PERSISTENCE OF THE NOCTURNAL THYROTROPIN SURGE AND PRESERVATION OF THE SLEEP-RELATED VARIATIONS OF TSH IN AFRICAN TRYPANOSOMIASIS

The aim of this work was to study the nycthemeral and sleep-related va riations of thyrotropin (TSH) in sleeping sickness (Human African tryp anosomiasis). Six untreated patients were studied during 24 hours usin g 10 min blood sampling and polygraphic sleep recordings. These patien ts were compared to 5 healthy African subjects. The patients were sele cted during a medical investigation in Congo. Sleeping sickness was di agnosed clinically and confirmed by the detection of Trypanosoma bruce i gambiense in the blood, the cerebrospinal fluid, or in a lymph node puncture, and by a serologic immunofluorescence test. Blood was withdr awn continuously via a catheter and sampled into 10 min aliquots in an adjoining room. TSH was measured by a commercial IRMA kit. Sleep was recorded by continuous polysomnography and scored visually. The integr ity of the sleep-wake cycle varied greatly among patients, ranging fro m major disruption with insomnia to almost undisturbed nocturnal sleep . Mean TSH levels were slightly higher in the patients than in the con trols, although the difference was not significant. The nocturnal surg e was preserved in all but one patient and its amplitude was not diffe rent between patients and controls. There were more TSH pulses in the patients, maybe due to fragmented sleep with many awakenings. The rela tionships between sleep structure and TSH variations were preserved, w ith decreasing TSH levels during slow-wave sleep and increasing levels after awakenings. We conclude that contrarily to other biological rhy thms, the nycthemeral pattern of TSH is preserved in the sleeping sick ness patients. The TSH nocturnal surge persisted, unlike in other nont hyroidal illnesses. The relationships between TSH variations and sleep structure are also preserved, demonstrating the robustness of this as sociation.