Kernig's sign

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Kernig's sign is a clinical sign that indicates the presence of meningitis. It is named after the Russian neurologist Vladimir Mikhailovich Kernig, who first described it in 1882.

Clinical Presentation

Kernig's sign is elicited with the patient lying supine. The examiner flexes the patient's hip and knee to a right angle, and then attempts to extend the knee. A positive Kernig's sign is present if there is resistance to knee extension and pain in the hamstrings. This resistance and pain are due to irritation of the meninges, which are the protective membranes covering the brain and spinal cord.

Pathophysiology

The presence of Kernig's sign is associated with inflammation of the meninges, known as meningitis. This inflammation can be caused by various infectious agents, including bacteria, viruses, and fungi. The irritation of the meninges leads to increased sensitivity and pain when the nervous system is stretched, as occurs during the test for Kernig's sign.

Diagnostic Significance

Kernig's sign is one of several physical examination findings that can suggest meningitis. Other signs include Brudzinski's sign, nuchal rigidity, and photophobia. While the presence of Kernig's sign can support the diagnosis of meningitis, it is not definitive, and further diagnostic testing, such as lumbar puncture and cerebrospinal fluid analysis, is required to confirm the diagnosis.

History

Vladimir Mikhailovich Kernig first described the sign that bears his name in 1882. Kernig was a prominent neurologist in Russia and made significant contributions to the understanding of neurological diseases.

Related Conditions

Kernig's sign is most commonly associated with meningitis, but it can also be seen in other conditions that cause meningeal irritation, such as subarachnoid hemorrhage and certain types of encephalitis.

See Also

• Brudzinski's sign
• Meningitis
• Nuchal rigidity
• Lumbar puncture
• Cerebrospinal fluid