Diaphragmatic paralysis can be unilateral or bilateral.
Clinical features are highly variable according to underlying aetiological factor
- unilateral paralysis: asymptomatic in most of the patients as the other lung compensates.
- may have dyspnea, headaches, fatigue, insomnia and overall breathing difficulty
- bilateral diaphragmatic palsy can be a medical emergency; they present with severe dyspnea, even with mild exertion
- idiopathic: accounts for ~70% of the cases
- phrenic nerve palsy, which in turn can occur from
- Erb's palsy (birth trauma)
- muscular disorders
- iatrogenic causes
- cerebral hypoventilation syndrome (Ondine's curse)
Normally the right dome of diaphragm is higher in position as compared to left dome, if the left dome of diaphragm is elevated (>2 cm) diaphragmatic palsy should be suspected.
Fluoroscopic examination of the diaphragm ("sniff test") very useful in diagnosing a diaphragmatic paralysis. In normal individuals both hemidiaphragms descend with inspiration. In cases of unilateral diaphragmatic paralysis the affected side demonstrates a paradoxical upward movement.
An alternative to fluoroscopy in diagnosing this condition, particularly useful in the paediatric population. Real-time ultrasound is ideal for evaluation of spontaneous respiratory diaphragmatic motion (may require temporary disconnection of ventilator). This can be performed in the axial plane to compare the two hemidiaphragms simultaneously. Additional coronal or sagittal M-mode can help quantify degree of movement of each individual hemidiaphragm. Diagnostic criteria include paradoxical movement, excursion of less than 4 mm, and a difference > 50% between the excursion of one hemidiaphragm compared to the other.
Treatment and prognosis
Patients with unilateral diaphragmatic paralysis do not require treatment. There may be an option for phrenic nerve stimulation in some cases.
On a chest radiograph consider
- 1. Verhey PT, Gosselin MV, Primack SL et-al. Differentiating diaphragmatic paralysis and eventration. Acad Radiol. 2007;14 (4): 420-5. doi:10.1016/j.acra.2007.01.027 - Pubmed citation
- 2. Wilcox PG, Pardy RL. Diaphragmatic weakness and paralysis. Lung. 1989;167 (6): 323-41. Pubmed citation
- 3. Qureshi A. Diaphragm paralysis. Semin Respir Crit Care Med. 2009;30 (03): 315-20. doi:10.1055/s-0029-1222445 - Pubmed citation
- 4. Laroche CM, Mier AK, Moxham J et-al. Diaphragm strength in patients with recent hemidiaphragm paralysis. Thorax. 1988;43 (3): 170-4. Free text at pubmed - Pubmed citation
- 5. Valls-Solé J, Solans M. Idiopathic bilateral diaphragmatic paralysis. Muscle Nerve. 2002;25 (4): 619-23. Pubmed citation
- 6. Paltiel, Harriet. Pediatric Ultrasound, An Issue of Ultrasound Clinics. Volume 8, Issue 3 of The Clinics: Radiology. Elsevier Health Sciences, 2013