Don’t seek, don’t find: The diagnostic challenge of Wernicke’s encephalopathy

Abstract

Wernicke’s encephalopathy is caused by thiamine deficiency and has a range of presenting features, including gait disturbance, altered cognitive state, nystagmus and other eye movement disorders. In the past, Wernicke’s encephalopathy was described almost exclusively in the alcohol-dependent population. However, in current times, Wernicke’s encephalopathy is also well recognized in many other patient groups, including patients following bariatric surgery, gastrointestinal surgery, cancer and pancreatitis. Early recognition of Wernicke’s encephalopathy is vital, as prompt treatment can restore cognitive or ocular function and can prevent permanent disability. Unfortunately, Wernicke’s encephalopathy is often undiagnosed – presumably because it is relatively uncommon and has a variable clinical presentation. Clinical biochemists have a unique role in advising clinicians about potential nutritional or metabolic causes of unexplained neurological symptoms and to prompt consideration of thiamine deficiency as a potential cause in high-risk patient groups. The aim of this review is to summarize the clinical features, diagnosis and treatment of Wernicke’s encephalopathy and to highlight some non-traditional causes, such as after bariatric surgery.

Wernicke Encephalopathy in an Elderly Patient Due to Chronic Malnutrition From an Atypical Diet

“…Ocular findings can include nystagmus and conjugate gaze palsies due to the involvement of the oculomotor, abducens, and vestibular nuclei. The incidence of WE in the general population is approximately 0.4 to 2.8% compared to 12.5-35.0% in alcohol-dependent individuals [2,3,4]. Overall the prevalence ranges from 1 to 3% worldwide [5].…”

“…Although classically associated with alcohol dependence, WKS can occur in a vast range of medical conditions including severe malnutrition, AIDS and other immunodeficiency syndromes, hyperemesis gravidarum, acute pancreatitis, inflammatory bowel disease, malignancy, thyrotoxicosis, liver disease, and as a consequence of bariatric surgery and total parenteral nutrition [5,6]. The epidemiology of non-alcoholic associated WKS differs from that of the alcoholic form with an increased incidence in females (1.84:1), younger age of onset, shorter duration of precipitating illness, higher association with ocular disturbances rather than gait disturbance, and favorable morbidity and mortality outcomes [2,4].…”

“…Thiamine deficiency is the primary cause of WKS and may also cause other conditions such as 'Wet' and 'Dry' Beriberi, which affect the cardiovascular and neurological systems, respectively [4,7]. Thiamine (Vitamin B₁ is a water-soluble vitamin that cannot be endogenously synthesized by humans and must be obtained via dietary sources such as beef, poultry, cereals, nuts, and beans.…”

“…Therefore, conditions that predispose individuals to inadequate intake or malabsorption have been implicated in thiamine deficiency and the subsequent onset of WKS in a subset of these patients. Thiamine deficient and devoid states can deplete total body stores in as little as 18 days to up to 6 weeks [4,8]. In order to maintain total body thiamine reserves at 30-50 mg, the recommended daily intake of thiamine for adult men and women is 1.2 and 1.1 mg, respectively, and 1.4 mg during pregnancy and breastfeeding.…”

“…Thiamine predominantly exists in its bioactive form thiamine pyrophosphate (TPP, also called thiamine diphosphate) before undergoing hydrolysis to free thiamine and absorption in the jejunum [4,7,8]. After carrier-mediated transport across intestinal epithelia, free thiamine may enter erythrocytes and undergo rephosphorylation to TPP via cytoplasmic thiamine pyrophosphokinase [7].…”