Renal lesions associated with chronic ulcerative colitis

Does hypokalaemia cause nephropathy? An observational study of renal function in patients with Bartter or Gitelman syndrome

BACKGROUND

Hypokalaemic nephropathy has been described in patients with chronic potassium depletion; it is a condition in which proximal tubular vacuolization and interstitial fibrosis occur, resulting in a decline in glomerular filtration rate (GFR) and, in some cases, renal failure. It has been described in patients with chronic diarrhoea, eating disorders, laxative abuse and primary hyperaldosteronism; also occasionally in Bartter syndrome (BS), in which severe hypokalaemia accompanies significant renal sodium and water losses, though rarely in Gitelman syndrome (GS), in which there is equally severe hypokalaemia, but only modest sodium losses.

AIM

We hypothesized that hypokalaemic nephropathy may not be due to potassium depletion per se, but persistently elevated circulating levels of aldosterone, possibly with superimposed episodes of renal hypoperfusion.

DESIGN AND METHODS

We searched UK and European data sets to retrospectively compare serum and urinary parameters in patients with GS and BS.

RESULTS

The patients with GS often had lower serum potassium concentrations than patients with BS, but the BS patients had significantly higher serum creatinine concentrations and lower estimated GFRs (eGFR). BS patients had significantly higher fractional excretions of sodium compared with GS patients, as well as higher plasma renin activities and serum aldosterone levels.

CONCLUSION

These findings show that in genetically confirmed cases of BS and GS, the degree of hypokalaemia (as an index of chronic potassium depletion) does not correlate with GFR, and that on-going sodium and water losses, and consequent secondary hyperaldosteronism, may play a more important role in the aetiology of hypokalaemic nephropathy.

Extraintestinal manifestations in inflammatory bowel disease

Inflammatory bowel diseases (IBD) can be really considered to be systemic diseases since they are often associated with extraintestinal manifestations, complications, and other autoimmune disorders. Indeed, physicians who care for patients with ulcerative colitis and Crohn's disease, the two major forms of IBD, face a new clinical challenge every day, worsened by the very frequent rate of extraintestinal complications. The goal of this review is to provide an overview and an update on the extraintestinal complications occurring in IBD. Indeed, this paper highlights how virtually almost every organ system can be involved, principally eyes, skin, joints, kidneys, liver and biliary tracts, and vasculature (or vascular system) are the most common sites of systemic IBD and their involvement is dependent on different mechanisms.

IgA antiglomerular basement membrane nephritis associated with Crohn's disease: a case report and review of glomerulonephritis in inflammatory bowel disease

A case of glomerulonephritis in a 35-year-old man with Crohn's disease is described here. The patient presented with severe diarrhea, nephrotic range proteinuria, hematuria, microangiopathic hemolytic anemia, thrombocytopenia, hypocomplementemia, acute renal failure requiring hemodialysis, cryoglobulinemia, and extensive thrombotic gangrene of the distal upper and lower limbs. The patient did not respond to plasmapheresis and steroid therapy and died of upper gastrointestinal bleeding. Renal tissue obtained at autopsy showed IgA-mediated antiglomerular basement membrane crescentic glomerulonephritis. Linear staining of the glomerular basement membrane by non-IgG antibodies is quite unusual with only 11 cases previously reported in the worldwide literature, 8 caused by IgA. Glomerulonephritis is a rarely reported extraintestinal manifestation of inflammatory bowel disease, and there are only 24 previously described cases that are reviewed and summarized in this report. Glomerulonephritis occurred in the setting of active bowel inflammation in all cases, circulating immune complexes were found in nearly half the cases, and serum complements usually were normal. Renal insufficiency and nephrotic range proteinuria were typically present at the time of diagnosis of glomerulonephritis and most often improved in parallel with treatment of the gastrointestinal disorder. The histologic findings were varied and included membranoproliferative glomerulonephritis, mesangioproliferative glomerulonephritis, membranous nephropathy, IgA nephropathy, and IgM nephropathy. Thus, the authors present the first case of glomerulonephritis caused by antiglomerular basement membrane disease in association with inflammatory bowel disease.

Renal tubular injury is present in acute inflammatory bowel disease prior to the introduction of drug therapy

BACKGROUND

5-aminosalicylic acid (5-ASA) has been associated with renal complications in inflammatory bowel disease. Renal function is typically monitored using serum creatinine; however, significant disease may predate increases in creatinine.

AIMS

To identify whether markers of early renal disease (urinary albumin, alpha-1-microglobulin [alpha-1-M] and N-acetyl-beta-D-glucosaminidase [NAG], and serum cystatin C) are useful in the assessment of renal function in inflammatory bowel disease patients receiving 5-ASA.

METHODS

Twenty-one patients with a new diagnosis of inflammatory bowel disease were investigated. Samples were taken at diagnosis, and at 3-monthly intervals after the commencement of 5-ASA, for 1 year.

RESULTS

Mean creatinine clearance was 100 mL/min and did not change following treatment. Inflammatory bowel disease was not associated with albuminuria. Urinary N-acetyl-beta-D-glucosaminidase and alpha-1-microglobulin at diagnosis were increased in 10 (48%) and 11 (52%) patients, respectively: treatment was not associated with consistent changes in urinary protein excretion. There was a significant correlation between cystatin C and creatinine clearance both at diagnosis (r=-0.533, P=0.0275) and combining the initial and follow-up data (r=-0.601, P < 0.01), but not between creatinine and creatinine clearance (P > 0.05).

CONCLUSIONS

Tubular proteinuria is an extra-intestinal manifestation of inflammatory bowel disease irrespective of 5-ASA treatment. Tubular proteins are not useful predictors of an adverse renal response to 5-ASA. Serum cystatin C may be an improved marker of glomerular filtration rate in this setting.

Renal and urologic complications of inflammatory bowel disease

Renal and urologic complications are not uncommon in patients with inflammatory bowel disease, and can be directly or indirectly related to the underlying disease process or its treatment. Many of these patients have asymptomatic disease, or the urinary symptoms are nonspecific or overshadowed by bowel symptoms. By the time a urinary complication is considered, significant disease progression or renal damage may have occurred. These risks necessitate a high degree of diligence and periodic urologic evaluation as part of the long-term management of patients with inflammatory bowel disease.