**Question:** Confirmatory diagnosis of rabies on postmorbid examination: FMGE 09

**Core Concept:** Rabies is a viral disease primarily affecting the central nervous system, caused by the lyssavirus family, particularly the rabies virus. The disease typically presents with a progressive encephalitis and is transmitted through the saliva of infected animals. Postmorbid examination is used to confirm the diagnosis in fatal cases.

**Why the Correct Answer is Right:**

The correct answer, **D** (presence of intranuclear inclusion bodies in neurons), is based on the characteristic pathological findings observed during postmortem examination of a patient who has succumbed to rabies. Intranuclear inclusion bodies are formed due to the accumulation of viral proteins within the nucleus of infected neurons, a hallmark of rabies infection.

**Why Each Wrong Option is Incorrect:**

A. **Absence of intranuclear inclusion bodies:** This option is incorrect because the absence of this specific pathological finding would not confirm a diagnosis of rabies, as the disease can still be present despite their absence.

B. **Presence of only rabies neutralizing antibodies:** Rabies neutralizing antibodies are produced in response to rabies vaccination or natural infection. These antibodies do not directly confirm the diagnosis of rabies on postmorbid examination, as they can be present in cases of vaccinated individuals or post-exposure prophylaxis.

C. **Increased serum creatinine kinase levels:** Creatinine kinase (CK) is an enzyme involved in muscle function, and its increase is usually associated with muscle injury or inflammation. This option is incorrect because increased CK levels are not specific to rabies infection and can be seen in other conditions as well.

**Clinical Pearl:**

Postmortem examination remains crucial in confirming rabies diagnosis, especially in cases where the clinical suspicion is high but the disease has progressed rapidly or clinical samples could not be obtained during life. In such cases, the presence of intranuclear inclusion bodies in neurons is the key diagnostic finding on histopathological examination.

**Correct Answer Explanation:**

D. **Presence of intranuclear inclusion bodies:** This is the correct answer because these inclusions are specific to rabies virus infection and are found in the nucleus of infected neurons. They result from the accumulation of viral proteins within the nucleus, which is characteristic of rabies virus infection. This finding significantly strengthens the clinical suspicion of rabies in postmortem examination and contributes to the diagnosis.