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