Acquired metabolic disorders of the nervous system

Acquired metabolic disorders of the nervous systemMarianne Sajulga-Macias, MDClassification of the acquired metabolic disorders of the nervous system in adultsPresenting as a syndrome of confusion, stupor or coma ischemia-hypoxia hypercapnia hypoglycemia hyperglycemia hepatic failure reye syndrome azotemia disturbance of sodium, water balance & osmolality acidosis due to DM or renal failure Hashimotos disease myxedemaPresenting as a progressive extrapyramidal symptoms acquired hepatocerebral degeneration hyperbilirubinemia & kernicterus hypoparathyroidismPresenting as cerebellar ataxia hypothyroidism hyperthermia celiac sprue diseasePresenting as psychosis or dementia Cushing disease & steroid encephalopathy hyperthyroid psychosis & hypothyroidism hyperparathyroidism pancreatic encephalopathy Ischemic hypoxic encephalopathyBasic disorder is a lack of O2 and of blood flow to the brain, the result of failure of the heart and circulation or of the lungs and respirationMedical conditions that most often lead to it are:Global reduction in cerebral blood flowMIVentricular arrhythmiaAortic dissectionExternal or internal blood lossSeptic/traumatic shockHypoxia from suffocationDrowningStrangulationAspiration of vomitus, food or bloodCompression of the trachea by a mass or hemorrhageTracheal obstruction by a foreign bodyGeneral anesthesia accidentIschemic hypoxic encephalopathyMedical conditions that most often lead to it are:Diseases that paralyze the respiratory musclesGBSALSMyasthenia gravisDamages to the medulla and leads to failure of breathingCO poisoningIschemic hypoxic encephalopathyPhysiology of ischemic and hypoxic damageAutoregulationThere is compensatory dilatation of resistance vessels in response to a reduction in cerebral perfusion, which maintains blood flow at a constant rate

Ischemic hypoxic encephalopathyTransient ischemia incomplete infarctions in the border zones between major cerebral arteriesPredominant anoxia neurons in portions of hippocampus and deep folia of the cerebellum are vulnerableSevere anoxia and hypoxia generalized damage of the cerebral cortex, deep nuclei and cerebellumNuclear structures of the brainstem and spinal cordResistant to anoxia and hypotension and stop functioning only after the cortex has been damaged

Ischemic hypoxic encephalopathyClinical features of anoxic encephalopathy Mild degree of hypoxia without LOCInattentivenessPoor judgmentIncoordinationDegree of hypoxia that at no time abolish consciousness rarely, if ever, cause permanent damage to the nervous systemSevere global ischemia with prolonged LOCRecovery can be complete if breathing, airway and circulation are restored within 3-5 minutesBeyond 5 minutes, there is usually permanent damageBrain death syndromeMost severe degree of hypoxia, usually caused by circulatory arrest Complete unawareness and unresponsiveness with abolition of all brainstem reflexes

Posthypoxic neurologic syndromesPersistent coma or stuporDementia with or without extrapyramidal signsExtrapyramidal syndrome with cognitive impairmentChoreoathetosisCerebellar ataxiaIntention or action myoclonusAn amnesic state

Posthypoxic neurologic syndromesTwo watershed syndromesVisual agnosias including Balint syndrome (optic ataxia, psychic paralysis of gaze, simultagnosia) and cortical blindnessProximal arm and shoulder weakness sometimes accompanied by hip weakness (man in a barrel)

Prognosis of hypoxic ischemic brain injuryAccording to Levy et al:13% - attained a state of independent function within one year25% of patients on admission has absent pupillary light reflex none of them regained independence10% - on admission has PLR, eye movements, motor response better prognosisBooth & colleagues, 5 clinical signs at 1 day after cardiac arrest predicted a poor neurologic outcome or death:Absent corneal reflexAbsent PLRNo withdrawal to painAbsence of any motor responsetreatment of hypoxic ischemic brain injuryClear airwayCardiopulmonary resuscitationHypothermiaHypothermia After Cardiac Arrest Study GroupReduce the core temperature to 33C within 2H of the arrest and sustained this level for 12 hours in the first trial and between 32C and 34C for 24hours in the second studyBoth trials demonstrated improved survival and better cognitive outcome in survivorsControl seizureMyoclonusClonazepam 8-12mg daily in divided dosesHypoglycemic encephalopathyEssential biochemical abnormality is critical lowering of the blood glucoseGlucose ~ 30mg/dl confusional state and seizureGlucose ~ 10mg/dl comaNormal brain has a reserve of 1-2gm (30mmol/100gm of brain tissue) in the form of glycogenMost common cause:Accidental or deliberate overdose of insulin or diabetic agentIslet cell insulin secreting pancreatic tumorDepletion of the liver glycogenGlycogen storage disordersHypoglycemic encephalopathyGlucose ~30mg/dlNervousness, hunger, flushed facie, sweating, headache, palpitation, trembling, anxietyGlucose < 10mg/dlDeep coma, dilatation of pupils, shallow respiration, slow pulse, hypotoniaEEG diffuse slowing in the theta or delta rangeUremic encephalopathyClinical manifestation:Apathy, fatigue, inattentiveness, irritabilty usually the initial symptomsLater, there is confusion, dysarthria, tremor and asterixisEEG : diffusely and irregularly slow and may remain for several weeksImprovement of symptoms may not be evident for a day or after institution of dialysisClassification of the acquired metabolic disorders of the nervous system in adultsPresenting as a syndrome of confusion, stupor or coma ischemia-hypoxia hypercapnia hypoglycemia hyperglycemia hepatic failure reye syndrome azotemia disturbance of sodium, water balance & osmolality acidosis due to DM or renal failure Hashimotos disease myxedemaPresenting as a progressive extrapyramidal symptoms acquired hepatocerebral degeneration hyperbilirubinemia & kernicterus hypoparathyroidismPresenting as cerebellar ataxia hypothyroidism hyperthermia celiac sprue diseasePresenting as psychosis or dementia Cushing disease & steroid encephalopathy hyperthyroid psychosis & hypothyroidism hyperparathyroidism pancreatic encephalopathy Hepatocerebral degenerationPatients who survive an episode of hepatic comaClinical featuresTremor of the head and armAsterixisGrimacingChoreic movementsTwitching of the limbsDysarthriaImpairment of intellectual function imaging: gliosis of both cerebral hemisphere and the lenticular nuclei