In the latest Case Record of the Massachusetts General Hospital, a 72-year-old woman with end-stage renal disease (ESRD) was admitted to the hospital because of nausea, vomiting, and abdominal pain and distention. The patient had been receiving continuous ambulatory peritoneal dialysis for 18 months for ESRD presumed to be due to diabetic nephropathy
Patients undergoing peritoneal dialysis account for about 6% of the ESRD (end-stage renal disease) population in the United States. In general, for peritoneal dialysis to be successful, the patient must be motivated and cognitively intact and must have preserved peritoneal anatomy. In most studies, patients who begin treatment with hemodialysis and those who begin treatment with peritoneal dialysis appear to have similar outcomes.
• What is the appropriate empiric therapy for suspected peritoneal dialysis-associated peritonitis?
When there is a high clinical index of suspicion for peritonitis associated with peritoneal dialysis, the authors recommend the administration of empiric antibiotics before culture results are available. Antibiotics can be delivered intraperitoneally or intravenously. Both gram-positive and gram-negative coverage should be provided. Gram-positive coverage should be either first-generation cephalosporin or vancomycin; gram-negative coverage should include pseudomonas coverage with the use of third-generation cephalosporin, quinolone, or gentamicin (although depleting residual renal function is a concern with gentamicin use).
• What is encapsulating peritoneal sclerosis?
Encapsulating peritoneal sclerosis is associated with diffuse sclerosis of the peritoneal membrane. Chronic abdominal pain, bowel dysfunction, malnutrition, and small-bowel and large-bowel obstruction can ensue. Encapsulating peritoneal sclerosis has been seen in association with recurrent peritonitis. Hemoperitoneum is an occasional finding. The median duration on dialysis for a patient with encapsulating peritoneal sclerosis is 5.1 years, but a small number of cases are seen after a patient has had only 1 or 2 years of peritoneal dialysis. CT findings include matted bowel, peritoneal thickening, calcification, and ascites. In 15% of patients, there may be no imaging abnormality. The condition carries a high risk of death, and there are limited therapeutic options.
Morning Report Questions
Q: How is tuberculous peritonitis diagnosed?
A: The diagnosis is challenging and is often delayed; less than half of all cases are diagnosed before 6 weeks after presentation. The classic finding on peritoneal fluid analysis is a predominance of neutrophils. Peritoneal-fluid smears for acid-fast bacilli are notoriously insensitive — positive smears are associated with only 3% of culture-confirmed or pathologically confirmed cases. The sensitivity of peritoneal-fluid culture for mycobacteria has been low, at 30%, but may be increased with the use of newer BACTEC systems (Becton Dickinson). There are a number of newer, relatively noninvasive tests that may confirm M. tuberculosis as the causative organism more rapidly than culture, including polymerase-chain-reaction (PCR) assay, peritoneal-fluid measurement of adenosine deaminase, and serum measurement of CA-125. Rapid nested-PCR and molecular-beacon assays (Xpert MTB/RIF) have high sensitivity in smear-negative pulmonary and extrapulmonary tuberculosis. The standard for the diagnosis of tuberculous peritonitis is laparoscopy. The sensitivity of visual inspection alone, with evidence of peritoneal nodules, is high, ranging from 84 to 100%. Similar sensitivities are achieved with pathological and microbiologic investigations of peritoneal-biopsy specimens.
Q: Do standard anti-tuberculous regimens need to be altered in patients with end-stage renal disease?
A: Isoniazid and rifampin are not affected by kidney function or by hemodialysis; therefore, standard dosing is appropriate. Pyrazinamide is cleared by dialysis and should be administered after hemodialysis. There are case reports of blindness in patients with ESRD who are receiving ethambutol, thus the authors indicated it is reasonable to substitute a fluoroquinolone as first-line therapy in such a case.