From the Guidelines
Mycobacterium avium complex (MAC) infection typically presents with symptoms such as fever, night sweats, weight loss, abdominal pain, and diarrhea, particularly in immunocompromised individuals, as noted in a 2007 statement by the American Thoracic Society and Infectious Diseases Society of America 1.
Clinical Presentation
The clinical manifestations of MAC can be diverse and may resemble other infections, making diagnosis challenging. Key symptoms include:
- Fever (80% of cases)
- Night sweats (35% of cases)
- Weight loss (25% of cases)
- Abdominal pain or diarrhea
- Severe anemia, with a hematocrit of less than 25%
- Elevated alkaline phosphatase and lactate dehydrogenase levels These symptoms often develop within 1 to 2 months before the onset of bacteremia with the organism, as reported in the 2007 study 1.
Patient Profile
MAC infections commonly affect individuals with pre-existing conditions, such as advanced HIV infection, or those with compromised immune systems. In these patients, the disease can disseminate throughout the body, causing more severe symptoms.
Diagnosis and Treatment
Diagnosis of MAC requires specialized cultures from respiratory specimens or blood. Treatment typically involves a multi-drug regimen of antibiotics, including macrolides, ethambutol, and rifampin, and is often continued for an extended period, as indicated by the 2007 guidelines 1.
From the FDA Drug Label
(2) Clinically significant disseminated MAC disease, defined as MAC bacteremia accompanied by signs or symptoms of serious MAC infection, including one or more of the following: fever, night sweats, rigors, weight loss, worsening anemia, and/or elevations in alkaline phosphatase. In association with the decreased incidence of bacteremia, patients on rifabutin showed reductions in the signs and symptoms of disseminated MAC disease, including fever, night sweats, weight loss, fatigue, abdominal pain, anemia, and hepatic dysfunction
The symptoms of Mycobacterium avium complex (MAC) include:
- Fever
- Night sweats
- Rigors
- Weight loss
- Worsening anemia
- Elevations in alkaline phosphatase
- Fatigue
- Abdominal pain
- Hepatic dysfunction 2
From the Research
Symptoms of Mycobacterium Avium Complex
- The symptoms of Mycobacterium avium complex (MAC) infection can manifest as disseminated infection, soft tissue infection, chronic pneumonia, or hypersensitivity pneumonitis 3.
- Pulmonary symptoms, nodular or cavitary opacities on a chest radiograph or high-resolution computed tomographic scan with multifocal bronchiectasis and multiple small nodules, plus positive culture results from two sputum specimens or one bronchoscopic specimen are consistent with MAC pulmonary disease 3.
- Disseminated MAC infection is a common complication of late-stage HIV-1 infection, and patients with low CD4 cell counts remain at risk 4.
- The infection can cause bacteremia, which is a common complication in patients with AIDS, and the most effective treatment for this infection remains unclear 5.
Disease Manifestation
- MAC infection may manifest as: + Disseminated infection + Soft tissue infection + Chronic pneumonia + Hypersensitivity pneumonitis 3
- The disease can also cause suppurative lymphadenitis and subcutaneous or soft-tissue abscesses in patients who show a good immunological and virological response to HAART 6.
Patient Risk Factors
- Patients with low CD4 cell counts are at risk of developing MAC infection 4.
- Patients who ignore their serological status for HIV, or who are not receiving or do not tolerate HAART, are at high risk of developing disseminated MAC disease 6.
- Younger age, no use of HAART, and enrollment before 1996 are factors associated with developing MAC 4.