Paroxysmal non-epileptic events Category Condition Clinical features Investigations ...

Differential diagnosis of seizures with fever The following diagnostic possibilities exist, these not being mutually exclusive. 1. The convulsion is not an epileptic seizure nor an anoxic seizure but is a rigor or an hallucination or febrile myoclonus or febrile ataxia. 2. The seizure is a febrile syncope similar to a syncope suffered by adults with influenza and fever. 3. The seizure is a syncope due to ventricular tachyarrhythmia precipitated by fever Brugada syndrome (a sodium channelopathy with several...

Condition Clinical Investigations Down syndrome Infantile spasms common (2%) and easily overlooked Interictal EEG slow general spike wave or hypsarrhythmia (chromosomes of course) 1p36 deletion Dysmorphism with straight eyebrows and deep-set eyes, the most common seizure type is infantile spasms Karyotype, fluorescent in situ hybridization, multiplex ligation-dependent probe amplification Ring chromosome 14 ...

EEG pattern in common epileptic seizures Seizure type Semiology Ictal EEG Ictal EMG (both deltoids) Comments ...

 

This test measures basal and post-exercise venous lactate and ammonia levels. The blood lactate is measured after the fist has been clenched repeatedly for 1 minute with the arm made ischaemic using a sphygmomanometer. Samples are taken at -10 minutes (pre-exercise) and at 0, 1, 3, 5, 10 and 20 minutes following release of the cuff. A normal response is characterized by a lactate increase of 3-5 fold over baseline with a peak at 1-3 minutes post-exercise, while ammonia increases 5-10 fold over the same time. An absent or inadequate (less than 1.5-fold) increase in lactate is...

This is a method for stressing the pterin system, but may be unreliable. It was developed as a biochemical marker for pterin synthesis defects associated with dopamine-responsive dystonia, especially GTP-CH deficiency. A dose of 100mg/kg of phenylalanine is used. A phenylalanine/tyrosine ratio >7.5 is suggestive, but not diagnostic, of a pterin synthesis defect. The phenylalanine must rise above 600umol/l. for the test to be valid. This test has low sensitivity and specificity.

Employed for definitive diagnosis of Niemann-Pick type C phenotype.

Usually done in peroxisomopathies, but essential for diagnosis of DBP deficiency when plasma studies are normal.