Lead Poisoning and Seizures. Dayna Ryan, PT, DPT Winter 2012. Lead Poisoning. Overview Normal blood lead level is “0” Toxicity is not evident until blood lead levels build up over months or years Toxic threshold is lower in children & pregnant women High levels can be fatal
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Lead Poisoning and Seizures Dayna Ryan, PT, DPT Winter 2012
Lead Poisoning • Overview • Normal blood lead level is “0” • Toxicity is not evident until blood lead levels build up over months or years • Toxic threshold is lower in children & pregnant women • High levels can be fatal • Lesion Site • CNS or PNS • In children: brain (encephalopathy with scattered hemorrhages) • In adults: peripheral myelin or axon (peripheral neuropathy)
Lead Poisoning • Etiology • In children: lead-based paint in old building (prior to 1978) • Contaminated air, water, soil, toys, glazed dishware, imported canned food, cosmetics • Onset • After months of exposure unless large amount • Faster absorption with inhalation
Signs & Symptoms • Muscle weakness that can progress to paralysis • affect UEs more, cause wrist drop • Atrophy of muscles • Tremor • Abnormal DTRs (CNS lesion ↑, PNS lesion↓) • Chronic exposure in children • Mental retardation, learning disabilities • Hyperactivity, behavior problems • Loss of appetite, vomiting, abdominal pain • Unusual paleness from anemia • Sluggishness, fatigue • Fasciculations (twitches)
Lead Poisoning • Diagnosis • Blood test • Slowed motor NCVs • Fibrillation potential on EMG • Prognosis depending on • Length & level of lead exposure • Whether myelin (initial exposure) or axon (prolonged exposure) is damaged • Treatments • Remove the source! • Chelating agents to bindthe lead so that it's excreted in the urine
Epilepsy / Seizure“Electrical storm in the brain” • Epilepsy • Chronic disorder characterized by recurrent episodes of seizures due to excessive discharge of cerebral neurons • Seizure • Involuntary movement or convulsions • Altered mental awareness • Due to excessive electrical activity in the brain
Etiology • Mostly idiopathic (unknown) • Genetic predisposition in 1% of cases • Any major disease or illness • In older adults age > 50, CVA is # 1 cause • Chaotic excessive electrical discharge of large aggregates of neurons in the brain
General Characteristics • Tonic: jaw fixed, hand clenched • Clonic: rhythmic jerky contractions & relaxation, biting, froth on lips • Non-convulsive: changes in behaviors • Onset • Mostly occur unpredictably at any time • Some are provoked
Classification of Seizure • Partial seizure • Simple partial • Complex partial (most common) • Generalized seizure • Tonic-Clonic (i.e. Grand Mal) • Absence (i.e. petit mal) **most common type • Sometimes, simple or complex partial can develop into generalized tonic-clonic
Simple Partial (focal seizure) • Patients are conscious during seizure • Unilateral hemispheric involvement, from a distinct, focal area of cerebral cortex • Symptoms could be motor, somatosensory, or visual, depending on the brain area involved.
Complex Partial • Altered or loss of consciousness • Involve bilateral hemispheres, usually temporal lobes • Automatic, involuntary, repetitive behaviors • Clumsy movements • Confused, mumbling, pulling clothing, head turns
Tonic-Clonic (grand mal) • Sudden loss of consciousness & fall • Tonic: generalized rigidity • Clonic: very rapid generalized jerking movements • Postictal: altered speech, weakness, disorientation, muscle soreness, HA
Sudden cessation of ongoing consciousness activity • Stares into space • Only minor convulsive muscle activity or loss of postural control • Simple, brief, automatic movements • More common in children, usually remit in adulthood Absence Seizures (Petit Mal)
Epilepsy • Diagnosis • History from patient & observation from bystanders • EEG • Identify underlying diseases, rule out other causes • Treatment • Education • Anticonvulsants (e.g. Gabapentin) • Surgery • Vagal nerve stimulation – sends inhibitory signals to cerebrum • Prognosis • Increased mortality rates (due to underlying condition) • Death from asphyxia (eating or swimming during a seizure) • 20 X risks of sudden death (cardiac arrhythmia, MI) • Remission = 75% in idiopathic seizure diagnosed before age 10