Modification of Meningeal Signs by Concomitant Hemiparesis

Abstract

SINCE Kernig's description1 in 1907 of a localized sign pointing to meningeal disease, there has been a constantly increasing body of knowledge concerning such phenomena. It was evidently Kernig's early belief that the "leg sign" which he first described was a specific finding for epidemic cerebrospinal meningitis. This early belief was, of course, unfounded, and Kernig later corrected his statement, since the reaction is present in many other varieties of meningeal irritation. Many different, but related, signs of meningeal irritation have since been described, although none is of greater clinical importance than the Kernig leg sign. The purpose of this presentation is to point out the modification of the meningeal sign which frequently occurs when hemiparesis and meningeal irritation are present concomitantly. The recognition of this modification is of clinical importance, as will be shown. In addition, a study of the modification sheds further light on the poorly understood neurophysiologic mechanisms on which the occurrence of the meningeal signs depends.The Kernig leg sign was often described for a patient in the sitting position with his legs dangling over the side of the bed. If one leg is then passively extended on the thigh, a certain amount of reflex contraction of the hamstring muscles will prevent full extension in the patient with meningeal irritation. Since many patients with meningeal irritation are too ill to sit comfortably on the side of the bed, a modified version of the test is more commonly used to elicit the sign. The patient lies supine in bed while one leg is lifted passively so that the thigh is at right angles to the trunk and the leg is at right angles to the thigh. With the thigh in this position, passive extension of the leg on the thigh is attempted. In the patient with meningeal irritation the extension will be halted by contraction of the hamstring muscles. In addition to the limitation of passive extension of the leg, other phenomena occur with regularity.

Attenuation of Kernig's sign by concomitant hemiparesis: forgotten aspects of a well known clinical test

“…The present study confirms the results of Thorner’s forgotten paper from 1948 2. In addition to Thorner, who only noted attenuation of Kernig’s sign by concomitant hemiparesis without performing any quantification, the quantitative evaluation of Kernig’s sign was carried out in the present study.…”

“…As long ago as 1907, the German–Russian physician Vladimir Kernig noticed an attenuation of his “Kernig’s leg sign” on the paretic side in patients with meningeal irritation and concomitant hemiparesis 1. The American neurologist Thorner described in 1948 a modification of various meningeal signs on the paretic side 2. According to Thorner, Kernig’s sign as well as the rarer Brudziński’s sign can be both symmetric and asymmetric.…”

“…In the case of asymmetric meningeal signs, hemiparesis on the side of less pronounced meningeal signs should be assumed. On the contrary, meningeal signs should always be symmetric in meningitis and subarachnoid haemorrhage without parenchymal involvement and paresis 2. Thorner pointed to an attenuation of meningeal signs on the paretic side as a very quick and easy method of diagnosing unilateral motor deficits 3.…”

Vladimir Kernig (1840?1917)

“…Thorner erwog, dass eine gestörte Überleitung der reflektorischen Antwort zu den Unterschenkelbeugern über die betroffene Pyramidenbahn die Abschwä-chung des Kernig-Zeichens auf der paretischen Seite erklären könne [15].…”

“…Im Fall einer Asymmetrie meningealer Zeichen sei auf der Seite des schwächer auslösbaren Kernig-Zeichens von einer konkomitanten Hemiparese auszugehen. Bei reinen meningealen Syndromen ohne Paresen, beispielsweise infolge von Meningitiden oder Subarachnoidalblutungen, sei das Kernig-Zeichen dagegen immer symmetrisch ausgebildet [15].…”