6A Epilepsy class ppt.pptx

Epilepsy Dr. Md. Shamshir Alam Learning Objectives • Describe the epidemiology and social impact of epilepsy. • Define terminology related to epilepsy, including seizure, convulsion, and epilepsy. • Describe the basic pathophysiology of seizures and epilepsy. • Differentiate and classify seizure t...

Epilepsy Dr. Md. Shamshir Alam Learning Objectives • Describe the epidemiology and social impact of epilepsy. • Define terminology related to epilepsy, including seizure, convulsion, and epilepsy. • Describe the basic pathophysiology of seizures and epilepsy. • Differentiate and classify seizure types when provided a description of the clinical presentation of the seizure and electroencephalogram. Definitions Seizures: • A seizure is a sudden, uncontrolled burst of electrical activity in the brain. It can cause changes in behavior, movements, feelings and levels of consciousness. Epilepsy: • Two or more seizures at least 24 hours apart that don't have a known cause is considered to be epilepsy. • Epilepsy is a common neurological (CNS) condition characterized by recurrent seizures (that usually occur unpredictably) loss of consciousness with or without body movements. Convulsion: • A sudden, violent, irregular movement of the body, caused by involuntary contraction of muscles and associated with brain disorders such as epilepsy. Epidemiology • Fourth most common neurologic disorder globally. • Highest number with extremes ages: child and old age. • Children-highest cases under 5 years; most new cases occurring under 2 years . • Older: high frequency among older than 65: 1.5%. • Mortality rate with epilepsy is 2 to 3 times that of the general population. • At least 10% of the general population will have one seizure from any cause in their lifetime • Around 50 million people worldwide have epilepsy. • Prevalence in developing countries is higher due to parasitic illnesses like cysticercosis. Epidemiology • WHO data 2018 for Oman: • Epilepsy Deaths in Oman reached 39 or 0.38% of total deaths. • The age adjusted Death Rate is 0.95 per 100,000 of population. • Ranks Oman 144th in the world. Strong provoking stimulus/Trigger factor • Drug overdose and withdrawal: • Alcohol, Barbiturate, or benzodiazepine • Acute neurologic condition: brain hemorrhage • Systemic conditions: • Hypocalcemia, hypoglycemia, uremia, and eclampsia • Some patients have seizures with fever -- febrile seizures. Risk factors • Sleep deprivation • Physical and mental exhaustion • Missed doses of anti-epileptic drugs in patients • Alcohol withdrawals, recreational drug misuse • Flickering lights (like TV, computer screens generalized epilepsy syndrome) • Intercurrent infections • Metabolic disturbances • Uncommon reasons like loud noises, very hot baths, etc. Etiology In 20-30% cases causes are known. Rest 70-80% are idiopathic (unknown cause). 1.Inherited/ genetic causes: single gene mutation (< 2%), multiple genes Plus environmental factors, genetic disorders (Down syndrome, Dravet ), > 200 genes have the capability to causes epilepsy. 2.Acquired causes: head trauma, neurosurgery, cerebrovascular diseases, infections (meningitis, influenza, toxoplasmosis, mumps, measles, syphilis), metabolic disorders (hypoglycemia, hypocalcemia), intracranial neoplasm. 3.Congenital causes: inborn error of metabolism 4.Drugs that can induce seizures: anesthetics, antimalarial, some antibiotics, antidiabetics, antispastics, antipsychotics, antidepressants, mood stabilizers. 5.Withdrawal of drugs: alcohol, barbiturates, BZDs, antiepileptics. Pathophysiology • Neurotransmitters are of two types: inhibitory NTs and excitatory NTs • Inhibitory NTs (INTs): GABA (Gamma amino butyric acid) acts on ion channels and increases chloride out flow and decreases chances of action potential generation. • Excitatory NTs (ENT): Aspartate and gulumate allows sodium and calcium influx which paves way for action potential generation. • Seizures occur due to the imbalance between the above inhibition and excitation. Pathophysiology …2 Classification of Seizures: 3 categories • Focal seizures (partial seizures): • start only one side of the brain • Generalized seizures (primary generalized): • start in a bilaterally distributed network (eg, a network encompassing both sides of the brain) Classification of Epilepsy I. Focal (Partial) Seizures (80% 0f adult epilepsy) 1. Simple Partial Seizures 2. Complex Partial Seizures 3. With secondary generalization II. Generalized Seizures 4. 5. 6. 7. 8. 9. Absence Seizures Myoclonic Seizures Tonic Seizures Generalized Tonic-Clonic Seizures Atonic Seizures Status epilepticus Focal seizures: manifestations 1.Simple partial seizures – without impairment of consciousness It is associated with motor signs (convulsive jerking, lip smacking), sensory and somatosensory signs (paresthesias, aura), autonomic signs (sweating, flushing, behavioral manifestations (dysphasia, structured hallucinations). 2.Complex partial seizures – with impairment of consciousness There is impaired consciousness which follows seizures. It involves purposeless behaviors, aimless walking, hallucination (visuals, auditory), aggressive behavior. 3.Secondary generalized seizures Partial onset evolving to generalized tonic-clonic seizures Generalized seizures: manifestations 1.Absence seizures: also known as “petit-mal” epilepsy. Happens exclusively in childhood and early adolescents. Associated with alterations of consciousness, staring with occasional eye-blinking, enuresis. These attacks last only for few seconds and often go unrecognized. 2.Myoclonic seizures: also known as “bilateral massive epileptic myoclonus”. It is associated with involuntary, rhythmic jerking of facial, limb/ trunk muscles. 3.Clonic seizures: rhythmic jerking movements of the arms and legs, sometimes on both sides of the body. 4.Tonic seizures: it is associated with sustained muscle contractions (stiffening of the body). Generalized seizures: manifestations 5. Generalized tonic-clonic seizures: Also called as “grand-mal seizure”. It leads to sudden loss of consciousness; the individual becomes rigid and falls to the ground. There are interrupted respirations, extended legs, rapid bilateral muscle jerking, heavy salivation, tongue biting, headache, confusion. It lasts for one minute. Status epilepticus: a state when grandmal seizures occurs repeatedly with no recovery of consciousness between attacks. 6. Atonic seizures: known as ‘drop attack’. Occurs mainly in children. Associated with sudden loss of postural tone and the individual falls to the ground. Diagnosis • Neurological examination/ neuropsychological test: • Evaluation of Behavior, motor abilities, mental functions and other symptoms. • Medical history • Genetic history and testing • Electroencephalogram (EEG) • tracks electrical signals from the brain. • CT and MRI scan: used to detect abnormities in brain (tumor, bleeding, cysts). • Positron emission tomography (PET): used to visualize active areas of brain and detect abnormalities. • Functional magnetic resonance imaging (fMRI): • used to measure small changes in blood flow that occur in the brain. • SPECT (single photon emission computerized tomography): • used when MRI and EEG did not pinpoint the location in brain where the seizures are originating.