) RTA while reviewing their pathogenesis from a physiological "bottom-up" approach. In addition, the factors involved in the generation of metabolic acidosis in both type I and II RTA are reviewed highlighting the importance of altered renal ammonia production/partitioning and new HCO3- generation. Our understanding of the underlying tubular transport and extrarenal abnormalities has significantly improved since the first recognition of RTA as a clinical entity because of significant advances in clinical acid-base chemistry, whole tubule and single-cell H+/base transport, and the molecular characterization of the various transporters and channels that are functionally affected in patients with RTA. Despite these advances, additional studies are needed to address the underlying mechanisms involved in hypokalemia, altered ammonia production/partitioning, hypercalciuria, nephrocalcinosis, cystic abnormalities, and CKD progression in these patients.

Recurrent Hypokalemia leading to Flaccid Quadriparesis: A Renal or Connective Tissue Disorder

Hypokalemic periodic paralysis (hypoKPP) is a clinical entity characterized by recurrent skeletal muscle paralysis due to a decrease in serum potassium levels; hypoKPP can have either a primary (familial) or a secondary cause. One of the secondary causes of hypoKPP is distal renal tubular acidosis (dRTA). Distal renal tubular acidosis (dRTA) is diagnosed when the urinary pH is greater than 5.3 and in the presence of hyperchloremic metabolic acidosis and hypokalemia, with one of the causes being primary Sjögren's syndrome (pSS). PSS can have both glandular and extra glandular manifestations, with dryness of the eyes and mouth being the most common presenting symptoms. DRTA arising from pSS is very unusual, occurring in fewer than 2% of the cases of Sjogren's syndrome (SS). Here, we report on a case of recurrent flaccid quadriparesis that appears to have been caused by distal RTA, resulting in hypokalemia; upon further investigation and clinical evaluation, the patient was diagnosed with pSS.

Anesthetic considerations in a parturient with renal tubular acidosis and hypothyroidism undergoing cesarean delivery

Renal tubular acidosis, associated with hypothyroidism, is rare. We present the case of a woman with known renal tubular acidosis and treated hypothyroidism who underwent emergency cesarean delivery under uneventful combined spinal-epidural anesthesia. The rationale for choosing the anesthetic technique and the potential risks associated with anesthesia and renal tubular acidosis are discussed.

Furosemide/Fludrocortisone Test and Clinical Parameters to Diagnose Incomplete Distal Renal Tubular Acidosis in Kidney Stone Formers

BACKGROUND AND OBJECTIVES

Incomplete distal renal tubular acidosis is a well known cause of calcareous nephrolithiasis but the prevalence is unknown, mostly due to lack of accepted diagnostic tests and criteria. The ammonium chloride test is considered as gold standard for the diagnosis of incomplete distal renal tubular acidosis, but the furosemide/fludrocortisone test was recently proposed as an alternative. Because of the lack of rigorous comparative studies, the validity of the furosemide/fludrocortisone test in stone formers remains unknown. In addition, the performance of conventional, nonprovocative parameters in predicting incomplete distal renal tubular acidosis has not been studied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a prospective study in an unselected cohort of 170 stone formers that underwent sequential ammonium chloride and furosemide/fludrocortisone testing.

RESULTS

Using the ammonium chloride test as gold standard, the prevalence of incomplete distal renal tubular acidosis was 8%. Sensitivity and specificity of the furosemide/fludrocortisone test were 77% and 85%, respectively, yielding a positive predictive value of 30% and a negative predictive value of 98%. Testing of several nonprovocative clinical parameters in the prediction of incomplete distal renal tubular acidosis revealed fasting morning urinary pH and plasma potassium as the most discriminative parameters. The combination of a fasting morning urinary threshold pH <5.3 with a plasma potassium threshold >3.8 mEq/L yielded a negative predictive value of 98% with a sensitivity of 85% and a specificity of 77% for the diagnosis of incomplete distal renal tubular acidosis.

CONCLUSIONS

The furosemide/fludrocortisone test can be used for incomplete distal renal tubular acidosis screening in stone formers, but an abnormal furosemide/fludrocortisone test result needs confirmation by ammonium chloride testing. Our data furthermore indicate that incomplete distal renal tubular acidosis can reliably be excluded in stone formers by use of nonprovocative clinical parameters.

[Urinary lithiasis as a systemic disease.]

Urinary lithiasis is a prevalent disorder of uncertain origin which provokes health problems through potential harm to the urinary system, renal parenchyma or the body as a whole, with a frequent trend to relapse. Historically urinary calculi have been studied and treated as an isolated disease but nowadays we know more about their connection with other pathological entities. In a small percentage of patients, diseases like primary hyperparathyroidism, tubular renal acidosis, inflammatory bowel disease or bariatric surgery have a fairly well studied physiopathological link with kidney stones. However, papers have been published recently describing connections between prevalent diseases such as bone disease or metabolic syndrome and nephrolithiasis. Attempts to prevent or treat these affections can possibly influence the other's prevalence since their trend to increase is clear in western countries.

Large vestibular aqueduct in distal renal tubular acidosis: High-resolution MR in three cases

High-resolution MR of the inner ear performed in 3 consecutive pediatric patients affected by distal renal tubular acidosis (dRTA) and progressive sensorineural hearing loss (SNHL) revealed enlarged vestibular aqueducts (LVA) (bilateral in 1 case and unilateral in 2). LVA is associated to sporadic, progressive SNHL, often secondary to minor head trauma and activities involving the Valsalva maneuver.

We believe that the presence of LVA may have contributed to the onset of SNHL and its progression in our patients, and therefore want to stress the importance of morphological studies of the inner ear in patients affected by dRTA and SNHL.

Abnormal distal renal tubular acidification in patients with low bone mass: prevalence and impact of alkali treatment

Chronic acid retention is known to promote bone dissolution. In this study, 23 % of patients with osteopenia/osteoporosis were diagnosed with abnormal distal renal tubular acidification (dRTA), a kidney dysfunction leading to chronic acid retention. Treating those patients with alkali-therapy shows improvement in bone density. To evaluate the prevalence of abnormal distal renal tubular acidification in patients with low bone mass (LBM) and the impact of additional alkali treatment on bone density in patients with concomitant LBM and dRTA,183 patients referred for metabolic evaluation of densitometrically proven low bone mass were screened for abnormal distal renal tubular acidification between 2006 and 2013. In all LBM urine pH (U-pH) was measured in the 2nd morning urines after 12 h of fasting. If U-pH was ≥5.80, LBM underwent a 1-day ammonium chloride loading, and U-pH was remeasured the next morning. If U-pH after acid loading did not drop below 5.45, patients were diagnosed with abnormal distal renal tubular acidification. Normal values were obtained from 21 healthy controls. All LBM with dRTA were recommended alkali citrate in addition to conventional therapy of LBM, and follow-up DXAs were obtained until 2014. 85 LBM underwent NH₄Cl loading. 42 LBM patients were diagnosed with incomplete dRTA (idRTA; prevalence 23.0 %). During follow-up (1.6-8 years) of idRTA-LBM patients, subjects adhering to alkali treatment tended to improve BMD at all sites measured, whereas BMD of non-adherent idRTA patients worsened/remained unchanged. (1) About one out of four patients with osteopenia/osteoporosis has idRTA. (2) Upon NH₄Cl loading, idRTA patients do not lower urine pH normally, but show signs of increased acid-buffering by bone dissolution. (3) In idRTA patients with low bone mass on conventional therapy, additional long-term alkali treatment improves bone mass at lumbar spine and potentially at other bone sites. (4) All patients with low bone mass undergoing metabolic evaluation should be screened for idRTA.

Systemic lupus erythematosus and renal tubular acidosis associated with hyperthyroidism. Case Report

A case of a 42-year-old female with hyperthyroidism was subsequently diagnosed to have systemic lupus erythematosus with distal RTA. The clinical examination on admission showed swelling of the knee joints and the urinalysis showed pH 6.5, pro 3+. Her blood routine results were as follows: white blood cells 1.85×109/L, platelets 100×109/L, erythrocyte 3.06×1012/L. The serum potassium was 3.11 mmol/L, 24 hour urinary electrolyte: K 68.87 mmol/24 H, antinuclear antibodies (ANA) 1:1 000, speckled pattern. The anti-double stranded DNA antibody (anti-dsDNA), anti SS-A(52) antibody and anti SS-A(60) antibody were positive. The light microscopy and immunofluorescence showed diffuse proliferative lupus nephritis. These data were compatible with the diagnosis of systemic lupus erythematosus. The diagnosis of hyperthyroidism and distal RTA is clear. This report showed that other autoimmune disease in the diagnosis of hyperthyroidism should not be ignored.

Clinical and Aetiological Spectrum of Hypokalemic Flaccid Paralysis in Western Odisha

OBJECTIVE

To study the clinical profile of hypokalemic flaccid paralysis (HKFP) and to evaluate its causes.

METHODS

Fifty cases of hypokalemic flaccid paralysis (HKFP) admitted between November 2012 to October 2014 were taken up in the study. Serum potassium level < 3.5 mmol/ltr has been taken as hypokalemia. All cases were studied for spot and/or 24 hour urinary sodium / potassium, serum potassium / calcium / magnesium. Hypokalemic periodic paralysis (HPP) were diagnosed if there was spot/24 hour urine potassium excretion < 20mmol/ltr in presence of hypokalemia and flaccid weakness without other causes. EMG and nerve conduction study were done to exclude polyneuropathy and myopathic cases.

RESULTS

Out of 50 cases of HKFP, male gender predominated (88%). Maximum number of cases (70%) occurred in 21 to 40 years of age. It occurred in all seasons but more in summer (58%). The precipitating factors were present in 76% of cases out of which high carbohydrate meal (28%), vomiting (16%), excessive sweating (8%), diarrhea (8%) and increased urination (12%) were present. Twenty percent of cases had recurrence (2 to 3 episodes most often) and 6% of cases had family history. Quadriparesis was seen in (54%), paraparesis (36%), hemiparesis (10%) and neck muscle weakness (32%). No case was present with respiratory paralysis or cranial nerve palsy. Twenty-one cases (42%) have very low potassium < 2.5 mmol/ltr, 11 cases (22%) with potassium level between 2.5 to 2.9 mmol/ltr and 18 cases (36%) with 3 to 3.5 mmol/ltr. There was no correlation between severity weakness and potassium level. Eleven cases (22%) had thyrotoxicosis and 3 cases (6%) were hypothyroid. Thirteen cases (26%) have excess urinary loss of potassium (≥20 mmol/ltr) of which 5 cases (10%) were distal renal tubular acidosis (dRTA), four cases (8%) were Gitelman's syndrome (GS) and in 4 cases exact cause could not be diagnosed. Non-renal / prior renal loss of potassium like diarrhea and excessive sweating was responsible in 8% cases each and vomiting in 10% of cases. One unique case of hypernatraemic hypokalemic paralysis (HHP) was found. Only 9 (18%) cases are hypokalemic periodic paralysis (HPP).

CONCLUSIONS

HKFP is a hetergenous group of disease of which a significant number of patients had thyroid disorders mostly in the form of thyrotoxicosis followed by renal tubular dysfunctions like dRTA and GS; non-renal and prior renal loss of potassium like diarrhea, excessive sweating and vomiting respectively. Early recognition and prompt management of these conditions will give gratifying result and prevent further attacks in some cases.

Recurrent Attacks of Hypokalemic Quadriparesis: An Unusual Presentation of Primary Sjögren Syndrome

We herein report the case of a 64-year old woman with recurrent attacks of hypokalemic quadriparesis which resulted from distal renal tubular acidosis (dRTA) secondary to Sjögren syndrome. The patient presented with sudden onset quadriparesis. A physical examination showed symmetric weakness of all four limbs. Severe hypokalemia (1.8 mEq/L), accompanied by normal anion gap metabolic acidosis, a positive urine anion gap and an inappropriately high urine pH pointed toward the diagnosis of dRTA. Further investigations disclosed primary Sjögren syndrome, which had not previously been recognized. On the basis of the current report and a review of the literature we suggest investigating the possibility of Sjögren syndrome in all patients with clinically unexplained dRTA.

Late Metabolic Acidosis Caused by Renal Tubular Acidosis in Acute Salicylate Poisoning

A 16-year-old man was transferred to our emergency department seven hours after ingesting 486 aspirin tablets. His blood salicylate level was 83.7 mg/dL. He was treated with fluid resuscitation and sodium bicarbonate infusion, and his condition gradually improved, with a decline in the blood salicylate level. However, eight days after admission, he again reported nausea, a venous blood gas revealed metabolic acidosis with a normal anion gap. The blood salicylate level was undetectable, and a urinalysis showed glycosuria, proteinuria and elevated beta-2 microglobulin and n-acetyl glucosamine levels, with a normal urinary pH despite the acidosis. We diagnosed him with relapse of metabolic acidosis caused by renal tubular acidosis.

[Nail changes associated with distal renal tubular acidosis in pediatric patients]

Renal tubular acidosis is a disease prevalent in childhood, responsible for a decrease in growth due inadequate acid-base levels regulation. It is well known that systemic conditions can generate or accompany nail changes by different pathophysiologic mechanisms, however no one has ever found or reported any association of onychopathy with renal tubular acidosis so far. That is why we would like to share our experience on this topic.

Clinical evaluation of Chinese patients with primary distal renal tubular acidosis

OBJECTIVE

Distal renal tubular acidosis (dRTA) is a hyperchloremic metabolic acidosis disorder characterized by a normal anion gap with abnormal urinary hydrogen (H(+)) excretion. At present, there are few available reports regarding the clinical status of primary dRTA. The primary objective of this study was to analyze the clinical features and outcomes of primary dRTA.

METHODS

This was a retrospective study performed in patients with primary dRTA who were hospitalized at Ruijin Hospital between March 1996 and July 2009; the clinical features of these patients were analyzed.

RESULTS

This study included 95 consecutive inpatients: 40 men (42.11%) and 55 women (57.89%). Among them, 60 had hypokalemia (63.12%), 29 had complete dRTA and 66 had incomplete dRTA. The mean urine calcium levels of the patients with and without urinary lithiasis were 0.10±0.04 and 0.07±0.05 mmol/24 h・kg, respectively (p=0.04). The blood pH values of the patients with and those without bone disease were 7.37±0.06 and 7.32±0.06, respectively (p=0.01). A total of 8.33% (8/27) of the patients had tubular proteinuria.

CONCLUSION

Hypokalemia is the most common clinical manifestation of primary dRTA. Primary dRTA can also be accompanied by proximal tubular dysfunction. Controlling the urine calcium and citrate levels is crucial for the treatment of nephrocalcinosis and/or nephrolithiasis, while restoring the blood pH to the normal level is essential for controlling bone disease.

Clinical and biochemical findings in Mexican patients with distal renal tubular acidosis

INTRODUCTION

Renal tubular acidosis (RTA) is a rare disease characterized by a normal serum anion gap, sustained metabolic acidosis, low concentration of plasma bicarbonate, variable hyperchloremia and hypokalemia and conserved glomerular filtration rate. RTA is developed during the first year of life and produces failure to thrive and anorexia. Primary distal RTA (type 1) is a renal syndrome with a reduced ability to excrete the acid load through the collecting ducts and impairment to concentrate the urine causing polyuria and dehydration.

OBJECTIVE

Evaluate the current health status and describe the clinical findings and progress of Mexican patients with distal RTA. Demonstrate the distal urinary acidification defect by measuring the urinary pCO2 tension in alkaline urines.

MATERIAL AND METHODS

We looked for infants in tertiary care hospitals with a clinical history of normal serum anion gap, metabolic acidosis, hypokalemia, hyperchloremia, nephrocalcinosis, sensorineural hearing loss and inability for urine acidification under systemic metabolic acidosis. Biochemical analysis were performed periodically. Alkali medication was not suspended in one patient to assess urinary acidification with oral administration of sodium bicarbonate (2 mEq/Kg) and acetazolamide (500 mg/1.73 m2 body surface). Urinary pCO2 levels were determined at 60 and 90 min.

RESULTS

Three children, one adolescent and one adult with distal RTA were found. They had an infant history of dehydration, failure to thrive, anorexia, vomiting, muscle paralysis, hypercalciuria, urinary infections, polyuria, polydipsia and polyhidramnios during pregnancy. Severe nephrocalcinosis was detected in all patients whereas sensorineural hearing loss was developed in four cases. Under the alkali medication all cases but one were normocalciuric. A patient developed kidney failure. The urinary acidification test confirmed the innability to eliminate the acid load.

CONCLUSION

Early diagnosis in infancy and continuos alkali medication were of great benefit for most of the patients. Urinary pCO2 levels in alkaline urine provided an index for collecting duct hydrogen-ion secretion. To our knowledge this is the first report of mexican patients with distal RTA.