Wernicke Encephalopathy Clinical Presentation

The 3 components of the classic triad of Wernicke encephalopathy are encephalopathy, ataxic gait, and some variant of oculomotor dysfunction. All 3 features of the triad are recognized in only about one third of cases.

Consideration for Wernicke encephalopathy should be given to patients with any evidence of long-term alcohol abuse or malnutrition and any of the following: acute confusion, ataxia, ophthalmoplegia, memory disturbance, hypothermia with hypotension, and delirium tremens.

A high proportion of patients with acute Wernicke encephalopathy who survive develop Korsakoff psychosis, also called Korsakoff syndrome, characterized by potentially irreversible retrograde amnesia (inability to recall information) and anterograde amnesia (inability to assimilate new information), with varying degrees of other cognitive deficits.^[11]

Wernicke encephalopathy should be considered when any patient with long-term malnutrition presents with confusion or altered metal status. Significant overlap exists between Wernicke encephalopathy and Korsakoff psychosis. For this reason, the two entities have been described together as Wernicke-Korsakoff syndrome.

Alcohol abuse, AIDS, malignancy, hyperemesis gravidarum, prolonged total parenteral nutrition, iatrogenic glucose loading in any predisposed patient, and other disorders associated with grossly impaired nutritional status have been associated with Wernicke-Korsakoff syndrome.

Bariatric surgery

More than 100,000 weight-loss procedures are performed annually in the United States alone, and the numbers are rising. Post ̶ bariatric surgery patients have a limited capacity for food intake during the initial weeks after a bariatric procedure. The body's reserves of thiamine can be depleted after only 20 days of inadequate supply. Therefore, post ̶ bariatric surgery patients may still be frankly obese when presenting with Wernicke encephalopathy symptoms caused by thiamine deficiency.^[8]

Ocular abnormalities are the hallmarks of Wernicke encephalopathy. The oculomotor signs are nystagmus, bilateral lateral rectus palsies, and conjugate gaze palsies reflecting cranial nerve involvement of the oculomotor, abducens, and vestibular nuclei. Less frequently noted are pupillary abnormalities such as sluggishly reactive pupils, ptosis, scotomata, and anisocoria. The most common ocular abnormality is nystagmus, not complete ophthalmoplegia.^[5]

Encephalopathy is characterized by a global confusional state, disinterest, inattentiveness, or agitation. The most constant symptoms of Wernicke encephalopathy are the mental status changes.^[5] Stupor and coma are rare.

Gait ataxia is often a presenting symptom.^[7] Ataxia is likely to be a combination of polyneuropathy, cerebellar damage, and vestibular paresis. Vestibular function, usually without hearing loss, is universally impaired in the acute stages of Wernicke encephalopathy. In less severe cases, patients walk slowly with a broad-based gait. However, gait and stance may be so impaired as to make walking impossible. Cerebellar testing in bed with finger-to-nose and heel-to-shin tests may not illicit any notable deficit; thus, it is important to test for truncal ataxia with the patient sitting or standing.^[11]

In addition to ophthalmoplegia and ataxia, 80% of adults will have some degree of peripheral neuropathy, which may include weakness, foot drop, and decreased proprioception.

Thiamine deficiency has recently been shown to possibly cause a gastrointestinal syndrome of nausea, vomiting, abdominal pain, and lactic acidosis.^[3]

Other symptoms that may occur in addition to, or in place of, the classic triad include hypothermia, hypotension, and coma.^[11] Thiamine deficiency often affects the temperature-regulating center in the brainstem, which can result in hypothermia.

Hypotension can be secondary to thiamine deficiency either through cardiovascular beriberi or thiamine deficiency–induced autonomic dysfunction.^[7] Coma is rarely the sole manifestation of Wernicke encephalopathy.

Of patients surviving Wernicke encephalopathy, an important percentage have Korsakoff psychosis, characterized by the following: retrograde amnesia (inability to recall information), anterograde amnesia (inability to assimilate new information), decreased spontaneity and initiative, and confabulation.

Other manifestations of thiamine deficiency involve the cardiovascular system (wet beriberi) and peripheral nervous system (nutritional polyneuropathy).

Manifestations of thiamine deficiency in infants are constipation, agitation, apathy, vomiting, lack of appetite, and later, diarrhea, grunting, nystagmus, convulsions, unconsciousness, and cardiomyopathy.^[2]