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Updated: Jul 17, 2026
09:43
Functional and Morphological Assessment of Diaphragm Innervation by Phrenic Motor Neurons
Published on: May 25, 2015
Idiopathic bilateral diaphragmatic paresis
Mônica Corso Pereira1, Rodrigo Frange Miziara Mussi, Reinaldo Alexandre de Carvalho Massucio
1Universidade Estadual de Campinas, School of Medical Sciences, Campinas, Brazil. corso@mpcnet.com.br
Summary
This case study highlights bilateral diaphragmatic paresis, a rare cause of severe dyspnea. Diagnosis was confirmed by paradoxical respiration and lack of phrenic nerve response to stimulation.
Area of Science:
- Medicine
- Pulmonology
- Neurology
Background:
- Investigating severe dyspnea in a patient where common causes like lung, neuromuscular, and heart diseases were excluded.
- Focusing on respiratory mechanics and diaphragm function due to persistent unexplained symptoms.
Observation:
- Patient presented with severe dyspnea specifically when reclining.
- Paradoxical respiration was observed in the dorsal decubitus position, indicating abnormal diaphragm movement.
- Oxygenation and forced vital capacity significantly decreased when moving from orthostatic to supine positions.
Findings:
- Bilateral diaphragmatic paresis was diagnosed.
- Maximal inspiratory pressure was markedly reduced.
- Normal response to transcutaneous diaphragm stimulation contrasted with absent response to phrenic nerve stimulation, localizing the issue to the phrenic nerve pathway.
Implications:
- Highlights the importance of considering diaphragmatic dysfunction in unexplained dyspnea.
- Emphasizes the diagnostic value of positional changes and specific electrophysiological tests.
- Suggests potential for targeted diagnostic and therapeutic strategies for phrenic nerve related diaphragmatic weakness.
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