What could be causing my violently convulsing leg during sleep, which occurred for a couple of hours one night about 3 weeks ago, and what are the potential treatments?

Violent Leg Convulsions During Sleep: Evaluation and Management

You should be evaluated promptly by a physician to rule out nocturnal seizures, as violent convulsions lasting hours are atypical for benign sleep-related movement disorders and warrant neurological assessment.

Differential Diagnosis

Your symptoms require differentiation between several distinct conditions:

Most Concerning: Nocturnal Seizures

• Violent convulsions lasting "a couple of hours" are highly unusual for benign sleep movement disorders and raise concern for focal motor seizures or epileptic activity 1
• Lack of awareness during the episode is consistent with seizure activity, though also seen in some parasomnias 1
• The single isolated occurrence 3 weeks ago without recurrence is somewhat reassuring but does not exclude seizure disorder 1

Sleep-Related Movement Disorders (Less Likely Given Severity)

Periodic Limb Movements of Sleep (PLMS):

• Typically involves stereotyped movements (dorsiflexion of toe/foot or triple flexion) occurring every 20-40 seconds during light sleep 2
• Movements are usually not described as "violent convulsions" and rarely last hours continuously 3, 2
• Patient is unaware during sleep, which fits your presentation 2

Propriospinal Myoclonus:

• Involves jerks arising in axial muscles with slow propagation to limbs 4
• Occurs during relaxed wakefulness before sleep, not during established sleep 4
• Disappears once sleep spindles appear on EEG 4

Restless Legs Syndrome (RLS):

• Characterized by uncomfortable sensations and urge to move legs, typically with awareness 5, 3
• Symptoms worsen in evening/night and are relieved by movement 1
• Your lack of awareness argues against RLS 5

Immediate Evaluation Required

Critical History Elements to Assess

• Any tongue biting, urinary incontinence, or confusion upon awakening (suggests seizure) 1
• Medications: antiepileptic drugs, diuretics, calcium channel blockers, lithium can cause leg movements 6, 7
• Neurological "alarm symptoms": numbness, weakness, speech disturbance, gait problems, memory issues 1
• Sleep quality and daytime functioning 1, 5

Essential Diagnostic Workup

• Neurological examination focusing on lower limb strength, gait, reflexes, and any focal deficits 1
• EEG with sleep recording to evaluate for epileptiform activity during sleep 2, 4
• Video polysomnography to capture and characterize the movements if they recur 4
• Blood tests: electrolytes, renal function, thyroid function, calcium, HbA1c 1
• Serum ferritin and transferrin saturation if PLMS suspected (supplement if ferritin ≤75 ng/mL) 5, 3

Management Algorithm

If Seizure Activity Confirmed:

• Antiepileptic medication as directed by neurology 7
• Avoid seizure triggers and ensure safety during sleep 7

If PLMS/Sleep Movement Disorder Confirmed:

• First-line: Alpha-2-delta ligands (gabapentin enacarbil, pregabalin) per American Academy of Sleep Medicine 5, 3
• Iron supplementation if ferritin ≤75 ng/mL or transferrin saturation <20% 5, 3
• Review and discontinue offending medications (diuretics, calcium channel blockers) 6

If Isolated Event with Negative Workup:

• Watchful waiting with sleep diary 1
• Reassess if symptoms recur 5
• Address any identified metabolic abnormalities 6

Critical Pitfalls to Avoid

• Do not dismiss violent, prolonged leg movements as "just restless legs" without proper evaluation 3, 2
• Do not assume benign etiology based on single occurrence—seizures can be infrequent initially 7
• Do not start dopamine agonists for presumed PLMS without confirming diagnosis, as they cause augmentation with long-term use 3
• Ensure any sleep apnea is treated before starting alpha-2-delta ligands due to respiratory depression risk 5