Sleeping sickness

Definition:

Sleeping sickness is an infectious parasitic disease carried by tsetse flies from the Trypanosoma brucei family of parasites and characterized by inflammation of the brain and the covering of the brain (meninges).

Alternative Names:

African trypanosomiasis

Causes, incidence, and risk factors:

Sleeping sickness is caused by two organisms, T. brucei rhodesiense and T. brucei gambiense. Rhodesiense produces the more severe form of the illness.

After a person is bitten by an infected fly, a red painful swelling develops at the site of the fly bite, similar to that seen in Chagas disease. From this site of inoculation, the parasite invades the blood stream causing episodes of fever, headache, sweating, and generalized enlargement of the lymph nodes. Parasites then invade the central nervous system (early with rhodesiense and later with gambiense) where they produce the symptoms typical of sleeping sickness.

Ultimately the parasites invade the brain, causing first behavioral changes such as fear and mood swings followed by headache, fever, and weakness. Simultaneously, the patient may develop myocarditis.

Death may occur within 6 months from cardiac failure or infection if the person is infected with rhodesiense. Gambiense infection may require up to 2 years before symptoms of infection in the central nervous system appear.

Gambiense-infected people develop drowsiness during the day, but insomnia at night. Sleep becomes uncontrollable as the disease progresses until the patient becomes comatose.

Risk factors include living in those parts of Africa where the disease is found and being bit by tsetse flies. The incidence is extremely low in the U.S., and is only found in travelers from those areas.

Symptoms:

Swollen red painful nodule at site of inoculation
Generalized lymphadenopathy (swollen lymph nodes all over the body)
Headache
Fever
Sweating
Anxiety
Increased sleepiness
Insomnia at night
Mood changes
Drowsiness
Uncontrollable urge to sleep

Signs and tests:

Physical examination may show signs of meningoencephalitis (inflammation of the brain and meninges).

Tests include the following:

Peripheral blood smear (demonstrates motile trypanosomes in blood)
Lymph node aspiration (demonstrates motile trypanosomes in node material)
CSF (demonstrates motile trypanosomes in CSF)
Low red blood cell count in blood
Elevated globulin levels
Low albumin levels
Elevated ESR
Antibody and antigen test are not very helpful

Treatment:

Medications used to treat this disorder include:

Suramin (Antrypol)
Melarsoprol
Pentamidine

Expectations (prognosis):

Untreated rhodesiense infection is almost universally fatal. Gambiense infection causes the classic "sleeping sickness" disease. Both diseases should be treated immediately upon diagnosis. The diseases are easier to treat during the blood-borne stage and more difficult to treat once meningoencephalitis develops.

Complications:

Injury related to falling asleep while driving or engaging in similar activities
Progressive damage to the nervous system

Calling your health care provider:

Call your health care provider if symptoms of this disorder develop. It is important to begin treatment as soon as possible.

Prevention:

Pentamidine injections protect against gambiense, but have not yet been demonstrated as effective against rhodesiense. Insect control could help prevent the spread of sleeping sickness.

Review Date: 8/17/2001
Reviewed By: Camille Kotton, M.D., Infectious Diseases Division, Massachusetts General Hospital and Brigham and Women's Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.

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