Lead Poisoning and Seizures
Dayna Ryan, PT, DPTWinter 2012
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
Lead Poisoning
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)
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 bind the lead so that it's
excreted in the urine
Lead Poisoning
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)
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
Epilepsy