Differentials
Malaria
SIGNS / SYMPTOMS
Signs and symptoms in early stages of disease are similar.
Absence of inoculation chancre or enlarged cervical nodes.
Response to antimalarials.
Dual infection is frequent in endemic areas.
INVESTIGATIONS
Malaria rapid diagnostic test is positive. High rates of false-positive results occur with sera from Trypanosoma brucei gambiense patients in malaria antigen detection tests.[113] Confirm malaria by microscopic examination.
Microscopic examination does not exclude diagnosis of human African trypanosomiasis (HAT), as co-infection is frequent.[114] It is possible to find the trypanosomes in thick and thin films when looking for Plasmodium.
Typhoid fever
SIGNS / SYMPTOMS
Similar signs and symptoms in early stages of disease.
Absence of inoculation chancre.
Response to antibiotics.
INVESTIGATIONS
If a Widal test is performed, a rise in antibody titres in serum against O and H antigens suggests typhoid.
Isolation of Salmonella typhi in blood culture confirms typhoid.
Relapsing fever
SIGNS / SYMPTOMS
Clinical presentation is similar to first-stage HAT.
Absence of inoculation chancre.
No response to antibiotics.
INVESTIGATIONS
Presence of Borrelia in blood films clearly orientates the diagnosis.
Fever of unknown origin in adults
SIGNS / SYMPTOMS
Epidemiological data may suggest HAT.
Absence of enlarged cervical nodes or an inoculation chancre suggests that it may not be HAT.
INVESTIGATIONS
Absence of trypanosome detection by microscopy.
Fever of unknown origin in children
SIGNS / SYMPTOMS
Epidemiological data may suggest HAT.
Absence of enlarged cervical nodes or an inoculation chancre suggests that it may not be HAT.
INVESTIGATIONS
Absence of trypanosome detection by microscopy.
Tuberculous scrofula
SIGNS / SYMPTOMS
General status and presence of enlarged cervical nodes may be similar in tuberculous scrofula and HAT, but the consistency of the cervical lymph nodes in tuberculosis is usually different (bigger, fluctuant, matting).
INVESTIGATIONS
Presence of acid-fast bacilli (AFB) on microscopy.
Tuberculous meningitis
SIGNS / SYMPTOMS
Second-stage HAT can have a similar presentation.
Cranial and peripheral nerve involvement is more frequent in tuberculous meningitis.
Antecedents of pulmonary tuberculosis can aid diagnosis.
INVESTIGATIONS
Presence of AFB on microscopy or cerebrospinal fluid (CSF) culture.
Encephalitis
SIGNS / SYMPTOMS
Second-stage HAT can present as an encephalitis, but viral encephalitis usually has more focal neurological deficit.
Epidemiological data can orientate the diagnosis.
INVESTIGATIONS
CSF analysis (protein, IgM, etc.) may be similar.
Peripheral blood smear, blood culture, throat swab, sputum culture, or CSF culture will show causative organism.
Cryptococcal meningitis
SIGNS / SYMPTOMS
Clinical presentation can be similar to second-stage HAT.
Epidemiological data can show differences.
Presence of progressive, severe headache.
INVESTIGATIONS
Cryptococcal antigen and Indian ink stain are usually positive.
HIV infection
SIGNS / SYMPTOMS
Clinical presentation can be similar to second-stage HAT; however, co-infection is possible.
INVESTIGATIONS
HIV test is positive. High rates of false-positive results occur with sera from T b gambiense patients in HIV antibody detection tests.[115] Confirm HIV infection by other tests and after treating HAT.
If the trypanosome is not immediately detected, HIV is often suspected.[29][30][116][117]
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