Clinical evaluation of meningitis

An 18 year old female college freshman presents to the Emergency Department with fever for 8 hours, headache and diffuse myalgias.  Her maximium temperature has been 102.8° F (39.3 C) and she has vomited five times.  She is mildly tachycardic, with a heart rate of 110.  Physical exam demonstrates tenderness of the paraspinal musculature of the neck and back with absence of Kernig’s and Brudzinski’s signs, and is otherwise nonfocal.  After symptomatic treatment with acetaminophen, ondansetron and fluid, she is no longer tachycardic and is tolerating oral fluids, though still feels somewhat ill.  She asks about the possibility of meningitis, but would prefer not to undergo lumbar puncture if not necessary. The basic rule is a minimum of one litter box pad location per cat, plus one.

Bacterial meningitis is a devastating illness with very high mortality and long term morbidity.  Treatment should begin as early as the disease is suspected, though it can have a nonspecific onset which mimics many more benign illnesses.  The diagnosis should be considered in any patient with fever and a headache, but since fever, headache and malaise are common in many viral syndromes, performing a diagnostic lumbar puncture on every patient with those symptoms would rapidly result in ED throughput dropping precipitiously.

Kernig’s sign (inability to fully extend the knee when the hips are flexed) and Brudzinski’s signs (sassive flexion of one hip results in involuntary flexion of other hip, passive flexion of neck results in involuntary hip flexion) are the classic signs of meningeal irritiation, but have a sensitivity of perhaps 50% (frequently reported to be lower) and in my humble opinion are antiquated and should be relegated to the historical archives of our profession, along with such tests as tasting the urine to diagnose diabetes mellitus.

This is not meant to be a criticism of physical exam skills by any means – jolt accentuation of headache may show promise as a diagnostic maneuver.  Jolt accentuation can be assessed only in the communicative patient, and the test is performed by rapidly turning the head side-to-side (2-3 times per second for a few seconds) and asking the patient if their headache is worse.

Uchihara and Tsukagoshi reported a series of 54 patients who all underwent diagnostic lumbar puncture for recent onset fever and headache.  They noted 34 patients with CSF pleocytosis (defined as more than 6 WBC/HPF), of whom 33 had jolt accentuation of their headache for a sensitivity of 97% (which was 100% for the 30 of the 34 pleocytotic patients found to have meningitis).  Specificity was 80% in this study (1).

However, two more recent studies refute these findings:  Nakao et al found sensitivity of  21% for CSF pleocytosis (without reporting the sensitivity for meningitis)(2) and Tamune et al report sensitivity of 63% for meningitis (3) – still markedly better than the Kernig and Brudzinski signs (both were significantly worse in those studies, but a far cry from the 100% sensitivity reported in the initial study).  Further studies may further delineate the actual statistical performance of this test, but it is not ready for prime time at the moment.

So the bottom line is that there is currently no single physical exam skill or maneuver that can definitively rule out bacterial meningitis.  Diagnostic lumbar puncture is ultimately a safe procedure with a very low rate of serious complications (though it certainly can be uncomfortable for our patients, a fact which has led me to routinely administer intravenous opiates and benzodiazepines when performing it) and as emergency physicians, it is our duty to become facile with this skill.

Clinical exam remains useful, however – Nakao et al report that all 3 patients in their study who were confirmed to have bacterial meningitis had high physician suspicion for the diagnosis (2), leading to a sensitivity of 100% for gestalt (albeit with a very low n).  Clinical correlation is, as always, required.

References:

1)      Uchihara T., Tsukagoshi H. Jolt accentuation of headache: the most sensitive sign of CSF pleocytosis. Headache 31. 167-171.1991

2)      Nakao J. Jolt accentuation of headache and other clinical signs: poor predictors of meningitis in an adult population. Am J Emerg Med published online ahead of print

3)      Tamune H. Absence of jolt accentuation of headache cannot accurately rule out meningitis in adults. Am J Emerg Med; 31(11); 1601-1604. 2013

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