3-18
danger to others.
Symptom: Acute Diarrhea
COL (Ret) Peter McNally, MC, USAIntroduction: Diarrhea is a change in bowel habits marked by numerous, watery stools. Diarrhea episodes
lasting longer than 30 days are chronic and may require sophisticated evaluation and management. Acute
diarrhea is common, with Americans suffering 1-2 episodes each year. Fortunately, most episodes (>90%) of
acute diarrhea are mild and self-limited. Proper management of acute severe diarrhea is vital as this illness is
the second leading cause of death in developing countries where SOF teams are frequently deployed. Consult
medical intelligence sources before deployment for major causes of diarrhea in each area of operations.
There are numerous causes of diarrhea: parasites, bacteria, viruses, food poisoning, chemical agent exposure,
chronic disease, malabsorption and many others.
Subjective: Symptoms
Diarrhea (with or without blood, mucus, pus); fever often above 102°F; orthostatic dizziness, mental status
changes; abdominal pain (may be severe and unremitting). The basic clinical presentations can be divided
as follows:
Bloody diarrhea (dysentery): e.g., Shigella, some E. coli
Purging with voluminous diarrhea (>1 liter of stool/hr): e.g., cholera, antibiotic related pseudomembranous
colitis (C. difficile)
Vomiting with minimal diarrhea: e.g., food poisoning (toxins), some viruses
Chronic diarrhea: e.g., Giardia, malabsorption of food
Gross bleeding per rectum: e.g., GI bleed: perforated hollow viscus (intestine, etc.) or hemorrhoid;
hemorrhagic colitis (E. coli)
Simple diarrhea without a specific cause: usually viral, inflammatory bowel disease
Focused History: Have you ever had this diarrhea before? (Recurrent diarrhea may be due to chronic
disease.) Have you had blood or pus in your diarrhea? (typical of dysentery) Have you had diarrhea that
was all just blood? (typical of GI bleed) How long have you had the diarrhea? (Chronic diarrhea does
not resolve in 4 weeks; cholera may cause extreme diarrhea and death within days.) Are you vomiting
also? (typical of toxin ingestion) Have you been taking antibiotics? (typically within the past month for
pseudomembranous colitis)
Objective: Signs
Using Basic Tools:
Vital Signs: Fever, hypotension, tachycardia, orthostatic changes in heart rate and blood pressure.
Inspection: May appear dehydrated, weak and disoriented.
Auscultation: Usually rapid bowel sounds are evident. Absent bowel sounds with abdominal distention and
tympani suggest megacolon or perforation.
Percussion: Tympani and distention suggest dilated bowel loops.
Palpation: Mild diffuse tenderness is usual. Spleen enlargement may be seen in typhoid fever.
Using Advanced Tools: Lab: CBC with differential for infection, anemia; urinalysis to avoid renal failure from
dehydration; stool sample for O & P, blood and leukocytes
Assessment:
Differential Diagnosis
Shigellosis dysentery - fever, abdominal pain, urgency (tenesmus), diarrhea contains blood (Hemocult
positive), mucus and pus.
Salmonellosis (typhoid fever) - minimal diarrhea, prolonged high fever, delirium, bacteremia, enlargement of
the spleen and abdominal pain. Without prompt diagnosis and treatment, this can be a severe 4-week illness.
Amebic dysentery - bloody diarrhea, toxic megacolon (extreme dilation of colon), liver abscess and death.
Cholera - rapid progression, voluminous diarrhea can lead to hypovolemic shock and DEATH within 1-2 days.
Pseudomembranous (C. difficile) colitis - watery diarrhea may be voluminous (Hemocult positive), and
associated with fever and acute megacolon.