Brudzinski sign test: how to perform and interpret it

The Brudzinski sign test is a bedside neurological maneuver used to detect meningeal irritation. The examiner flexes a supine patient’s neck and watches for involuntary hip and knee flexion. A positive result points hard at meningeal irritation, most urgently bacterial meningitis. A negative result excludes nothing.

A diagnostic accuracy appraisal in the Annals of Indian Academy of Neurology reported sensitivity as low as 5% in culture-proven cases. Specificity ran above 95%. This guide covers how to elicit the sign, how to read the result, and when to escalate.

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Key takeaways

The Brudzinski sign test is positive when passive neck flexion causes involuntary hip and knee flexion in a supine patient.

Specificity runs above 95%, but sensitivity has been reported as low as 5%, so a negative result excludes nothing.

The sign is read alongside Kernig’s sign, nuchal rigidity, and the patient’s whole presentation.

A positive finding with fever, headache, or altered consciousness warrants immediate escalation and empirical treatment.

Practice management software like Pabau can capture meningeal sign results directly in the patient record.

What is the Brudzinski sign test?

The Brudzinski sign test is a clinical examination maneuver that screens for meningeal irritation. It works by eliciting an involuntary lower-limb reflex in response to passive neck flexion. Józef Brudziński, a Polish physician, first described it in 1909.

The sign belongs to a family of classical meningeal irritation signs used at the bedside in suspected meningitis. Clinicians use it as part of a broader meningeal examination, never in isolation. It sits alongside nuchal rigidity and Kernig’s sign in the classic triad.

The test is performed with the patient lying supine and relaxed. The examiner lifts the head off the bed, flexing the neck forward toward the chest. A positive result occurs when the patient involuntarily draws up the hips and knees. The patient cannot suppress that reflex, which is what gives the finding its clinical weight.

Why neck flexion moves the legs

The meninges (dura mater, arachnoid mater, and pia mater) encase the central nervous system from the skull down through the spinal canal. When they are inflamed, the structures they enclose become taut and sensitized.

Passive neck flexion elongates the spinal cord and its surrounding meningeal sheaths. In a healthy patient that stretch causes no discomfort and no lower-limb movement. With meningeal inflammation present, the same stretch produces pain and mechanical tension along the cord.

The body responds by reflexively flexing at the hips and knees. That movement shortens the spinal canal and relieves the stretch. It is the physiological basis of Brudzinski’s sign.

How to perform the Brudzinski sign test: step by step

Correct patient positioning and a smooth, controlled maneuver are what keep the result trustworthy. Rushed flexion produces both false positives and false negatives.

1. Position the patient supine. The patient lies flat on their back with the legs straight and relaxed. Remove the pillow and flatten the bed.
2. Establish a relaxed baseline. Ask the patient to relax completely. Note whether the hips and knees are already flexed at rest, which may point to a musculoskeletal cause.
3. Place your hands. Cup the back of the patient’s head with both hands. One hand on the occiput and one on the sternum also works, and it stabilizes the chest.
4. Flex the neck forward slowly. Lift the head and bring the chin toward the chest in a smooth, deliberate motion. Do not force flexion against resistance, which itself suggests nuchal rigidity.
5. Observe the lower limbs immediately. Watch for involuntary flexion at the hips and knees as the neck flexes. The movement should be spontaneous and symmetric.
6. Document the finding. Record it as positive when involuntary hip and knee flexion is present, or negative when the limbs stay still. Note any confounding factors.

A patient who cries out during neck flexion without moving the lower limbs may have nuchal rigidity alone. Both findings matter, and both warrant further investigation.

Interpreting a positive Brudzinski sign

A positive Brudzinski sign indicates meningeal irritation. On its own it confirms no specific diagnosis. The common causes are bacterial meningitis, viral meningitis, and subarachnoid hemorrhage (SAH). Each one inflames or irritates the meningeal layers, which triggers the same reflex response to neck flexion.

Bacterial meningitis is the most clinically urgent cause. Treat a positive sign as an emergency in any patient with fever, severe headache, photophobia, or altered consciousness. Viral meningitis usually runs a milder course, though the sign can be positive in both.

Subarachnoid hemorrhage irritates the meninges through blood in the subarachnoid space, which triggers the same reflex pathway. Clinical context helps separate it from infectious causes. A thunderclap headache onset and the absence of fever both point toward SAH. Imaging and lumbar puncture are still required to confirm it.

Differential diagnosis: other causes of a positive finding

Several conditions beyond meningitis and SAH produce a positive Brudzinski sign. Work through the full differential before you commit to an interpretation.

• Bacterial meningitis (most urgent): fever, purpuric rash, rapid deterioration
• Viral meningitis: slower onset, milder systemic illness, no rash
• Subarachnoid hemorrhage: thunderclap headache, no fever, onset at exertion
• Carcinomatous meningitis: known malignancy, subacute onset, cranial nerve palsies
• Tuberculous meningitis: immunocompromised or endemic exposure history, indolent course
• Encephalitis with meningeal involvement: behavioral change, focal neurology

Read the finding alongside the whole clinical picture. That means vital signs, headache characteristics, rash distribution, cerebrospinal fluid analysis, neuroimaging, immune status, and travel history.

Diagnostic accuracy: sensitivity and specificity

Two findings dominate the evidence. When Brudzinski’s sign is present, it is highly specific for meningeal irritation. When it is absent, the diagnosis stays open.

The Mehndiratta appraisal found sensitivity of roughly 5% in culture-proven bacterial meningitis. The BMJ Education in Practice review reports a range of 27% to 97% across study populations. That spread reflects differences in disease severity, patient age, and immune status.

Those figures change what each bedside outcome is worth, and the panel below sets out all three.

Brudzinski’s sign vs Kernig’s sign: key differences

Kernig’s sign is the other classic meningeal irritation test, and the two are assessed together. Their elicitation techniques differ. Both detect the same underlying phenomenon, because meningeal inflammation makes stretching of the cord and nerve roots painful.

Neither sign alone confirms or excludes meningeal disease. Two positives together raise clinical confidence in a meningeal process considerably. Two negatives still leave lumbar puncture and neuroimaging on the table where the history points that way. Our guide to the Kernig’s sign test covers the technique and its own accuracy data.

Other meningeal irritation signs used alongside Brudzinski’s

In practice the test is one of three bedside assessments combined in suspected meningitis. Knowing all three helps you build a fuller picture before confirmatory testing.

Nuchal rigidity is resistance to passive neck flexion, felt by the examiner as stiffness. It produces no lower-limb movement. The same neck flexion maneuver elicits it, and it can coexist with Brudzinski’s sign. On its own it has low specificity in older adults.

Jolt accentuation of headache is tested by asking the patient to rotate the head horizontally at about two cycles per second. A positive result is a worsening of an existing headache. The BMJ Education in Practice review reports sensitivity above 90% in some populations, with lower specificity.

Use all three together, alongside the patient’s full presentation. Record every meningeal sign you performed and its result, including the negative ones.

Limitations of the sign in practice

Low sensitivity is the most significant limitation, and it bites where the test matters most. Among prospectively studied patients with confirmed bacterial meningitis, the sign may be absent in over 95% of cases.

Several patient groups are particularly likely to test negative while meningeal disease is present.

• Elderly patients: reduced muscle tone and comorbid musculoskeletal disease can mask the reflex response
• Immunocompromised patients: the inflammatory response driving meningeal irritation may be attenuated
• Early-stage disease: meningeal inflammation may not yet be severe enough to produce the reflex
• Sedated or reduced-consciousness patients: voluntary and reflex motor responses may be suppressed
• Patients with cervical spine disease: limited or painful neck flexion prevents proper elicitation

The BMJ review states plainly that the absence of meningeal signs cannot exclude meningitis. So record a negative finding with the same care as a positive one. Note anything that stopped you eliciting the sign reliably.

When to escalate: red flags and emergency referral

A positive Brudzinski sign test in a symptomatic patient is a medical emergency until proven otherwise. Speed of treatment in bacterial meningitis is directly linked to outcome. Do not wait for lumbar puncture results when clinical probability is high.

Escalate immediately when a positive or suspected positive sign occurs alongside any of the following:

• Fever and severe headache with acute onset
• Photophobia or phonophobia
• Non-blanching petechial or purpuric rash
• Altered consciousness or confusion
• Focal neurological signs
• Seizures
• Thunderclap headache (maximum intensity at onset, raising concern for SAH)

Current guidance from NICE guideline NG240 recommends empirical antibiotic therapy before lumbar puncture in suspected bacterial meningitis. That applies where the patient is deteriorating, or where immediate lumbar puncture is contraindicated. The CDC publishes parallel guidance on meningitis diagnosis and management for US practitioners.

Documenting Brudzinski’s sign in clinical records

Documentation is where a bedside finding becomes part of the patient’s history. A thin note costs the next clinician the handover detail they need, and it weakens the record if the patient presents again.

A best-practice note on the test covers the following:

• The maneuver performed: specify “passive neck flexion” to distinguish it from other elicitation methods
• The result: positive (involuntary hip and knee flexion) or negative (no lower-limb movement)
• Confounding factors: note if cervical disease, sedation, or patient agitation limited reliability
• Associated findings: nuchal rigidity, Kernig’s sign result, jolt accentuation if tested
• Clinical context: the reason the test was performed, such as headache with fever
• Action taken: referral, escalation, lumbar puncture ordered, or monitoring plan

Structured templates inside an EMR make this faster and harder to skip. A neurological exam checklist prompts for each sign, its result, and any confounder, so nothing is left to memory. Our guide to safer clinical notes makes the same case for writing negative findings down explicitly.

Primary care meets most of these presentations first. GP clinic software with structured examination templates keeps the finding in the patient record, where the next clinician will find it.

How Pabau keeps meningeal exam findings in the record

Most practices record a meningeal examination as free text, when they record it at all. The maneuver takes thirty seconds and the note takes longer, so the detail gets compressed into “neuro exam NAD”. The next clinician cannot tell whether Brudzinski’s sign was negative or never attempted.

Practice management software like Pabau lets you build the examination into the note itself. A neurological template prompts for each meningeal sign, its result, and the confounders that limited it. Those answers are stored as structured fields in the patient record, so they stay searchable.

Pabau Scribe, our AI medical scribe, writes the consultation up from the conversation and files the findings in the same record. Clinicians spend less time typing after a high-acuity assessment. The note still shows what was tested, what was found, and what happened next.

Document neurological findings without slowing the consultation

Pabau Scribe, our AI scribe, captures examination findings and clinical reasoning in structured records. Clinicians spend less time typing and more time with patients.

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Conclusion

The Brudzinski sign test earns its place at the bedside because a positive finding forces action. Specificity above 95% makes it meaningful when present. Sensitivity as low as 5% makes it unsafe to lean on when absent.

Perform it as one part of a meningeal examination, record what you found, and record what stopped you finding it. Book a demo to see how Pabau keeps neurological examination findings structured and searchable in the patient record.

Continue your research

Assessing the other classic meningeal sign? Kernig’s sign test covers the technique, the positive finding, and how the two signs are read together.

Need a structured neurological examination record? Neurological exam checklist gives you a printable prompt for each sign and its result.

Grading consciousness alongside the meningeal signs? Glasgow Coma Scale template sets out the eye, verbal, and motor scores with their scoring rules.

Planning care once meningitis is confirmed? Meningitis nursing care plan template sets out the diagnoses, goals, and interventions to document.

Working up the headache that brought the patient in? Headache physical exam walks through the wider examination that surrounds these meningeal signs.

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