The incidence of the Wernicke-Korsakoff syndrome cannot be stated with precision, but it had been a common disorder as noted in the introductory comments. At the Cleveland Metropolitan General Hospital, for example, in a consecutive series of 3,548 autopsies in adults (for the period 1963 to 1976), our colleague M. Victor (1990) found the pathognomonic lesions in 77 cases (2.2 percent). The disease affects males slightly more often than females and the age of onset is fairly evenly distributed between 30 and 70 years. In the past few decades, the incidence of the Wernicke-Korsakoff syndrome has fallen in the alcoholic population, but it is being recognized with increasing frequency among nonalcoholic patients in a variety of clinical settings that are prone to include malnutrition, including iatrogenic ones.
The triad of clinical features described by Wernicke of ophthalmoplegia (with nystagmus), ataxia, and disturbances of mentation and consciousness is still clinically useful provided that the signs are carefully sought, and one recognizes that all features will not be present. The disease may begin with ataxia, followed in a few days or weeks by mental confusion, or there may be confusion alone, or the more or less simultaneous onset of ataxia, nystagmus, and ophthalmoparesis with or without confusion. In approximately one-third of cases, one component of this triad may be the sole manifestation of the disease. Timely treatment with thiamine can prevent the permanent
Korsakoff-amnesic component of the disease. A schematic representation of the various features is shown in Fig. 40-1, adapted from the series of 131 autopsied proved cases described by Harper et al. The notable aspects are that all 3 of the typical signs were present in only 16 percent; 1 sign in 31 percent, usually confusion alone; 2 signs in 28 percent; and no signs reported or detected during life in 19 percent. A description of each of the major manifestations follows.
Eye movement abnormalities The diagnosis of Wernicke disease is made most readily on the basis of the ocular signs. These consist of (1) nystagmus that is both horizontal and vertical and mainly gaze-evoked, (2) weakness or paralysis of the lateral rectus muscles, and (3) weakness or paralysis of conjugate gaze. Usually there is some combination of these abnormalities (see Chap. 13).
Nystagmus is the most frequent eye movement abnormality seen in Wernicke’s disease, followed in frequency by lateral rectus weakness, which is bilateral but not necessarily symmetrical. With complete paralysis of the lateral rectus muscles, nystagmus is absent in the abducting eyes and it becomes evident as the weakness improves under treatment. The palsy of conjugate gaze varies from merely a paretic nystagmus on extreme gaze to a complete loss of ocular movement in horizontal or vertical movements. Horizonal conjugate gaze palsy is more common than vertical gaze palsy, and isolated paralysis of downward gaze is a known but unusual manifestation. A pattern that simulates internuclear ophthalmoplegia has also been seen. In advanced stages of the disease there may be a complete loss of ocular movements and the pupils, which are otherwise usually spared, may become miotic and nonreacting. Ptosis, small retinal hemorrhages, involvement of the near–far focusing mechanism, and evidence of optic neuropathy occur occasionally, but neither we nor our colleagues have observed papilledema that was included in Wernicke’s original description. These ocular signs are highly characteristic of Wernicke disease and disappearance of nystagmus and an improvement in ophthalmoparesis within hours or a day of the administration of thiamine confirms the diagnosis.