Differentials
Dravet syndrome
SIGNS / SYMPTOMS
An intractable epilepsy with seizure onset in the first year of life.
Affected children have prolonged and repeated febrile and afebrile generalised or unilateral convulsive seizures, as well as interictal myoclonus and ataxia. Nocturnal generalised tonic-clonic seizures predominate.
There is mild to severe intellectual disability, and variable motor abnormalities.
INVESTIGATIONS
Electroencephalogram (EEG) at onset may be normal. However, later in the course of the disease EEG is abnormal.
Myoclonic jerks are associated with bursts of irregular spike and waves, or polyspike and waves, on the EEG.
Interictal EEG may be normal in the first year of life, but gradually becomes abnormal with slowing of background.
Sleep features are usually maintained.
One third of the children show de novo mutations of the SCN1A gene.[34]
Benign familial infantile seizures
SIGNS / SYMPTOMS
A clinical entity characterised by focal seizures with or without secondary generalisation, occurring in clusters.
Onset between 4 months and 8 months of age. Psychomotor development is normal, and seizures usually resolve within the first year of life.
Mode of inheritance is autosomal dominant.[35]
INVESTIGATIONS
The interictal EEG is normal. The ictal EEG shows diffuse discharge with onset in the central occipital region.
Laboratory, radiological, and neurological findings are normal.
A genetically heterogeneous condition with loci mapped to chromosomes 16 and 19.
Benign sleep myoclonus
SIGNS / SYMPTOMS
A non-epileptic condition characterised by myoclonic jerks that occur only during sleep and stop abruptly when the child is aroused.
It is frequently confused with epileptic seizures during infancy.
It resolves by 1 year of life.[36]
INVESTIGATIONS
EEG is normal.
Gastrointestinal reflux
SIGNS / SYMPTOMS
Reflux may mimic seizures, especially in the infant and neonate.
Sandifer's syndrome is a variant that presents with neck or trunk twisting.
INVESTIGATIONS
EEG is normal.
pH probe studies demonstrate abnormally low pH.
Benign myoclonus of infancy
SIGNS / SYMPTOMS
Syndrome similar to infantile spasms with features of flexion spasm in early infancy.
The series of spasms can occur during wakefulness, during sleep, and immediately after awakening.
There is no mental and psychomotor involvement, and infants have a normal development.
INVESTIGATIONS
EEG is normal during wakefulness and sleep.
Infantile colic
SIGNS / SYMPTOMS
Intermittent prolonged bouts of crying and stiffening.
INVESTIGATIONS
EEG is normal.
Benign infantile head drops
SIGNS / SYMPTOMS
Frequent head drops with onset at 3-6 months of age.
This entity is self-limited.
INVESTIGATIONS
EEG is normal.
Motor stereotypies
SIGNS / SYMPTOMS
Can mimic spasms.
Stereotypies can present in children with autism spectrum disorder and other developmental disorders.
They typically present at a later age than infantile spasms, though usually before the age of 3 years old.
INVESTIGATIONS
EEG is normal.
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