Ms. L is a 22-year-old woman who comes to your office in August complaining of cough and fever. She reports that she was in her usual state of health until 3 days ago when a cough developed. Two days ago, a low-grade fever (37.2°C) developed, which increased to 38.8°C yesterday. She reports that her sputum is yellow and that she has no chest pain or shortness of breath.
The framework for the differential diagnosis of acute respiratory complaints is anatomic and microbiologic. Although there are a myriad of viral and bacterial (and occasional mycobacterial) infections that infect the respiratory tree, a practical approach addresses 3 issues:
Where is the infection (sinuses, tracheobronchial tree, alveoli)?
Will the patient benefit from antibiotics?
Among patients with pneumonia, clinicians must separate the common community-acquired pneumonias (CAPs) from the less common but important pneumonias due to aspiration, tuberculosis (TB), and opportunistic infections. Diagnostic and treatment algorithms that summarize the approach to patients with acute respiratory infections appear at the end of the chapter. (see Figures 9–3 and 9–4)
Diagnostic approach: acute cough and fever.
Response to the results of the CXR in patients with cough and fever.
Differential Diagnosis of Acute Coughand Congestion
Opportunistic (eg, Pneumocystis jiroveci pneumonia [PCP])
On physical exam, Ms. L is in no acute distress. Vital signs are RR, 18 breaths per minute; BP, 110/72 mm Hg; pulse, 92 bpm; temperature, 38.6°C. Pharynx is unremarkable; lung exam reveals normal breath sounds without crackles, dullness, bronchophony, or egophony.
|At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?|
The differential diagnosis for Ms. L includes acute bronchitis, influenza, aspiration pneumonia, and CAP. Ms. L's high fever is a pivotal feature of this case. Acute bronchitis is not usually associated with significant fever (unless caused by influenza). Influenza can cause high fevers and chest symptoms but almost always occurs between December and May. Therefore, despite Ms. L's normal lung exam, the high fever raises the possibility of CAP and makes this the leading diagnosis. Table 9–1 lists the differential diagnosis.
Table 9–1. Diagnostic Hypotheses for MS. L. |Favorite Table|Download (.pdf)
Table 9–1. Diagnostic Hypotheses for MS. L.
|Diagnostic Hypothesis||Clinical Clues||Important Tests|
Shortness of breath
Crackles or dullness on lung exam
Log In to View More
If you don't have a subscription, please view our individual subscription options below to find out how you can gain access to this content.
Want remote access to your institution's subscription?
Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.
If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.
AccessMedicine Full Site: One-Year Subscription
Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, and more.
Pay Per View: Timed Access to all of AccessMedicine
24 Hour Subscription $34.95
48 Hour Subscription $54.95
Pop-up div Successfully Displayed
This div only appears when the trigger link is hovered over.
Otherwise it is hidden from view.