Differential Diagnosis in Neurology

2.5. Status Epilepticus

Major Motor Status Epilepticus

• General features:
  • 40–80/100,000 patients
  • Mortality of 22%
  • Occurs in 14% of patients after control of GCTS has been established
• Repetitive tonic-clonic movements or components that last for seconds to minutes
• Consciousness is not regained within three minutes prior to the onset of a new seizure
• Associated features:
  • Autonomic changes:
    • Increased heart rate, greater than 120 beats/minute
    • Pupillary changes (dilated)
    • Hyperhidrosis
    • Temperature to 103 degrees Fahrenheit (rarely > 104°F)
• Rare sequelae:
  • Cardiac arrest
  • Neurogenic pulmonary edema
  • Duodenal ulcer (first segment of the duodenum)
• Serum evaluation:
  • Severe acidosis: pH 7.1–7.2 in the serum
  • Hyperkalemia > 5 mEq/dl
• CSF evaluation:
  • Up to 100 neutrophils/mm³
  • Acidosis (pH of 6.8)

Differential Diagnosis of Adult Major Motor Status Epilepticus

• Non-compliance with medication
• Frontal lobe brain tumor
• Metabolic abnormalities from organ failure or hypoglycemia
• Illicit drugs (cocaine, amphetamines)
• Vascular malformation or infarction
• Infectious disease:
  • Opportunistic organisms (HIV associated)
  • Herpes simplex encephalitis
  • Meningitis
• Remote cerebral scar
• Alcohol related (withdrawal)

Psychomotor or Complex Partial Seizure (temporal lobe) Status Epilepticus

• Clinical features:
  • Confused dazed appearance
  • Patient partially responsive to verbal commands
  • De novo or perservative automatisms
  • Myoclonic jerks and eye twitches (intermittent)
  • Patient is ambulatory
  • May last for hours
  • Fugue state:
    • Prolonged temporal lobe status epilepticus
    • Patient able to perform activities of daily living or more complex tasks such as driving
    • Sudden recovery
    • Amnestic for the event
    • Usually less than 30 minutes; may last for hours

Differential Diagnosis of Adult Complex Partial Status Epilepticus of Temporal Lobe Origin

• Non-compliance with mediations in a temporal lobe seizure patient
• Astrocytic tumors of the temporal lobe
• Medial temporal lobe sclerosis
• Vascular malformation
• Severe head trauma
• Hematoma
• Migrational disorders: chromosomally linked and sporadic

Focal Motor Statis Epilepticus in an Adult

• Differential diagnosis:
  • Stroke or vascular insult (Menshikoff's syndrome)
  • Arteriovenous malformation
  • Cavernous hemangioma (that has recently bled)
  • Rasmussen's encephalitis (children and adolescents most often affected)
  • Mitochondrial encephalomyopathy (children and adolescents)
  • Opportunistic infection in a patient with HIV

Status Epilepticus of the Occipital Cortex (status epilepticus amauroticus)

• Cortical blindness
• Unilateral nystagmus

Epilepsia Partialis Continua (EPC)

• General features:
  • Spontaneous focal jerking of a body part
  • Duration: days, months, or years
  • Aggravated by:
    • Movement
    • Sensory stimuli
  • May occur in isolation
  • 40% of patients with EPC
    • Cognitive or neurologic decline
• EPC in children:
  • Rasmussen's encephalitis
  • Migrational disorder
  • mt-DNA disorders
  • Autoantibodies against GluR3 and munc-18
• EPC in adults:
  • Stroke or vascular insult (Menshikoff's Syndrome)
  • Arteriovenous malformation
  • Cavernous hemangioma
  • Brain tumor (meningioma)
  • Mitochondrial encephalomyelopathy (most often children or in adolescents)
  • Kuf's disease late onset form)
    • Type A progressive myoclonic epilepsy
    • Type B:
      • Dementia
      • Behavior disorder
      • Facial dyskinesia
      • Absence of generalized epileptiform discharges

Non-Convulsive Status Epilepticus (NCSE)

• Types
  • Generalized NCSE
  • Partial NCSE
  • Diagnosed by the ictal EEG
• Generalized NCSE (absence status; "petit mal status")
  • Definition: Multiple seizures or continuous seizure activity on EEG with non-convulsive clinical correlate
  • Fluctuating confusion of varying intensity
  • Mirror-facial myoclonus
  • Cognitive and behavior change
  • 50% of patients demonstrate bilateral myoclonus during the ictus
  • EEG: symmetric ictal activity
  • Precipitating factors of absence status (nonconvulsive status epilepticus)
    • Carbamazepine
    • Hyperventilation
    • Inadequate drug levels
    • Infections
    • Noncompliance with medication
    • Benzodiazepine withdrawal
    • Hypoparathyroidism
    • Menses
    • Generalized convulsions
    • Head trauma
    • Alcohol
    • Recent surgery
    • Sleep deprivation
    • Emotional upset
    • Renal failure
    • Pregnancy
    • Methohexital
  • Occurs in 8% of comatose patients
• Partial NCSE:
  • Various non-convulsive symptoms with or without confusion
  • Continuous or recurrent focal epileptiform EEG pattern
• Parietal NCSE:
  • Symptoms
    • Somatosensory
    • Visual
    • Auditory
    • Vegetative
    • Psychic
    • Cognitive
    • Affective
  • No loss of consciousness
• NCSE of frontal lobe origin
  • Prolonged periods of continuous confusion without visible ictal signs
  • May have focal lesions in the frontal lobe
  • May occur in the middle aged or elderly
  • Absence status may occur without overt confusion

Differential Diagnosis of Absence Status

• Prolonged post ictal encephalopathy
• Depression
• Acute or interictal psychosis
• Factitious disorders
• Medication overdose
• Psychotropic drug withdrawal
• Toxic metabolic encephalopathy
• Amnesia and automatisms syndrome (from TLE)
• Transient global amnesia
• Transient unresponsiveness in the elderly