AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Background

Mycobacterium avium complex (MAC) consists of two species—M avium and Mycobacterium intracellulare. MAC causes disseminated infection in immunocompromised hosts, but only a minority of immunocompetent hosts develop MAC lung disease. Patients with underlying lung disease or immunosuppression may develop progressive lung disease secondary to MAC. More than 95% of MAC infections in patients with AIDS are caused by M avium, while 40% of infections in immunocompetent patients are caused by M intracellulare. MAC is the most common cause of infection by nontuberculous mycobacteria (NTM) in patients with AIDS.

MAC is ubiquitous in distribution. It has been isolated from freshwater and saltwater worldwide. The common environmental sources of MAC include aerosolized water, piped hot water systems, including household and hospital water supplies, house dust, soil, birds, farm animals, and cigarette components such as tobacco, filters, and paper.

Pathophysiology

The modes of transmission include inhalation through the respiratory tract and ingestion via the GI tract.

MAC can invade and translocate across the mucosal epithelium. They subsequently infect the resting macrophages in the lamina propria and spread in the submucosal tissue; they are then carried to the local lymph nodes by lymphatics. In immunocompromised hosts, such as patients with AIDS, they are subsequently spread via hematogenous route to the liver, spleen, bone marrow, and other sites.

Patients with AIDS and lymphomas usually develop disseminated MAC (DMAC) infection when their CD4 count falls to less than 50 cells/µL. In patients with AIDS, colonization of the GI or respiratory tract has been associated with an increased risk of developing MAC bacteremia. Approximately 60% of patients colonized in one series developed bacteremia; however, screening cultures from the respiratory or GI tract is not useful because most patients who develop bacteremia are not colonized prior to developing disseminated disease.

The most important risk factor for MAC infection in patients negative for HIV is underlying lung disease. Pulmonary infection is the most common manifestation in these patients. It can also cause lymphadenitis in children. MAC has surpassed Mycobacterium scrofulaceum as the most common cause of cervical adenitis in developed countries.

Both tumor necrosis factor (TNF)–a and interferon gamma (IFN-gamma) play important roles in defending against mycobacterial infections. Like other mycobacteria, MAC can also cause disseminated infection in multiple family members who have genetic defects resulting in deficiency of IFN-gamma receptor expression or IFN-gamma production.

MAC has also been associated with the pulmonary infection and bronchiectasis in elderly women without a pre-existing lung disease. This group of patients are believed to develop pulmonary MAC infection as a result of voluntary cough suppression that results in stagnation of secretions, which is suitable for growth of the organisms. This particular type of infection is also referred to as Lady Windermere syndrome.

Frequency

United States

Infections with NTM were reported more frequently after the cases of tuberculosis declined in the 1950s. During 1979-80, NTM represented one third of mycobacterial isolates reported to the Centers for Disease Control and Prevention (CDC), and 61% of these were MAC. Two of the most predominant NTM infections in the United States are MAC and Mycobacterium kansasii.

DMAC is the most common mycobacterial infection in patients with advanced AIDS. Its prevalence increased in 1980s and early 1990s with the advent of HIV and AIDS in the United States but has declined since with the use of highly effective antiretroviral therapy (HAART). Prior the widespread use of combination antiretroviral therapy, 30% of patients with HIV developed DMAC. In a 1996 study, only 2% of patients receiving HAART, including a protease inhibitor, developed DMAC.

Mortality/Morbidity

Immunocompetent patients may have MAC in their sputum without any evidence of lung disease. A transient colonization with MAC was reported in up to 11% of patients with tuberculosis in 1950s. Repeated isolation of MAC from sputum, even in the absence of obvious lung disease, may signify an underlying slow progression of lung disease.

• Prior to the availability of newer macrolides, the life expectancy of a patient with AIDS and DMAC was 4 months. In a 1999 study, patients treated with rifabutin, ethambutol, and clarithromycin had a median survival time of 9 months. Life expectancy is now longer because of the advent of HAART. The most common complication of DMAC is anemia that may require transfusion. Treatment success rate in patients without HIV have ranged from 20-90% in various studies, with an average of 50-60% clinical success and 60-75% of sputum conversion rates.
• The clinical course of pulmonary MAC in patients with HIV is usually indolent. Approximately 50% of patients in one study were alive 5 years after diagnosis. Patients with extensive parenchymal involvement may die of progressive respiratory failure, but patients with more limited disease have a low mortality rate.
• In children, MAC lymphadenitis generally has a benign course. It may resolve spontaneously or rupture and form a sinus tract in untreated cases.

Race

• MAC infection has no predilection for any race.

Sex

• A recent study showed that, regardless of underlying disease, M intracellulare is more pathogenic and tends to infect women increasingly beyond menopause. The prevalence rate of MAC in postmenopausal women was 1.86% in this study (Han, 2005).

Age

• Elderly women may be more likely to contract pulmonary MAC disease of the middle lobe, lingula, or both, which is also known as Lady Windermere syndrome.

CLINICAL

Section 3 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

History

M avium complex (MAC) infection usually presents in 1 of 3 forms: (1) pulmonary MAC in immunocompetent hosts, (2) disseminated MAC (DMAC) in individuals with advanced AIDS, or (3) lymphadenitis in children.

• Pulmonary MAC infection in immunocompetent hosts generally presents with cough, sputum production, weight loss, fever, lethargy, and night sweats. The onset of symptoms is insidious. Symptoms may be present for weeks to months. Many patients have only a chronic cough with purulent sputum production. Hemoptysis is rare in MAC infection. Less commonly, MAC may be a cause of hypersensitivity pneumonitis. Series of cases of hypersensitivity pneumonitis have been reported secondary to exposure to MAC in hot tubs.
• Patients with advanced AIDS (generally with CD4 counts <50 cells/µL) and DMAC infection commonly present with fever of unknown origin (FUO). They usually also have sweating, weight loss, fatigue, diarrhea, shortness of breath, and right upper quadrant abdominal pain. Additionally, patients with AIDS have been reported to have mastitis, pyomyositis, cutaneous abscess, brain abscess, GI mycobacteriosis, and immune reconstitution syndrome associated with MAC, which has been reported in patients with underlying MAC infection presenting shortly after the introduction of HAART.
• MAC lymphadenitis is predominantly a disease of children aged 1-4 years, primarily involving unilateral cervical lymph nodes. It usually involves submandibular and submaxillary lymph nodes, although preauricular, postauricular, and submental nodes may also be affected. Rarely, infection of the axillary, epitrochlear, or inguinal lymph nodes may develop following direct cutaneous inoculation. The lymph nodes usually enlarge insidiously but may enlarge more rapidly in younger children. Generally, they resolve spontaneously. The lymph nodes may also caseate and rupture through the skin, forming a sinus tract with chronic discharge.
• Less commonly, patients may present with skin and soft tissue infections, osteomyelitis, peritonitis (in patients with cirrhosis), bursitis, septic arthritis, and tenosynovitis.

Physical

Physical findings in MAC infection depend on the form of infection and type of patient.

• In immunocompetent patients with pulmonary MAC infection, generally lung crackles, rhonchi, or both can be heard on auscultation. Additionally, depending on the type of lung lesion and severity of infection, patients may have tachypnea, dullness on chest percussion, or bronchial breath sounds.
• DMAC infection in patients with AIDS can cause generalized wasting, skin pallor, tender hepatosplenomegaly, and lymphadenopathy.
• Lymphadenitis in children can cause unilateral enlargement of submandibular, preauricular, parotid, or postauricular lymph nodes. They are usually multiple, rubbery to firm, and may appear to be fixed to the deeper structures. They may become matted together as the disease progresses. The overlying skin may appear shiny, thin, and erythematous or violaceous. Sinus tracts may be present in advanced cases.
• Patients with synovitis may present with pain and swelling of a joint or features of bursitis or tenosynovitis.

Causes

MAC infections are caused by M avium and M intracellulare, which belong to the Runyon group 3 mycobacteria.

Some of the known predisposing factors for MAC infections are as follows:

• Pulmonary MAC infection is associated with chronic lung diseases, such as chronic obstructive pulmonary disease (COPD), chronic bronchitis, bronchiectasis, cystic fibrosis, mitral valve prolapse, skeletal abnormalities (eg, pectus excavatum, mild scoliosis, straight back), or lung cancer.
• MAC infection in patients with AIDS or lymphoreticular malignancies is associated with a CD4⁺ lymphocyte count of less than 50 cells/µL.
• Deficiency of IFN-gamma and TNF-a production and absence or defects of IFN-gamma receptors are also associated with infections with MAC and other mycobacteria.

DIFFERENTIALS

Section 4 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Other Problems to be Considered

Mumps
Parotid tumor
HIV wasting

WORKUP

Section 5 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Lab Studies

• Most of the patients with pulmonary M avium complex (MAC) infection have positive sputum on acid-fast bacillus (AFB) stain. Mycobacterial cultures grow MAC in about 1-2 weeks, depending on the culture technique and bacterial burden. However, interpretation of sputum AFB stain and culture may be difficult, as MAC can colonize the respiratory tract without causing clinical infection.
• In 1997, the American Thoracic Society (ATS) established diagnostic criteria for nontuberculous mycobacterial lung disease, regardless of the host's HIV status. The following criteria apply to symptomatic patients with a nodular or cavitary infiltrate revealed by chest radiograph or high-resolution computerized tomography (HRCT) scanning that shows multifocal bronchiectasis or multiple small nodules.
• • If at least 3 sputum or bronchial wash results are available from the previous 12 months, diagnosis requires either 3 positive culture results in the setting of negative AFB smear results or 2 positive culture results and 1 positive AFB smear result.
  • If only 1 bronchial wash is available, diagnosis requires positive culture results with heavily positive (2+, 3+, or 4+) AFB smear results or heavily positive (2+, 3+, or 4+) growth results on solid media.
  • If sputum or bronchial wash evaluations are nondiagnostic or if another disease cannot be excluded, diagnosis requires transbronchial or open-lung biopsy that yields either an NTM or compatible histopathologic features (granulomatous inflammation or AFB) plus 1 or more sputum or bronchial washings that are positive for an NTM.
• In a study that looked at the significance of positive sputum culture results using ATS guidelines for the diagnosis of NTM infection, only 7 of 46 patients with HIV and 1 of 34 patients without HIV but with MAC positive sputum met the clinical, bacteriologic, and radiographic criteria for pulmonary disease caused by MAC.
• Blood cultures in appropriate mycobacterial culture media should be drawn from patients with suspected disseminated MAC (DMAC) infection. This should be routinely performed in patients with advanced AIDS and persistent undiagnosed febrile illness. Cultures generally take 5-12 days to turn positive. Early in the course of infection, bacteremia may be low level or intermittent, in which case blood culture results may not be positive. Later in the course of infection, blood cultures are invariably positive.
• Diagnosis of lymphadenitis caused by MAC is based on a high level of clinical suspicion and biopsy of the nodes with histological and microbiological confirmation. Fine needle aspiration of lymph nodes has been used to obtain tissue for diagnosis when complete excision is not feasible. Results of acid-fast staining of tissue or pus are usually negative because of the small number of bacilli present. The culture result may take a few weeks to become positive. Nucleic acid amplification methods can provide a more rapid diagnosis. Skin testing (tuberculin test) contributes very little in establishing diagnosis.
• The species-specific molecular probes are used for rapid identification of mycobacterial species grown in culture (eg, Mycobacterium tuberculosis, M kansasii, MAC). Various nucleic acid amplification techniques (eg, polymerase chain reaction [PCR], ligase chain reaction, transcription-mediated amplification) are also used for this purpose, as well as for direct detection of mycobacteria in the sputum. However, these assays still need further refinement to improve their sensitivity to detect mycobacteria directly in patient's specimens.
• Mycobacterial susceptibility testing for various antimycobacterial agents are available in specialized laboratories.

Imaging Studies

• Chest radiography generally reveals MAC pulmonary lesions. However, in cases with limited lung infection, CT scanning of the chest and even HRCT scanning are needed to reveal the lung lesions. HRCT scanning has been shown to be more sensitive than chest radiography for revealing pulmonary abnormalities associated with MAC infection.
• • Patients with pulmonary MAC infection with underlying lung disease often have cavities revealed by imaging studies. Typically, these patients show fibrocavitary changes and nodules that involve the upper lung zones.
  • Elderly women without underlying lung disease but with MAC pulmonary infection develop a fibronodular bronchiectasis that often involves the lingula and right middle lobe. Surveys of patients with fibronodular bronchiectasis have documented MAC infection in 25-50% of patients.
  • Other radiological changes include atelectasis, consolidation, "tree in bud" appearance, and "ground glass" opacities.
• In patients with AIDS and DMAC infection, CT scan of the abdomen reveals retroperitoneal or periaortic lymphadenopathy and hepatosplenomegaly.

Other Tests

• Patients with DMAC usually have elevated transaminase and alkaline phosphatase levels.
• They are also usually anemic and occasionally pancytopenic due to bone marrow suppression secondary to the infection.

Procedures

• Bronchoscopy and transbronchial biopsy may be needed to diagnose pulmonary MAC infection. Alternatively, a CT-guided needle biopsy, video-assisted thoracoscopic (VAT) biopsy, or open lung biopsy may be performed, depending on the size and location of the lesion.
• Procedures that may be helpful to establish diagnosis of DMAC infection in patients with AIDS include lymph node biopsy, bone marrow biopsy, and liver biopsy. These procedures are indicated if the blood cultures fail to grow the mycobacteria. They are also helpful to exclude other causes of lymphadenopathy, anemia, or pancytopenia. Liver biopsy is rarely necessary to establish diagnosis of MAC.
• The procedure for lymphadenitis in children generally involves lymph node biopsy or complete excision of lymph nodes. A needle aspiration is performed for inaccessible nodes, such as those that overlie the facial nerve.

Histologic Findings

Histologic findings include necrotizing and nonnecrotizing granulomas and positive AFB smear results. The number of AFB is usually higher than in Mycobacterium tuberculosis infection. Patients with HIV have evidence of DMAC in multiple organs, but granuloma formation is less common. DMAC infection in patients with AIDS typically demonstrates the presence of sheets of macrophages laden with AFB.

Histologic findings of lymph nodes in children infected with MAC in a reported series generally showed bright eosinophilic serpiginous necrosis with nuclear debris scattered throughout the necrotic foci. Most of these cases also had Langhans-type giant cells, but infiltration by plasma cells and neutrophils was not consistently seen.

Patients with hypersensitivity pneumonitis secondary to MAC infection show multiple well-formed nonnecrotizing granulomas positive for AFB.

TREATMENT

Section 6 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Medical Care

Compared with tuberculosis, M avium complex (MAC) is relatively resistant to chemotherapeutic agents. MAC is intrinsically resistant to common antituberculosis drugs but is fairly susceptible to some antimycobacterial drugs, such as macrolides (clarithromycin, azithromycin), ethambutol, clofazimine, and rifamycins (especially rifabutin). In general, MAC infection is treated with 2 or 3 antimicrobials for at least 12 months.

• Antimicycobacterial agents used for treatment of MAC infection includes clarithromycin, azithromycin, rifabutin, ethambutol, levofloxacin, and amikacin. Second-line antituberculosis (anti-TB) drugs are also occasionally used.
• Newer fluoroquinolones, linezolid, and ketolides also demonstrate good in vitro activity against MAC and other mycobacteria, although not enough clinical data support their use against MAC infection.
• Treatment of pulmonary MAC infection in nonimmunocompromised patients involves a combination of a newer macrolide (azithromycin or clarithromycin), ethambutol, and rifabutin. Clofazimine has been successfully used in place of rifamycins with good outcome. Streptomycin has also been used successfully in combination with macrolides for the first 6-12 weeks in patients with cavitary disease. A macrolide-containing regimen has been shown to carry a cure rate of about 56%, including the dropouts and relapses in the analysis. Macrolides carry high rates of intolerance. Clarithromycin, a cytochrome P-450 inhibitor, interacts with many drugs metabolized in the liver. Similarly, rifamycins are known to induce hepatic enzymes and can alter metabolism of many drugs taken concomitantly.
• For treatment of patients with AIDS and disseminated MAC (DMAC) infection, combination of a newer macrolide antibiotic (clarithromycin, azithromycin) with ethambutol and rifabutin is probably the most active regimen.
• • Clear evidence demonstrates the efficacy of clarithromycin and azithromycin, but monotherapy with only one agent can lead to resistance. Published data suggest efficacy of azithromycin for MAC infection (55-60% success). Ethambutol appears to be the best second choice to combine with a macrolide. Rifabutin should be used as a third agent.
  • A study that compared clarithromycin and ethambutol (dual-therapy) with clarithromycin, ethambutol, and rifabutin (triple-therapy) showed improved microbiological clearance and survival in the triple-therapy arm.
  • A major problem with rifabutin is drug interactions. Higher doses of rifabutin (600 mg/d) are associated with higher rates of uveitis. Higher doses of clarithromycin (1000 mg bid) are associated with higher mortality rates.
• Fever should improve within 2-4 weeks of beginning therapy. If patients remain febrile longer than expected, repeat blood cultures and assess susceptibilities to antimicrobial agents. If the isolate is susceptible to macrolide and the infection is not responding to therapy, consider adding other agents such as a fluoroquinolone (eg, levofloxacin) or amikacin.
• Chemoprophylaxis is recommended for patients with HIV with a CD4+ lymphocyte count of less than 50 cells/µL. The drug of choice is either clarithromycin or azithromycin. One study that compared clarithromycin with placebo revealed an incidence of MAC bacteremia of 5.6% in patients taking clarithromycin and 15.5% in those taking placebo. Patients taking clarithromycin also had an improved survival rate. More than 50% of patients taking clarithromycin who developed bacteremia were infected with clarithromycin-resistant isolates.
• Rifabutin is an alternative to the macrolides for MAC prophylaxis. Rifabutin-associated drug interactions and complications, such as uveitis, make this agent difficult to use. Patients should be monitored closely for side effects.
• After starting antiretrovirals, if a patients' CD4 count rises to more than 100 for a sustained period and viral load response is good, prophylaxis can possibly be discontinued.
• Surgical excision of the affected lymph nodes remains the treatment of lymphadenitis in children. Antibiotics are generally not required.
• Patients with a defect in the IFN-gamma pathways may show a better response if IFN-gamma is given in addition to the antimicrobials.

Surgical Care

• Pulmonary MAC infection in patients with lung disease may require surgical excision of focal pulmonary nodules. Lobectomy has also been recommended for more extensive lung infection in patients who have not responded to antibiotics in the past. This, however, does not occur as often now that more potent antibiotics are available.
• Surgical excision of the infected nodes is curative in more than 95% of children with lymphadenitis.

Consultations

• Consultants for MAC infections in patients with AIDS include an infectious diseases specialist, a general surgeon for lymph node biopsy, a gastroenterologist for liver biopsy, and a hematologist-oncologist for bone marrow biopsy.
• Consultants for patients with lung disease who develop pulmonary MAC infection include an infectious diseases specialist, a pulmonologist, and a cardiothoracic surgeon.
• Consultants for lymphadenitis in children include an infectious diseases specialist, a general surgeon, and an ear, nose, and throat (ENT) specialist.

Diet

• No special diet restrictions are necessary.

MEDICATION

Section 7 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

The drugs used most often for treatment of M avium complex (MAC) include clarithromycin, azithromycin, ethambutol, and rifabutin. Amikacin is used for refractory cases. Combination therapy is important to enhance efficacy and prevent resistance. Duration of treatment is not established. In general, patients with MAC pulmonary infection should be treated for a minimum of one year or until 12 months after sputum has converted to negative for MAC. The rate of relapse is high, especially if the treatment duration is too short. A long-term treatment, however, is harder to tolerate and can increase the medication adverse effects.

Drug Category: Antibiotics

Empiric antimicrobial therapy must be comprehensive.

FOLLOW-UP

Section 8 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Further Inpatient Care

• Patients with AIDS may generally be admitted with FUO. They may also need to be admitted for various other reasons, including inpatient workup of fever and hepatitis, dehydration, wasting and failure to thrive, starting intravenous antibiotics, nonadherence, or other concurrent illnesses.
• Patients with pulmonary M avium complex (MAC) infection may need to be admitted for a lung biopsy or surgical resection of infected lung.
• Children with lymphadenitis may need to be admitted for surgical excision of infected lymph nodes.

Further Outpatient Care

• Carefully monitor patients with AIDS for adverse effects of medications, especially for hepatotoxicity and uveitis. They may also require transfusion. Antiretroviral agents should be started concurrently for a faster and better response. Patients should also be monitored for immune reconstitution syndrome.
• Carefully monitor patients with lung disease who develop pulmonary MAC infection for adverse effects of medications.
• After completion of treatment, patients should be monitored clinically and radiologically for relapse of the infection.

In/Out Patient Meds

• Clarithromycin or azithromycin in combination with ethambutol and rifabutin are the first-choice drugs. Alternatively, clofazimine, streptomycin, amikacin, or levofloxacin may be used to substitute one of the first-line agents.

Transfer

• Patients with AIDS may need to be transferred to a facility with an infectious diseases or HIV specialist for workup and treatment.
• Patients with pulmonary infection may need to be transferred to a facility that offers bronchoscopy. They may also require transfer for surgical resection of infected lung tissue.

Deterrence/Prevention

• The Department of Health and Human Services panel recommends that patients with AIDS and CD4 cell counts of less than 50 cells/µL should receive a prophylactic antibiotic to prevent MAC infection. The first-line agent for MAC prophylaxis should be a macrolide, either clarithromycin or azithromycin. Alternatively, rifabutin can also be used. Patients who have received treatment for MAC should stay on the treatment regimen until their CD4 count improves to more than 100 cells/µL.

Complications

• Patients with AIDS may develop anemia or weight loss, or they may die.
• Patients with lung disease may develop respiratory insufficiency or weight loss, or they may die.

Prognosis

• In recent studies, life expectancy for patients with AIDS and MAC infection is 9 months, but with HAART, it is probably much longer.
• Patients with lung disease and pulmonary MAC infections with focal nodules usually have a benign course. Patients with more extensive disease have a 90% chance of recovery and a 20% chance of relapse.

Patient Education

• Instruct patients with AIDS on how to monitor for potential adverse effects of their medications as well as how to recognize signs of anemia that might indicate the need for a transfusion.
• Educate patients with lung disease who develop pulmonary MAC infection about potential adverse effects of their medications.
• For excellent patient education resources, visit eMedicine's Bacterial and Viral Infections Center and Procedures Center. Also, see eMedicine's patient education article Bronchoscopy.

MISCELLANEOUS

Section 9 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Medical/Legal Pitfalls

• Macrolides are likely to interact with drugs metabolized in the liver.
• Ethambutol may cause optic neuritis and blindness, especially with coexisting renal dysfunction.
• Rifampin and rifabutin may decrease the effectiveness of contraceptives. Advise patients of this potential effect. Rifabutin is also known to cause uveitis, for which patients need regular eye examination.
• Failing to offer prophylaxis to patients with HIV with a CD4⁺ lymphocyte count of fewer than 50 cells/µL may lead to development of disseminated MAC (DMAC) infection.

ACKNOWLEDGMENTS

Section 10 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

The authors and editors of eMedicine gratefully acknowledge the contributions of previous coauthor William B Harley, MD, to the development and writing of this article.

MULTIMEDIA

Section 11 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

Media file 1:  CT thorax of a 77-year-old woman who presented with chronic cough and sputum production, without a history of underlying pre-existing lung disease. Sputum culture grew Mycobacterium avium complex. The diagnosis was Lady Windermere syndrome.
	View Full Size Image
Media type:  CT

REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• Multimedia
• References

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• Oldfield EC 3rd, Fessel WJ, Dunne MW. Once weekly azithromycin therapy for prevention of Mycobacterium avium complex infection in patients with AIDS: a randomized, double-blind, placebo-controlled multicenter trial. Clin Infect Dis. Mar 1998;26(3):611-9. [Medline].
• Pierce M, Crampton S, Henry D. A randomized trial of clarithromycin as prophylaxis against disseminated Mycobacterium avium complex infection in patients with advanced acquired immunodeficiency syndrome. N Engl J Med. 1996;335:384-91. [Medline].
• Reich JM, Johnson RE. Mycobacterium avium complex pulmonary disease presenting as an isolated lingular or middle lobe pattern. The Lady Windermere syndrome. Chest. Jun 1992;101(6):1605-9. [Medline].
• Shafran SD, Mashinter LD, Phillips P. Successful discontinuation of therapy for disseminated Mycobacterium avium complex infection after effective antiretroviral therapy. Ann Intern Med. Nov 5 2002;137(9):734-7.
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Article Last Updated: Aug 11, 2006