A case of giardiasis presents w ith –
**Core Concept**
Giardiasis is an intestinal infection caused by the protozoan Giardia lamblia, leading to malabsorption and gastrointestinal symptoms. The pathogenesis involves attachment of the parasite to the intestinal mucosa, causing disruption of the brush border membrane and leading to malabsorption of nutrients.
**Why the Correct Answer is Right**
The correct answer is **malabsorption**. This occurs due to the attachment of Giardia to the intestinal mucosa, leading to the production of cysteine proteases that disrupt the brush border membrane, impairing the absorption of nutrients. The malabsorption of fats, carbohydrates, and proteins leads to symptoms such as diarrhea, weight loss, and abdominal distension. The small intestine is particularly affected, as it is the primary site of nutrient absorption.
**Why Each Wrong Option is Incorrect**
**Option A:** **Diarrhea** is a common symptom of giardiasis, but it is not the primary pathophysiological mechanism. Diarrhea is a result of malabsorption, not the cause.
**Option B:** **Vomiting** is not a typical symptom of giardiasis. While it may occur in some cases, it is not a characteristic feature of the infection.
**Option C:** **Fever** is not a primary symptom of giardiasis. Giardia infections are typically asymptomatic or cause mild symptoms, and fever is not a typical presentation.
**Clinical Pearl / High-Yield Fact**
Giardiasis can be diagnosed by detecting the parasite or its antigens in stool samples. However, a negative test does not rule out the infection, as the parasite may be present in low numbers or the infection may be in the early stages.
**Correct Answer:** A. Malabsorption