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Infantile Spasms

By

M. Cristina Victorio

, MD, Akron Children's Hospital

Reviewed/Revised Mar 2023
View PATIENT EDUCATION

Infantile spasms are seizures characterized by sudden flexion of the arms, forward flexion of the trunk, extension of the legs, and hypsarrhythmia on electroencephalography. Treatment is adrenocorticotropic hormone, oral corticosteroids, or vigabatrin.

Infantile spasms last a few seconds and can recur many times a day. They usually manifest in children < 1 year of age. Seizures may resolve spontaneously by about 5 years of age but are often replaced by other types of seizures.

Pathophysiology is unknown; however, infantile spasms may reflect abnormal interactions between the cortex and brain stem.

Causes of Infantile Spasms

Usually, infantile spasms occur in infants with serious brain disorders and developmental abnormalities that often have already been recognized. These disorders may include

Sometimes the cause of infantile spasms cannot be identified.

Symptoms and Signs of Infantile Spasms

Spasms begin with a sudden, rapid, tonic contraction of the trunk and limbs, sometimes for several seconds. Spasms range from subtle head nodding to contraction of the whole body. They involve flexion, extension, or, more often, both (mixed). The spasms usually occur in clusters, often several dozen, in close succession and occur typically after children wake up and occasionally when falling asleep. Sometimes, at first, they are mistaken for startles.

Developmental delays (see Childhood Development Childhood Development Descriptions of development are often divided into specific domains, such as gross motor, fine motor, language, cognition, and social/emotional growth. These designations are useful, but substantial... read more ) may be present before the onset of infantile spasm. In infants with normal development, developmental regression can occur (eg, children may stop smiling or lose the ability to sit up or roll over).

Symptoms and signs reference

  • 1. Riikonen R: Long-term outcome of West syndrome: A study of adults with a history of infantile spasms. Epilepsia 37(4):367–372, 1996. doi: 10.1111/j.1528-1157.1996.tb00573.x

Diagnosis of Infantile Spasms

  • Electroencephalography (EEG) with awake and asleep stages

  • Neuroimaging, preferably MRI

  • Testing to identify the cause unless an underlying significant neurologic disorder has already been identified

Previous history (eg, neonatal hypoxic-ischemic encephalopathy) and/or symptoms and signs suggest the diagnosis of infantile spasms in some children. Physical and neurologic examinations are done, but often no pathognomonic findings are identified except in tuberous sclerosis complex Tuberous Sclerosis Complex (TSC) Tuberous sclerosis complex is a dominantly inherited genetic disorder in which tumors (usually hamartomas) develop in multiple organs. Diagnosis requires specific clinical criteria and imaging... read more Tuberous Sclerosis Complex (TSC) .

EEG is done to confirm the diagnosis and check for specific abnormalities. Typically, the interictal pattern is hypsarrhythmia (chaotic, high-voltage polymorphic delta and theta waves with superimposed multifocal spike discharges). Multiple variations (eg, focal or asymmetric hypsarrhythmia) are possible. The ictal pattern is usually a sudden, marked and diffuse attenuation of electrical activity.

Neuroimaging, preferably MRI, is done if it has not already recently been done.

Tests to determine the cause

If it is not clear from neuroimaging or the previous history, tests to determine the cause may include

  • Laboratory tests (eg, complete blood count with differential; measurement of serum glucose, electrolytes, blood urea nitrogen, creatinine, sodium, calcium, magnesium, phosphorus, serum amino acids, and urine organic acids; liver tests) if a metabolic disorder is suspected

  • Genetic testing (epilepsy gene panels are available)

  • Cerebrospinal fluid (CSF) analysis to check for metabolic disorders

Treatment of Infantile Spasms

  • Intramuscular adrenocorticotropic hormone (ACTH)

  • Oral corticosteroids

  • Vigabatrin (especially for tuberous sclerosis complex)

Infantile spasms are not responsive to typical antiseizure medications.

The standard therapies for infantile spasms can be any one of the following.

ACTH can be given daily IM as either high-dose (150 units/m2) ACTH or low-dose (20 units/m2) ACTH. The Pediatric Epilepsy Research Consortium (PERC) recommends the higher dose, given for 2 weeks and then tapered down every 3 days until 29 days of treatment are completed. If low-dose therapy is tried and has not stopped spasms within 2 weeks, the higher dose is used.

Corticosteroids (eg, oral prednisone) are given for 4 to 7 weeks. A regimen recommended by PERC uses oral prednisolone as follows:

  • Days 1 to 14: 10 mg 4 times a day

  • Days 15 to 19: 10 mg 3 times a day

  • Days 20 to 24: 10 mg 2 times a day

  • Days 25 to 29: 10 mg once a day

Vigabatrin is the drug of choice when the spasms are caused by tuberous sclerosis complex Tuberous Sclerosis Complex (TSC) Tuberous sclerosis complex is a dominantly inherited genetic disorder in which tumors (usually hamartomas) develop in multiple organs. Diagnosis requires specific clinical criteria and imaging... read more Tuberous Sclerosis Complex (TSC) . It is also often used in children with an established preexisting serious brain injury or malformation and in those who do not tolerate or respond to ACTH. Dosage of oral vigabatrin is 25 mg/kg 2 times a day, increased gradually over about a week up to 75 mg/kg 2 times a day if needed. There is insufficient evidence that any other antiseizure medication or the ketogenic diet is effective.

There is evidence that the more quickly effective therapy is initiated, the better the neurodevelopmental outcome, particularly when no cause is identified.

Treatment reference

Key Points

  • Infantile spasms last a few seconds and can recur many times a day; they may resolve spontaneously by about 5 years of age but are often replaced by other types of seizures.

  • Usually, infantile spasms occur in infants with serious brain disorders and developmental abnormalities that often have already been recognized; tuberous sclerosis complex is a common cause.

  • Do electroencephalography to confirm the diagnosis, and other tests (eg, brain MRI and metabolic and genetic testing) to evaluate the cause of infantile spasm.

  • Infantile spasms can be treated with adrenocorticotropic hormone (ACTH), vigabatrin (the drug of choice for spasms caused by tuberous sclerosis complex), or oral corticosteroids.

Drugs Mentioned In This Article

Drug Name Select Trade
Sabril, VIGADRONE, VIGPODER
Aluvea , BP-50% Urea , BP-K50, Carmol, CEM-Urea, Cerovel, DermacinRx Urea, Epimide-50, Gord Urea, Gordons Urea, Hydro 35 , Hydro 40, Kerafoam, Kerafoam 42, Keralac, Keralac Nailstik, Keratol, Keratol Plus, Kerol, Kerol AD, Kerol ZX, Latrix, Mectalyte, Nutraplus, RE Urea 40, RE Urea 50 , Rea Lo, Remeven, RE-U40, RYNODERM , U40, U-Kera, Ultra Mide 25, Ultralytic-2, Umecta, Umecta Nail Film, URALISS, Uramaxin , Uramaxin GT, Urea, Ureacin-10, Ureacin-20, Urealac , Ureaphil, Uredeb, URE-K , Uremez-40, Ure-Na, Uresol, Utopic, Vanamide, Xurea, X-VIATE
Deltasone, Predone, RAYOS, Sterapred, Sterapred DS
AK-Pred, AsmalPred, Econopred, Econopred Plus, Flo-Pred, Hydeltrasol, Inflamase Forte, Inflamase Mild, Millipred , Millipred DP, Millipred DP 12-Day, Millipred DP 6 Day, Ocu-Pred , Ocu-Pred A, Ocu-Pred Forte, Omnipred, Orapred, Orapred ODT, Pediapred, Pred Mild, Predalone, Pred-Forte, Prednoral, Pred-Phosphate , Prelone, Veripred-20
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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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