What are the symptoms and management of petit mal (absence) seizures?

Symptoms of Petit Mal (Absence) Seizures

Petit mal seizures present as brief episodes of impaired consciousness lasting only seconds, characterized by sudden staring spells with abrupt onset and termination, often accompanied by subtle motor manifestations like eyelid fluttering or facial myoclonia. 1, 2

Core Clinical Features

Primary Symptom: Altered Consciousness

• The hallmark is impaired consciousness (absence) that occurs suddenly and terminates abruptly, distinguishing these seizures from other types 1, 2
• Consciousness is not completely lost but rather altered—patients do not fall down during these episodes 3
• The impairment can range from severe to mild or even inconspicuous, depending on the specific epilepsy syndrome 2
• Episodes are characteristically brief, lasting only seconds (typically 2-30 seconds) 2

Motor Manifestations

• Myoclonic jerks, particularly of facial muscles and eyelids, are the most common motor symptom 2
• Clonic, tonic, and atonic components may occur alone or in combination 2
• Automatisms (repetitive purposeless movements) can accompany the altered consciousness 2
• Autonomic disturbances may be present 2

Diagnostic Characteristics

EEG Findings

• The EEG shows the pathognomonic pattern of generalized 3-4 Hz spike-and-wave or polyspike-and-wave discharges 1, 2
• These discharges may be brief (2-5 seconds) or prolonged (15-30 seconds), continuous or fragmented 2
• The intradischarge frequency typically ranges from 2.5-5 Hz 2

Provocative Factors

• Hyperventilation precipitates typical absence seizures in approximately 90% of untreated patients, making it a valuable diagnostic maneuver 2
• Seizures can also be triggered by photic stimulation, pattern stimuli, video games, and mental or emotional factors 2

Age and Epidemiology

• Typical absence seizures usually begin in childhood or adolescence 2, 4
• They occur in approximately 10-15% of adults with epilepsy, often combined with other generalized seizure types 2
• The disorder may remit with age but can persist lifelong in some patients 2, 5

Important Clinical Distinctions

What Absence Seizures Are NOT:

• Unlike grand mal (tonic-clonic) seizures, absence seizures do not cause falls because consciousness is altered rather than completely lost 3
• There is typically no prolonged post-ictal confusion, unlike other seizure types 3
• Tongue biting, blue face, and prolonged tonic-clonic movements are NOT features of absence seizures—these suggest generalized tonic-clonic seizures instead 3

Absence Status Epilepticus

• Approximately 30% of patients with absence epilepsy will experience absence status epilepticus, characterized by prolonged or repetitive absence seizures 2, 6
• This presents as a fluctuating confusional state and requires emergency EEG for diagnosis 6
• Intravenous benzodiazepines typically produce rapid clinical and EEG normalization 6

Management Approach

First-Line Medications

• Ethosuximide is FDA-approved specifically for absence (petit mal) seizures and controls approximately 70% of cases 1, 2
• Valproic acid controls absences in 75% of patients and is preferred when other generalized seizure types coexist (controls GTCS in 70% and myoclonic jerks in 75%) 2
• Lamotrigine controls absences and GTCS in 50-60% of patients but may worsen myoclonic jerks 2

Important Treatment Considerations

• Ethosuximide alone is unsuitable if grand mal seizures coexist, as it does not protect against tonic-clonic seizures 2, 4
• Concurrent administration of medications for both absence and grand mal seizures is recommended, as patients with petit mal are prone to developing major motor seizures 4
• Combination therapy with low-dose lamotrigine added to valproic acid may have dramatic beneficial effects in resistant cases 2

Common Pitfalls

• Do not assume patients will "outgrow" absence epilepsy—follow-up studies show many continue to have seizures into adulthood 5
• Be aware that valproic acid carries a risk of fatal hepatic toxicity (estimated at 1 in 20,000), which may make it undesirable for some patients, particularly women of childbearing age 2, 5
• Ethosuximide can cause side effects including nausea, vomiting, stomach pain, dizziness, and weight loss 1