Rheumatic chorea; clinical, neurophysiological, and laboratory study

ABSTRACT

Rheumatic Chorea [Rh.C.] is the only extrapyramidal syndrome presents with hypotonia. However the pathogenesis of this hypotonia is not known. Still it is not known whether it is due to peripheral or central lesion. This work was designed to study the neurophysiologic and laboratory correlates of hypotonia in Rh. C. patients. The study included 20 patients with Rheumatic Chorea [15 females and 5 males] with mean age 77.7 +/- 5.5, they were subjected to complete neuropsychiatric examination with evaluation of the duration and severity of chorea, electrophysiologic studies including; Distal Latency [DL], Motor Conduction Velocity [MCV], Compound Muscle Action Potential [cMAP], F.wave, H.Reflex latencies; and laboratory studies including; detection of ESR, ASOT, and serum immunoglobulin IgG. Neurophysiologic parameters were matched to that of 30 control subjects with mean age [13.1 + 5.4], and serum immunoglobulin G was compared to that of 12 normal control subjects with mean age 14.2. The study revealed that 70% were experiencing their 1[st] choreic acute attack, 15% had history of recurrence. [2[nd] attack] and 15% had chronic persistent Rh.C. Neurological examination revealed that 80% of our patients had hypotonia. Choreic movement were generalized in 95% of cases, but mostly asymmetrical [55%]. Neurophysiologic studies revealed generalized disruption of peripheral nerve function in comparison to controls, mainly of mixed type [50%.]. In the demyelinating type; proximal involvement was more common than distal involvement. ESR was elevated in 65% and 95% of cases at the 1[st] and 2[nd] hour respectively, while positive ASOT was recorded in 30% of cases only. There was significant positive correlation between serum level of IgG and various studied neurophysiologic parameters [F-wave and H-Reflex latencies, DL, and MCV]. But there was no significant relation between the distribution of hypotonia and the studied neurophysiologic parameters, which may suggest a possible role of other contributing factors, not yet studied