Patients presenting with peritoneal ascites represent a common therapeutic and diagnostic challenge for emergency physicians. By the very nature of their systemic disease, these patients often present with a multitude of symptoms that are just as likely caused by underlying illnesses as they are by an ascitic infection.
We all have no trouble recognizing the classic triad of spontaneous bacterial peritonitis (SBP)—fever, abdominal pain, and worsening ascites—but less than a quarter of patients presenting with SBP will manifest such symptoms. (Dig Liver Dis 2001;33:41.) Some older data sets suggested that up to 12 percent of cirrhotic patients present for admission harbor peritonitis, prompting the revision of the American Association for the Study of Liver Diseases (AASLD) Practice Guideline dictating that all patients undergo diagnostic paracentesis prior to hospitalization. (Hepatology 2013;57:1651.)
This recommendation lacks important nuance, however; it would seem silly, for example, to tap a trauma patient just because he walked through our doors, but it does underline the low threshold we should have for peritoneal fluid analysis in patients with ascites who are presenting with the classic triad, GI symptoms, vital sign abnormalities, or any other concerning clinical findings.
Why is this incumbent upon us? Our waiting rooms overflow with patients requesting flu swabs and with victims of asymptomatic hypertension, and the time investment in performing paracentesis, much less waiting for lab analysis of the collected fluid, seems almost wasteful when the patient is headed for a room upstairs anyway. Isn't this something that can be referred for hospitalist disposition or to the inpatient proceduralist? With or without a dose of antibiotics to cover our bases, the arguments against ED paracentesis are not without merit. After all, a slim possibility of simmering infection lacks the emergency moniker we often use as a barometer of necessity.
Nonetheless, I firmly believe that performing paracentesis and diagnosing SBP should ride high on our list of priorities. A diagnostic tap takes all of a few minutes, no more than an ultrasound-guided IV, for which we're called on at an alarmingly increasing rate. Early diagnosis of SBP matters not only because of the high mortality associated with it (nearly 40% in most cohorts) but also because early ED intervention makes a difference. (Hepatology 2013;57:1651.) Albumin infusion, an often-forgotten but critical therapy when delivered quickly after diagnosis, can save lives.
The benefit of albumin infusion in SBP is not entirely known, although multiple possible mechanisms have been identified. Albumin has been demonstrated to alleviate endotoxemia, block lipopolysaccharide-stimulated neutrophil activity, and modulate nitric oxide activity, mitigating systemic vasodilation and capillary leak. Most saliently, however, two randomized clinical trials have demonstrated a consistent reduction in renal failure and mortality when albumin is infused after diagnosis of SBP. (N Engl J Med 1999;341:403; J Dig Dis 2002;3:32.) Importantly, this mortality benefit came when albumin was administered within six hours of diagnosis, placing the onus of therapy and the opportunity of intervention squarely in the lap of emergency physicians.
The 2012 AASLD guideline, based largely on the trial by Sort, et al., recommended that patients with SBP who also have concomitant azotemia or bilirubin elevation receive IV albumin (1.5 g/kg) within six hours of detection as well as 1.0 g/kg on day three. (Hepatology 2013;57:1651.) It's a large volume of colloid, and it typically requires an impetus of purpose that seems rare outside of the ED. When so much of our daily practice makes little impact in comparison, however, the chance to prevent renal failure or save a life is an opportunity and an obligation we shouldn't pass up.