Tuesday, March 17, 2009

Getting Back to (or, at?) Spontaneous Bacterial Peritonitis

Today we discussed many complications of portal hypertension, including:
  1. Ascites
  2. Gastroesophageal Varices
  3. Hepatic Encephalopathy
  4. Hepato-renal syndrome
  5. Hepato-pulmonary syndrome

The issue of Spontaneous Bacterial Peritonitis came up.

The diagnosis is relatively straight forward - a diagnostic paracentesis is performed and sent for cell count and differential, culture and sensitivity, albumin (make sure you have a serum albumin), and total protein. You can also send off for glucose, LDH, and amylase. Remember - the pathogenesis of this conditions is from translocation of gut bacteria into the ascitic fluid....patients with low protein (eg immunoglobulins) are at a significantly higher risk for developing bacterial peritonitis. You can read more about the Serum-Ascites Albumin gradient here. If the cultures are positive, or if there are >250 polymorphonuclear leukocytes per mm3, you have a diagnosis. Hooray.

Treatment revolves around covering organisms that have translocated - the vast majority being E. coli and Klebsiella, but other G- and sometimes G + organisms are the culprit. Ceftriaxone is a good agent, but there are certainly others that will work just fine. Intravenous albumin has also been shown to reduce renal failure and death when given with antibiotics on days 1 and 3 of treatment.
Here is the original article on the benefits of IV Albumin in the treatment of SBP.

Prophylaxis: Okay, now you're entering a world of hurt. This is an area fraught (yes, "fraught") with controversy. Let's start with a few reasonable words - patients who have a history of SBP and have high risk factors (read: low ascites protein) are at significant risk of developing SBP again - with associated morbidity and mortality. So it would seem reasonable to use prophylactic therapy to prevent this from happening. There are many issues with this, such as developing bacterial resistance, cost, dangers of being on prolonged antibiotics, efficacy, which drug to use, and how often to use it. Currently, there are a couple of well described patterns of prophylaxis:
  • Q weekly: Cipro given once per week at 750mg. Here is a link to the original trial. (Note: other Abx have been used q weekly as well).
  • Q daily: Cipro given daily at 500 mg. Here is a recent trial showing benefit. (other drugs have been used successfully q daily as well).
Read the articles, critique them, ask around, digest the information, and come up with your own opinion on what you think is the appropriate prophylaxis.

Check out the stigmata of chronic liver disease here.

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