Once again, reviewing the differential diagnosis for ACUTE COUGH (<2 weeks’ duration):
|Upper Respiratory Tract||Lower Respiratory Tract|
- ? >65 yo; esp. >80 yo
- O2 Sat <92%
- Resp >28 / Pulse >120 / BP <90
- Comorbidities (renal insuff., liver failure, malignancy, etc)
Last time (Acute Cough – 1) we addressed patients who have either a cough plus upper respiratory symptoms, or just a cough alone, with nothing to suggest lower respiratory tract disorders. When do we worry about lung disease? [I say “worry,” because patients suffocate from the lungs, not the nose].
1) Acute Cough PLUS fever is worrisome.
2) Cough PLUS true dyspnea is certainly worrisome.
3) Cough PLUS abnormal lung sounds — well, something’s going on in there!
COUGH PLUS FEVER
Generates a serious work-up if persisting >3 days without starting to improve. So let’s discuss our approach in the first few days of onset. Our main job is R/O Pneumonia, easily done by Chest X-ray. But we can’t order a CXR on everyone with cough and fever. How to pick & choose:
INFLUENZA SEASON — late Nov. through April [in Northern Hemisphere]:
If abrupt onset fever, myalgias, & cough, just diagnose Influenza (“The Flu”). Consider a nasopharyngeal swab for Influenza antigen if results immediately available (some tests only identify Influenza A, not B).
When to get a Chest X-Ray (CXR) in febrile patients with cough during flu season, mainly to R/O Pneumonia. If any of the following:
***Dyspnea on Exertion (DOE) (convincingly described by patient):
- If CXR is normal, might still be “the Flu,” but that can be worse, because bacterial pneumonia is easier to treat.
- Pulmonary Embolus isn’t listed in the differential since it doesn’t really present with a prominent cough, but can certainly cause DOE & a low-grade fever. Consider if risk factors [see posting Acute SOB-2].
***Rales [inspiratory crackles], either focal [suspect Pneumonia] or bibasilar [suspect CHF, either provoked by influenza, or actually Myocarditis].
***Compromised Host [much more likely to get Pneumonia]. Includes the elderly & pregnant women. And don’t forget how & when to suspect AIDS in the unknowing, untested patient [Clues to Undiagnosed HIV]. Patients without seasonal flu vaccine need anti-virals (also if CDC alerts that this year’s vaccine has missed culprit strains).
***Fever Began After Several Days of a Viral Syndrome: Suspect secondary bacterial pneumonia. Defining chronology of illness is always a key to diagnosis.
NOT INFLUENZA SEASON — If the patient looks well, febrile but otherwise normal vital signs and O2 Sat, you can proceed as above, getting a CXR only if the starred circumstances exist. Call it “Viral Syndrome” (can’t say “Flu” if it’s not in season). Resist the urge to Rx antibiotics.
But absolutely Get a CXR if the fever persists past Day #3 without abating.
- Acute Cough + Fever + normal CXR = Virus.
- Acute Cough + Fever + Abnormal CXR = Pneumonia
***Fever, Cough, & Focal Rales — Some people would argue that this is undoubtedly pneumonia, so just treat. That’s OK in children >5 y.o. Adults are more likely to die from pneumonia, so they warrant a CXR if you entertain the diagnosis. [This as per guidelines from American Thoracic Society, Infectious Disease Society of America (IDSA), & Pediatric Infectious Disease Society.] If CXR will be delayed, certainly treat.
- Can pneumonia occur with a normal CXR? During the first 24 hours in a small minority of patients. The danger of assuming “yes” is that it becomes so easy to prescribe antibiotics (why get the test if you’ll Rx anyway?).
***Fever, Cough, & patient presents on Day #1 of Illness — some evidence suggests that such patients may be sick enough that pneumonia is more likely.
Pneumonia — This is an “anatomic” diagnosis, but whenever you identify an infection, you can’t treat without knowing the “microbiologic” diagnosis, i.e., What’s the Bug? Treatises abound about differences between “typical” & “atypical” community-acquired pneumonias, and the causative organisms. But the bottom line is, there’s no good way to tell! So major professional organizations all recommend empiric treatment based on risk factors.
American Thoracic Society & Infectious Disease Society of America recommend a macrolide; for patients with co-morbidities it’s a respiratory fluoroquinolone, OR high dose beta-lactam plus a macrolide. The Canadian Thoracic Society agrees. The British Thoracic Society pushes Amoxicillin, as does the American Academy of Pediatric (first-ever guidelines came out in 2011). Why the difference?????
The North Americans worry about “atypicals” like Mycoplasma. The Brits only care about the real killer — Streptococcus pneumoniae (Pneumococcus). See posting Infectious Disease – 3; click here for links to Guidelines.
I should move to the U.K. In my mind, only care about Pneumococcus. It’s likely the main culprit, easily overgrown & hard to culture in studies. Mycoplasma is usually self-limiting [no decent studies with outcome data]! And more & more Pneumococcal resistance to azithromycin is emerging.
ACUTE COUGH plus ABNORMAL LUNG SOUNDS but NO FEVER
Depends on what the sounds are:
Wheezes — Diagnose “Acute Bronchitis” [viral]. This presupposes there’s no history of similar recurrent episodes. Alert the patient that this could be the beginning of Asthma, but that you’re reluctant to paste such a label on them at this point. If the patient smokes, say the same about Chronic Bronchitis [all the more reason to quit]. Give an albuterol inhaler, which can help in all cases. Maintain follow-up, in case it is Asthma requiring better [“controller”] therapy.
Rhonchi [gurgles or squeaks, inspiratory or expiratory] — Same as for Wheezes
Prolonged Expiratory Phase — Don’t forget to pay careful attention to the ratio of inspiration to expiration. I > E is normal. E > I is bronchospasm, same as Wheezes, same as Rhonchi.
Bibasilar Rales — Congestive Heart Failure (CHF). Seek other signs & symptoms:
- DOE, Orthopnea, Paroxysmal Nocturnal Dyspnea
- Cardiac Risk Factors, Anginal Chest Pain, Anginal Equivalents on exertion
- Edema, JVD/HJR, Cardiac Gallops.
- If you make this diagnosis, you absolutely must determine the underlying cause. See posting Acute SOB – 3.
Focal Rales — Suggests pneumonia in patient with acute cough, which is unlikely in the absence of fever. Still, I order a CXR. If it’s normal, we have it documented for every other time the patient presents with cough and [now baseline] rales.
Pure Stridor — Think tracheal.
ACUTE COUGH plus DYSPNEA (& normal lung exam)
Normal-sounding lungs might still be Asthma. I’d buy the diagnosis if the patient gave a history of other episodes. But otherwise, acute cough plus dyspnea is worrisome — I get a CXR. A CXR is mandatory if there are Objective Signs of Dyspnea or risk factors for CHF [especially age].
Dyspnea always makes me worry about a Pulmonary Embolism. But here we’re discussing patients who present with a chief complaint of COUGH. The more prominent the cough, the more it overshadows any complaint of dyspnea, the less I worry about a PE.
But might it be visa versa? Could the “chief complaint,” i.e. the reason they sought care, really be “trouble breathing”? If we gently explore our patient’s symptoms, without leading them on, & feel that maybe dyspnea is of equal or greater import to them, then see our discussion of Dyspnea, posting Acute SOB – 2]. And among COPD patients, who have higher incidences of PEs, the less the cough compared with dyspnea, the more to worry [see Moua & Wood, Int J COPD 2008;3:277-84].
ACUTE COUGH with PURULENT SPUTUM (& no nasal symptoms)
What to make of it? First of all, I need to see it, then & there in the exam room. Otherwise, well, it’s just not occurring often enough to impress me. The same stuff can’t also be coming from the nose. And it needs to be nice and dark green. Early morning sputum that sits overnight often turns colors, which is irrelevant.
Smokers who produce purulent sputum probably have an exacerbation of Chronic Bronchitis, and antibiotics help. Rarely, I’ve seen a non-smoker with normal CXR (i.e. bronchitis) who produced similar junk that Gram-stained for H. flu or Pneumococcus. But unless we’re strict about this parameter, we’ll be giving antibiotics to everyone.
Brief Clarification on the Differences Among Acute Bronchitis, Chronic Bronchitis, & Asthma
*** Acute Bronchitis is a viral infection. If bacteria are ever implicated (highly unlikely), it’s still self-limiting. Some patients get post-viral bronchospasm & inflammation just like asthma, treated like asthma, but it resolves within 3 months and doesn’t recur.
- “Recurrent Bronchitis” is undoubtedly really asthma; providers chickened out and gave antibiotics when they heard rhonchi.
*** Chronic Bronchitis means that loss of mucociliary clearance has allowed bacteria to colonize the bronchi. It’s almost always a smoker’s disease. It recurs in exacerbations [treated like asthma], sometimes with purulent sputum [antibiotics help then], rarely with frank cor pulmonale [right heart failure — hospitalization helps].
*** Asthma = recurrent bronchospasm & inflammation from environmental triggers [you knew that already].
Some Final Comments:
** WARNING — Once again, always carefully inquire about similar past episodes. Anyone who gets “Acute Bronchitis” several times a year really has Asthma.
** Hemoptysis — what to do if the patient says they “cough up blood”? How much?
- If they’re just occasional specks, ignore it for now.
- If frequent specks or streaks, ask about blood in the nose. Examine the nose. Examine the gums. If you see blood, it’s probably the source. If not, get a CXR.
- If they cough small clumps of blood, get a CXR.
** “Cardiac Asthma” — You hear wheezing or rhonchi, but it’s really pulmonary edema (CHF). This is rare. Still, in the older patient with cardiovascular risks, keep heart failure in mind. In the younger patient who doesn’t improve on bronchodilators, consider Myocarditis (see posting Acute SOB-4).
Next Posting: on to Chronic Cough (>2-3 weeks duration and not improving)