MAC refers to various non-tuberculous mycobacteria such as M. avium, M. intracellulare, and M. paratuberculosis. MAC can appear as isolated lymphadenitis among HIV infected children. Defective cell mediated immunity with CD 4 count as low as < 50 cells/cumm is an important risk factor for development of MAC. Lungs, liver, spleen, GI tract, bone marrow and lymph nodes are common sites involved.
Clinical features
Isolated pulmonary disease is rare. Patients present with recurrent fever, weight loss or failure to thrive, neutropenia, night sweats, fatigue, chronic Diarrhea and recurrent abdominal pain. Patients have lymphadenopathy, hepatomegaly and splenomegaly. Associated laboratory findings of neutropenia, anemia and leukopenia are seen.
Diagnosis
Is accomplished by isolation of organism from blood or biopsy sites (bone marrow, lymph node or other tissues). Culture can yield the organisms in 2 weeks. Culture is necessary for species identification.
Treatment
Combination therapy with a minimum of 2 drugs is recommended. Clarithromycin or Azithromycin plus Ethambutol is recommended. Additional drugs such as Rifabutin, Ciprofloxacin, Amikacin or Streptomycin may be considered depending on severity of the disease. For disseminated disease, 3 or 4 drugs are essential. Most patients show improvement within 4-6 weeks. Treatment should then be continued with 2 drugs.
Prophylaxis
- After initial treatment, secondary prophylaxis is recommended for life time.
- As per CD4 count primary prophylaxis is advocated. In infants, CD4 count <750/cumm, between 1-2 years CD4 count < 500/cumm, 2-6 years CD4 count < 75/cumm, > 6 years CD4 count < 50/cumm.
- Any child in CDC Class C or WHO Stage IV.
- Prophylaxis may be stopped if CD4 percent is more than 15% for 6 months and ART has been continued for more than 12 months and child is asymptomatic.
- For primary prophylaxis any one of the 2 drugs (clarithromycin, Azithromycin) is used for prophylaxis.
- Secondary prophylaxis consists of 2 drugs out of the following clarithromycin or Azithromycin and Rifabutin or Ethambutol or Ciprofloxacin.
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Drugs
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Dosage
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Clarithromycin
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15 mg/kg/day PO BD (max 500 mg/day)
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Azithromycin
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20 mg/kg/day PO weekly (max 1.25 gm/day
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Ethambutol
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15-20 mg/kg/day PO OD (max 1.5 gm/day)
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Rifabutin
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5-10 mg/kg/day PO OD (max 300 mg/day)
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Ciprofloxacin
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20-30 mg/kg/day PO/IV OD/BD (max 1.5 gm/day)
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