EpistemisSelective orthopnea of diaphragmatic origin
Specialty: Respiratory.
Why it occurs
- Isolated bilateral diaphragmatic paralysis (dyspnea appears almost immediately when adopting the supine position, forcing the patient to sit, because the flaccid diaphragm is pushed towards the thorax by the abdominal viscera and gravity, drastically reducing expiratory vital capacity)
- Amyotrophic lateral sclerosis (ALS) of bulbar or spinal onset with early diaphragmatic weakness
- Amyotrophic neuralgia or Parsonage-Turner syndrome with bilateral involvement of the phrenic nerve
- Girdle myopathies or fascioscapulohumeral dystrophy (weakness of the axial and diaphragmatic support muscles)
- High cervical trauma with stable partial injury to the roots of the phrenic nerves (C3-C5).
Initial workup
Comparative spirometry (sitting vs. supine); Diaphragmatic ultrasound in recumbent position (measurement of excursion and increase in inspiratory thickness); diaphragmatic electromyography; Dynamic diaphragmatic fluoroscopy; Nocturnal polysomnography with transcutaneous CO2 monitoring.
red flags
Fall in forced vital capacity (FVC) greater than 30% when moving from the sitting position to the supine position in functional tests, severe nocturnal hypoxemia with prolonged desaturations, intense morning headache due to nocturnal CO2 retention, or absolute inability to remain lying down for more than 30 seconds.
Standard management
- The therapeutic pillar is ventilatory support with nocturnal biphasic positive pressure (BiPAP)
- There are no specific drugs to regenerate the paralytic diaphragm
- Pyridostigmine — 60 mg orally every 6 hours if associated with neuromuscular junction disorders such as myasthenia gravis
- IPratropium bromide (inhaled to optimize concurrent airway resistance).
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
- 4