For today’s USMLE® Step 1-style question, we examine the case of a woman who is brought into the ER by her partner after experiencing a sudden episode of jerky movements and loss of consciousness.
A 23-year-old woman is brought to the emergency department by her partner due to an episode of jerky movements that involved stiffening and twitching all over her body. According to the partner, the episode started 30 minutes ago while the patient was working on her laptop, and it lasted approximately one minute. The patient lost consciousness after the episode for approximately 5 minutes. The patient has recently been under significant stress working on a company presentation. Past medical and surgical history is noncontributory, and the patient has not had any previous similar episodes. She takes no medications. Vitals are within normal limits. The patient appears confused and is unable to recall what happened. Physical examination shows a bite mark on the left side of the tongue. Which of the following is the most likely diagnosis?
A. Generalized tonic-clonic seizure
B. Vasovagal syncope
C. Epilepsy
D. Status epilepticus
E. Psychogenic non-epileptic seizure
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The correct answer to today’s USMLE® Step 1 Question is…
A. Generalized tonic-clonic seizure
Before we get to the Main Explanation, let’s look at the incorrect answer explanations. Skip to the bottom if you want to see the correct answer right away!
Incorrect answer explanations
The incorrect answers to today’s USMLE® Step 1 Question are…
B. Vasovagal syncope
Incorrect: Although emotional or orthostatic stress can be an inciting event for a vasovagal syncope in young individuals, syncope is not followed by the confusion, and the patient usually recalls a prodrome of pallor, dizziness, nausea or diaphoresis.
C. Epilepsy
Incorrect: The diagnosis of epilepsy requires a history of at least two unprovoked (or reflex) seizure occurring more than 24 hours apart. This patient who has not had any previous similar episodes could not be diagnosed with epilepsy yet.
D. Status epilepticus
Incorrect: Status epilepticus is diagnosed when there is a continuous seizure activity of ≥5 minutes or ≥2 discrete seizures between which there is incomplete recovery of consciousness. It is a neurological emergency. This patient had a single seizure lasting only 1 minute and subsequently regained consciousness.
E. Psychogenic non-epileptic seizure
Incorrect: PNES is derived from psychological underpinnings. The condition tends to occur in front of witnesses and in stressful situations. Its duration is usually longer than 2 minutes, and vocalization is observed during the episode. Moreover, tongue bite and postictal confusion are not usually seen.
Main Explanation
This patient’s generalized jerky movements lasting less than 5 minutes, accompanied by loss of consciousness and postictal state are consistent with a diagnosis of generalized tonic-clonic seizure (GTCS).
Seizures are defined as sudden, uncontrolled excessive synchronous electrical disturbance in the brain that can be focal (affecting a single area of the brain) or generalized (involving both the hemispheres). GTCS is the most common type of generalized seizures. It manifests as a generalized stiffness of muscles (tonic phase) that is followed by jerking and twitching (clonic phase). Patients tend to lose consciousness during the episode, which remains for a few minutes following cessation of the episode; this sequence is then followed by a gradual regaining of consciousness. The episode is usually accompanied by tongue biting (as seen in this patient), urinary and/or fecal incontinence, and amnesia of the event, but these symptoms are not required for the diagnosis. Certain triggers or precipitants tend to lower seizure threshold; common triggers include, but are not limited to, strong emotions, flashing lights, fever, stress and lack of sleep.
It is important to note that one seizure episode does not mean the patient has epilepsy. The diagnosis of epilepsy requires a history of at least two unprovoked seizures occurring more than 24 hours apart.
Major Takeaway
Seizures are the result of a sudden, uncontrolled, excessive, synchronous electrical disturbance in the brain. Generalized tonic-clonic seizures manifest as a generalized stiffness of muscles (tonic phase) that is followed by jerking and twitching (clonic phase).
References
- Fisher, R. S., Cross, J. H., D’souza, C., French, J. A., Haut, S. R., Higurashi, N., … & Peltola, J. (2017). Instruction manual for the ILAE 2017 operational classification of seizure types. Epilepsia, 58(4), 531-542.
- Lowenstein, D. H., Bleck, T., & Macdonald, R. L. (1999). It’s time to revise the definition of status epilepticus.
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