There may be a latent period of several months in which health seems normal, to be followed by the sleeping-sickness stage. It has also been noted that untreated cases, as well as those receiving more or less treatment, may remain in good health for periods up to several years. There is therefore reason to believe that certain cases may not enter upon the sleeping sickness stage.
Fig. 32.—Cases of trypanosomiasis showing the edema especially about eyes. (Ruge and zur Verth after Koch.)
The Stage of Sleeping Sickness.—In this stage the mentality becomes more weakened. The native from being happy and willing to work becomes morose and apathetic. This change of disposition is frequently the first thing to be noted in a patient by his family. There is a tendency to gaze into the distance. The speech is rather low and tremulous like that of a tired, sleepy child. The tongue especially shows a decided tremor which may also be present in the lips and hands.
The gait is one of weakness and apathy—a shuffling gait. The reflexes may be exaggerated. Romberg’s sign may be present but the Argyll-Robertson pupil has not been noted. There may be an alternation of periods of crying and laughing which with the occasional exhibition of intention tremor and rarely nystagmus may make one think of multiple sclerosis. The patient tends to sleep even when lying in a bright sunlight. Again he may go to sleep with a morsel of food in his mouth. Notwithstanding the apparent stupid state of the patient, he will, when aroused, answer fairly intelligently but with apathy and retardation. The hebephrenic and catatonic manifestations of dementia praecox may be exhibited in some cases.
Finally the patient becomes weaker and more emaciated. The pulse becomes rapid and feeble, the blood pressure being extremely low. The mouth becomes dry, the teeth covered with sordes and bed sores develop. There may be convulsions. The coma and general weakness become more marked and the patient dies. Frequently terminal pneumonias or dysenteries bring about the end.
The sleeping sickness stage rarely lasts longer than a year and even with treatment not more than two years.
The Symptoms in Detail
The Nervous System.—Headache and lack of mental concentration may be early features of the disease. Deep hyperaesthesia, or Kérandel’s sign, often present. Patients tend to be morose and apathetic. Tremor of tongue and lips are rather constant signs about the commencement of the stage of sleeping sickness. Early insomnia gives way to the drowsiness that characterizes the second stage. There is very little disturbance of sensory or motor functions until near the end. Epileptiform convulsions may be late manifestations. Coma deepens as the end approaches.
The Temperature Curve.—The febrile paroxysms, which may not be present in natives until the sleeping-sickness stage, show great irregularity of course and a marked remission in the morning. The fever may be absent for several weeks to return later. Trypanosomes are more apt to be present in the peripheral circulation during the fever than when the temperature is normal.