Diarrheal Illness

Abstract

Diarrhea, qualitatively defined as an increase in stool frequency and liquid content, is a frequent complaint in patients presenting to emergency departments. Although most cases are uncomplicated viral infections, the most frequent causes of dangerous underlying entities are often not viral. In uncomplicated cases, laboratory testing for metabolic derangements is not required unless there are signs of moderate to severe dehydration or the patient has particular risks, such as chronic kidney disease. Secondary infections associated with antibiotic use (C difficile–associated diarrhea), other significant nosocomial exposures, recent international travel history, the presence of a nonintact immune system (HIV/AIDS, cancer/chemotherapy), and exposure to high-risk environments (including zoonotic exposures, outbreak-prone environments such as day care facilities) increase the likelihood of a bacterial or other infectious cause requiring either microbiologic testing or empirical antimicrobial treatments. Diarrhea is often present as a feature of clinically significant noninfectious conditions, including complications of inflammatory bowel diseases (Crohn disease and ulcerative colitis), overdoses, and withdrawal syndromes. In such cases, after hemodynamic stability has been ensured, advanced workup and treatment are guided by the underlying condition and antecedent risks, not the presence of diarrhea per se. Oral rehydration is the first step in management for mild dehydration caused by uncomplicated diarrhea. Intravenous fluids may be necessary in moderate to severe dehydration and in cases of electrolyte derangement requiring resuscitation where fluid choice and rate are paramount, as well as in patients who cannot tolerate oral intake. In cases of suspected bacteria-caused diarrhea, antibiotics, most often fluoroquinolones, reduce both the severity and duration of illness. In patients safe for home management, antidiarrheal agents such as loperamide may be used in uncomplicated and resolving cases. Probiotics appear safe in most cases and impart a small but clinically detectable decrease in the duration and severity of illness. Although there have been fears of bacterial outbreaks following natural disasters, improvements in local and global health efforts have led to decreases in cholera outbreaks, and typical viral causes of diarrhea are generally the most common causes. This review contains 4 figures, 5 tables and 32 references Key words: Clostridium difficile, diarrhea, infectious diseases, inflammatory bowel diseases, medication side effects, overdose syndromes, sepsis, traveler’s diarrhea, zoonotic infections