A farmer rearing sheep, presented with complaints of fever and weakness for the last one month. There is generalised lymphadenopathy. There was also associated hepatomegaly. Biopsy of liver showed non caseating granuloma. These are most likely due to infection with:
**Core Concept**
The patient's presentation of fever, weakness, generalized lymphadenopathy, hepatomegaly, and non-caseating granuloma in the liver biopsy is suggestive of a systemic infection that triggers a chronic inflammatory response. This condition is often associated with a specific type of granulomatous disease.
**Why the Correct Answer is Right**
The patient's symptoms and laboratory findings are consistent with a diagnosis of Q fever, caused by Coxiella burnetii. This bacterium is typically acquired through inhalation of contaminated aerosols, such as those found in sheep farms. The non-caseating granuloma in the liver biopsy is a characteristic histopathological feature of Q fever. The patient's immune response to the infection leads to the formation of granulomas, which are collections of immune cells that attempt to wall off the infected area.
**Why Each Wrong Option is Incorrect**
* **Option A:** Tuberculosis (TB) is a possible cause of granulomatous disease, but it typically presents with caseating granulomas, not non-caseating ones. TB also often affects the lungs and lymph nodes, but the patient's liver involvement and sheep farm exposure are more indicative of Q fever.
* **Option B:** Brucellosis is another zoonotic infection that can affect sheep farmers, but it typically presents with symptoms such as fever, weight loss, and joint pain, without the characteristic non-caseating granulomas.
* **Option D:** Cytomegalovirus (CMV) can cause systemic infection and granulomatous disease, but it is more commonly seen in immunocompromised patients, such as organ transplant recipients or HIV/AIDS patients.
**Clinical Pearl / High-Yield Fact**
Sheep farmers are at increased risk of contracting Q fever due to their occupational exposure to infected animals and their products. This highlights the importance of implementing proper infection control measures and wearing protective gear when handling livestock.
**Correct Answer: C. Coxiella burnetii.**