Acute kidney injury manifesting as renal tubular acidosis with proximal and distal renal tubular dysfunction in a dog with acute pancreatitis

Correlation between baseline anion gap and early acute kidney injury in patients with acute pancreatitis in the intensive care unit: A single-center retrospective cohort study

OBJECTIVE

Acute pancreatitis (AP) is an acute inflammatory disease that can lead to multiple system dysfunction, including acute kidney injury (AKI). AKI occurs in 10%-42% of AP patients, and studies have shown that early (48 hours) acute pancreatitis associated acute kidney injury (AP-AKI) can increases the risk of death in acute pancreatitis. Anion gap (AG) is a common index in clinical evaluation of acid-base imbalance and an important index in critically ill patients. The aim of this study was to investigate the relationship between baseline anion gap values and early acute kidney injury in patients with acute pancreatitis in intensive care unit.

METHODS

Our data were derived from inpatients admitted to Beth Israel Deaconess Medical Center (BIDMC) in the United States between 2008 and 2019. A total of 4,017 adult patients with acute pancreatitis admitted to the ICU were enrolled in the study, and 475 were enrolled according to the exclusion and inclusion criteria. Only the baseline value and one day after arrival to the intensive care unit (ICU) were considered for all laboratory test values. According to previous literature and clinical significance, AG was divided into two groups: low value (< 16mmol/L) group and high value (≥16mmol/L) group, and logistics univariate and multifactor regression analysis was applied to verify the relationship between anion gap and AKI risk.

RESULTS

Only 157 of the 475 AP cases had an AG level below 16 mmol/L, whereas 318 patients had an AG level over 16 mmol/L. Within 48 hours, 89 and 240 cases (56.7% and 75.5%) and the low- and high-AG groups had AKI. In AP cases, an elevated AG was related to an increased risk of AKI [odds ratio (OR) = 1.06, 95% confidence interval (CI): 1.03-1.1], and is a nonlinear relationship. When controlling for other factors, this correlation was still significant. Compared to the lower group, high-AG (≥16mmol/L) values can increase the risk of early acute kidney injury in patients with acute pancreatitis (OR = 2.35, CI: 1.57-3.53).

CONCLUSION

Anion gap (AG) is an independent risk factor for early acute kidney injury in patients with acute pancreatitis, and has a nonlinear relationship with 48-hour AKI. Higher AG(≥16mmol/L) values can significantly increase the risk of AP-AKI.

A review of renal tubular acidosis

OBJECTIVE

To review the current scientific literature on renal tubular acidosis (RTA) in people and small animals, focusing on diseases in veterinary medicine that result in secondary RTA.

DATA SOURCES

Scientific reviews and original research publications on people and small animals focusing on RTA.

SUMMARY

RTA is characterized by defective renal acid-base regulation that results in normal anion gap hyperchloremic metabolic acidosis. Renal acid-base regulation includes the reabsorption and regeneration of bicarbonate in the renal proximal tubule and collecting ducts and the process of ammoniagenesis. RTA occurs as a primary genetic disorder or secondary to disease conditions. Based on pathophysiology, RTA is classified as distal or type 1 RTA, proximal or type 2 RTA, type 3 RTA or carbonic anhydrase II mutation, and type 4 or hyperkalemic RTA. Fanconi syndrome comprises proximal RTA with additional defects in proximal tubular function. Extensive research elucidating the genetic basis of RTA in people exists. RTA is a genetic disorder in the Basenji breed of dogs, where the mutation is known. Secondary RTA in human and veterinary medicine is the sequela of diseases that include immune-mediated, toxic, and infectious causes. Diagnosis and characterization of RTA include the measurement of urine pH and the evaluation of renal handling of substances that should affect acid or bicarbonate excretion.

CONCLUSIONS

Commonality exists between human and veterinary medicine among the types of RTA. Many genetic defects causing primary RTA are identified in people, but those in companion animals other than in the Basenji are unknown. Critically ill veterinary patients are often admitted to the ICU for diseases associated with secondary RTA, or they may develop RTA while hospitalized. Recognition and treatment of RTA may reverse tubular dysfunction and promote recovery by correcting metabolic acidosis.

Transient distal renal tubular acidosis with nephrogenic diabetes insipidus after general anaesthesia in a dog

A 3-year-old, 3.5 kg, female spayed Pomeranian was referred due to persistent vomiting, anorexia, polyuria and polydipsia, 7 days after receiving general anaesthetic for a medial patellar luxation correction. Physical examination revealed lethargy, tachypnoea and 7% dehydration. Complete blood count and serum chemistry results were unremarkable, and venous blood gas analysis revealed hypokalaemia and hyperchloraemic metabolic acidosis with a normal anion gap. Urinalysis revealed a urine specific gravity (USG) of 1.005, pH of 7.0 and proteinuria, and the bacterial culture was negative. Based on these results, the dog was diagnosed with distal renal tubular acidosis, and potassium citrate was prescribed to correct metabolic acidosis. In addition, concurrent diabetes insipidus (DI) was suspected because the dog showed persistent polyuria, polydipsia and a USG below 1.006 despite dehydration. After 3 days of initial treatment, acidosis was corrected, and vomiting resolved. Desmopressin acetate and hydrochlorothiazide were also prescribed for DI, but the USG was not normalized. Based on the insignificant therapeutic response, nephrogenic DI was highly suspected. DI was resolved after 24 days. This case report describes the concomitant presence of RTA and DI in a dog after general anaesthesia.

Outcome of Acquired Fanconi Syndrome Associated with Ingestion of Jerky Treats in 30 Dogs

Acquired canine proximal renal tubulopathy (Fanconi syndrome) related to excessive ingestion of jerky treats has been recognized since 2007. This study aimed to improve knowledge about the syndrome’s characteristics, especially long-term outcome. By reaching out to veterinarians and dog owners, dogs suspected of jerky induced Fanconi syndrome were identified. The dog’s medical records were reviewed, and owners interviewed. Data was analyzed using linear mixed models (p < 0.05 was considered statistically significant) and descriptive statistics are reported. Thirty dogs, median body weight 6.8 (range 1.2−59) kg and age 6.5 (0.5−14) years, were enrolled as suspected cases based on history of jerkey ingestion and confirmed normoglycemic/hypoglycemic glycosuria. Clinical signs included polydipsia (23/30), polyuria (21/30), lethargy (19/30), weight loss (15/30), hyporexia (11/30), vomiting (7/30), diarrhea (7/30) and no clinical signs (2/30). Para-clinical findings included azotemia (6/28), hypophosphatemia (9/25), metabolic acidosis (3/8), hypokalemia (6/20), proteinuria (13/26), aminoaciduria (4/4), hematuria (22/29) and ketonuria (7/27). Clinical signs resolved in 22/28 within 11 (0.3−52) weeks and glycosuria resolved in 28/30 within 6.5 (1−31) weeks. There were no associations between serum creatinine and urea and the amount/duration of jerky ingestion. Serum symmetric dimethylarginine concentrations were only available for a few dogs, therefore no conclusion was achieved on a possible association with duration of jerky ingestion. Apart from a larger percentage of dogs achieving complete recovery, the current findings are in agreement with previous reports.