Approach to shortenss of breath April 29th

COPD exacerbation had come up this week (as discussed by star resident Haifa). I am currently at a conference but thought I'd share some breathing pearls. I will have a separate post on COPD

Shortness of breath is a very common complaint we see in the in and outpatient setting. Having a easy list to memorize will help your approach and thus a better chance of you finding the causes, and not miss the "must not miss" diagnoses.

Simple put... causes of shortness of breath are

1. Heart

2. Lung

3. Anemia

4. Anxiety

Notice anxiety as a cause should NOT be your number one differential, even with a known anxiety disorder can most definitely cause an individual to feel SOB, it should be considered after other causes have been ruled out.

So what are some heart causes?

working inside to outside is a way not to miss anything

1. Heart valves, mitral stenosis, mitral regurg, aortic stenosis, aortic regurg, shunts (particularly right to left where deoxygenated blood is bypassing the lungs)

2. conduction system: fast heart rates like afib, VT, vfib, bradycardias can disease effective stroke volume thus less blood to tissues

3. myocardium (systolic/diastolic heart failure), STEMI/NSTEMI can cause fluid in lungs/alveolar edema. Myocarditis

4. pericardium - pericaridits, pericardial tamponade.

Lungs:

Inside to outside

1.Airways

Extrathoracic =  larynx - laryngeal edema, tumor/mss

Intra thoracic – bronchial airways: asthma, copd

3. Alveoli - edema from CHF, pus from pneumonia, ARDS

4. Interstitial - granulomatous disease, sarcoidosis, wegeners. Pneumoconiosis - silicosis, coal miners lung

5. Pleural - pneumothorax, pleural effusion, mass

6. Diaphragm/MSK - this is a trickier category, myopathy, electrolytes, neuromuscular like myasthenias gravis and obesity go in this category.

Anemia: Note, o2 sats will be normal, but total oxygen carrying capacity to tissues will be low. Also carbon monoxide poisoning, methemoglobinemia fit here. At ACP this year I saw an interesting case of a patient with methemoglobinemia from benzocaine that was sprayed to numb the throat before NG tube insertion. Co-oximetry is a type of blood gas analysis that would pick this up.

So you're on call at 3 am, and get called about a patient who develops sudden shortness of breath, what do you do?

That's a patient that should be assessed.. always. Ask for vital signs over the phone, is the patient maintaining there airway, can they speak in full sentences? These are things to ask nursing staff as you will want to prioritize how soon this patients needs to be seen. Let's face it, chest pain and shortness of breath are probably 2 highly feared things to get paged bout.

When we approach our patient, we obviously want to find the cause, but we always need to consider our must not miss diagnoses.

This short list is classically for chest pain but also works for shortness of breath

1.    tension pneumothorax

2.    aortic Dissection

3.    pericardial effusion/tamponade

4.    embolus (PE)

5.    myocardial infarction

Some use the mnemonic TAPEM (which may or may not work for you).

Notice that although nothing beats a good history, characterizing of the pain, and physical exam, a chest x ray and ECG will pick up the majority of the above (not necessarily diagnostic but will not be NORMAL).