A 28-year-old patient with end-stage renal disease (ESRD) on continuous ambulatory
peritoneal dialysis (CAPD) for two months presents with fever, abdominal pain and cloudy
dialysis fluid. There is no diarrhea or vomiting and the pain has been present for about 12 hours.
The patient has ESRD secondary to chronic glomerulonephritis, there is no history of diabetes,
urinary infections or antibiotic use. Examination reveals a temperature of 38.9 C (102 F), and
blood pressure of 110/70 mm Hg. The throat is clear, as are the lungs. Cardiac examination
reveals a grade 2/6 systolic murmur. Abdominal examination reveals decreased bowel sounds
with diffuse tenderness. There is mild rebound. There is no edema or skin rash. A complete
blood count shows a leukocyte count of 14,200/mm3, hemoglobin is 12.5 g/dL. Peritoneal fluid
is cloudy with 1,000 white blood cells, 85% of which are polymorphonuclear leukocytes. Gram’s
stain of fluid is negative. Cultures of blood and peritoneal dialysis fluid are taken. Which of the
following is the most appropriate initial step in management?
A. Fluconazole
B. Immediate removal of dialysis catheter.
C. Intravenous vancomycin
D. Intravenous gentamicin
E. Oral ciprofloxacin
Explanation:
The correct answer is C. Peritonitis in a patient on CAPD is usually due to gram-positive
pathogens such as Staphylococcus aureus or epidermidis. It is usually characterized by
abdominal pain and over 100 white blood cells (typically polymorphonuclear leukocytes) in a
sample of peritoneal dialysis fluid. Intravenous vancomycin would be a reasonable treatment to
cover gram-positive pathogens.
Fluconazole (choice A) would be indicated for a fungal infection. Fungal peritonitis is not
usually seen until patients have been treated with multiple antibiotics or are further
immunosuppressed.
Immediate removal of the dialysis catheter (choice B) is usually not needed unless the patient has
a peritonitis that has not improved with a trial of antibiotics.
Intravenous gentamicin (choice D) has good gram-negative coverage but would not be an ideal
drug to cover Staphylococcus.
Ciprofloxacin (choice E) would be a very broad spectrum antibiotic that would not be a first
choice as a single antibiotic to treat staphylococcal peritonitis. Further, the oral route may not be
adequate as patients with peritonitis may have nausea and vomiting.