Examination discloses varying degrees of motor, sensory, and reflex loss. As the symptoms suggest, the signs are symmetrical, and more severe in distal than in proximal portions of the limbs, and often confined to the legs. In some cases, the disproportionate affection of motor power may be striking, taking the form of a footand wrist-drop, but the proximal muscles are usually affected as well (indicated, for example, by climbing stairs or by difficulty in arising from a squatting position). In a few patients, the weakness appears to be most severe in the proximal muscles. Absolute paralysis of the legs had been observed in the past only rarely; immobility caused by contractures at the knees and ankles in neglected patients was a more common occurrence. Tenderness of muscles on deep pressure is a highly characteristic finding, elicited most readily in the muscles of the feet and calves. In the arms, tendon reflexes are sometimes retained despite a loss of strength in the hands. In patients in whom pain and dysesthesias are prominent and motor loss is slight, the reflexes at knee and ankle may be retained or even of greater than average briskness. This attests to the predominant affection of the small nerve fibers.
Excessive sweating of the soles and dorsal aspects of the feet and of the volar surfaces of the hands and fingers is a common manifestation of alcohol-induced nutritional neuropathy. Postural hypotension is also sometimes associated, indicative of involvement of the peripheral sympathetic nerve fibers.
Sensory loss or impairment may involve all the modalities, although one may be affected out of proportion to the others, usually pain and temperature. One cannot predict from the patient’s symptoms which mode of sensation might be affected disproportionately. In patients with impairment of superficial sensation (i.e., touch, pain, and temperature), the border between impaired and normal sensation is not sharp but shades off gradually over a considerable vertical extent of the limbs.
Patients in whom pain is the outstanding symptom do not constitute a distinct group in terms of their neurologic signs. Pain and dysesthesias may be prominent in patients with either severe or slight degrees of motor, reflex, and sensory loss. The term hyperesthetic is used commonly to designate the exquisitely painful form of neuropathy but is not well chosen; as pointed out in Chap. 7, one is usually able, by using finely graded stimuli, to demonstrate an elevated threshold to painful, thermal, and tactile stimuli in the “hyperesthetic” zone. Once the stimulus is perceived, however, it has a painful and diffuse, unpleasant quality (hyperpathia). Tactile evocation of pain or burning is an example, as mentioned, of allodynia.
In most patients with nutritional polyneuropathy, only the limbs are involved and the abdominal, thoracic, and bulbar muscles are usually spared; however, we have encountered 2 cases in which there was sensory loss in the pattern of an escutcheon over the anterior thorax and abdomen. In the most advanced instances of neuropathy, hoarseness and weakness of the voice and dysphagia as a result of degeneration of the vagus nerves may be added to the clinical picture.
Some idea of the incidence of the motor, reflex, and sensory abnormalities and the combinations in which they occur can be obtained from Table 40-1, which is based on Victor’s (1984) examination of 189 nutritionally depleted alcoholic patients. Noteworthy is the fact that only 66 (35 percent) of the 189 patients showed the clinical picture of polyneuropathy in its entirety, that is, a symmetrical impairment or loss of tendon reflexes, sensation, and motor power affecting legs more than the arms and the distal more than the proximal segments of the limbs. In the remaining patients, the motor-reflex-sensory signs occurred in various combinations.