Cystic Fibrosis/ Sleep Apnea

What is the most common pneumonia in those w/ CF?

Pseudomonas aeruginosa (think PACF)

Pathophysiology

-              Autosomal recessive

-              CF gene codes for CFTR (cystic fibrosis transmembrane regulator) which regulates Na/Cl transport across membranes

-              Mutation: decreased Na absorption and Cl secretion (lacks water)

-              Result of impaired ion transport: dehydrated, thick, sticky mucous secretion in lung, leading to impaired mucociliary clearance and bacterial infections (especially pseudomonas aeruginosa) and increased salt content in sweat

What do the tenacious secretions effect?

The whole body

o   Sinuses

o   Pancreas: dehydrated secretions, desiccated and loss of obstructed ducts, lost exocrine function

o   Sweat glands: we normally retrieve salts from sweat, cannot do that, so sweat is salty (excrete more than we normally would)

§  High chloride in sweat (really both but that’s how we test)  

o   Respiratory

§  Pseudomonas aeruginosa

§  Bronchiectasis

o   GI sx

§  Pancreatic steatorrhea (cannot produce enzymes to digest fat, excrete in stool) greasy stools, difficulty absorbing fat soluble vitamins

§  Meconium ileus (cannot poop as baby)

§  Recurrent pancreatitis

o   Male infertility

CF diagnosis

A: presence of clinical features or sibling w/ CF, positive newborn screen

AND

B: two elevated sweat chloride tests on separate days OR genetic testing

-              Sweat test: give pilocarpine to make you sweat, analyzed w/ chloridometer

-              Sweat content ≥60Eq/L of chloride=CF diagnosis

What do we assess in CF patients?

-              Pancreatic exocrine function (fecal fat content, high=lost exocrine)

-              Pulmonary radiology

-              Bronchiectasis on CT: permanently damaged, widened, and scarred airways cause excessive mucus production, cough, infection, SOB

o   Signet ring sign: black dilated airway is larger than accompany pulmonary artery (white)   

PFTs: obstructive disease

-              Sputum cultures to survey for pseudomonas aeruginosa (and also staph aureus, other microbes)

How do we treat the lungs in CF?

o   ABCDs of airway clearance

§  Airway opener: bronchodilator

§  Break-up mucous: mucus thinner

§  Clearance: airway clearance w/ high frequency chest wall stimulator

§  Destroy bacteria: antibiotics- could potentially be long-term

·      Azithromycin, ciprofloxacin or tobramycin  for pseudomonas coverage

o   Advanced disease: oxygen, non-invasive ventilation

o   Other therapy: anti-inflammatories (steroids- bring along infection risk), exercise, lung transplant (in an otherwise healthy pt)

o   NEW DRUG: CFTR Modulator (super expensive) to improve CFTR function (doesn’t work in those w/o the protein)

Sleep Apnea: OSA/Central, Severity Index 

-              Produces daytime sleepiness

-              OSA: obstructive sleep apnea, sleep interruption due to repeated upper airway narrowing or collapse (obstruction, good inspiratory effort-trying to breath)

o   Apnea: cessation of airflow for 10 or more seconds

o   Hypopnea: reduction in air flow

-              Central sleep apnea (less of concern for us): absence of inspiratory effort (brain isn’t telling you to breath)

-              Disease severity: apnea-hypopnea index (AHI) mild 5-14/hour, moderate 15-30/hour, severe more than 30 wakings/hour

Sleep Apnea: pathophys, risk factors, sx, diagnosis, tx

Pathophys: pharyngeal muscles relax in sleep, creating soft tissue laxity in the airway, which can cause snoring (and obstruction w/ severity)

-              Brief awakening restores airway (muscles tense)  

Risk factors: obesity, hypertension, alcohol use, sedatives, tonsillar hypertrophy

Sx: excessive daytime sleepiness, mood alteration, difficulty concentrating, sleep-related choking or gasping (very sensitive predictor)

Dx: has to be objective, gold standard is polysomnography (home SA tests can only detect moderate to severe disease)

Tx: weight loss, reduce alcohol before bed, avoid sedatives

-              Positive airway pressure (CPAP/APAP)

-              Oxygen not recommended