Mucostasis

Mucostasis refers to stagnation of mucus within the airways due to impaired clearance or altered mucus properties, leading to accumulation, obstruction, and risk of infection. It is a feature of various respiratory diseases and can occur after acute injury or during critical illness.

Normal mucociliary clearance involves mucus secretion by goblet cells and submucosal glands, ciliary beating, and cough. Mucostasis arises when mucus becomes overly viscid or abundant, ciliary function is reduced or absent, or airway architecture is distorted. Contributing factors include dehydration, smoking, inhaled toxins, chronic inflammation, genetic disorders, neuromuscular impairment, and certain medications.

Clinically, mucostasis may present with productive cough, chest tightness, dyspnea, wheeze, and recurrent infections. It can lead to mucus plugging, atelectasis, and decreased gas exchange. It is a common problem in cystic fibrosis, primary ciliary dyskinesia, bronchiectasis, chronic bronchitis, asthma with mucus plugging, post-extubation states, and after thoracic surgery.

Diagnosis relies on clinical assessment supplemented by imaging such as chest radiography or CT showing mucus plugs, and sometimes bronchoscopy. Pulmonary function testing and evaluation of mucociliary clearance may be used. Differentials include other causes of airway obstruction.

Management aims to enhance mucus clearance and treat underlying disease. Approaches include hydration and humidification, airway clearance techniques (chest physiotherapy, devices that generate oscillations), inhaled mucolytics (N-acetylcysteine), hypertonic saline, bronchodilators, and antibiotics for infection. In cystic fibrosis and other conditions, disease-specific therapies (CFTR modulators, genetic counseling) are employed. Prognosis varies with the underlying condition and the effectiveness of clearance.