Cystic fibrosis (CF) is an inherited disease of the mucus secreting glands that line certain organs and body cavities, primarily the lungs, pancreas, liver, intestines, sinuses and ears. Normal mucus is a slippery, watery substance that keeps the linings of these areas moist and helps to prevent infection. But CF causes mucus to become thick and sticky, allowing it to build up. In the lungs, such buildup makes it easy for bacteria to grow, leading to repeated lung infections with possible serious damage over time. Shortness of breath, reduced exercise tolerance and frequent coughing are common with CF.
What does this mean for divers?
Of immediate concern to the diver is that thickened mucus can block small airways in the lung such that the air within cannot escape. Trapped gas that expands per Boyle’s law during ascent from depth can result in pulmonary barotrauma. Should gas bubbles leaking from a traumatized lung enter arterial circulation, an arterial gas embolism can form and impede or prevent oxygen from getting to target organs like the brain, which is a very serious matter indeed.
There also is the possibility of CF-related involvement of the sinuses and ears, with resultant problems in equalization and infection. Despite these concerns, there are stories about individuals who scuba without incident.
It may be possible for divers to be cleared for diving by a qualified pulmonologist, given that the person were free of or have only minimal lung disease proper (e.g., asthma, chronic bronchitis) and were free of or well-controlled in regards to electrolyte imbalances, nasal passage disease/abnormality, liver problems, digestive problems, diabetes, and other medical issues that can be associated with CF. Evaluation of the fitness of the diver affected with CF would at a minimum include pulmonary function testing (PFTs), a high-resolution CAT scan of the chest, and ENT examination of the nose, sinuses and ears. Along with making sure that dive ops and dive buddies are informed of the diver’s disease, all gear with access to the lungs, i.e., regulator system, should be regularly sanitized to reduce the risk of infection.