Metabolic Encephalopathies Flashcards
Metabolic Encephalopathy
-subacute onset of a confusional state marked by fluctuating, alterations of consciousness, that progressively worsens if untreated
Metabolic Encephalopathy: Pathophysiology
- diverse mechanisms lead to diffuse involvement of all brain structures
- permanent brain injury can usually be avoided by prompt diagnosis & treatment
Metabolic Encephalopathy: Evaluation Strategy
-1st identify that the patient suffers from a metabolic encephalopathy, then clarify & treat the etiologic diagnosis
Metabolic Encephalopathy: SIgns/Symptoms
- acute alteration of consciousness/mental status
(arousal: inc. delirium, dec. lethargy, stupor, coma)
(content: dec. attention, orientation & memory, cognition & HIF, inc, hallucinations, delusions) - seizures
- altered respiration (hypo/hyperventilation)
- altered pupil light reactivity
- altered ocular motility
- altered motor activity
Non-chemical Encephalopathy Permanent?
more than chemical
Wernicke/Korsakoff Encephalopathy
-Alcoholics, Malnutrition
-Ophthalmoparesis
-Ataxia
-Confusion
-Amnesia
-Peripheral Neuropathy
-dorsomedial thalamus/mamillary body/periaqueductal gray atrophy & petechial
hemorrhage
-transketolase dec (90-140 mgm)
-thiamine before a glucose load
Wet Beriberi
-B1 deficiency, high output cardia failure
Dry Beriberi
- B1 deficiency
- polyneuropathy, lower limbs > upper limbs, Pain & touch decrease/paresthesia, loss of ankle & knee reflex, axonal degeneration
Pellagra
- Niacin Deficiency
- uncommon
- causes dementia & polyneuropathy
- diffuse involvement of CNS & PNS neurons
B6 (Pyridoxine) Deficiency
- causes polyneuropathy in adults
- causes seizures during infancy
B12 Deficiency
Cause: pernicious anemia, fish tapeworm, gastric cancer, veg. diet, bariatric surgery, sprue, NO abuse
- subacute combined degeneration
- dec. vibration/postion sense (+ Romberg sign)
- Lhermitte’s sign, (electric-like sensation upon neck flexion), distal paresthesias, weakness, spastic gait with hyperreflexia or hyporeflexia, visual imparment, confusion, dementia, depression
B12 Deficiency: Pathology Lab Treat
- demyelination of dorsal columns, corticospinal tracts, cerebral white matter, optic nerves, peripheral nerves
- Blood Smear, low normal B12, inc. methylmalonic acid & homocysteine levels
- treatment: treat etiology, cyanocobalamin weekly & then monthly
Deficiency Amblyopia B Complex Deficiencies
- Lesion: optic nerve, papillomacular bundle
- Bilateral & mostly symmetrical
- visual acuity dec/blindness
- central or centrocecal scotoma: for color
- optic disc pallor
- Pathology: loss of myelin/axon
- tobacco/alcohol amblyopia
Diabetes
- small vessel disease in brain with lacunar infarctions
- Argyll Robertson pupil
- ophthalmoparesis and diplopia
- compressive nerve syndromes
Hypoglycemia
-confusion/coma
-seizures
-pupiles dilated
-reflexes brisk
-Babinskis’ extensor
-blood sugar low
IV glucose response
Hyperglycemia
- confusion/coma
- seizures +/-
- pupils small
- ref. dec
- Babinskis flexor
- blood sugar high
- acetone +/-
- no IV glucose response
Diabetic Neuropathy
- sensory polyneuropathy
- autonomic neuropathy
- diabetic ophthalmoplegia
- diabetic mononeuritis
- mononeuritis multiplex
- diabetic amyotrophy
Hypoxia Encephalopathy
- watershed areas b/w arteries
- hippocampus
- deep foli of cerebellum
Features (drowsiness, EEG slow, seizures, myoclonus, amnesia after recovery)
Causes of Hypoxia
- cardiac arrest
- CO poisoning
- inc. altitude sickness
- COPD/CO2 narcosis
Posthypoxia Syndrome
- persistent coma/vegetative
- dementia/amnesia
- parkinson’s syndrome
- myocionus
Chronic Hepatic Disease with Encephalopathy
-concusion, seizures, slow EEG with triphasic waves, peripheral asterixis, myoclonus
(polyneuropathy - alcholic liver disease)
-brisk reflex
Uremic Encephalopathy
- memory deficits & dementia
- encephalopathy with confusion, seizures
- myoclonus
- dysequilibrium syndrome with dialysis & inc. tendency for bleeds intracranially
- asterixis with flapping tremor
- peripheral neuropathy, proximal muscle weakness, low Ca levels
Metabolic Encephalopathy: Toxin
- organic chemicals
- Heavy metals (As, Mn, Hg, Al)
- plant poisons (peyote, mushrooms)
- animal poisons (domoic acid)
Metabolic Encephalopathy: Endocrine
-hypo/hyperthyroidism, parathyroidism, glycemia, adrenocoriticsm
