Which condition is characterized by a positive Brudzinski sign?

A positive Brudzinski sign is a clinical indicator typically associated with meningitis. This sign is observed when a healthcare provider flexes the neck of a patient, and the patient's involuntary response is to flex their knees and hips. This reactive movement indicates irritation of the meninges, the protective membranes surrounding the brain and spinal cord, which occurs in conditions such as meningitis.

Meningitis is an infection that can be caused by various pathogens, including bacteria and viruses, and often presents with other symptoms such as fever, headache, and neck stiffness. The Brudzinski sign is specifically a part of the neurological examination aimed at identifying meningeal irritation.

Other conditions listed, such as hemorrhoids, sinusitis, and pneumonia, do not cause meningeal irritation and thus would not result in a positive Brudzinski sign. Hemorrhoids are vascular structures in the anal canal, sinusitis is an inflammation of the sinuses, and pneumonia is an infection of the lungs, none of which involve the central nervous system in a way to provoke this specific sign.