**Question:** The commonest cause of death in diphtheritic child after few weeks of infection is:

A. Cardiovascular collapse
B. Encephalitis
C. Respiratory distress
D. Septicemia

**Core Concept:** Diphtheria is a severe bacterial infection caused by the bacterium Corynebacterium diphtheriae, which primarily affects the respiratory tract. The disease is characterized by the formation of a pseudomembrane in the throat, leading to airway obstruction and respiratory distress.

**Why the Correct Answer is Right:** Diphtheria is primarily a respiratory illness. Although respiratory distress is a possible complication, the commonest cause of death in diphtheritic children after a few weeks of infection is cardiovascular collapse due to the production of a toxin by Corynebacterium diphtheriae. The toxin leads to myocardial damage, arrhythmias, and cardiac failure.

**Why Each Wrong Option is Incorrect:**

A. Cardiovascular collapse due to diphtheria toxin is the primary cause of death, not respiratory distress. Encephalitis (option B) is a rare complication, and septicemia (option D) is less common than cardiovascular collapse.

**Clinical Pearl:** Diphtheria is a preventable disease due to the availability of effective vaccines. In recent years, diphtheria cases have decreased significantly in most countries, but it remains a concern in some regions with low vaccination rates. It is essential to ensure that vaccination programs are accessible and up-to-date to prevent severe complications and save lives.

**Correct Answer:** D. Septicemia