The Multiple Aspects of Cystic Fibrosis Treatment

The lung manifestations of Cystic Fibrosis include thick respiratory secretions associated with recurrent or even chronic pneumonia. These problems s are managed with chest physiotherapy that includes a PEP mask, and postural drainage in addition to a percussive vest, bronchodilators, intermittent aerosolized tobramycin, aggressive IV antibiotics when needed, and hypertonic saline and/or aerosolized DNase.

Though aerosolized DNase and hypertonic saline have different mechanisms of action, no studies have shown clear benefit of one over the other. No study has shown any benefit of simultaneous use either. However, aerosolized DNase is significantly more expensive than hypertonic saline and so is used less often.

Another key to the treatment of Cystic Fibrosis involves anti-inflammatory therapy. Both steroids and ibuprofen have been the mainstay of anti-inflammatory therapy in the past. Interestingly, current evidence actually suggests that the macrolide class of antibiotics act as effective anti-inflammator drugs with improved outcomes. This is perhaps related to the additional antibiotic control. Many older Cystic Fibrosis patients may be placed on the macrolide clarithromycin to be taken once nightly.

In a patient with a history of nontuberculosis (nonTB) mycobacterium infection, there are important issues that must be considered in antibiotic management. Therefore, it is suggested that Cystic Fibrosis patients are tested for nonTB (NTB) mycobacteria before starting macrolide therapy to avoid induction of macrolide resistance.

The most common NTB mycobacteria are M. avium complex, M. kansasii and M. abscessus. M. abscessus is the most pathogenic of these three and belongs to a group called rapidly growing mycobacteria' that includes M. fortuitum and M. chelonae.

M. abscessus can cause pulmonary infections, particularly in those with underlying lung disease such as cystic fibrosis, as well as superficial cervical lymphadenopathy. Infection of the skin, soft tissue (especially sinuses) and tenosynovitis is possible.

Diagnosis of lung disease caused by NTB mycobacteria requires 3 or more sputum cultures for Acid Fast Bacilli with species identification. Of note, species identification may take quite a long time. Therefore, NTB mycobacterial infection that is causing tissue injury or clinical deterioration should be treated with multiple antibiotics.

Susceptibility testing of the cultures against a variety of antibiotics can help guide therapy. For example, M. abscessus is resistant to antituberculosis agents but antibiotics such as clarithromycin, doxycycline, imipenem, fluoroquinolones, amikacin and linezolid may be used.

Successful management of cystic fibrosis is quite complicated. However, with early diagnosis and appropriate multifactorial treatment many patients with cystic fibrosis now live into their twenties.