Download Clinical syndromes and alcohol misuse - Wk 1-2

Clinical syndromes and alcohol misuse
1. Describe the clinical features of Wernicke-Korsakoff syndrome
Thiamine (vitamin B1) deficiency may result in the slowly evolving clinical disorder beriberi, which
is associated with cardiac failure or neurological damage. In certain affected individuals, thiamine
deficiency may also lead to the development of psychotic symptoms or ophthalmoplegia, a syndrome
termed Wernicke Encephalopathy. This organic brain disorder results from damage primarily to the
mamillary bodies, dorsomedial nuclei of the thalamus and adjacent areas of grey matter:
 Hypothalamus: Which regulates body temperature, growth and appetite and has a role in
emotional response. It also controls pituitary functions including metabolism and hormones).
 Mamillary Bodies: involved in processing of recognition memory functions.
Without prompt treatment the acute presentation of Wernicke Encephalopathy can progress to the
irreversible deficits of Korsakoff’s syndrome, characterised clinically by memory disturbances and
confabulation. Because the two terms are closely linked, the term Wernicke-Korsakoff syndrome is
often applied.
Clinical Features:
Beri Beri:
 Wet Beri Beri: causes generalised oedema due to biventricular heart failure with pulmonary
congestion.
 Dry Beri Beri: displays with chronic peripheral neuropathy and/or foot drop, and may progress
to Wernicke-Korsakoff syndrome.
Wernicke’s Encephalopathy:
 Nystagmus: Involuntary, rapid, rhythmic movement of the eyeball.
 Ophthalmoplegia: Paralysis of one or more extraocular muscles
 Ataxia: Lack of muscle co-ordination, unsteady gait, tremor, Fine motor functions
 Confusion, Headache, Vomiting
 Apathy & Agitation: Individuals often appear apathetic and inattentive
Korsakoff’s Syndrome:
 Amnesia: A permanent gap in memory
 Confabulation: Make up or invent information to compensate for poor memory.
 Impaired Learning: Of new information or tasks.
 Macrocytic anaemia
2. Outline the range of multiple causative factors - psychological, genetic, environmental involved in the syndrome.
The metabolically active form of thiamine is thiamine diphosphate which plays a major role as a
cofactor in glucose metabolism. The enzymes which are dependent on thiamine diphosphate are
associated with the TCA Cycle. Thus, anything that encourages glucose metabolism will exacerbate
an existing clinical or sub-clinical thiamine deficiency. In individuals with sub-clinical thiamine
deficiency, a large dose of glucose (either as sweet food, etc. or glucose infusion), can precipitate the
onset of overt encephalopathy.
With reduced ATP-generation due to metabolising glucose via the anaerobic pathway, the brain is
starved of energy and its nerves demyelinated due to buildup of lactic acid.
Environmental Factors:
Thiamine deificiency can arise as a result of malnutrition - in Australia this is most commonly due to
chronic alcohol abuse and associated poor diet, as an alcoholic obtains enough energy from ethanol
and has a significantly reduced desire to eat. However in other countires thiamine deficiency can be
brought about by severe malnutrition, particularly in diets consisting mainly of polished rice, which is
thiamine deficient. Other causes include malabsorption (gastritis, gastric malignancy, small bowel
resections), protracted vomiting (hyperemesis gravidarum), patients who undergo prolonged
intravenous (IV) therapy without (Vitamin B1) supplementation, frequent haemodialysis.
Psychological Factors:
 Depression: Not eating enough or correctly leads to vitamin deficiency
 Other mental illness that involve psychosis: See above
 Anorexia nervosa
Genetic Factors:
There is some evidence to suggest a genetic disposition to decreased thiamine absorption.
3. Outline the investigation of the Wernicke-Korsakoff syndrome.
Diagnosis of Wernicke-Korsakoff syndrome is by clinical impression and can sometimes be
confirmed with formal Neuropsychological assessment. Wernicke's encephalopathy typically presents
with ataxia and nystagmus, and Korsakoff's psychosis with anterograde and retrograde amnesia and
confabulation upon relevant questioning.
Investigations:
 Physical examination, including neurological and cranial nerve examinations
 BGL, LFT, EUC
 FBC, BAC (nb alcohol is metabolised at 7mg/hr or 100mg/kg body/hr)
 Head CT (trauma) – give contrast (iodide) to highlight vascularity
Prevention of the Wernicke-Korsakoff complex requires immediate use of high doses of thiamine,
which can reverse those in earlier stages. Treatment consists of immediately giving 50 to 100 mg
thiamine IV before administering glucose-containing fluids (in that order, see above). However, the
person's confusion may take some time to subside. This initial intravenous dose is followed by
supplemental oral doses. There is then no treatment for established Korsakoff’s syndrome.