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Clinical Aspects of Infectious Diarrhea. M. Hong Nguyen, M.D. OBJECTIVES. To generate the differential diagnosis of infectious diarrhea based on patients’ signs and symptoms. To review the important points associated with selected diarrheal infectious agents.
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Clinical Aspects of Infectious Diarrhea M. Hong Nguyen, M.D.
OBJECTIVES • To generate the differential diagnosis of infectious diarrhea based on patients’ signs and symptoms. • To review the important points associated with selected diarrheal infectious agents. • To formulate the general work-up and management of patients with diarrhea
Approach to Patients with Diarrhea 1. Duration of symptoms 2. Incubation period • Description of stool: a. Volume/texture b. Presence of blood, mucus (bowel ulceration) and PMN (inflammatory) 4. Associated symptoms or signs: • Systemic illness/fever - invasive pathogen. • Vomiting as predominant symptoms: viral or food poisoning • Abdominal pain: inflammatory process (Shig, Camp, C. diff; particularly EHEC) • Persistent abdominal pain and fever: Yersinia
Approach to Patients with Diarrhea (cont) • Epidemiologic factors: • Travel history • Food history • Common source of infection • Day care exposure • Recent antibiotics/chemotherapy
1. Duration of Diarrhea • Community-acquired or traveler’s diarrhea: • Acute (< 14 day) • Viruses • Bacteria: • Campylobacter > Salmonella > Shigella; pathogenic E. coli • Yersinia, Vibrio cholera • C. difficile (antibiotics, chemoRx) • Persistent diarrhea (> 14 day): • Parasites • Bacteria: Salmonella, Yersinia (less common) • Nosocomial diarrhea: • C. difficile
3b. Diarrhea Characteristics • Presence of mucus: • Small # mucus: irritable bowel syndrome • Large # mucus: invasive diarrhea • Blood: inflammatory or ischemia • Infection with invasion of mucosa • Ischemia • Diverticulosis, diverticulitis • Inflammatory bowel disease (ulcerative colitis) • Radiation injury • PMN: colonic mucosal inflammation • Infection • Inflammatory bowel disease
Enterobacteriacae-lactose (-): Salmonella Shigella Yersinia Enterobacteriacae- lactose (+): Pathogenic E.coli: ETEC EHEC Others: Campylobacter jejuni Yersinia enterocolitica Vibrio cholerae Bacterial Causes of Diarrhea
Work-up and Management of Diarrhea • Non-inflammatory diarrhea: • Rehydration • Antiperistaltic agent (loperamide) • Inflammatory diarrhea: • Rehydration • Antiperistaltic agent • avoid unless given with antibiotic • Antimicrobial if indicated • usually a quinolone
Enteric Fever • Causative organisms: • Salmonella typhi and paratyphi • Campylobacter fetus • Yersinia enterocolitica • Blood cultures: (+) for > 90% of patients • Stool cultures: (+)
Enteric Fever • Early: • Flu-like symptoms • Worsening abdominal pain • Constipation (diarrhea rare) • Later: • High fever: >40oC. • Temperature-pulse dissocation • Septic shock • Skin: rose spots