Diaphragm dysfunction: how to diagnose and how to treat?

Abstract

The diaphragm, crucial for respiratory function, is susceptible to dysfunction due to various pathologies that can affect the nervous system, neuromuscular junction or the muscle itself. Diaphragmatic dysfunction presents with symptoms ranging from exertional dyspnoea to respiratory failure, significantly impacting patients' quality of life. Diagnosis involves clinical evaluation complemented by imaging and pulmonary function tests. Chest radiography, fluoroscopy, and ultrasonography are pivotal in assessing diaphragmatic movement and excursion, offering varying sensitivities and specificities based on the type and severity of dysfunction. Ultrasonography emerges as a noninvasive bedside tool with high sensitivity and specificity, measuring diaphragm thickness, thickening fraction, and excursion, and enabling monitoring of disease progression and response to treatment over time. Treatment strategies depend on the underlying aetiology and severity, ranging from conservative management to interventions such as surgical plication or diaphragmatic pacing. Ventilatory support, particularly noninvasive ventilation, plays a pivotal role in treatment, enhancing lung function and patient outcomes across unilateral and bilateral dysfunction. Despite advances in diagnostic techniques, awareness and systematic evaluation of diaphragmatic function remain inconsistent across clinical settings. This review consolidates the current understanding of diaphragmatic dysfunction, highlighting diagnostic modalities and treatment options to facilitate early recognition and management of this entity.

FIGURE 1

Causes of diaphragmatic dysfunction. CABG: coronary artery bypass graft.

FIGURE 2

Paradoxical thoracoabdominal breathing. a) Diaphragm contracting normally during tidal breathing: with its contraction, the diaphragm moves caudally, increasing the abdominal pressure and reducing intrapleural pressure. Consequently, the abdomen moves outward and intra-alveolar pressure decreases, facilitating the influx of air that inflates the lungs. b) Dysfunction of the diaphragm: in cases of diaphragmatic dysfunction, the diaphragm loses the ability to contract during inspiration. Therefore, as the thoracic cage expands, the diaphragm moves cranially and abdominal pressure decreases, with an inward movement of the abdomen during thoracic cage expansion. This paradoxical abdominal movement is a characteristic observation during inspiratory phases in diaphragmatic dysfunction, particularly in the supine position.