Infantile spasms

Range of different shudders and twitches seen in babies and infants. Shudders and stereotypy can be dramatic, self stimulating behaviours, many kinds! Esp at 6-9/12, triggered by excitement but can also be boredom! So context important.  Can have a few together, but cluster would suggest epileptic.  Looks well. 

Differential is myoclonus, spasms (where at start may appear neurologically normal).

Infantile spasms are easy when classic, but are often atypical so can be difficult! 90% present before age 1, typically 3-7 months. Usually followed by upset so often confused with colic. Mostly when awake, arousal. Clusters of synchronous flexor spasms, usually of legs but possibly of head on torso. Definition is 0.5-2secs, so longer than jerk, some people think of an initial fast contraction followed by slower phase. Salaam attack is flexion of head and legs plus adduction of arms into midline. Rarely extensor, or mixed flexion of trunk and extension of limbs. Subtle presentations may just be chin. Can be unilateral.

Needs EEG to be sure, and even sleep EEG at that.  Low threshold since urgent treatment required.

Making diagnosis is urgent, as better initial control (in those without underlying aetiology) seem to have better developmental outcome). 

West syndrome – described by neurologist in his own son. Combination of spasms, developmental regression and hypsarrhythmia (see below). May initially be developmentally normal, become less visually attentive.  Flexion of head and trunk, arms extend/flex, abduct/adduct (can be asymmetrical if underlying hemiplegia).  Briefly upset or dazed, may be grimace.  On waking or falling asleep. Various Youtube videos available.

Rarely metabolic (consider PKU, Menkes, molybendum cofactors along with others). More often structural esp tuberosclerosis (TS – about 70% ) but also lissencephaly. Can be acquired eg post meningitis or congenital infection. Associated with Downs syndrome (actually more responsive to treatment).  Do Woods lamp and genetics. 20% cryptogenic.


EEG by definition is abnormal, but in early phase standard awake EEG may be normal so consider sleep EEG.  Classical hypsarrhythmia in 50-70% = chaotic, high voltage.  But can be asymmetric.  If structural lesion, may be burst suppression (sudden high voltage then brief flattening) or focal features.


ICISS (2016) showed combination of steroids and vigabatrin superior to either alone. High doses of both needed. ACTH or prednisolone at prescriber’s discretion (ACTH is alternate day injection, expensive). 

Visual field loss with vigabatrin is seen in adults on long term treatment.  Weaned as soon as possible. Side effects with both common, esp infection. 

Not yet clear if resolution of EEG findings important. Spasms settle by mid-childhood as neurodevelopmental delay evolves, most develop other epilepsy eg Lennox Gastaut. Treatment is often difficult, and most children do not have a good neurological outcome (with or without underlying brain disorder). [Cochrane Rev. PMID: 18843624]

Remember to avoid live vaccines after high dose steroids, varicella prophylaxis.

Mechanism for steroids not understood!