Brudzinski Sign
The correct answer is C - Brudzinski. This sign is elicited when passive flexion of the neck in a supine patient causes involuntary flexion of the hips and knees. 1
Definition and Technique
Brudzinski's sign is performed by placing the patient supine and passively flexing the patient's neck; a positive sign occurs when this maneuver causes involuntary (reflexive) flexion of both the patient's hips and knees. 1
Clinical Utility and Limitations
While this is a classic meningeal sign, it is important to understand its severe diagnostic limitations:
- Brudzinski's sign has extremely poor sensitivity of only 9% in adults, meaning it misses 91% of meningitis cases 2, 1
- In pediatric patients, sensitivity improves to 66% but remains inadequate to exclude disease 2, 1
- The sign has low diagnostic accuracy for predicting cerebrospinal fluid pleocytosis 2, 1
- Specificity is relatively high (85-95%), but the poor sensitivity makes it clinically unreliable 3
Critical Clinical Guidance
UK Joint Specialist Societies guidelines explicitly state that Kernig's sign and Brudzinski's sign should not be relied upon for diagnosis of meningitis (Grade 2B recommendation). 4
The absence of Brudzinski's sign cannot be used to exclude bacterial meningitis. 2, 1 This is a critical pitfall - a negative Brudzinski's sign provides false reassurance in the vast majority of meningitis cases.
Practical Implications
- All patients with suspected meningitis require hospital referral and cerebrospinal fluid examination regardless of whether Brudzinski's sign is present or absent 2, 1
- CSF analysis remains the cornerstone of diagnosis with the highest diagnostic accuracy 2, 1
- No single clinical sign of bacterial meningitis is present in all patients 2, 5
- The classic triad of fever, neck stiffness, and altered mental status is present in only 41-51% of bacterial meningitis cases 2, 5
Document the presence or absence of headache, altered mental status, neck stiffness, fever, rash, seizures, and signs of shock, but proceed to lumbar puncture based on clinical suspicion rather than physical examination findings alone. 4