Which pathogen is associated with Waterhouse-Friderichsen syndrome?

• A. Staphylococcus aureus
• B. Neisseria meningitidis
• C. Streptococcus pneumoniae
• D. Haemophilus influenzae

Answer: (B)

Waterhouse-Friderichsen syndrome is the result of fulminant meningococcemia causing bilateral adrenal hemorrhage and acute adrenal failure. The organism most classically linked to this presentation is Neisseria meningitidis, a bloodstream-invading bacteria that can trigger disseminated intravascular coagulation, leading to hemorrhage in the adrenal glands. This adrenal destruction manifests as sudden shock, often with purpura and rapid deterioration, which is why Neisseria meningitidis is the best answer. Other organisms listed can cause meningitis or sepsis, but they are not characteristically associated with the adrenal hemorrhage pattern seen in Waterhouse-Friderichsen syndrome.