Meningism is the triad of nuchal rigidity, photophobia (intolerance of bright light) and headache. It is a sign of irritation of the meninges, such as seen in meningitis, subarachnoid hemorrhages and various other diseases. "Meningismus" is the term used when the above listed symptoms are present without actual infection or inflammation; usually it is seen in concordance with other acute illnesses in the pediatric population. 
The main clinical signs that indicate meningism are nuchal rigidity, Kernig's sign and Brudzinsky's signs. None of the signs are particularly sensitive; in adults with meningitis, nuchal rigidity was present in 30% and Kernig's or Brudzinsky's sign only in 5%.
Nuchal rigidity is the inability to flex the head forward due to rigidity of the neck muscles; if flexion of the neck is painful but full range of motion is present, nuchal rigidity is absent.
Kernig's sign (after Vladimir Mikhailovich Kernig, Russian-Baltic German neurologist 1840-1917) is positive when the leg is fully bent in the hip and knee, and subsequent extension in the knee is painful (leading to resistance).. This may indicate subarachnoid haemorrhage or meningitis. Patients may also show opisthotonus—spasm of the whole body that leads to legs and head being bent back and body bowed forward.
Josef Brudzinski (1874-1917), a Polish pediatrician, is credited with several signs in meningitis. The most commonly used sign (Brudzinski's neck sign) is the appearance of involuntary lifting of the legs in meningeal irritation when lifting a patient's head.
Other signs attributed to Brudzinsky:
- The symphyseal sign, in which pressure on the pubic symphysis leads to abduction of the leg and reflexive hip and knee flexion.
- The cheek sign, in which pressure on the cheek below the zygoma leads to rising and flexion in the forearm.
- Brudzinski's reflex, in which passive flexion of one knee into the abdomen leads to involuntary flexion in the opposite leg, and stretching of a limb that was flexed leads to contralateral extension.
- Brain tumors
- Cerebellar tumors
- Cerebral hemorrhage
- Intracerebral abscesses
- Lead intoxication
- Meningiosis carcinomatosa
- Muscular tenseness of the cervical spine
- Subarachnoid hemorrhage
- ICD9Data.com - Diagnosis Codes, Meningismus
- Thomas KE, Hasbun R, Jekel J, Quagliarello VJ (2002). "The diagnostic accuracy of Kernig's sign, Brudzinski's sign, and nuchal rigidity in adults with suspected meningitis". Clin. Infect. Dis. 35 (1): 46–52. PMID 12060874.
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- Brudzinski J (1909). Un signe nouveau sur les membres inférieurs dans les méningites chez les enfants (signe de la nuque). Arch Med Enf 12: 745-752.
- Brudzinski J (1916). Über neue Symptome von Gehirnhautentzündung und -reizung bei Kindern, insbesondere bei tuberkulösen. Berl Klin Wochensch 53: 686-690.
- Brudzinsky J (1908). Über die kontralateralen Reflexe an den unteren Extremitäten bei Kindern. Wien Klin Wochensch 8: 255-61.
- Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:77 ISBN 1591032016
- Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:68 ISBN 140510368X