A 50 years old male presented to the office with exertional shortness of breath and orthopnea. He exercises regularly, has no impairment of normal daily activities. Not taking any medication, with no history of allergies. He does not smoke or drink, and there is no previous medical history.
On physical examination, he looks well, not obese, afebrile, blood pressure 118/84 mmHg, pulse 68 /minutes, and respiratory rate 16 /minutes. JVP normal, no cyanosis, edema or clubbing. The rest of the physical exam was normal including cardiovascular and respiratory system.
Laboratory Studies showed no abnormalities. Chest X-ray and CT of the chest was normal, erect FEV and FVC and TLCO normal. Baseline oxygen saturation 98%
Resting and exercise ECG normal
What is the most likely clinical diagnosis?
What other investigations would you perform?
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5 comments:
This is certainly tough one. Little more h/o would have been helpful, like any previous episode, any stridor? Given this information:
1) most likely it's related to upper respiratory tract, could be Vocal cord dysfunction or paroxysysmal laryngospasm or exercise induced asthma. Unlikely to cardiac exertional SOB, as negative exercise ECG.
2) Laryngoscopy and Full PFT with exercise challange and methacholine challange.
Based on his history and normal investigations, early stages of pulmonary hypertension could be suspected. I would like to do an echo or a TEE to get a clearer picture. It could be followed by right hight heart catheterization to measure the pressure in pulmonary arteries.
1.)ALS(Amyotrophic lateral sclerosis)
2.)physical examination and treatment NIPPV.
I-The mosy likely clinical diagnosis is Diaphragmatic weakness
The keys in this question are:
a-SOB in the supine position(Orthopmea)
b-No signs of CHF
c-Not obese
d-Erect FEV and FEV are both normal
Think why I would mention and add erect FEV if it is not important.
In this case most likely this is a bilateral diaphragmatic nerve palsy.
-Causes of Diaphragmatic weakness:
1-Cervical Trauma
2-Neck surgery
3-Thyroid surgery
4-CABG
5-Mediastinal tumor resection
6-Lymphoma
7-Lung cancer
8-Herpes zoster infection
9-Systemic lupus erythematosus
10-Multiple sclerosis
11-Amyotrophic lateral sclerosis
12-Hyperthyroidism/hypothyroidism
13-Amyloidosis
II- To confirm your diagnosis
1-Pulmonary function test in erect and supine position
2-Sniff test via fluoroscopy (more senstive in unilateral phrenic weakness than bilateral)
3-Ultrasonography.
4-Dynamic MRI.
5-Phrenic nerve conduction test.
-Normally there is a reduction of up to 20%, and patients with BDP have a reduction in the range of >50%, whereas in patients with UDP the range is 20-50%
-Chest x-rays are neither sensitive nor specific for diaphragmatic dysfunction
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