Share this:
Katherine, Alumni Mentor
@katemn

Posts: 1501
Joined: Nov 21, 2011

NEWCOMERS .. ONE EXPLANATION I FOUND ON MAC/MAI TO HELP YOU

Posted by @katemn, Jul 7, 2017

MAC/MAI .. just ONE article I have come across that I felt might help Newcomers in understanding their diagnosis of MAC/MAI .. a LOT of information to digest but I hope you find it helpful! Hugs! Katherine (I have left out information on Aids .. for most of our arriving Newcomers that has not been an issue.)

https://patient.info/doctor/mycobacterium-avium-complex Synonyms: Mycobacterium avium-intracellulare, MAI There are two discrete species in the Mycobacterium avium complex (MAC): Mycobacterium avium (M. avium). Mycobacterium intracellulare (M. intracellulare). They are both opportunistic pathogens that affect the immunocompromised. They can affect immunocompetent people, especially those with pre-existing lung disease. MAC is ubiquitous. However, only a minority of people exposed to MAC will acquire infection. It usually only affects the lungs in the immunocompetent.

Pathophysiology M. intracellulare causes 40% of MAC infections in the immunocompetent. Transmission is via the respiratory (inhalation) and the gastrointestinal (ingestion) routes. There are many environmental sources of MAC including:[5] Piped hot water systems (household and hospital). Aerosolised water (eg, hot tubs). House dust. Soil. Birds and farm animals. Tobacco, cigarette filters and paper. In those with pre-existing lung disease, MAC usually just leads to pulmonary infection. The infection may (rarely) appear in elderly ladies with no pre-existing lung disease who chronically suppress the cough reflex and therefore allow respiratory secretions to stagnate. This is known as Lady Windermere syndrome.[6] MAC can also present as a hypersensitivity pneumonitis. This can occur in those exposed to water vapour containing MAC (commonly in poorly maintained indoor hot tubs or swimming pools).[7] Risk factors immunosuppression. Bronchiectasis. Cystic fibrosis. Chronic obstructive pulmonary disease (COPD). Pulmonary malignancy.

Presentation Pulmonary MAC infection Insidious onset. Features include: Cough. Excessive sputum production. Dyspnoea (difficult or labored breathing). Haemoptysis (coughing of blood). Fever and night sweats. Fatigue. Weight loss. Nonspecific focal chest signs: crackles, wheeze, bronchial breathing, dullness to percussion. Clubbing (in cases with underlying bronchiectasis).

Disseminated MAC infection ..] Features include: Fever (may present as pyrexia of unknown origin). Sweating. Malaise. Dyspnoea (difficult or labored breathing). Diarrhoea. Significant weight loss with marked wasting. Generalised lymphadenopathy (disease of the lymph nodes) Pallor. Tender hepatosplenomegaly (disorder where both the liver and spleen swell beyond their normal size) Cutaneous involvement.

Pulmonary disease
• Sputum AFB staining: this is positive in most with MAC.
• Sputum culture: takes 1-2 weeks to detect the organism but doesn’t differentiate between infection or just colonisation. A number of positive cultures are usually required for diagnosis and there are set criteria.
• CXR: may show cavitary changes, nodules and parenchymal involvement, particularly in middle and upper lobes, and mediastinal lymphadenopathy.
• CT scan of the chest: this may be needed to show lung involvement.
• Bronchoscopy and transbronchial biopsy/CT-guided needle biopsy: this may be needed to make the diagnosis. There are specific histological changes in the lung tissue. Last Checked: 29 August 2014

REPLY

Yes, thank you- I have read that very informative article many times. I don’t know about you Katherine, but sometimes I feel like I have read everything on the planet about MAC/MAI, which is kind of funny really. Prior to the MAC diagnosis I never even heard of it. It was the same with sarcoidosis. We never heard of that one either till my husband ended up with it. And yes, knowledge is power! Take care.

@irene5

Yes, thank you- I have read that very informative article many times. I don’t know about you Katherine, but sometimes I feel like I have read everything on the planet about MAC/MAI, which is kind of funny really. Prior to the MAC diagnosis I never even heard of it. It was the same with sarcoidosis. We never heard of that one either till my husband ended up with it. And yes, knowledge is power! Take care.

Jump to this post

@irene5, Irene, I’m hoping it might be helpful for Newcomers hungry for information. Hugs! Katherine

Good summary about MAC/MAI. Pretty much covers the major points that we have tried to put across to a number of newcomers so far. Will be very helpful for the future newcomers.

Thank you, Katherine, for posting that helpful information. I’m afraid I’m becoming a Lady Windermere!

@jula73

Thank you, Katherine, for posting that helpful information. I’m afraid I’m becoming a Lady Windermere!

Jump to this post

@jula73, Jula .. join the crowd! There are many of us in the Group that would fit that description! Hugs! Katherine

@jula73 Hello Jula! I am a mentor filling in for Katherine while she is on a hiatis. We haven’t heard from you in awhile. I am wondering how you are doing and if you ever got treatment for your MAC infection? We are here for you! – Terri M.

Please login or register to post a reply.