Seizures: Pathology review

00:00 / 00:00



Seizures: Pathology review



Seizures: Pathology review

USMLE® Step 1 questions

0 / 11 complete


USMLE® Step 1 style questions USMLE

of complete

A 23-year-old woman is brought to the emergency department by ambulance because her body started shaking violently 10 minutes ago at a nearby bus stop. She was waiting for a bus with her partner when she suddenly fell down and started having stiffening and jerking movements involving all four extremities. Past medical history is significant for epilepsy, for which the patient takes lamotrigine. The partner notes the patient recently started taking a combined oral contraceptive pill. Her temperature is 37.5°C (99.5°F), pulse is 112/min and regular, respirations are 22/min and blood pressure is 108/68 mmHg. The patient is unable to respond to vocal commands. Physical examination shows ongoing symmetric rhythmic jerking of the limbs. After appropriate supportive treatment, the patient is given a drug intramuscularly, after which the jerking subsides. Which of the following best describes the mechanism of action of the drug administered?  

Memory Anchors and Partner Content


On the neurology ward, a 7-year old male, called Stefan, is brought by his mother. His mother is worried because he has several episodes every day where he loses consciousness for a few seconds. His teacher also complains that she often catches him daydreaming during the lesson. Next to Stefan, there’s a 17-year old male, called Jacob, who seems sluggish and tired. His friends brought him because he suddenly started “shaking and jerking” and he lost consciousness for about two minutes. His medical history is otherwise insignificant. Now, there’s also an 11-year old female, called Megan, who also seems lethargic. Her father is very upset because he witnessed an episode of twitching of her left foot that lasted a few minutes. Megan was unconscious and has no memory of the event. Finally, there’s a 19-year old female, called Joanna, that has had repetitive episodes of sudden and rapid jerking movements with loss of consciousness for the past few months. They usually occur when she wakes up in the morning and especially during periods of sleep deprivation.

Okay, so all of them had a seizure episode. A seizure is a paroxysmal motor, sensory or autonomic event that occurs due to abnormal, excessive and synchronous electrical discharges from neurons in the brain. Seizures usually last less than 5 minutes. If it lasts more than 5 minutes, it’s called status epilepticus. Epilepsy is a chronic disease of the brain that predisposes an individual to having recurrent unprovoked seizures; that is seizures without a clear triggering cause. Epilepsy is typically diagnosed when an individual has two or more unprovoked seizures separated by at least twenty-four hours.

Okay, now seizures are broadly classified into two types, generalized and focal seizures. Generalized seizures arise from both cerebral hemispheres at the same time, while focal seizures arise from specific areas in one cerebral hemisphere. However, focal seizures can spread to both cerebral hemispheres, causing a generalized seizure. When this happens, it’s appropriately called secondary generalization of a focal seizure.


A seizure is a paroxysmal event due to abnormal electrical activity in the brain that can cause changes in behavior, consciousness, or movement. A seizure shouldn't be confused with epilepsy, which is said when two or more unprovoked seizures occur. Epilepsy is a chronic disorder that predisposes the individual to have recurrent seizures, and can't be diagnosed based on a single episode of seizures alone.

Seizures can be classified into generalized and focal seizures. Generalized seizures arise from both cerebral hemispheres at the same time, and almost always cause a sudden impairment of consciousness; whereas focal seizures arise from specific areas in one cerebral hemisphere, and present as a dysfunction of the part of the body controlled by the affected part of the brain.

When evaluating an individual with seizures, it's first important to identify the possible trigger. Diagnostic tests such as a CBC (complete blood count), electrolytes, liver function tests, and glucose levels, must be done to reveal potential causes. An EEG (electroencephalography) can also be done to assess the type of seizure. Treatment for seizures may involve supportive therapy, treating the underlying causes when possible, and antiseizure medications to manage convulsions.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  4. "DeGowin's Diagnostic Examination, Tenth Edition" McGraw-Hill Education / Medical (2014)
  5. "Epilepsy" Lippincott Williams & Wilkins (2007)
  6. "Cochrane Database of Systematic Reviews" undefined (undefined)
  7. "Ion Channel Genes and Epilepsy: Functional Alteration, Pathogenic Potential, and Mechanism of Epilepsy" Neuroscience Bulletin (2017)
  8. "The Blood?Brain Barrier and Epilepsy" Epilepsia (2006)

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.