Mycobacterium avium complex (MAC) infection

A31.0


DESCRIPTION

Atypical mycobacterium, causing disease in extremely immunocompromised patients.
MAC infection in HIV-infected children usually presents with disseminated disease, often enlarged intra-abdominal lymph nodes and pancytopaenia.
Pulmonary, GIT or skin disease is less common.

DIAGNOSTIC CRITERIA

  • MAC may be isolated from blood, bone marrow, lymph node, other sterile fluids and tissues.
  • Confirm diagnosis with a biopsy for histology and culture or 2 culture-positive sputa or gastric aspirates. MAC commonly colonizes the lungs and when isolated is most frequently not of clinical relevance. When diagnosis is in doubt consult a paediatric infectious disease specialist or microbiologist prior to initiating therapy.
  • PCR line probe test can be used for diagnosis.

GENERAL AND SUPPORTIVE MEASURES

  • If MAC infection is localised to a single enlarged peripheral lymph node, an excision of the lymph node is therapeutic.

MEDICINE TREATMENT

Specialist initiated.
Identify and treat predisposing immune suppression.
Therapy consists of a combination of at least two medicines.

  • Macrolide e.g.:
  • Clarithromycin, oral, 7.5mg/kg/dose 12 hourly.
    OR
  • Azithromycin, oral 10 mg/kg/day, if currently on efavirenz.
    PLUS
  • Ethambutol, oral, 20–25 mg/kg once daily.

REFERRAL

  • Poor response to treatment should be referred for consideration of a quinolone, amikacin, or rifabutin.