ALCOHOL AND THE NERVOUS SYSTEM

DR M KAKAZA

COMMON COMPLICATIONS

• Nutritional deficiency• Diseases partly nutritional in origin• Direct effects of alcohol• Abnormalities of electrolytes and osmolality• Diseases of uncertain pathogenesis

A. Nutritional Complications

• Wernicke’s Encephalopathy• Korsakoff’s syndrome• Pellagra

1. Wernicke’s Encephalopathy

• Clinical features include:•Confusion•Opthalmoplegia•Ataxia

• MRI features: ( T2, Diffusion-weighted and FLAIR)Signal changes in periaqueductal gray matter, medial thalami and mamillary bodies

Wernicke’s Encephalopathy….

• Treatment:– Thiamine 100mg ivi stat then daily throughout

the acute stageNB alcoholics may have poor intestinal absorption

Wernicke’s Encephalopathy….

• Other causes:– Hyperemesis of pregnancy– Systemic malignancy– GIT surgery– Prolonged iv feeding– Re-feeding after prolonged fast– Anorexia nervosa– Dieting and gastric plication– AIDS

2. Korsakoff’s Syndrome

• Russian Psychiatrist• Wernicke and Korsakoff’s syndrome are

different stages of the same disease process.• Korsakoff’s follows Wernicke’s and tends to

appear as ocular symptoms and encephalopathy improve

Korsakoff’s syndrome….

• Memory is impaired out of proportion to other cognitive functions – Amnestic syndrome

• Have inability to form new memory

Korsakoff’s Syndrome….

•Clinical features:•Memory loss•Confabulation•Alertness, attention, social behavior intact

•Localization of the lesion•Diencephalon•Temporal lobes

3. Pellagra

• Due to Nicotinic acid deficiency• From Italian ‘pelle agra’ which means ‘dry

skin’• Nicotinic acid is converted to NAD and NADP • NAD and NADP are coenzymes required in the

metabolism of carbohydrates

Pellagra…..

• Clinical triad:–Dementia–Dermatitis–Diarrhea

Pellagra….

• Communities that depend on corn for their diet can suffer from pellagra.

• Corn lacks tryptophan, a precursor that can be converted to nicotinic acid in the body.

Pellagra….

• Bread is now enriched with niacin• Treatment:–Nicotinic acid ivi 25mg bd or tds

B. Direct Effects of Alcohol

• Acute intoxication• Fetal alcohol syndrome• Alcohol withdrawal seizures• Delirium tremens

Stages of acute alcohol intoxication

BLOOD LEVEL• 0.01 – 0.05• 0.03-0.12• 0.09-0.25• 0.18-0.30• 0.25-0.40• 0.35-0.50• 0.45+

STAGESubclinicalEuphoriaExcitementConfusionStuporComaDeath

C. Abnormalities of Serum Electrolytes and osmolality

• Hyponatremia• Hypocalcemia• Hypomagnesemia• Hypophosphatemia

Central pontine myelinolysis

D. Diseases at least partly nutritional in origin

• Alcoholic neuropathy• Amblyopia

1 Alcoholic Neuropathy

• Most common complication• Distal symmetrical polyneuropathy• Mixed sensory motor disorder• Pathology – Axonal loss• Pathogenesis:– Direct alcohol neurotoxicity– Thiamine deficiency

2. Amblyopia

• Vision loss caused by a selective lesion of the optic nerves

• History – chronic alcoholic, poor dietary intake, loss of weight

• Most likely due to nutritional deficiency• Treatment – Good nutrition , B vitamins• Prognosis – Improves on treatment (despite

continued drinking)

E. Diseases of uncertain pathogenesis

• Alcoholic myopathy• Alcoholic dementia• Cerebellar degeneration• Marchiafava-Bignami Syndrome

1. Cerebellar Degeneration

• Associated with long-standing use of alcohol• Patients often have neuropathy as well• Presentation –Progressive unsteadiness of gait– Trunkal ataxia

Cerebellar Degeneration….

•Pathological changes:•Selective atrophy of the anterior and

superior parts of the vermis

•Histological changes:•Purkinje’s cells most severely affected

4. Marchiafava-Bignami Syndrome

• Italian pathologists • Described in 1903

• Clinical picture difficultMental slowing, Motor slowing, Personality or behaviour changes, Incontinence, Seizures, Dysarthria and hemiparesis

Marchiafava-Bignami Syndrome….

• Patholological changes:– Selective demyelination of the corpus

callosum