Prospective long-term evaluation of incomplete distal renal tubular acidosis in idiopathic calcium nephrolithiasis diagnosed (treated) by low-dose NH4CL loading – gender prevalences and impact of alkali treatment

Purpose Prospective evaluation of the prevalence of incomplete distal renal tubular acidosis (idRTA) in idiopathic calcium stone formers (ICSF) diagnosed by half-dose ammonium chloride loading (NH4Cl, 0.05 g/kg body weight/day) and impact of alkali treatment of idRTA. Methods Evaluation of 386 consecutive idiopathic calcium stone formers (ICSF) (280 males, 106 females) for idRTA. If screening fasting urine pH was > 5.80, 1-day NH4Cl loading was performed without severe adverse effects. Normally, urine pH falls below 5.45. Results Sixty-four idiopathic calcium stone formers exhibited idRTA, one complete dRTA. Prevalence was higher in women (25.4%) than in men (13.6%). Thus, for more equilibrated comparisons, we formed pairs of 62 idiopathic calcium stone formers (ICSF) with and 62 without idRTA, matched for gender, age, BMI and serum creatinine. Idiopathic calcium stone formers with idRTA more often had hypercalciuria (p < 0.025) and urine citrate < 2 mmol/d (p < 0.05), formed calcium phosphate stones more frequently, exhibited higher numbers of stones/year (1.4 ± 1.5 vs. 0.9 ± 0.8, p = 0.034) and 2.5 times more intrarenal calcifications (4.6 ± 5.9 vs. 1.8 ± 3.6, p = 0.002). All idiopathic calcium stone formers with idRTA were recommended chronic alkali therapy. After 4–15 years of follow-up, stone events /years follow-up (stone passage or urologic intervention) were higher in patients non-adherent to alkali therapy (0.61 ± 0.92) than in patients adherent to treatment (0.11 ± 0.21, p = 0.006). Conclusion Incomplete distal renal tubular acidosis is 1.8-fold more prevalent among female idiopathic calcium stone formers, predicts more stone recurrences, predisposes to calcium phosphate stones and is associated with 2.5 times more intrarenal calcifications vs. non-idRTA patients. Chronic alkali treatment reduces clinical stone recurrences by 5.5 times. Graphical abstract

Distal renal tubular acidosis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem disorder of autoimmune etiology. Renal involvement is frequently seen in SLE. Tubular dysfunction is also seen in SLE. Authors report a case of distal renal tubular acidosis in patient with SLE.

Hypokalemic Paralysis Leading to Respiratory Failure: An Unusual Presentation of Sjogren’s Syndrome

Sjogren’s Syndrome (SS) is a chronic multisystemic autoimmune inflammatory disorder with predominant exocrine gland involvement resulting in dryness of the eyes and mouth. Among extra glandular manifestations, renal involvement is commonly seen, which can be in the form of Renal Tubular Acidosis (RTA). SS may at times present as mild hypokalaemia with distal RTA but severe hypokalemia resulting in respiratory failure is rare. Here we report a case of twenty-five-year-old female presenting in emergency room with flaccid quadriparesis and hypercapnic respiratory failure. Further evaluation revealed hypokalemia (Potassium (K+) 1.6mmol/L) with distal renal tubular acidosis along with a background of primary Sjogren’s Syndrome. We illustrate that the possibility of Sjogren’s Syndrome should be considered in a young female who present with rapidly progressive weakness, hypokalemia and distal renal tubular acidosis with respiratory failure.

Clinical and Molecular Findings in a Moroccan Family with Primary Distal Renal Tubular Acidosis and Deafness by Mutation of ATP60A4 Gene: Case Report

Primary distal renal tubular acidosis (dRTA) is a rare genetic disease characterized by distal tubular dysfunction leading to metabolic acidosis and alkaline urine. It is associated with impaired acid excretion by the intercalated cells in the renal collecting duct. dRTA is developed during the first months of life and the main clinical and biologic features are failure to thrive, vomiting, dehydration, anorexia, hyperchloremic non-anion gap metabolic acidosis, hypocitraturia, hypercalciuria and nephrocalcinosis. The disease is caused by defects in genes involved in urinary distal acidification: ATP6V0A4 and ATP6V1B1 for the recessive form, and SLC4A1 for the dominant form. Some dRTA cases due to recessive gene mutations are associated with hearing impairment. We report the case of two siblings with dRTA, and early-onset SNHL, due to ATP6V0A4 mutations, and whose parents are heterozygous carriers of ATP6V0A4 mutations.

Idiopathic hypokalemia in lupus nephritis - A newly recognized entity

Background:Various causes of hypokalemia from renal potassium wasting, including distal renal tubular acidosis, have been described in lupus nephritis (LN). We report a phenomenon of otherwise unexplained hypokalemia among a population with LN. Methods:From our population of 403 patients with LN, we identified a cohort of 20 patients with idiopathic hypokalemia (HK), defined by serum potassium < 3.5 mmol/L without any apparent explanation. This cohort is compared to 90 LN controls (CON) and 10 LN patients with distal renal tubular acidosis (RTA) from the same population. Results:The HK cases had lower median serum potassium compared to CON and RTA subjects (3.26 vs 4.00 vs 3.75 mmol/L, respectively; p < 0.001). The median serum bicarbonate was normal in HK and CON but low in RTA (26.0 vs 25.0 vs 19.4 mmol/L; p < 0.001). The median urine pH was abnormally high only in the RTA group (6.00 vs 6.25 vs 6.67; p = 0.012). The median serum magnesium was modestly lower in HK compared to the CON and RTA groups (1.73 vs 2.00 vs 1.85 mg/dL; p = 0.002). While both HK and RTA showed a higher rate of seropositivity than CON for anti-Ro/SSA (79% and 80% vs 37%, respectively; p < 0.001), only HK revealed a higher rate of seropositivity than CON for anti-RNP (84% vs 42%; p = 0.003) and only RTA showed a higher rate of seropositivity than CON for anti-La/SSB (40% vs 12%; p = 0.046). Conclusions:A syndrome of idiopathic hypokalemia was revealed in 20/403 (5%) of patients within our LN population and proved to be distinct from the renal tubular acidosis that occurs in LN. Furthermore, it was associated with a distinct pattern of autoantibodies. We speculate that idiopathic hypokalemia is the result of a novel target of autoimmunity in LN affecting renal tubular potassium transport.

Hypokalaemic quadriparesis with respiratory failure due to latent Sjogren syndrome

Sjogren’s syndrome (SS) is an autoimmune disease with involvement of multiple organs, including both glandular and extraglandular organs. Usually involvement of glandular organs manifests before the extraglandular ones, but when the sequence is reversed, diagnosis may be missed. Hypokalaemic quadriparesis in SS is not uncommon. Respiratory failure in hypokalaemia is not usually seen, but in SS, it has been reported. We report a case of a 55-year-old woman who presented with sudden onset flaccid quadriparesis and respiratory muscle paralysis secondary to severe hypokalaemia. On detailed investigation, she was detected to have distal renal tubular acidosis secondary to clinically inapparent and asymptomatic SS.