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Signature ✍️
- Orthopnea: ↑ dyspnea while lying flat(ter)
- Trepopnea: ↑ dyspnea while lying on one side
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DDx 🏳️🌈
Common 🛌
- ↑ Venous Return: decompensated CHF
Uncommon 🛌
- Diaphragmatic
- ↓ Strength
- Myelopathy
- Transverse myelitis DDx
- Phrenic neuropathy
- Bilateral
- Polyneuropathy
- Unilateral
- S/p CT surgery vs. ablation
- Viral neuritis (e.g. VZV)
- Cervical spine disease
- Neuralgic amyotrophy
- Intra-thoracic inflammation (e.g. sclerosing mediastinitis)
- NMJ dysfunction
- Myasthenia Gravis
- Lambert Eaton
- Myopathy
- ↑ Load
- ↑ airway pressure
- COPD
- Tracheobronchomalacia
- ↑ abdominal pressure
- Diffuse
- Obesity
- Ascites
- Focal
- Hepatomegaly
- Splenomegaly
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Principles❗️
- Pathophysiology 🛌 : in decompensated CHF, orthopnea is due to ↑ venous return. In diaphragmatic issues, orthopnea is due to 1) ↓ gravitational support during inspiration, which brings out ↓ diaphragm strength 2) ↑ diaphragmatic load (i.e. abdominal contents are now sitting on top of the diaphragm vs. chest wall restriction)
📚 For this reason, orthopnea due to diaphragmatic failure can be multifactorial & due to both weakness & load issues. In these situations, objective weakness may be fairly unimpressive (e.g. limb strength 4+/5), but if the diaphragmatic load is high (e.g. BMI of 50), that weakness will be brought out when the patient lies flat
- Bedside Diaphragm Strength 🌬️ : for a more formal assessment, respiratory therapists can perform a “negative inspiratory force” test for patients on the floor, with a negative pressure greater than 60 cm H2O considered normal. Quick screens you can do yourself include asking patient to count as many numbers as possible using one breath
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References 📚
- Framework adapted from @CPSolvers
- Clinical practice of @ASanchez_PS
