Differentials
Alcohol intoxication
SIGNS / SYMPTOMS
A high blood alcohol level can confirm alcohol intoxication but does not exclude coexistent Wernicke encephalopathy, because the clinical symptoms and signs overlap.
INVESTIGATIONS
Blood alcohol level >100 mg/dL in alcohol intoxication.
Alcohol withdrawal
SIGNS / SYMPTOMS
Patients with delirium tremens present with tachycardia, hypertension, agitation, diaphoresis, mydriasis, hallucinations, and seizures.
INVESTIGATIONS
This is a clinical diagnosis; there are no specific differentiating tests.
Viral encephalitis
SIGNS / SYMPTOMS
Patients typically present with any combination of cognitive impairment, altered sensorium, seizures, fever, or focal neurologic deficits.
INVESTIGATIONS
Cerebrospinal fluid (CSF) typically shows a pleocytosis and elevated CSF protein.
In certain viral encephalitides, abnormal MRI and EEG findings help distinguish them from Wernicke encephalopathy.
Miller Fisher syndrome
SIGNS / SYMPTOMS
Patients typically present with ophthalmoplegia, ataxia, and reduced or absent reflexes.
Mental status is rarely affected in this condition unless complications of respiratory failure or autonomic insufficiency ensue.
It is usually preceded by a viral illness.
INVESTIGATIONS
AntiGQ1b or antiGT1b antibodies are positive in serum, and cerebrospinal fluid analysis shows cyto-albuminologic dissociation. Nerve conduction studies may show evidence of axonal loss and prolonged F waves.
Bickerstaff brainstem encephalitis
SIGNS / SYMPTOMS
Patients typically present with diplopia, ataxia, and altered sensorium.
INVESTIGATIONS
MRI shows high intensity T2 abnormalities in the brainstem, cerebellum, and thalamus. AntiGQ1b antibodies are positive in serum. Cerebrospinal fluid shows elevated protein and a lymphocytic pleocytosis.
Top of the basilar syndrome (paramedian thalamic infarction) or deep cerebral venous thromboses
SIGNS / SYMPTOMS
Patients present with acute onset of neurologic deficits that are typically maximal at onset. The symptoms and signs can mimic those of Wernicke encephalopathy.
INVESTIGATIONS
MRI with diffusion accompanied by angiographic evidence of vascular occlusion in a person with vascular risk factors helps distinguish this from Wernicke encephalopathy.
Primary central nervous system lymphoma
SIGNS / SYMPTOMS
In some patients, primary central nervous system (CNS) lymphoma has a predilection to spread along periventricular pathways, and its clinical manifestations may mimic those of Wernicke encephalopathy.
INVESTIGATIONS
Cerebrospinal fluid analysis may show positive cytology, flow cytometry, or positive Epstein-Barr virus viral polymerase chain reaction. The typical lesions of Wernicke encephalopathy are symmetric; CNS lymphoma is typically asymmetric with accompanying necrosis.
Toxic encephalopathies
SIGNS / SYMPTOMS
Unless there is a witness to the intoxication, or the patient is known to have access to offending medications or toxins, the presenting symptoms and signs are difficult to distinguish from those of Wernicke encephalopathy.
Offending drugs and toxins include phenytoin, aspirin, carbamazepine, phenobarbital, benzodiazepines, methyl bromide, methanol, ethylene glycol.
INVESTIGATIONS
A urine drug and volatile toxicology screen should be done in all patients presenting with altered sensorium in whom a clear etiology is not identified after initial evaluation.
Metabolic encephalopathies
SIGNS / SYMPTOMS
Hepatic and uremic encephalopathies can cause varying degrees of cognitive dysfunction.
INVESTIGATIONS
A comprehensive metabolic panel, blood gas analyses, and serum ammonia can help distinguish metabolic encephalopathies from Wernicke encephalopathy.
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