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

The precise neurological evaluation of patients with a depressed level of consciousness may present a challenge, even for experienced neurologists. Meningeal signs, particularly Kernig’s sign and neck stiffness, are helpful in suggesting the diagnosis of meningeal irritation in intracranial infections, oedema or haemorrhage and belong to the limited number of physical signs examined in patients with coma or altered mental status. 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 Brudzinski’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 Diminution of Kernig’s sign on the paretic side was …