CHAPTER 52

Miscellaneous Neurologic Signs

Miscellaneous neurologic signs—some of them reflexes, some closely related to the defense and postural reflex mechanisms, and others more varied in nature—are elicited in certain diseases of the nervous system. Some of these are quite important, especially the signs of meningeal irritation; others are arcane and primarily of historical interest.

Signs of Meningeal Irritation

Meningeal signs are elicited most frequently when the meninges are inflamed—from infection (e.g., bacterial meningitis) or from the presence of a foreign material (e.g., blood in the subarachnoid space). Meningismus is a term that refers to the presence of nuchal rigidity and other clinical signs of meningeal inflammation. Meningism is sometimes used synonymously with meningismus, but it is also used to refer to a syndrome characterized by neck stiffness without meningeal inflammation, seen in patients with systemic infections, particularly young children.

The clinical manifestations of meningeal irritation are varied and depend on the severity of the process. Accompaniments depend on etiology but commonly include headache, pain, and stiffness of the neck; irritability; photophobia; nausea and vomiting; and other manifestations of infection, such as fever and chills. The various maneuvers used to elicit meningeal signs produce tension on inflamed and hypersensitive spinal nerve roots, and the resulting signs are postures, protective muscle contractions, or other movements that minimize the stretch and distortion of the meninges and roots.

In a rational clinical examination article on the early recognition of acute meningitis, only 10 of 139 papers adequately addressed the utility of the clinical examination in confirmed cases of meningitis. In suspicious circumstances, the absence of fever, neck stiffness, and altered mental status effectively eliminates meningitis (sensitivity, 99% to 100% for the presence of one of these findings). Of the classic signs of meningeal irritation, only one study has assessed Kernig’s sign, and no studies subsequent to the original report have evaluated Brudzinski’s sign (see below). Forgie reviewed the current relevance of the classic eponymous signs of meningitis because more recent studies have suggested lower sensitivities and specificities compared to the original descriptions. These changes in sensitivity and specificity may be related to differences in examination technique, changes in the epidemiology and demographics of meningitis, an evolution in the pathogens causing meningitis, and changes in management.

Nuchal (Cervical) Rigidity

Nuchal rigidity is the most widely recognized and frequently encountered sign of meningeal irritation, and the diagnosis of meningitis is rarely made in its absence. It is characterized by stiffness and spasm of the neck muscles, with pain on attempted voluntary movement as well as resistance to passive movement. The degree of rigidity varies. There may be only slight resistance to passive flexion, or marked spasm of all the neck muscles. Nuchal rigidity primarily affects the extensor muscles, and the most prominent early finding in meningeal irritation is resistance to passive neck flexion. The physician is unable to place the patient’s chin on his chest, but the neck can be hyperextended without difficulty; rotatory and lateral movements may also be preserved. With more severe nuchal rigidity, there may be resistance to extension and rotatory movements as well. Extreme rigidity causes retraction of the neck into a position of opisthotonos, the body assuming a wrestler’s bridge or arc de cercle position, with the head thrust back and the trunk arched forward (Figure 52.1). Rigidity may be absent in meningitis when the disease is fulminating or terminal, when the patient is in coma, or in infants.

FIGURE 52.1 Opisthotonos in a patient suffering from tetanus; painting by Sir Charles Bell, 1809. Dr. Bell was a noted artist as well as physician (see Chapter 16).

Stiffness and rigidity of the neck may occur in other conditions. A common problem is to distinguish restricted neck motion due to cervical spondylosis or osteoarthritis from nuchal rigidity. Patients with osteoarthritis typically have difficulty with rotation and lateral bending of the neck; these motions are usually preserved in patients who have meningismus, unless the meningeal irritation is extremely severe. Restricted neck motion may also occur with retropharyngeal abscess, cervical lymphadenopathy, neck trauma and as a nonspecific manifestation in severe systemic infections. Extrapyramidal disorders, particularly progressive supranuclear palsy, may also cause diffuse rigidity of the neck muscles. Meningeal signs may occur with increased spinal fluid pressure, and nuchal rigidity may be a manifestation of cerebellar tonsillar (foramen magnum) herniation. Meningeal irritation may also cause resistance to movement of the legs and back, with the patient lying with legs drawn up and resisting passive extension.

Kernig’s Sign

There is some variability in the descriptions of how to elicit a Kernig’s sign. Kernig described an involuntary flexion at the knee when the examiner attempted to flex the hip with the knee extended. The more common method is to flex the hip and knee to right angles and then attempt to passively extend the knee; this movement produces pain, resistance, and inability to fully extend the knee. Another definition of Kernig’s sign is inability to extend the knee to over 135 degrees while the hip is flexed (Figure 52.2). There is some overlap between Kernig’s sign and Lasègue’s (straight leg raising) sign. The technique is similar, but Lasègue’s sign is used to check for root irritation in lumbosacral radiculopathy (see Chapter 47). Both Kernig’s sign and straight leg raising are positive in meningitis because of diffuse inflammation of the nerve roots and meninges, and positive with acute lumbosacral radiculopathy because of focal inflammation of the affected root. In radiculopathy, the signs are usually unilateral, but in meningitis they are bilateral.

FIGURE 52.2 Method of eliciting Kernig’s sign.

Brudzinski’s Neck Sign

Placing one hand under the patient’s head and flexing the neck while holding down the chest with the other hand causes flexion of the hips and knees bilaterally (Figure 52.3). With severe meningismus, it may not be possible to hold the chest down, and the patient may be pulled into a sitting position with only the examiner’s hand behind the head. Occasionally, there may be extension of the hallux and fanning of the toes, and sometimes arm flexion. The leg may fail to flex on one side when meningeal irritation and hemiplegia coexist. The three tests, straight leg raise, Kernig’s, and Brudzinski’s, can quickly be done in that order.

FIGURE 52.3 Brudzinski’s sign. Flexing the neck causes the knees to flex.

Other Meningeal Signs

Jolt accentuation refers to an exacerbation of headache induced by quick, horizontal head rotations at two or three times per second. The 1999 rational clinical examination review concluded that in patients with fever and headache, jolt accentuation is a useful adjunct, with a sensitivity of 100%, specificity of 54%, positive likelihood ratio of 2.2, and negative likelihood ratio of 0 for the diagnosis of meningitis, but subsequent investigations have been less enthusiastic.

To avoid spinal flexion, the patient with meningitis may sit in bed with the hands placed far behind, the head thrown back, the hips and knees flexed, and the back arched (Amoss’s, Hoyne’s, or tripod sign). Other meningeal signs are summarized in Table 52.1. Brudzinski described several signs of meningeal inflammation in patients with tuberculous meningitis that likely reflected involvement of the parenchyma more than the meninges.

TABLE 52.1 Miscellaneous Neurologic Signs

Signs of Tetany

The clinical manifestations of tetany include spasm and tonic contractions of the skeletal muscles, principally the distal muscles of the extremities. There may be carpopedal spasm, with tonic contraction of the muscles of the wrists, hands, fingers, feet, and toes (see Chapter 30). There is hyperexcitability of the entire peripheral nervous system, as well as the musculature, to even minimal stimuli. Sensory nerve involvement may cause paresthesias in the hands, feet, and perioral region. Tetany is related to hypocalcemia, hypomagnesemia, or alkalosis. Either hypocalcemia or alkalosis causes a decrease in the ionized calcium level. Certain neurologic signs may be present that aid in making a diagnosis on the basis of the clinical examination alone. They are more easily obtained if the patient first hyperventilates for a few minutes (latent tetany). Severe tetany may cause seizures, laryngospasm, stridor, and respiratory arrest.

Chvostek’s Sign

Tapping over the facial nerve causes a twitch, spasm, or tetanic, cramp-like contraction of some or all of the ipsilateral facial muscles (Table 16.2). Two points of stimulation have been described: just below the zygomatic process of the temporal bone, in front of the ear (Chvostek’s sign), and midway between the zygomatic arch and the angle of the mouth (Schultz’s sign). Sometimes, the response may be elicited merely by stroking the skin in front of the ear. The sign is minimal if only a slight twitch of the upper lip or the angle of the mouth results, moderate if there is movement of the ala nasi and the entire corner of the mouth, and maximal if the muscles of the forehead, eyelid, and cheek also contract (see Video Link 52.1). When the response is marked, even muscles supplied by the trigeminal nerve may respond. Chvostek’s sign is the result of a hyperexcitability of the motor nerves, in this instance the facial nerve, to mechanical stimulation. It is an important sign in tetany but may occur in other conditions in which there is hyperreflexia, such as in lesions of the corticospinal tract, and in children with epilepsy. It is present in a majority of neonates and disappears during childhood.

Chvostek’s sign is elicited by percussing over the pes anserinus. The motor Tinel’s sign has been reported as evidence of abnormal mechanosensitivity in entrapment neuropathies but may also occur in normals. Both Chvostek’s sign and the Lust peroneal phenomenon (Table 52.2) are probably examples of a motor Tinel’s sign.

TABLE 52.2 Other Signs of Tetany

Trousseau’s Sign

Ischemia of the peripheral nerve trunks increases nerve excitability and causes spontaneous discharges. Compression of the arm by manual pressure, a tourniquet, or a sphygmomanometer cuff is followed first by distal paresthesias that progress centripetally, then by twitching of the fingers, and finally by cramping and contraction of the muscles of the fingers and hand with the thumb strongly adducted and the fingers stiffened, slightly flexed at the metacarpophalangeal joints, and forming a cone clustered about the thumb (obstetrician’s or accoucheur’s hand, main d’accoucheur, Figure 52.4, see Video Link 52.2). There may be a latent period of 1/2 to 4 minutes. Similar pressure around the leg or thigh will cause pedal spasm. A modification is to keep a moderately inflated sphygmomanometer cuff on one arm for about 10 minutes and then remove it and have the patient hyperventilate; typical tetanic spasm occurs earlier in the previously ischemic arm. Trousseau’s sign is more specific than Chvostek’s sign for latent tetany. As many as 4% of healthy controls may have a positive Trousseau’s sign; its sensitivity is unknown, but it can be absent in patients with definite hypocalcemia.

FIGURE 52.4 Trousseau’s sign in hypocalcemia. The wrist and metacarpophalangeal joints are flexed, the interphalangeal joints are hyperextended, and the thumb is opposed.

Other signs of tetany are reviewed in Table 52.2.

Video Links

Video Link 52.1. Chvostek’s sign. https://www.youtube.com/watch?v=kvmwsTU0InQ

Video Link 52.2. Trousseau’s sign. https://www.youtube.com/watch?v=kvmwsTU0InQ

Bibliography

Afhami S, Dehghan Manshadi SA, Rezahosseini O. Jolt accentuation of headache: can this maneuver rule out acute meningitis? BMC Res Notes 2017;10:540.

Agarwal KS, Baijal N, Tiwari L, et al. Swan-neck sign of the big toe–association with hypocalcaemia. Trop Doct 2007;37:238–239.

Athappan G, Ariyamuthu VK. Images in clinical medicine. Chvostek’s sign and carpopedal spasm. N Engl J Med 2009;360:e24.

Attia J, Hatala R, Cook DJ, et al. The rational clinical examination. Does this adult patient have acute meningitis? JAMA 1999;282:175–181.

Forgie SE. The history and current relevance of the eponymous signs of meningitis. Pediatr Infect Dis J 2016;35:749–751.

Kamalanathan S, Balachandran K, Parthan G, et al. Chvostek’s sign: a video demonstration. BMJ Case Rep 2012;2012. pii: bcr2012007098.

Méneret A, Guey S, Degos B. Chvostek sign, frequently found in healthy subjects, is not a useful clinical sign. Neurology 2013;80:1067.

Montagna P, Liguori R. The motor Tinel sign: a useful sign in entrapment neuropathy? Muscle Nerve 2000;23:976–978.

Nakao JH, Jafri FN, Shah K, et al. Jolt accentuation of headache and other clinical signs: poor predictors of meningitis in adults. Am J Emerg Med 2014;32:24–28.

Narayan SK, Sivaprasad P, Sahoo RN, et al. Teaching video NeuroImage: Chvostek sign with Fahr syndrome in a patient with hypoparathyroidism. Neurology 2008;71:e79.

Rehman HU, Wunder S. Trousseau sign in hypocalcemia. CMAJ 2011;183:E498.

Uchihara T, Tsukagoshi H. Jolt accentuation of headache: the most sensitive sign of CSF pleocytosis. Headache 1991;31:167–171.