Diagnosis codes underestimate chronic kidney disease incidence compared with eGFR-based evidence: a retrospective observational study of patients with type 2 diabetes in UK primary care

BACKGROUND

Type two diabetes (T2D) is a leading cause of both chronic kidney disease (CKD) and onward progression to end-stage renal disease. Timely diagnosis coding of CKD in patients with T2D could lead to improvements in quality of care and patient outcomes.

AIM

To assess the consistency between estimated glomerular filtration rate (eGFR)-based evidence of CKD and CKD diagnosis coding in UK primary care.

DESIGN & SETTING

A retrospective analysis of electronic health record data in a cohort of people with T2D from 60 primary care centres within England between 2012 and 2022.

METHOD

We estimated the incidence rate of CKD per 100 person-years using eGFR-based CKD and diagnosis codes. Logistic regression was applied to establish which attributes were associated with diagnosis coding. Time from eGFR-based CKD to entry of a diagnosis code was summarised using the median and interquartile range.

RESULTS

The overall incidence of CKD was 2.32 (95% confidence interval [CI] = 2.24 to 2.41) and significantly higher for eGFR-based criteria than diagnosis codes: 1.98 (95% CI = 1.90 to 2.05) versus 1.06 (95% CI = 1.00 to 1.11), respectively; P<0.001. Only 45.4% of CKD incidences identified using eGFR-based criteria had a corresponding diagnosis code. Patients who were younger, had a higher CKD stage (G4), had an observed urine albumin-to-creatinine ratio (A1), or no observed HbA1c in the past year were more likely to have a diagnosis code.

CONCLUSION

Diagnosis coding of patients with eGFR-based evidence of CKD in UK primary care is poor within patients with T2D, despite CKD being a well-known complication of diabetes.

Potential impact of NICE guidelines on referrals from primary care to nephrology: a primary care database and prospective research study

BACKGROUND

National Institute for Health and Care Excellence 2021 guidelines on chronic kidney disease (CKD) recommend the use of the Kidney Failure Risk Equation (KFRE), which includes measurement of albuminuria. The equation to calculate estimated glomerular filtration rate (eGFR) has also been updated.

AIM

To investigate the impact of the use of KFRE and the updated eGFR equation on CKD diagnosis (eGFR <60 mL/min/1.73 m2) in primary care and potential referrals to nephrology.

DESIGN AND SETTING

Primary care database (Secure Anonymised Information Linkage Databank [SAIL]) and prospective cohort study (UK Biobank) using data available between 2013 and 2020.

METHOD

CKD diagnosis rates were assessed when using the updated eGFR equation. Among people with eGFR 30-59 mL/min/1.73 m2 the following groups were identified: those with annual albuminuria testing and those who met nephrology referral criteria because of: a) accelerated eGFR decline or significant albuminuria; b) eGFR decline <30 mL/ min/1.73 m2 only; and c) KFRE >5% only. Analyses were stratified by ethnicity in UK Biobank.

RESULTS

Using the updated eGFR equation resulted in a 1.2-fold fall in new CKD diagnoses in the predominantly White population in SAIL, whereas CKD prevalence rose by 1.9-fold among Black participants in UK Biobank. Rates of albuminuria testing have been consistently below 30% since 2015. In 2019, using KFRE >5% identified 182/61 721 (0.3%) patients at high risk of CKD progression before their eGFR declined and 361/61 721 (0.6%) low-risk patients who were no longer eligible for referral. Ethnic groups 'Asian' and 'other' had disproportionately raised KFREs.

CONCLUSION

Application of KFRE criteria in primary care will lead to referral of more patients at elevated risk of kidney failure (particularly among minority ethnic groups) and fewer low-risk patients. Albuminuria testing needs to be expanded to enable wider KFRE implementation.

Cognitive performance is associated with glomerular filtration rate in patients with chronic kidney disease: results from the CKD-REIN cohort

BACKGROUND

Chronic kidney disease (CKD) is associated with cognitive impairment in general population. We assessed the association between kidney and cognitive functions in patients with CKD and the influence of cardiovascular (CV) risk factors, and depression on this association.

METHODS

The CKD-Renal Epidemiology and Information Network cohort included 3033 patients with CKD stages 3-4, followed for 5 years. Cognitive function was assessed with the Mini-Mental State Examination (MMSE) and estimated glomerular filtration rate (eGFR) with the CKD-Epidemiology Collaboration equation-creatinin formula. Evolution of the MMSE score over time and its association with baseline eGFR were investigated with linear mixed models. We assessed the risk of incident cognitive outcome (hospitalisation or death with relevant International Classification of Disease-10 codes), with a Cox proportional hazard model.

RESULTS

The mean age was 66.8, the mean eGFR was 33 mL/min/1.73 m² and 387 patients (13.0%) had an MMSE score below 24 at baseline. A 10 mL/min/1.73 m² decrement of baseline eGFR was associated with a mean MMSE decrease of 0.12 (95% CI 0.04 to 0.19) after adjustment for demographic characteristics, depression, CV risk factors and disease; but baseline eGFR was not associated with MMSE temporal evolution. HR for cognitive outcome during follow-up (median 2.01 years) associated with a 10 mL/min/1.73 m² decrement of baseline eGFR was 1.35 (1.07, 1.70) (p=0.01) after adjustment.

CONCLUSIONS

In patients with CKD, lower eGFR was associated with worse cognitive performance and incident cognitive events, independently of demographics, CV risk factors and depression.

TRIAL REGISTRATION NUMBER

NCT03381950.

Primary biliary cholangitis presenting with Fanconi syndrome: an important phenotype

A woman in her 50s was referred to nephrology clinic due to progressive chronic kidney disease. She exhibited features of proximal renal tubulopathy, namely Fanconi syndrome, including normoglycaemic glycosuria, normal anion gap metabolic acidosis, and intermittent hypouricaemia and hypophosphataemia. Kidney biopsy showed tubulointerstitial inflammation and focal chronic damage. In addition, antimitochondrial antibodies were present and she had abnormal liver blood tests. A unifying diagnosis of primary biliary cholangitis with an associated renal tubulopathy and interstitial nephritis was made. She was commenced on sodium bicarbonate, ursodeoxycholic acid and oral prednisolone, leading to an improvement in liver biochemistry. Kidney function was stabilised, but a sustained improvement was not seen. This case acts as a reminder of the rare association of tubulointerstitial nephritis and Fanconi syndrome with primary biliary cholangitis, which may be an under-recognised phenotype.

Concurrent development of encapsulating peritoneal sclerosis and calciphylaxis in a patient with peritoneal dialysis for end-stage renal disease

Both encapsulating peritoneal sclerosis (EPS) and calciphylaxis are rare but severe complications involving patients with end-stage renal disease. In this report, we discuss a unique case of a 73-year-old female patient who had undergone 8 years of peritoneal dialysis for IgA nephropathy and concurrently developed these two synchronous complications within 3 months of each other. Diagnosis and management of both conditions were discussed in detail as well as the possible association between the two. With surgical treatment for EPS and measures to minimise bone mineral disorder abnormalities, both complications have been successfully managed to date.

Unusual cause of light chain cast nephropathy

Acute kidney injury due to light chain cast nephropathy is increasingly recognised in patients with haematological malignancies; however, the management and prognosis of this disease remain poorly understood. We describe a case of a 78-year-old woman with known chronic lymphocytic leukaemia (CLL) who presented with fatigue and weight loss. She was found to have acute kidney injury, which rapidly worsened during admission. Kidney biopsy showed light chain cast nephropathy and bone marrow biopsy confirmed B-cell CLL. She was started on ibrutinib, halting further deterioration in her renal function and avoiding renal replacement therapy in the first 8 months.

Erdheim-Chester disease: a rare cause of bilateral renal artery stenosis, mimicking large vessel vasculitis

A man in his 50s with resistant hypertension and history of Langerhans cell histiocytosis (LCH) was referred to rheumatology after suspicion of inflammatory arteritis was raised. This followed detection of bilateral renal artery stenosis during investigation for severe hypertension refractory to medical therapy. CT angiography revealed diffuse wall thickening of the abdominal aorta, in keeping with an aortitis. However, there was no serological or clinical evidence suggestive of a vasculitic process. Medical history included cranial diabetes insipidus, subclavian artery stenosis and spinal stenosis requiring surgery, over the course of 8 years. These findings led to consideration of Erdheim-Chester disease (ECD), a form of non-Langerhans cell histiocytosis, where there is abnormal proliferation of histiocytes which causes tissue fibrosis and sclerosis of the long bones. Subsequent plain radiographs of the long bones revealed appearances consistent with a diagnosis of ECD. Thus, a diagnosis of an LCH/ECD overlap syndrome was made.

Refractory focal segmental glomerulosclerosis caused by Alport syndrome detected by genetic testing after three decades

A woman in her 50s with a three-decade history of biopsy-proven focal segmental glomerulosclerosis and a family history of end-stage kidney disease presented with worsening proteinuria and declining kidney function after three decades of immunosuppressive therapy. While a repeat kidney biopsy did not reveal findings diagnostic of Alport syndrome, genetic testing demonstrated a heterozygous mutation in COL4A5, which confirmed the diagnosis of X-linked Alport syndrome. The heterozygous in-frame deletion mutation may explain her intact hearing and relatively mild symptoms. Genetic testing enables diagnosis of Alport syndrome of various phenotypes, some of which cannot be diagnosed conventionally with clinical course and kidney biopsy. Genetic disorders including collagen IV nephropathy should be considered as a differential diagnosis in patients with focal segmental glomerulosclerosis, especially when a patient has early-onset proteinuria, a family history of kidney disease, syndromic features or proteinuria refractory to glucocorticoid treatment.

Hyperglycinuria: diagnosis in middle age

Isolated hyperglycinuria is a rare disorder that is associated with osteoporosis and renal calculi. We report findings in a middle-aged, black woman who presented for renal function evaluation with a history of transient hypobicarbonataemia associated with topiramate therapy. She displayed the full triad of high urinary glycine, early-onset osteopenia despite normal reproductive hormones, and renal calculus with high urinary oxalate, phosphate and uric acid. Parathyroid hormone and fibroblast growth factor 23 were both normal. Formal genetic testing did not reveal mutations in SLC6A20, SLC6A18, SLC6A19, SLC36A2, the known genes associated with glycinuria; however, black individuals are poorly represented in the genetic databases. It may well be that otherwise unidentified mutations may be present or that topiramate may result in a lingering proximal tubule defect even after cessation of the drug.

Mechanical stress-related haemolysis in a paediatric haemodialysis patient

Haemodialysis (HD) is a common kidney replacement therapy (KRT) used in the management of children with end-stage kidney disease (ESKD). We describe the case of a 2-year-old child who developed mechanical intraluminal haemolytic anaemia secondary to the acute angulation of the HD line. In contrast to reports of arteriovenous fistula-associated haemolysis, onset was insidious in nature and detected through review of subtle serial biochemical and haematological changes. Development of hyperbilirubinaemia during HD was modest due to the partial clearance of bilirubin via HD-enabled diffusion. The only persistent and consistent marker was the post-HD rise in lactate dehydrogenase in association with decreasing haemoglobin. We propose that mechanical stress-induced haemolysis should be considered in children on HD who develop unexplained or persistent anaemia with resistance to increasing doses of iron and erythropoiesis-stimulating agent supplementation.

Usefulness of renal diffusion-weighted magnetic resonance imaging for early diagnosis of tubulointerstitial nephritis and uveitis (TINU) syndrome

A teenage girl presented with fever after aspirin use. Examination revealed no organ-specific symptoms. The serum creatinine level and urine analysis findings were normal. The drug lymphocyte stimulation test was positive for aspirin. Diffusion-weighted magnetic resonance imaging (DW-MRI) revealed hyperintensity in both kidneys although serum creatinine was only mildly elevated. A subsequent kidney biopsy confirmed acute interstitial nephritis (AIN). She later developed uveitis and the final diagnosis was tubulointerstitial nephritis and uveitis (TINU) syndrome, possibly triggered by aspirin, requiring systemic and topical corticosteroid therapies. TINU syndrome should be considered in young patients with fever of unknown origin and a history of nonsteroidal anti-inflammatory drug use. This is the first reported case suggesting the usefulness of DW-MRI, which is safe for children without exposure to ionising radiation, in detecting early-stage AIN before apparent kidney impairment.

Timely explantation of tobramycin-impregnated beads and bone cement to avoid haemodialysis in a patient with worsening renal failure

A male patient with right total knee arthroplasty complicated by prosthetic joint infection on intravenous antimicrobials developed an acute kidney injury (AKI) with creatinine up to 7.3 mg/dL ('normal' range (0.5-1.2 mg/dL)) after hardware removal and tobramycin loaded polymethylmethacrylate beads and spacer placement. The AKI was initially attributed to intravenous vancomycin. Despite discontinuing vancomycin, the AKI worsened. A tobramycin level was collected and resulted at 5.5 µg/mL. Due to high suspicion for aminoglycoside-induced renal toxicity and to prevent haemodialysis, the antibiotic cement spacer with tobramycin-impregnated beads was removed. After the removal, tobramycin level rapidly decreased and renal functions improved. AKI is an increasingly recognised complication related to antibiotic-loaded bone cement (ALBC) due to the systemic absorption of antibiotics. With this case we highlight the early recognition of ALBC-induced renal toxicity necessitating explantation of ALBC and beads in order to prevent haemodialysis and emphasise monitoring aminoglycoside levels in the early postoperative period.

Rare yet catastrophic presentation of undiagnosed antiphospholipid syndrome

A previously well 31-year-old woman initially presented to the emergency department with pneumonia, however, was found to be hypertensive and have new-onset cardiomegaly. She was admitted for intravenous antibiotics and concurrently a series of investigations were conducted to investigate hypertension and cardiomegaly. During the course of admission, she developed acute kidney injury and was found to have acute chronic occlusion in the abdominal aorta. She was diagnosed with catastrophic antiphospholipid syndrome. This is a rare form of antiphospholipid syndrome with a high mortality rate. Thus, it is important that clinicians are aware of this syndrome to facilitate early diagnosis and initiation of treatment.

Reactivation of IgA vasculitis following COVID-19 vaccination

A 23-year-old man presented to the acute assessment unit with acute-onset haematuria within 24 hours of receiving his second dose of the Pfizer-BioNTech COVID-19 vaccine. He had been diagnosed with IgA vasculitis 8 months previously. IgA vasculitis is an autoimmune condition characterised by palpable purpura affecting the lower limbs, abdominal pain, arthralgia and renal disease. He was diagnosed with an acute exacerbation of IgA vasculitis and was discharged with oral prednisolone. Reactivation or first presentation of IgA vasculitis is a rare but increasingly recognised complication of COVID-19 vaccination. This is an important new differential in the assessment of patients with haematuria following COVID-19 vaccination.

IgG4-related tubulointerstitial nephritis

A 67-year-old man was referred to the renal team following an episode of acute kidney injury on a background of chronic kidney disease. He had a 9-year history of steroid-sensitive arthritis, epigastric pain and isolated submandibular gland enlargement. He was noted to have a raised eosinophil count, total serum protein and total immunoglobulin G4 (IgG4) level as well as a serum hypocomplementaemia. A renal biopsy showed a tubulointerstitial nephritis with lymphoplasmacytic infiltrates, fibrosis and IgG4-positive plasma cells on immunohistochemistry. A diagnosis of IgG4-related disease was made based on clinical presentation and pathology. Renal function improved with glucocorticoids and the patient was successfully transitioned to azathioprine as a steroid-sparing agent.

Painful skin lesion in a patient on haemodialysis: a diagnosis not to miss

An 81-year-old man was admitted under the care of a plastic surgery team with a 10-day history of a painful left lower leg skin lesion after a punch biopsy of a naevus. His background history includes end-stage kidney disease secondary to hypertensive nephropathy, on intermittent haemodialysis via fistula. Other significant background history includes stroke, hypertension and ischaemic heart disease with coronary artery stents. There was no history of warfarin use. He was initially treated with a 5-day course of oral antibiotics with no improvement. He was referred to the hospital where he was admitted under the plastic surgery team who had completed the punch biopsy for intravenous antibiotics for presumed cellulitis. During his admission, the nephrology service were consulted to prescribe routine inpatient haemodialysis. Further history taking and wound review identified a 10-day history of an extremely painful skin lesion with an eschar and surrounding dusky, purpuric skin. Given the disproportionate pain and black eschar which are not in keeping with cellulitis, a diagnosis of calciphylaxis was made. He was commenced sodium thiosulfate on haemodialysis.

Spontaneous renal artery dissection: an elusive diagnosis

Spontaneous renal artery dissection is a rare condition with an often non-specific presentation, resulting in a challenging diagnosis for clinicians. This is the case of a 39-year-old man who presented with an acute-onset right flank pain, mild neutrophilia and sterile urine. CT of abdomen and pelvis showed a patchy hypodense area in the right kidney originally thought to represent infection. He was treated as an atypical pyelonephritis with antibiotics and fluids. When his symptoms failed to improve, a diagnosis of renal infarction was considered and CT angiogram of the aorta revealed a spontaneous renal artery dissection. He was managed conservatively with systemic anticoagulation, antihypertensive treatment and analgesia and discharged home with resolution of his symptoms and normal renal function.

Palliative radiation treatment used for multiple purposes in a single irradiation field

In this case report, radiation therapy was performed for bilateral hydronephrosis developed during multiple bone metastases of breast cancer and ileus due to peritoneal dissemination. The patient's preirradiation creatinine level was 8.2 mg/dL, which decreased by the fourth day after starting irradiation therapy. Creatinine level ultimately decreased to 0.6 mg/dL. Pain due to lumbar spine metastasis alleviated and ileus was resolved, allowing the patient to live at home for approximately 5 weeks. The effect of radiotherapy for bilateral hydronephrosis and gastrointestinal obstruction was rapid and good. Palliative radiation treatment can be used for multiple purposes, and in the present patient, we were able to prolong the vital prognosis.

Urinary retinol binding protein predicts renal outcome in systemic immunoglobulin light-chain (AL) amyloidosis

Renal risk stratification in systemic immunoglobulin light-chain (AL) amyloidosis is according to estimated glomerular filtration rate (eGFR) and urinary protein creatinine ratio (uPCR), the latter attributed to glomerular dysfunction, with proximal tubular dysfunction (PTD) little studied. Urinary retinol binding protein 4 (uRBP), a low molecular weight tubular protein and highly sensitive marker of PTD, was prospectively measured in 285 newly diagnosed, untreated patients with systemic AL amyloidosis between August 2017 to August 2018. At diagnosis, the uRBP/creatinine ratio (uRBPCR) correlated with serum creatinine (r = 0·618, P < 0·0001), uPCR (r = 0·422, P < 0·0001) as well as both fractional excretion of phosphate and urate (r = 0·563, P < 0·0001). Log uRBPCR at diagnosis was a strong independent predictor of end-stage renal disease {hazard ratio [HR] 2·65, [95% confidence interval (CI) 1·06-6·64]; P = 0·038}, particularly in patients with an eGFR >30 ml/min/1.73 m2 [HR 4·11, (95% CI 1·45-11·65); P = 0·008] and those who failed to achieve a deep haematological response to chemotherapy within 3 months of diagnosis [HR 6·72, (95% CI 1·83-24·74); P = 0·004], and also predicted renal progression [HR 1·91, (95% CI 1·18-3·07); P = 0·008]. Elevated uRBPCR indicates PTD and predicts renal outcomes independently of eGFR, uPCR and clonal response in systemic AL amyloidosis. The role of uRBPCR as a novel prognostic biomarker merits further study, particularly in monoclonal gammopathies of renal significance.

Multiple abdominal artery dissections: how to distinguish two rare diseases

A 59-year-old woman was referred to the emergency room with acute abdominal pain. A CT scan revealed multiple dissections and microaneurysms of the superior mesenteric, the hepatic and the renal arteries. Stenting of the superior mesenteric artery was required. A non-invasive diagnostic procedure was instrumental to establish the diagnosis and guide appropriate treatment, which resulted in a rapid and sustained recovery.

Atypical haemolytic uraemic syndrome: a case of rare genetic mutation

Complement-mediated kidney disease has been an evolving area in the field of nephrology. Atypical haemolytic uraemic syndrome (aHUS) is a rare thrombotic microangiopathy that affects multiple organs, particularly kidneys. The disease is characterised by a triad of haemolytic anaemia, thrombocytopenia and acute kidney injury (AKI). aHUS is most commonly caused by dysregulation of alternative complement pathway. In contrast to shiga toxin-associated haemolytic uraemic syndrome, diarrheal prodrome is usually absent in children with aHUS. We report a 2-year, 9-month-old boy who presented with acute dysentery and AKI. He had an unusual prolonged course of illness with hypocomplementaemia; hence, genetic testing was performed. He had a storming course in the hospital and succumbed to complications of the disease. Genetic study revealed digenic mutation in Complement Factor I and C3 Therefore, it is important to differentiate aHUS from other thrombotic microangiopathies to improve the outcome.

Neonatal polycystic kidney disease: a novel variant

Polycystic kidney disease (PKD) is a condition typified by multiple renal cysts and renal enlargement. Classification is usually determined by mode of inheritance-autosomal dominant PKD (ADPKD) or autosomal recessive PKD (ARPKD). ARPKD frequently presents in fetal life, but here we report a rare case of a family with two siblings diagnosed with ADPKD manifesting in utero with novel genetic findings. During the first pregnancy, enlarged cystic kidneys were noted at the gestational age (GA) of 18 weeks, which became progressively larger and anyhdramnios ensued by GA of 25 weeks. The couple opted to terminate the pregnancy. The second pregnancy similarly presented with bilateral enlarged cystic kidneys, but amniotic fluid remained normal throughout and she delivered at GA of 36 weeks. Genetic testing revealed the fetus to be heterozygous in AD PKD1, which is known to cause ADPKD and heterozygous for a hypomorphic allele for ADPKD of uncertain significance. The fetus was also found to be heterozygous in the AR PKHD1 gene with a variant not previously described in the literature. Where fetal features consistent with ARPKD are identified in the setting of familial ADPKD, this fetal manifestation of ADPKD, resulting from combined variants in the PKD1 gene, should be considered.

Antiglomerular basement membrane (anti-GBM) disease with clinical and histological features that bridge the typical to atypical spectrum

We describe antiglomerular basement membrane (anti-GBM) disease with rapidly progressive glomerulonephritis and concurrent parainfluenza pneumonia. Circulating anti-GBM antibodies were barely detectable and disappeared rapidly following corticosteroids, cyclophosphamide and plasma exchange. Kidney biopsy demonstrated strong linear GBM staining for IgG and IgG4 and unusually prominent endocapillary hypercellularity, suggesting 'atypical anti-GBM disease', although glomerular necrosis and crescents were also seen. When kidney function deteriorated further, despite persistently absent circulating anti-GBM antibodies, a repeat kidney biopsy was performed, showing crescents in 100% of glomeruli with ongoing endocapillary hypercellularity and strong IgG and IgG4 GBM staining. This case highlights complexities in the diagnosis of anti-GBM disease, with clinical and histological features bridging the atypical to typical anti-GBM disease spectrum. We hypothesise that these findings might be explained by the presence of IgG4 (rather than traditional IgG1 or IgG3) autoantibodies. To our knowledge, this is also the first report of parainfluenza associated with anti-GBM disease.

DLG5 variants are associated with multiple congenital anomalies including ciliopathy phenotypes

BACKGROUND

Cilia are dynamic cellular extensions that generate and sense signals to orchestrate proper development and tissue homeostasis. They rely on the underlying polarisation of cells to participate in signalling. Cilia dysfunction is a well-known cause of several diseases that affect multiple organ systems including the kidneys, brain, heart, respiratory tract, skeleton and retina.

METHODS

Among individuals from four unrelated families, we identified variants in discs large 5 (DLG5) that manifested in a variety of pathologies. In our proband, we also examined patient tissues. We depleted dlg5 in Xenopus tropicalis frog embryos to generate a loss-of-function model. Finally, we tested the pathogenicity of DLG5 patient variants through rescue experiments in the frog model.

RESULTS

Patients with variants of DLG5 were found to have a variety of phenotypes including cystic kidneys, nephrotic syndrome, hydrocephalus, limb abnormalities, congenital heart disease and craniofacial malformations. We also observed a loss of cilia in cystic kidney tissue of our proband. Knockdown of dlg5 in Xenopus embryos recapitulated many of these phenotypes and resulted in a loss of cilia in multiple tissues. Unlike introduction of wildtype DLG5 in frog embryos depleted of dlg5, introduction of DLG5 patient variants was largely ineffective in restoring proper ciliation and tissue morphology in the kidney and brain suggesting that the variants were indeed detrimental to function.

CONCLUSION

These findings in both patient tissues and Xenopus shed light on how mutations in DLG5 may lead to tissue-specific manifestations of disease. DLG5 is essential for cilia and many of the patient phenotypes are in the ciliopathy spectrum.

Adult Xp11.2 translocation renal cell carcinoma managed effectively with pazopanib

Xp11.2 translocation renal cell carcinoma (TRCC) is a rare and aggressive variant of renal cell carcinoma (RCC) when presenting in adults. We report a case of a man in his early 40s who was diagnosed with stage III Xp11.2 TRCC and underwent radical nephrectomy. Seven months following the surgery, an adrenal nodule and bilateral pulmonary nodules were discovered. He underwent cryoablation of the adrenal nodule and systemic treatment with daily pazopanib. He displayed stable disease for approximately 6 years. Following this period, multiple hospitalisations interrupted daily pazopanib therapy resulting in progression of disease. His regimen was then changed to ipilimumab and nivolumab, followed by current daily therapy with axitinib. The patient now shows stable disease in his 10th year after diagnosis. This case study demonstrates the efficacy of pazopanib for metastatic Xp11.2 TRCC and warrants further investigation to supplement the guidelines regarding the use of targeted therapy for TRCC.

Hypermagnesaemia causing mesenteric ischaemia and small bowel infarction

We present a case of mesenteric ischaemia caused by hypermagnesaemia after ingestion of a large oral dose of magnesium citrate, which resulted in smooth muscle relaxation, hypotension and bowel infarction. The patient had a history of chronic bowel dysmotility and renal impairment. On operative exploration, the bowel was noted to have a distinct pattern of ischaemia along its antimesenteric border. Small bowel resection was performed, and the patient was left in discontinuity, with definitive repair and anastomosis performed 24 hours later. The patient's magnesium level was 8.39 mg/dL, which was treated with intermittent haemodialysis and eventually normalised over several sessions. Our patient recovered and was discharged after a month-long hospitalisation. She returned shortly after with respiratory failure and died. On review of the literature, we identified similar cases and present a pathophysiological mechanism of hypermagnesaemia causing mesenteric ischaemia, consistent between our cases and those already reported.

Fulminant granulomatosis with polyangiitis presenting with diffuse alveolar haemorrhage following COVID-19

A 40-year-old man developed granulomatosis with polyangiitis (GPA) following a mild case of COVID-19. Initially, he experienced mild migrating joint pain for 2 months prior to testing positive for SARS-CoV-2 but dramatically worsened following resolution of his infection. The pain continued to progress until he suddenly develope haemoptysis, prompting him to present to a local hospital. The diagnosis of diffuse alveolar haemorrhage secondary to GPA was confirmed with labs, imaging and histopathology. Precipitous deterioration of GPA with concurrent COVID-19 infection indicates a possible temporal relationship. Since the onset of the pandemic, SARS-CoV-2 has been anecdotally associated with the development of various connective tissue disorders. The overlapping clinical presentations and similar appearance on lung imaging present clinicians with a diagnostic challenge. This underscores the importance of having a high index of suspicion of autoimmune diagnoses in patients who present with new or worsening findings following a COVID-19 infection.

Zinner syndrome: two cases and review of the literature

Zinner syndrome (ZS) is a rare congenital malformation due to abnormal development of the urogenital tract. It is caused by a growth failure of the distal part of the Müllerian duct in early embryogenesis. It is characterised by the triad of unilateral renal agenesis, ipsilateral seminal vesicle cyst and ipsilateral ejaculatory duct obstruction. Over the years, several cases have been reported in the literature since the initial report by Zinner in 1914. This syndrome is frequently misdiagnosed because it may present different patterns and the symptoms may be not specific. In this paper, we present two patients with two different patterns of presentation of Zinner syndrome.

SYmptom-Based STratification of DiabEtes Mellitus by Renal Function Decline (SYSTEM): A Retrospective Cohort Study and Modeling Assessment

Background: Previous UK Biobank studies showed that symptoms and physical measurements had excellent prediction on long-term clinical outcomes in general population. Symptoms and signs could intuitively and non-invasively predict and monitor disease progression, especially for telemedicine, but related research is limited in diabetes and renal medicine. Methods: This retrospective cohort study aimed to evaluate the predictive power of a symptom-based stratification framework and individual symptoms for diabetes. Three hundred two adult diabetic patients were consecutively sampled from outpatient clinics in Hong Kong for prospective symptom assessment. Demographics and longitudinal measures of biochemical parameters were retrospectively extracted from linked medical records. The association between estimated glomerular filtration rate (GFR) (independent variable) and biochemistry, epidemiological factors, and individual symptoms was assessed by mixed regression analyses. A symptom-based stratification framework of diabetes using symptom clusters was formulated by Delphi consensus method. Akaike information criterion (AIC) and Bayesian information criterion (BIC) were compared between statistical models with different combinations of biochemical, epidemiological, and symptom variables. Results: In the 4.2-year follow-up period, baseline presentation of edema (-1.8 ml/min/1.73m2, 95%CI: -2.5 to -1.2, p < 0.001), epigastric bloating (-0.8 ml/min/1.73m2, 95%CI: -1.4 to -0.2, p = 0.014) and alternating dry and loose stool (-1.1 ml/min/1.73m2, 95%CI: -1.9 to -0.4, p = 0.004) were independently associated with faster annual GFR decline. Eleven symptom clusters were identified from literature, stratifying diabetes predominantly by gastrointestinal phenotypes. Using symptom clusters synchronized by Delphi consensus as the independent variable in statistical models reduced complexity and improved explanatory power when compared to using individual symptoms. Symptom-biologic-epidemiologic combined model had the lowest AIC (4,478 vs. 5,824 vs. 4,966 vs. 7,926) and BIC (4,597 vs. 5,870 vs. 5,065 vs. 8,026) compared to the symptom, symptom-epidemiologic and biologic-epidemiologic models, respectively. Patients co-presenting with a constellation of fatigue, malaise, dry mouth, and dry throat were independently associated with faster annual GFR decline (-1.1 ml/min/1.73m2, 95%CI: -1.9 to -0.2, p = 0.011). Conclusions: Add-on symptom-based diagnosis improves the predictive power on renal function decline among diabetic patients based on key biochemical and epidemiological factors. Dynamic change of symptoms should be considered in clinical practice and research design.

Two cases of secondary AA amyloidosis involving the skin and chronic kidney infection with a nephrotic syndrome in a high-income country

We present two French cases of amyloid-associated (AA) amyloidosis secondary to chronic infections. Patient 1, a 51-year-old heroin addict, was hospitalised for chest pain and anasarca. During hospitalisation, a nephrotic syndrome with an inflammatory condition was discovered along with a chronic skin ulcer on his arm. Salivary gland and kidney biopsies confirmed the diagnosis of AA amyloidosis. Renal function quickly declined and haemodialysis was initiated 6 months later. Patient 2, a 55-year-old woman, was hospitalised for obstructive pyelonephritis secondary to coraliform lithiasis. Renal insufficiency with an impure nephrotic syndrome was found. After nephrectomy due to chronic pyelonephritis and an atrophic cortex on the abdominal scan, the histology revealed AA amyloidosis. Despite treatment with ACE inhibitors and control of inflammation, the nephrotic syndrome persisted with rapid decline of the kidney function.

Medical management of coral reef aorta through optimised diuretic use and angiotensin receptor blockade

Coral reef aorta (CRA) is a rare condition with potentially devastating complications. It is characterised by atherosclerotic calcification and stenosis of the visceral part of the aorta, usually occurring at the juxtarenal or suprarenal locations, and causing refractory hypertension and renal dysfunction. Surgical intervention, which is the recommended definitive treatment, is associated with significant morbidity and mortality. Endovascular stenting has been reported to be an alternative management option. To the best of our knowledge, this is the first case report to describe medical management of a patient with CRA with diuretics and angiotensin receptor blockade without surgical treatment.

Global REnal Involvement of CORonavirus Disease 2019 (RECORD): A Systematic Review and Meta-Analysis of Incidence, Risk Factors, and Clinical Outcomes

Introduction: The quantitative effect of underlying non-communicable diseases on acute kidney injury (AKI) incidence and the factors affecting the odds of death among coronavirus disease 2019 (COVID-19) AKI patients were unclear at population level. This study aimed to assess the association between AKI, mortality, underlying non-communicable diseases, and clinical risk factors. Methods: A systematic search of six databases was performed from January 1, 2020, until October 5, 2020. Peer-reviewed observational studies containing quantitative data on risk factors and incidence of renal manifestations of COVID-19 were included. Location, institution, and time period were matched to avoid duplicated data source. Incidence, prevalence, and odds ratio of outcomes were extracted and pooled by random-effects meta-analysis. History of renal replacement therapy (RRT) and age group were stratified for analysis. Univariable meta-regression models were built using AKI incidence as dependent variable, with underlying comorbidities and clinical presentations at admission as independent variables. Results: Global incidence rates of AKI and RRT in COVID-19 patients were 20.40% [95% confidence interval (CI) = 12.07-28.74] and 2.97% (95% CI = 1.91-4.04), respectively, among patients without RRT history. Patients who developed AKI during hospitalization were associated with 8 times (pooled OR = 9.03, 95% CI = 5.45-14.94) and 16.6 times (pooled OR = 17.58, 95% CI = 10.51-29.38) increased odds of death or being critical. At population level, each percentage increase in the underlying prevalence of diabetes, hypertension, chronic kidney disease, and tumor history was associated with 0.82% (95% CI = 0.40-1.24), 0.48% (95% CI = 0.18-0.78), 0.99% (95% CI = 0.18-1.79), and 2.85% (95% CI = 0.93-4.76) increased incidence of AKI across different settings, respectively. Although patients who had a kidney transplant presented with a higher incidence of AKI and RRT, their odds of mortality was lower. A positive trend of increased odds of death among AKI patients against the interval between symptom onset and hospital admission was observed. Conclusion: Underlying prevalence of non-communicable diseases partly explained the heterogeneity in the AKI incidence at population level. Delay in admission after symptom onset could be associated with higher mortality among patients who developed AKI and warrants further research.

Diabetic nephropathy and end-stage renal disease in a 28-year-old woman, or is it?

A 28-year-old Hispanic woman presented to the emergency department with pneumonia and bilateral pulmonary oedema, requiring admission to the intensive care unit. Additional history included type 1 diabetes mellitus, End Stage Renal Disease on haemodialysis and Hashimoto's disease. On further diagnostic evaluation, she was found to have systemic lupus erythematosus (SLE) with overlap syndrome. The goal of this case report was twofold: to share our holistic investigative processes and to explore how racial identity and experiences play a role in health disparities present in SLE. The diagnostic process was difficult because of language and socioeconomic barriers our patient experienced. Additionally, SLE in the Hispanic population has only recently been researched, limiting specifics about presentation and disease course. In the Hispanic population, SLE has increased morbidity and mortality when compared with the Caucasian population. Thus, our patient's case highlights the need for holistic practices when diagnosing patients, particularly in historically and presently marginalised identities.

Type 3 antenatal Bartter syndrome presenting with mild polyuria

Bartter syndrome (BS) is a well-recognised inherited tubular dysfunction that causes polyuria, metabolic alkalosis and hypokalaemia. Among BS cases, antenatal/neonatal BS (ABS) usually shows distinct polyhydramnios prenatally and presents features of BS in the early neonatal period. We encountered a premature infant with type 3 ABS presenting with mild polyuria and discuss the pathogenesis of mild polyuria in type 3 ABS. A male infant was born at 31 weeks' gestation. His mother received amniocentesis because of polyhydramnios. Hyponatraemia and hypokalaemia appeared within 3 days after birth. Metabolic alkalosis, hyperreninaemia and hyperaldosteronism were also identified. Temporary polyuria developed at 1 month after birth; however, the mean urine output during hospitalisation was within the normal range. CLCNKB compound heterozygous mutations were confirmed. Polyuria of type 3 ABS may be less severe than in other types of ABS. Lower urine sodium loss may be a characteristic feature of type 3 ABS.

Relapse of treated anti-GBM disease following hair dye use

An 18-year-old woman was treated for acute kidney injury (AKI) secondary to antiglomerular basement membrane (GBM) disease with prednisolone, cyclophosphamide and plasma exchange. She also had epistaxis at initial presentation with no other organ involvement and achieved good recovery of her kidney function. Two weeks after completing induction treatment, she re-presented with further AKI and pulmonary haemorrhage. She was recommenced on plasma exchange and steroids and was given rituximab. She recovered from her illness with significant improvement to her kidney function. The cause of her relapse was thought to be possibly due to the use of hair dye. This case highlights the importance of acknowledging potential environmental exposures to prevent relapses of disease. We were also able to demonstrate a case of successful treatment of anti-GBM disease with rituximab.

COVID-19-induced granulomatosis with polyangiitis

COVID-19 and granulomatosis with polyangiitis share many clinical and radiological features, making it challenging for clinicians to distinguish between the two. In this case report, we describe a patient who was diagnosed with COVID-19 in October 2020. One month later, she presented with persistent fatigue, shortness of breath and anaemia with worsening renal functions, found to have elevated antineutrophil cytoplasmic antibodies and antiproteinase 3 antibodies, and diagnosed with granulomatosis with polyangiitis.

Sporadic, classic-type renal angiomyolipoma with renal vein and inferior vena cava extension: an incidental case

Renal angiomyolipomas (AMLs) were first described in the early 1900s by Gravitz, but it was not until 1951 that they were named renal AML. These kidney tumours are rare, occurring in 0.13%-0.44% of the population. These mesenchymal tumours are composed of smooth muscle-like, adipocyte-like and epithelioid cells. Depending on the predominant cell population, it can be further subclassified into classic, epithelioid and AML with epithelial cyst. A 32-year-old woman presented with mild, intermittent, epigastric and right upper quadrant abdominal pain. Abdominal ultrasound revealed an incidental lesion within the inferior vena cava (IVC). A CT scan showed a lesion within the left renal vein extending into the IVC with 40% narrowing and a fat-containing mass in the lower pole of the left kidney of 15 mm suggesting an AML. Thrombectomy was performed. The specimen resulted positive for classic variant renal AML. Initial diagnosis is centred on imagining studies, based in fatty tissue concentration. The AML expresses melanocytic markers. This helps differentiate from renal cell carcinoma. Although AML is considered a benign condition, there is evidence of malignant transformation. Active surveillance is recommended for lesions <4 cm. Nephron sparing surgery is the procedure of choice. Nephrectomy is recommended if there is a high probability of malignancy. Mammalian target of rapamycin (mTOR) inhibitors have been proposed to be an alternative treatment.

Non-uremic calciphylaxis in a woman without end-stage renal disease

A woman in her 60s with a history of lower extremity vascular disease presented with extreme pain and wounds in her legs which had kept her from walking for several weeks. The patient's pain became intolerable throughout her hospital stay despite multiple surgical revascularisations. Biopsy of the patient's calf wounds revealed evidence of calciphylaxis, a diagnosis which corresponds with this patient's extreme pain. Our patient had no history of end-stage renal disease.

Prostatic cyst in a pediatric patient with autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inheritable form of renal cystic disease and is associated with cysts in other organs. Prostatic cysts are rare though and have not been reported in the paediatric population. Reported is the presence of a prostatic cyst that was incidentally noted on routine sonogram in a 15 year old with ADPKD.

Fenestrated endovascular abdominal aortic aneurysm repair with concomitant horseshoe kidney

Horseshoe kidney, representing abnormal fusion of the inferior renal poles, is a rare anatomic anomaly posing challenges in the setting of surgical abdominal aortic aneurysm repair. Historically, open repair has been the favoured surgical approach. However, due to the location of the renal isthmus and wide-ranging variation in anomalous renal vasculature, endovascular aneurysm repair (EVAR) has emerged as a popular, less invasive alternative. We describe one of the first published cases of two-fenestration EVAR in a patient with concomitant horseshoe kidney, followed by a discussion of current trends in surgical management. With the increasing availability to customise fenestrated grafts to patients' unique anatomy, this advanced EVAR technique may emerge as the preferred approach in certain cases.

Novel SLC12A3 mutation in Gitelman syndrome

Gitelman syndrome (GS) is an autosomal recessive disease characterised by the presence of hypokalaemic metabolic alkalosis with hypomagnesaemia and hypocalciuria. The prevalence of this disease is 1-10/40 000. GS is usually associated with mild and non-specific symptoms and many patients are only diagnosed in adulthood. The disease is caused by mutations in the SLC12A3 gene. We present the case of a 49-year-old man referred to a nephrology appointment due to persistent hypokalaemia and hypomagnesaemia. Complementary evaluation revealed hypokalaemia, hypomagnesaemia, metabolic alkalosis, hyperreninaemia, increased chloride and sodium urinary excretion, and reduced urinary calcium excretion. Renal function, remainder serum and urinary ionogram, and renal ultrasound were normal. A diagnosis of GS was established and confirmed with genetic testing which revealed a novel mutation in SLC12A3 (c.1072del, p.(Ala358Profs*12)). This novel mutation extends the spectrum of known SLC12A3 gene mutations and further supports the allelic heterogeneity of GS.

Recent advances in treatment of haemodialysis

Haemodialysis remains the most widely used treatment for patients with end-stage renal disease. Despite the progress that has occurred in the treatment of end-stage renal disease over the last six decades, there has been a failure to translate this into the desired clinical benefits, with morbidity and mortality rates among patients on haemodialysis remaining unacceptably high. Recently, however, there have been expectations that the significant advances that took place over the last few years may result in improved outcomes. New medications for the treatment of anaemia and secondary hyperparathyroidism, as well as novel trends in the areas of iron therapy, diabetes management and physical exercise are among the most important advances which, taken together, are changing the standards of care for patients on haemodialysis. The latest advances, of relevance not only to specialists in Renal Medicine but also to general practitioners caring for these patients, are reviewed in this collaborative paper.

Relationship between vasculitis and chronic lymphocytic leukaemia: a correlation without causation

We report a novel case of a patient who presented with new diagnoses of both cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCAs) positive vasculitis and chronic lymphocytic leukaemia (CLL). The patient was a 79-year-old man who presented with melena, haemoptysis, acute hypoxia and acute kidney injury. In the current literature, there are rare associations of c-ANCA vasculitis and malignancy, but very few, if any, relating c-ANCA vasculitis and CLL. This case is unique due to the presence of both pathologies and an uncommon presentation of the vasculitis. He presented with renal and pulmonary findings, unlike the dermal manifestations commonly seen with vasculitis. We think that this could be an easily overlooked combination of diseases and, therefore, the purpose of this case is to prevent delays in care that could affect patient outcomes and also to encourage further research into the relationship between these diseases.

Five biopsies, one diagnosis: challenges in idiopathic multicentric Castleman disease

A previously healthy 29-year-old man initially presented to the hospital with pleuritic chest pain and shortness of breath. Over the next 2 months he developed ongoing fevers and night sweats with recurrent exudative pleural effusions and ascites. He had an extensive infectious and autoimmune workup that was unremarkable. He had an initial lymph node biopsy that showed reactive changes only. He had an acute kidney injury and his renal biopsy revealed thrombotic microangiopathy. His liver biopsy showed non-specific inflammatory changes. His bone marrow biopsy showed megakaryocyte hyperplasia and fibrosis, which raised suspicion for the thrombocytopenia, ascites, reticulin fibrosis, renal dysfunction and organomegaly syndrome subtype of multicentric Castleman disease. This prompted a repeat lymph node biopsy, showing changes consistent with mixed type Castleman disease that fit with his clinical picture. He was initiated on steroids and siltuximab with significant clinical improvement.

Persistent viral shedding despite seroconversion in a kidney transplant recipient with severe extrapulmonary COVID-19

Renal transplant (RT) recipients are at increased risk for infectious complications. The clinical course of COVID-19 has been described in several RT recipients with varying clinical outcomes. Most present with pulmonary manifestations, however extrapulmonary presentations are not uncommon. Also, the timing and efficacy of seroconversion in transplant recipients is not well known. This report describes the duration of viral shedding and timing of seroconversion in a young adult RT recipient with COVID-19 who presented with severe diarrhoea and acute kidney injury requiring dialysis. She developed anti‐SARS‐CoV‐2 IgG antibody after 5 weeks despite persistently shedding the virus in the nasopharynx until 6 weeks after symptom onset. Further studies are needed to determine if immunosuppressed patients have prolonged viral shedding and are still contagious despite seroconversion.

63-year-old man with right biceps and right pectoralis major abscesses: an unusual case of pyomyositis

Pyomyositis is considered a great mimicker and masquerader. This case is of a 63-year-old man with diabetes who initially presented to the outpatient clinic afebrile with right shoulder pain. His work-up was negative, and he was discharged home. He subsequently presented to the emergency room (ER) two times for worsening right shoulder pain. During his first visit to the ER, his work-up was unremarkable, and he was discharged home. On his return to the ER, he was now febrile with inflammation involving his right upper extremity and right chest wall. Imaging studies of his right upper extremity and his right chest wall were consistent with multiple abscesses. Methicillin resistant Staphylococcus aureus was cultured from the abscess, and from blood and urine cultures. The diagnosis of pyomyositis was confirmed. This case illustrates the difficulty of diagnosing pyomyositis and the importance of including it in the differential diagnosis, especially in an immunocompromised patient.

Uneventful case of COVID-19 in a kidney transplant recipient

Kidney transplant recipients have been reported at a particularly high risk of severe COVID-19 illness due to chronic immunosuppression and coexisting conditions. Yet, here we describe a remarkably mild case of COVID-19 in a 62-year-old female who had a kidney transplantation 10 years earlier due to autosomal dominant polycystic kidney disease. The patient was admitted for 1 day; immunosuppressive therapy with tacrolimus and low-dose prednisolone was continued; and the patient recovered successfully without the use of antiviral agents or oxygen therapy. The case demonstrates that kidney transplant recipients are not necessarily severely affected by COVID-19. Withdrawal of immunosuppressive therapy could be associated with poorer outcomes and should not be implemented thoughtlessly.

Primary renal lymphoma: a comprehensive review of the pathophysiology, clinical presentation, imaging features, management and prognosis

Primary renal lymphoma (PRL) is defined as a non-Hodgkin's lymphoma restricted to kidneys with the absence of extensive nodal disease. It is an exceedingly rare clinicopathological entity, accounting for 0.7% of extranodal lymphomas. Published medical literature regarding the natural history and clinical outcomes of PRL remains limited. We describe a case of a young patient who presented with left shoulder pain, continuous fever, and unexplained weight loss as atypical initial manifestations of bilateral PRL, confirmed with the standard set of investigations. Furthermore, this article reviews the literature and discusses various aspects of PRL, including pathophysiology, presentation patterns, imaging and pathological characteristics, management, and prognosis. This paper serves to provide an update and aims to enhance the understanding of PRL. Timely diagnosis and treatment are imperative to achieve improved outcomes. Clinicians should maintain a high index of suspicion in order to prevent morbidity and mortality associated with this serious disease.