The most common cause of acute bloody diarrhea, also called dysentery, is:

BTSC Staff Nurse 1 August-2025

Medical & Surgical Nursing

Easy

Appeared in: BTSC Staff Nurse 1 August-2025

Explanation

Shigella is the most common bacterial cause of dysentery, which is defined as diarrhea with visible blood and mucus.
The bacteria invade the epithelial lining of the colon, causing inflammation, ulceration, and bleeding.
This invasive process leads to the characteristic symptoms of frequent, small, painful bowel movements containing blood and mucus.
While other organisms can cause bloody diarrhea, Shigella is the classic and most frequent pathogen for bacillary dysentery globally.

Option A: While certain strains like Enterohemorrhagic E. coli (EHEC) produce Shiga toxin and cause bloody diarrhea (hemorrhagic colitis), they are a less common cause of classic dysentery compared to Shigella.
Option B: Rotavirus is the leading cause of severe, dehydrating watery diarrhea in infants and young children. It does not invade the intestinal lining to cause bleeding.
Option C: Vibrio cholerae causes cholera, which is characterized by profuse, painless, watery diarrhea, often described as "rice-water stools." The mechanism is toxin-mediated fluid secretion, not mucosal invasion, so it does not cause bloody stools.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Acute Bloody Diarrhea (Dysentery) as background academic context rather than a clinical decision trigger.
Identifying the cause of diarrhea is crucial for management. Bacillary dysentery caused by Shigella may require antibiotics in severe cases, whereas viral (Rotavirus) or toxin-mediated (Cholera) diarrhea is primarily managed with rehydration.
Shigellosis is highly infectious and can be transmitted person-to-person via the fecal-oral route. Nurses must implement strict contact precautions and emphasize hand hygiene for patients, families, and staff to prevent outbreaks, especially in hospitals and daycare centers.
What if? If the patient was an infant with severe watery diarrhea and vomiting, but no blood in the stool, the most likely causative agent would be Rotavirus, and the priority of care would be aggressive fluid and electrolyte replacement.

How to Approach the Question

First, identify the key terms in the question: "most common cause," "acute bloody diarrhea," and "dysentery."
The term "dysentery" specifically points to an inflammatory condition of the intestines, usually the colon, that results in severe diarrhea containing blood and mucus.
Recall the common gastrointestinal pathogens and their typical presentations.
Differentiate between pathogens that cause watery diarrhea (like Rotavirus, V. cholerae) and those that cause inflammatory/bloody diarrhea (like Shigella, Campylobacter, EHEC).
Among the causes of bloody diarrhea, recall that Shigella is the classic and most common cause of bacillary dysentery worldwide.
Evaluate the options based on this knowledge to select the most fitting answer.

Concept Tested & Keywords

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