EpistemisPositional dyspnea due to unilateral diaphragmatic paralysis
Specialty: Respiratory.
Why it occurs
- Unilateral injury to the phrenic nerve of surgical origin (coronary bypass surgery, pulmonary lobectomy or cervical dissection that compromises the path of the nerve)
- Direct tumor invasion of the phrenic nerve by apical or anterior mediastinal bronchogenic carcinoma
- Localized motor neuropathy (Parsonage-Turner syndrome or neuralgic amyotrophy that affects the phrenic motor roots in isolation)
- Extrinsic compression of the nerve due to tuberculous or tumorous mediastinal lymphadenopathy
- Penetrating or closed trauma to the neck or upper thorax with section or contusion of the nerve.
Initial workup
Chest x-ray in standing and recumbent position (where a persistent elevation of a hemidiaphragm is observed, typically the right one, greater than two intercostal spaces); Dynamic diaphragmatic ultrasound (search for absent or paradoxical diaphragmatic excursion during deep inspiration); Diaphragmatic fluoroscopy (Sniff test); Magnetic resonance imaging (MRI) of the neck and mediastinum to evaluate the course of the phrenic nerve.
red flags
Presence of dyspnea when lying down accompanied by persistent daytime or nighttime hypoxemia, significant tachypnea when changing position, progressive loss of residual lung capacity in serial controls, or development of recurrent lobar basal atelectasis with associated pneumonia.
Standard management
- There are no specific pharmacological treatments to reverse phrenic nerve palsy.
- IPratropium bromide — inhaled, 40 micrograms every 8 hours to reduce associated bronchial resistance
- Muscle rehabilitation treatment and, in selected severe refractory cases, surgical diaphragmatic plication.
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Respiratory
- Listed causes
- 5
- Treatment options
- 3