Updated: 12/30/2021

Mycobacterium Other Than Tuberculosis (MOTTS)

Review Topic
  • Snapshot
    • A 4-year-old boy presents to the pediatrician by his mother due to noting a lump under his mandible. She first noticed the lump approximately 2 weeks ago and it has progressively increased in size. On physical exam, the patient does not appear to be in any acute distress. There is a 2-3 cm, nontender mass with parchment-like skin overlying the mass. The mass is drained and cultures and a polymerase chain reaction are sent of the mass. (Superficial lymphadenitis likely caused by MAC)
  • Introduction
    • Definition
      • infectious mycobacterium that is not tuberculosis, which can cause 4 clinical syndromes
        • pulmonary disease
          • caused by Mycobacterium avium complex (MAC)
        • superficial lymphadenitis
          • caused by
            • MAC (more common in children)
            • M. scrofulaceum
            • M. malmoense
        • disseminated disease in immunocompromised patients (e.g., AIDS)
          • most commonly caused by MAC
        • skin and soft tissue infection
          • most commonly caused by M. marinum
            • typically due to direct inoculation of the organism
      • Nontuberculous Mycobacterium
      • Disease
      • Clinical Presentation
      • Making the Diagnosis
      • Comments
      • Pulmonary disease
      • Symptoms are typically non-specific and depend if the patient has underlying pulmonary disease:
      • patients with underlying pulmonary disease typically present similar to tuberculosis (e.g., cough, weight loss, upper lobe infiltrates, and cavities)
      •  Symptoms include:
      • cough (dry or productive)
      • fatigue
      • malaise
      • dyspnea
      • weakness
      • Based and clinical and radiographic findings (e.g., nodular or cavitary opacities or multifocal bronchiectasis)
      •  Sputum acid-fast bacilli and culture
      •  Lung biopsy with mycobacterial histopathologic features (granulomatous inflammation or acid fact bacillus), if needed
      • --
      • Superficial lymphadenitis
      • Enlarged lymph nodes
      • most commonly the cervicofacial node in children
      • nontender and unilateral
      • enlarges over the course of weeks
      • Culture or polymerase chain reaction (PCR) of the fistula drainage, tissue, or caseous material
      • Most commonly affects children < 5 years of age
      • Disseminated disease
      • Fever
      •  Fatigue
      •  Malaise
      •  Anorexia
      •  Sequelae of organ involvement:
      • bone marrow (neutropenia and anemia)
      • hepatosplenomegaly
      • Blood cultures of the mycobacterium
      • Risk factors include
      • advanced HIV infection
      • hematologic malignancy
      • tumor necrosis alpha inhibitors or other immunosuppressive agents
      • Skin and soft tissue infection
      • Skin lesion
      • erythematous or bluish papule or nodule at the site of abrasion
      • lymphadenopathy may be present
      • Culture or PCR of the lesion
      • Fisherman or people who work at aquariums are at risk of developing M. marinum infection
  • Epidemiology
    • Incidence
      • the most common nontuberculous species that cause disease in humans in the United States are
        • MAC
        • M. kansasii
  • Treatment
    • Medical
      • macrolide, rifamycin, and ethambutol
        • indication
          • initial empiric treatment option for MAC
        • comments
          • in cases of macrolide-resistance, the regimen is changed to rifamycin, ethambutol, clofazimine, and an intravenous aminoglycoside
          • note, the appropriate treatment for M. marinum has not been identified
  • Complications
    • Dissemination of the nontuberculous mycobacterium can occur in severely immunocompromised patients
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