Osmosis from Elsevier - Seizures: Pathology review
The content provides an overview of various seizure types, including generalized and focal seizures, and their subtypes such as tonic-clonic, myoclonic, and absence seizures. It explains that seizures result from abnormal electrical discharges in the brain and can be provoked or unprovoked, with epilepsy being diagnosed after two or more unprovoked seizures. The video also covers febrile seizures in children and the importance of differentiating seizures from other conditions like syncope. Diagnostic approaches include blood tests, EEG, and imaging to identify potential causes. Treatment involves abortive and anti-epileptic medications, with specific drugs highlighted for different seizure types.
Key Points:
- Seizures are caused by abnormal electrical discharges in the brain and can be generalized or focal.
- Generalized seizures include tonic-clonic, myoclonic, and absence seizures, each with distinct characteristics.
- Diagnosis involves blood tests, EEG, and imaging to determine the cause and type of seizure.
- Treatment includes abortive medications for ongoing seizures and anti-epileptic drugs for prevention.
- Febrile seizures in children are linked to fever and can be simple or complex.
Details:
1. 🧒 Patient Profiles: A Glimpse into Neurological Cases
- Stefan, a 7-year-old male, experiences several daily episodes of brief loss of consciousness. His teacher reports frequent daydreaming, indicating potential absence seizures.
- Jacob, a 17-year-old male, experienced a sudden onset of shaking, jerking, and a 2-minute loss of consciousness, with an otherwise unremarkable medical history, suggesting possible generalized seizures.
- Megan, an 11-year-old female, displayed twitching in her left foot lasting a few minutes, with subsequent unconsciousness and no memory of the event, which may indicate focal seizures.
- Joanna, a 19-year-old female, has repetitive episodes of rapid jerking movements and loss of consciousness, primarily occurring upon waking and during sleep, pointing towards myoclonic seizures.
2. ⚡ Seizures & Epilepsy: Core Understandings
2.1. Seizures Overview
2.2. Epilepsy Overview
3. 🔍 Generalized Seizures: Types and Characteristics
- Generalized seizures are classified into motor and non-motor categories, each with distinct clinical presentations.
- Motor seizures include tonic-clonic, which involve muscle stiffness and convulsions, and clonic seizures that are characterized by rhythmic jerking movements.
- Non-motor seizures, such as absence seizures, involve brief lapses in consciousness and are often mistaken for daydreaming, highlighting the importance of accurate diagnosis.
- Understanding these subtypes is crucial for the development of effective treatment plans tailored to the specific seizure type.
4. 🌀 Tonic-Clonic and Myoclonic Seizures: In-Depth Analysis
- Tonic seizures involve sudden stiffening of the muscles, while clonic seizures involve rhythmic twitching, and these often occur together in tonic-clonic seizures.
- In a tonic-clonic seizure, individuals may involuntarily scream due to vocal cord contraction, experience eye rolling, and have impaired swallowing, which can lead to pooled respiratory secretions.
- Such seizures can also cause tongue biting and urinary or fecal incontinence due to intense muscle contractions.
- The postictal phase follows the seizure, where consciousness remains impaired from minutes to hours, causing sluggishness and difficulty in waking.
- Triggers for these seizures can include sleep deprivation, stress, and alcohol withdrawal, highlighting the need for lifestyle management in affected individuals.
5. 🧠 Atonic and Absence Seizures: Key Insights
- Myoclonic seizures involve sudden, rapid muscle contractions happening at a rate of 0.1 seconds, compared to clonic seizures where contractions occur at a rate of 1 to 2 seconds. They typically occur in the morning and are triggered by stress or sleep deprivation, making them particularly important to monitor for individuals under high stress, such as students during exams.
- Atonic seizures are characterized by a sudden loss of postural muscle tone lasting 1 to 2 seconds, causing individuals to collapse suddenly. Management may include wearing protective headgear to prevent injury from falls.
- Absence seizures, common in children and adolescents, involve sudden brief loss of consciousness for seconds to minutes without any change in muscle tone. These can occur dozens or hundreds of times per day and are often described as staring into space, impacting attention in educational settings.
- Treatment options for these seizures include medications such as ethosuximide for absence seizures and lifestyle modifications to reduce stress and ensure adequate sleep.
6. 🧐 Focal Seizures: Recognizing the Signs
- Focal seizures, previously known as partial seizures, are divided into those with and without impairment of consciousness, indicated by a postictal phase presence or absence.
- They manifest variably as motor, sensory, or autonomic symptoms based on the cortical area involved. For example, seizures in the primary motor cortex cause contralateral tonic or clonic movements.
- Auras are often the initial subtle neurological symptoms of focal seizures, presenting as automatisms (e.g., chewing, lip-smacking), unusual sensory perceptions, or emotional experiences like fear or déjà vu.
- Todd's paralysis, a temporary weakness following a focal motor seizure, affects the involved limb, serving as an important diagnostic marker.
- Differentiating between generalized tonic-clonic seizures and focal seizures that secondarily generalize can be challenging; key indicators include auras, unilateral symptoms, or Todd's paralysis, though these are not definitive.
- Understanding the impact of focal seizures on daily life is crucial; they can affect a patient's quality of life and ability to perform daily activities.
- Treatment options for focal seizures include medication, lifestyle adjustments, and in some cases, surgery to manage symptoms and improve life quality.
7. 🌡️ Febrile Seizures in Pediatrics
- Febrile seizures affect children aged 6 months to 5 years, triggered by fever.
- Two types: simple (generalized, <15 min, no recurrence within 24 hours) and complex (focal, >15 min, may recur within 24 hours).
- Human Herpes Virus 6 (HHV6) is significantly associated with febrile seizures, particularly causing roseola infantum.
- Roseola infantum presents with a high-grade fever for 3-5 days, followed by a rash.
- Management includes reassurance and education for parents, as simple febrile seizures do not typically lead to long-term issues.
- Complex febrile seizures may require further investigation and management due to potential underlying neurological conditions.
8. 🔬 Diagnostic & Causative Factors of Seizures
- Seizures, as complex symptoms, have diverse causes categorized by the VITAMINS mnemonic, each requiring specific diagnostic attention.
- Vascular causes: Include ischemic or hemorrhagic strokes and intracerebral hemorrhage. Diagnosis often involves imaging studies like CT or MRI scans to identify vascular events.
- Infectious causes: Encompass meningitis, encephalitis, or brain abscess. Laboratory tests such as CSF analysis are crucial for diagnosis.
- Traumatic causes: Include penetrating traumatic brain injury, e.g., gunshot wounds. Diagnosis typically involves immediate imaging and neurological assessment.
- Toxic causes: Result from substance abuse (e.g., cocaine, amphetamine overdose), alcohol withdrawal, isoniazid (leading to vitamin B6 deficiency), and bupropion, especially in those with eating disorders. Diagnosis involves toxicology screens and patient history evaluation.
- Autoimmune causes: Include CNS vasculitis or lupus. Diagnoses often involve immunological assays and clinical history.
- Metabolic causes: Involve electrolyte imbalances (hyponatremia, hypocalcemia), hypoglycemia, hyperglycemia, hyperthyroidism, liver or kidney disease, and thiamine deficiency, particularly in alcoholics. Diagnostic tests include blood panels and metabolic screenings.
- Idiopathic causes: Primarily refer to epilepsy, diagnosed through EEG and clinical evaluation.
- Neoplastic causes: Tumors can be detected through imaging and biopsy when necessary.
- Differential diagnoses: Important to distinguish between seizures and conditions like psychogenic seizures or syncope, which lack a postictal phase. Eclampsia is specifically considered in pregnant women with seizures and preeclampsia history.
- Effective seizure diagnosis requires differentiating between seizures and syncope, which often have prodromal symptoms and lack postictal phases, aiding in accurate diagnosis.
9. 🔎 Diagnosis & Treatment Strategies for Seizures
- Initiating seizure diagnosis involves assessing for prior seizures to determine potential epilepsy.
- For first-time seizures, a comprehensive diagnostic workup includes CBC, electrolytes, liver function tests, serum glucose, toxicology screen, and pregnancy test for women.
- If syncope is suspected, an ECG is recommended.
- CT or MRI brain imaging should be conducted if a structural lesion is suspected or if lab results are inconclusive.
- Suspected brain infections like meningitis warrant a lumbar puncture.
- Unidentified causes after workup classify the seizure as unprovoked, suggesting epilepsy.
- EEG testing determines whether epilepsy is generalized or focal, aiding in precise diagnosis, such as absence seizures with a three Hz spike-and-wave pattern.
- Treatment for ongoing seizures utilizes abortive therapy with benzodiazepines like diazepam, midazolam, and lorazepam, while prevention employs anti-epileptics like valproic acid, phenytoin, and phenobarbital.
- Ethosuximide is specifically for absence seizures, and magnesium sulfate is used for eclampsia.
- Seizures are due to abnormal brain electrical discharges, with epilepsy diagnosed after two or more unprovoked seizures, classified into generalized (tonic-clonic, myoclonic, atonic, absence) and focal types, with children at risk for febrile seizures, categorized as simple or complex.
10. 👩⚕️ Applying Knowledge: Patient Case Evaluations
- Stepan's symptoms suggest episodes of absence seizures, characterized by brief losses of consciousness and daydreaming.
- Jacob's experience aligns with a generalized tonic-clonic seizure, marked by whole-body convulsions.
- Megan likely had a focal seizure with loss of consciousness, specifically a partial complex seizure, affecting only her left foot.
- Joanna's symptoms indicate myoclonic seizures, involving rapid jerking movements, especially when sleep-deprived.
- A comprehensive diagnostic workup is recommended for all patients to identify the underlying causes of seizures.
- Patients with unprovoked seizures could be diagnosed with epilepsy after thorough evaluation.