HUMAN AFRICAN TRYPANOSOMIASIS (Sleeping Sickness)

A disease caused by trypanosomes (a protozoa) and transmitted to humans by several species of tsetse fly

Cause

  • Trypanosoma rhodesiense (mostly in the Central and Eastern regions of Uganda)
  • Trypanosoma gambiense (mostly in West Nile region)

Clinical features

  • May be history of tsetse fly bite and swelling at site of bite after 7-14 days (more often in T. rhodesiense, rarely in T. Gambiense)

T. Rhodesiense

  • Incubation is 2-3 weeks
  • Early stage (haemolymphatic stage): headache not responding to common analgesics, fever, generalised lymphadenopathy, joint pains
  • Late stage (meningoencephalitis stage): after some weeks, neurological and psychiatric symptoms like apathy, day sleepiness, paralysis, seizures
  • If not treated: cachexia, lethargy, coma and death within 3-6 months

T. gambiense

  • Similar to the rhodesiense but less acute and with slower progression
  • Incubation can last several years

Differential diagnosis

  • Malaria, meningitis
  • TB, HIV/AIDS

Investigations

  • Blood: Slides for trypanosomes
  • CSF: For trypanosomes, lymphocyte count
  • Aspirate from chancre/lymph node: for trypanosomes

Management

This is based on the findings of the CSF analysis, determining the stage of disease. To determine the medicine of choice, the disease is divided into two stages: early and late stage

STAGE FEATURES
Early (first)
stage
  • CSF is normal
  • Lymphocytes <5 cells/mm3
  • Total protein <37 mg/dl (by dye-binding
    protein assay) or < 25 mg/dl (by Double
    Standard & Centrifuge Method)
    yy Absence of trypanosomes (by Double
    Standard and Centrifuge Method)
Late (second)
stage
  • Lymphocytes > 5 cell/ mm3
    And/or
  • Presence of trypanosomes

Patient with suspected or diagnosed sleeping sickness
should be managed at referral facilities.

TREATMENT

Early (first) stage

T. rhodesiense sleeping sickness
For both children and adults

  • Suramin IV
    • A test dose of 5 mg/kg of body weight should first be administered to test for anaphylactic reaction
    • Followed by five injections of 20 mg/kg every 5 days interval
      1. Day 0: 5 mg/kg body weight
      2. Day 3: 20 mg/kg body weight
      3. Day 8: 20 mg/kg body weight
      4. Day 13: 20 mg/kg body weight
      5. Day 18: 20 mg/kg body weight
      6. Day 23: 20 mg/kg body weight

If anaphylaxis: do not administer

T. gambiense sleeping sickness

For both children and adults

  • Pentamidine IM 4 mg/kg daily for 7 days
    • Give food 1 hour before to prevent hypoglycaemia
    • The patient should be in a supine position during administration and 1 hour after to prevent hypotension

Late (second) stage

T. rhodesiense sleeping sickness
For both children and adults

  • IV Melarsoprol 2.2 mg/kg body weight daily for 10 days

T.gambiense sleeping sickness
Children ≤ 12 years and <35 kg

  • Eflornithine IV 150 mg/kg 6 hourly for 14 days (total dose of 600 mg/kg/day. Dilute 150 mg/kg dose of eflornithine into the 100 ml of distilled
    water. Administer the infusion over at least 2 hours

Children >12 years up to 15 years

  • Eflornithine IV 100 mg/kg 6 hourly for 14 days (total dose of 400 mg/kg per day). Dilute the eflornithine dose of 100 mg/kg into the 100 ml of
    distilled water. Administer the infusion over at least 2 hours (rate 20 drops/minute)

Adults >15 years

  • Nifurtimox/Elfornithine combination therapy (NECT)
  • Nifurtimox: 5 mg/kg every 8 hours orally for 10 days (15 mg/kg/day)
  • Plus Eflornithine 200 mg/kg 12 hourly for 7 days (400 mg/kg/day). Dilute Eflornithine dose of 200 mg/kg into 250 ml of distilled water and
    administer the infusion over at least 2 hours (50 drops/minute)
  • Infusions are given slowly to prevent convulsions
Relapses
  • IV melarsoprol 2.2 mg/kg once daily for 10 days

Note

  • Corticosteroids: Should be given to patients with late trypanosomiasis on melarsoprol who may have hypoadrenalism – the steroids may also reduce any drug reactions
  • Do not give hydrocortisone after day 24, even though the melarsoprol treatment is not yet complete If prednisolone is used instead of hydrocortisone, the anti-inflammatory action is similar but the correction of
    the hypoadrenalism will be much less marked
  •  Suramin: Do not use this medicine for early or late stage
    T. gambiense treatment in onchocerciasis-endemic areas as it may cause blindness in any onchocerciasis-infected patients by killing the filariae in the eye

Prevention

  • Trapping of tsetse flies
  • Clearing of bushes around homes and paths
  • Early detection and treatment of cases