# Wernicke’s encephalopathy is due to the deficiency of:
A. Thiamine
B. Vitamin B12
C. Niacin
D. Vitamin B2
The correct answer is A. Thiamine.
■ Thiamine deficiency in its early stage induces anorexia and nonspecific symptoms (e.g., irritability, decrease in short-term memory).
■ Prolonged thiamine deficiency causes beriberi, which is classically categorized as wet or dry, although there is considerable overlap. In either form of beriberi, patients may complain of pain and paresthesia.
■ Wet beriberi presents primarily with cardiovascular symptoms due to impaired myocardial energy metabolism and dysautonomia and can occur after 3 months of a thiamine deficient diet. Patients present with an enlarged heart, tachycardia, high-output congestive heart failure, peripheral oedema and peripheral neuritis.
■ Patients with dry beriberi present with asymmetric peripheral neuropathy of the motor and sensory systems with diminished reflexes. The neuropathy affects the legs most markedly, and these patients have difficulty rising from a squatting position.
■ Alcoholic patients with chronic thiamine deficiency also may have central nervous system (CNS) manifestations known as Wemicke's encephalopathy, consisting of horizontal nystagmus, ophthalmoplegia (due to weakness of one or more extraocular muscles), cerebellar ataxia, and mental impairment.
