sodium-bicarbonate and Nephritis--Interstitial

Renal tubular acidosis (RTA) is common in adults with primary Sjogren syndrome (pSS) but to date this condition has only been identified in 12 pediatric cases of pSS. Here we present the case of a 13-year-old, otherwise asymptomatic girl in whom the search for the etiology of incidentally found nephrocalcinosis led to diagnosis of distal RTA and nephrogenic diabetes insipidus secondary to SS-associated tubulointerstitial nephritis. Immunosupressive treatment and alkali/electrolyte supplementation resulted in stable renal function over the 6-year follow-up. A review of the literature focuses on two aspects of pSS: (1) the difficulties in diagnosing pSS in childhood and (2) clinical-pathological features, treatment and outcome of renal tubulointerstitial disease in childhood pSS. SS should be considered in older children, particularly females with otherwise unexplained RTA. A careful search for other renal dysfunctions is necessary, and renal biopsy may be of value in assessing the extent of renal damage and the need for immunomodulatory therapy.

Topics: Acidosis, Renal Tubular; Adolescent; Electrolytes; Female; Humans; Immunosuppressive Agents; Incidental Findings; Nephritis, Interstitial; Nephrocalcinosis; Sjogren's Syndrome; Sodium Bicarbonate; Treatment Outcome

A 61-year-old woman was admitted to our hospital because of muscle paralysis and was found to have severe hypokalemia. A gallium-67 scintigram revealed a positive accumulation in the bilateral salivary glands, and a labial minor salivary gland biopsy demonstrated a massive lymphocyte infiltrate around the salivary ducts. She was diagnosed with Sjögren's syndrome (SS) associated with renal tubular acidosis. Renal biopsy revealed tubulointerstitial nephritis with a mild focal infiltration of lymphocytes and plasma cells. These pathological features were compatible with SS with renal involvement. Acidosis and hypokalemia were corrected with sodium bicarbonate and potassium chloride, which relieved the patient's symptoms. Although steroid therapy has been reported to be effective in SS-associated tubulointerstitial nephritis, the patient's serum potassium level could be controlled without administering steroids during the first admission. Five years later, she was admitted again because of severe liver dysfunction attributed to autoimmune hepatitis. Oral administration of prednisolone resulted in the normalization of her transaminase levels, and the control of her serum potassium level became easier. It has been reported that patients with SS with salivary gland involvement tend to have hepatic complications, and those with hepatic complications tend to have renal involvement. Physicians should be aware of hepatic involvement, even if there is no liver dysfunction at the initial diagnosis of SS with salivary gland and renal involvement. It remains uncertain whether the administration of a low dose of steroids before the onset of autoimmune hepatitis might have prevented the development of liver dysfunction in our patient.

Topics: Acidosis, Renal Tubular; Administration, Oral; Female; Hepatitis, Autoimmune; Humans; Hypokalemia; Kidney; Lymphocytes; Middle Aged; Nephritis, Interstitial; Plasma Cells; Potassium Chloride; Prednisolone; Severity of Illness Index; Sjogren's Syndrome; Sodium Bicarbonate

Metabolic acidosis is a cause of renal disease progression, and alkali therapy ameliorates its progression. However, there are few reports on the role of renal acid-base transporters during alkali therapy. We evaluated the effect of sodium bicarbonate therapy and the role of acid-base transporters on renal disease progression in rats with a remnant kidney. Sprague-Dawley rats consumed dietary sodium bicarbonate (NaHCO3) or sodium chloride (NaCl) with 20% casein after a 5/6 nephrectomy. After being provided with a casein diet, the NaHCO3-treated group had higher levels of serum bicarbonate than the control group. At week 4, the glomerular filtration rate in the NaHCO3 group was higher than that in the NaCl group, and the difference became prominent at week 10. The glomerulosclerosis and tubulointerstitial damage indices in the NaHCO3 group were less severe compared with controls at week 4 and 10. The expression of the Na/H exchanger (NHE) was decreased, and apical reactivity was decreased in the NaHCO3 group, compared with the NaCl group. Endothelin-1 levels in the kidney were also decreased in the NaHCO3 group. Dietary sodium bicarbonate has the effects of ameliorating renal disease progression, which may be related to the altered expression of NHE in the remaining kidney.

Topics: Acidosis; Alkalies; Animals; Caseins; Disease Progression; Glomerular Filtration Rate; Glomerulosclerosis, Focal Segmental; Kidney; Male; Nephrectomy; Nephritis, Interstitial; Rats; Rats, Sprague-Dawley; Renal Insufficiency; Sodium Bicarbonate; Sodium Chloride; Sodium-Hydrogen Exchangers