Ruptured popliteal cyst and pyogenic arthritis.

Chadwick et al divided a group of patients with supraspinal myoclonus into three categories.3 One group responded poorly to serotonergic drugs-namely, clonazepam and 5-hydroxytryptophan; a second group had proximal myoclonus, prominent spikes on the electroencephalogram, excellent response to serotonergic drugs, and physiological features suggesting that abnormal discharges originated in the brain-stem reticular formation (reticular reflex myoclonus). The third group showed mainly distal myoclonus, few sharp waves on the electroencephalogram, and only moderate response to serotonergic drugs; a cortical origin of the myoclonus was postulated for this group. Recently Chadwick and French' suggested that two uraemic patients whom they studied clinically had reticular reflex myoclonus.