A case of giardiasis presents with –
**Core Concept**
Giardiasis is an intestinal infection caused by the protozoan parasite Giardia lamblia. The parasite adheres to the intestinal mucosa, leading to malabsorption of nutrients and electrolytes.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of giardiasis. Giardia lamblia adheres to the intestinal mucosa, causing damage to the microvilli and leading to malabsorption of fats, carbohydrates, and proteins. This results in steatorrhea, weight loss, and electrolyte imbalance.
**Why Each Wrong Option is Incorrect**
**Option A:** Diarrhea is a common symptom of giardiasis, but it is not the most characteristic symptom. Giardiasis often presents with malabsorption and weight loss.
**Option B:** Abdominal pain is not a typical symptom of giardiasis. The parasite primarily affects the small intestine, leading to malabsorption rather than pain.
**Option C:** Vomiting is not a characteristic symptom of giardiasis. The parasite primarily affects the small intestine, leading to malabsorption rather than vomiting.
**Clinical Pearl / High-Yield Fact**
Giardiasis can be diagnosed by identifying the parasite in stool samples or by detecting antigens in the stool. It is often associated with contaminated water or food sources.
**Correct Answer: D. Diarrhea.**