What are the differential diagnoses for a patient presenting with strawberry tongue, pharyngeal exudate, a 3/6 (grade 3 out of 6) blowing mitral murmur, and bilateral basal lung rales?

Differential Diagnoses for Strawberry Tongue, Pharyngeal Exudate, Mitral Murmur, and Bilateral Basal Rales

The most likely diagnosis is acute rheumatic fever (ARF) with carditis, though the presence of pharyngeal exudate is atypical and requires consideration of concurrent or alternative diagnoses including scarlet fever, infectious mononucleosis, or infective endocarditis.

Primary Consideration: Acute Rheumatic Fever with Carditis

ARF should be at the top of your differential given the combination of strawberry tongue, cardiac findings (mitral regurgitation murmur), and pulmonary findings (rales suggesting heart failure from carditis). 1

Key Diagnostic Features Supporting ARF:

• Strawberry tongue is a recognized oral manifestation of ARF, presenting with erythema and prominent fungiform papillae 1
• The 3/6 blowing mitral murmur represents carditis (a major Jones criterion), specifically mitral regurgitation from acute valvulitis 1
• Bilateral basal rales indicate pulmonary congestion from acute heart failure secondary to significant mitral regurgitation 1
• ARF requires evidence of preceding group A streptococcal (GAS) infection plus either 2 major criteria OR 1 major plus 2 minor manifestations 1

Critical Caveat - The Pharyngeal Exudate Problem:

Pharyngeal exudates are explicitly NOT seen in Kawasaki disease and are not typical of ARF. 1 This finding creates diagnostic tension and suggests three possibilities:

1. Concurrent or recent scarlet fever/streptococcal pharyngitis - The strawberry tongue and pharyngeal exudate are classic for scarlet fever, which is the GAS infection that triggers ARF 2
2. Infectious mononucleosis with concurrent GAS carrier state - Can present with strawberry tongue, pharyngeal exudate, and the patient may be a GAS carrier 3
3. Infective endocarditis - New mitral murmur with systemic findings 4, 5

Secondary Considerations

Scarlet Fever (Group A Streptococcal Pharyngitis)

This diagnosis explains the strawberry tongue and pharyngeal exudate perfectly but does NOT explain the mitral murmur or pulmonary rales. 2

• Presents with sudden-onset sore throat, fever (101-104°F), sandpaper-like rash, and strawberry tongue 2
• Pharyngeal exudate is common in streptococcal pharyngitis 2
• However, scarlet fever alone does not cause cardiac murmurs or pulmonary findings - these suggest either:
  • ARF as a complication (developing 2-3 weeks post-infection) 1
  • Concurrent cardiac pathology 1

Infectious Mononucleosis

Can mimic streptococcal pharyngitis with pharyngeal findings and strawberry tongue, but cardiac involvement is extremely rare. 3

• Presents with pharyngitis, strawberry tongue, and diffuse oral/pharyngeal erythema 3
• Pharyngeal exudate can occur despite being described as typically absent 3
• The mitral murmur and rales are NOT explained by mononucleosis alone 3
• Consider if patient has significant fatigue, generalized lymphadenopathy, and splenomegaly 3

Infective Endocarditis

Must be considered with any new cardiac murmur, especially with systemic signs of infection. 4, 5, 6

• New systolic murmur in the setting of fever and possible infection source is endocarditis until proven otherwise 4, 5
• Can present with mitral regurgitation from valve destruction 5, 6
• However, strawberry tongue is not a typical feature of endocarditis 4, 5
• Pulmonary rales could represent heart failure from acute valvular dysfunction 4, 6

Kawasaki Disease

Should be considered but is less likely given the pharyngeal exudate. 1

• Classic features include strawberry tongue, oral erythema, and fever ≥5 days 1
• Pharyngeal exudates are NOT seen in Kawasaki disease - this is a key distinguishing feature 1
• Cardiac involvement (coronary artery disease, myocarditis) can occur but typically not acute mitral regurgitation 1
• More common in children under 5 years old 1

Diagnostic Algorithm

Immediate Workup Required:

1. Confirm preceding GAS infection: Throat culture, rapid antigen detection test (RADT), anti-streptolysin O (ASO) titer, anti-DNase B 1, 2
2. Assess for ARF: Check acute phase reactants (ESR ≥30-60 mm/h, CRP ≥3.0 mg/dL depending on risk population) 1
3. Echocardiography: Essential to document mitral regurgitation, assess severity, rule out vegetations (endocarditis), and look for subclinical carditis 1
4. Blood cultures: If endocarditis suspected (before antibiotics) 4, 5
5. Monospot or EBV serology: If mononucleosis suspected based on clinical features 3

Decision Points:

• If GAS confirmed + elevated acute phase reactants + mitral regurgitation on echo: Diagnose ARF with carditis 1
• If blood cultures positive + vegetation on echo: Diagnose infective endocarditis 4, 5
• If monospot positive + GAS positive: Treat both conditions; patient may be GAS carrier with concurrent mononucleosis 3
• If only GAS positive without cardiac/systemic findings: Scarlet fever alone 2

Critical Management Implications

The presence of carditis (mitral regurgitation) and heart failure (rales) requires urgent intervention regardless of final diagnosis:

• For ARF: Initiate anti-inflammatory therapy, treat GAS infection, begin secondary prophylaxis to prevent recurrence 1
• For endocarditis: Prolonged IV antibiotics, monitor for complications, consider surgical intervention if severe valve destruction 4, 5
• For scarlet fever: Penicillin V 250-500 mg every 6-8 hours for 10 days (can prevent ARF if started within 9 days) 2

The bilateral basal rales indicate acute heart failure requiring diuretics and afterload reduction while the underlying cause is addressed. 1