What is the most likely diagnosis for a 19-year-old patient presenting with sore throat, cough, and chest tightness?

Most Likely Diagnosis: Acute Viral Upper Respiratory Tract Infection (Common Cold/Acute Bronchitis)

This 19-year-old patient almost certainly has an uncomplicated viral upper respiratory tract infection, and no testing is required unless specific red flags develop. 1, 2

Diagnostic Reasoning

The combination of sore throat, cough, and chest tightness in a young, otherwise healthy 19-year-old is classic for viral URI/acute bronchitis. 1, 2 The American Academy of Family Physicians states that approximately 70% of adults presenting with acute cough have an upper respiratory tract infection, making this the most likely diagnosis. 1

Key Clinical Features Supporting Viral URI:

• Age 19 years: Young adults are at very low risk for serious bacterial pneumonia or other complications 1
• Sore throat: This is a hallmark upper respiratory symptom that actually argues AGAINST pneumonia as the primary diagnosis 2
• Chest tightness: Pleuritic chest and back pain with coughing is common in acute bronchitis/tracheobronchitis and does not necessarily indicate pneumonia, especially without fever or focal findings 2

What Testing Should Be Done?

No testing is required in this patient unless specific red flags are present. 1, 2

When to Order Chest X-Ray:

A chest radiograph is indicated ONLY if you suspect pneumonia based on acute cough PLUS one of the following: 1, 2

• New focal chest signs on examination (rales, egophony, dullness to percussion)
• Dyspnea or tachypnea
• Fever persisting >4 days
• Abnormal vital signs

Without these findings, chest radiography is neither feasible nor cost-effective, as only 5-10% of patients with acute cough have pneumonia. 2 The European Respiratory Society notes that "fever, absence of URTI symptoms, dyspnea/tachypnea and abnormal chest signs" are the typical combination suggesting pneumonia—this patient has none of these. 2

When to Consider Other Testing:

• Rapid strep test: Only if pharyngitis is the dominant symptom, as most pharyngitis cases are viral (75-90% in adults), and antibiotics should only be prescribed if rapid strep test or culture is positive 1
• COVID-19 testing: Consider if there is fever, fatigue, or known exposure, particularly given the case reports of young adults (including a 24-year-old) presenting with fever and sore throat who had COVID-19 3
• Lung function tests: Only if there are at least two of the following suggesting underlying asthma/COPD: wheezing, prolonged expiration, history of smoking, symptoms of allergy 3

Critical Differential Diagnoses to Exclude

Pneumonia (Low Probability)

The absence of fever significantly reduces the likelihood of pneumonia. 2 The European Respiratory Society guidelines recommend suspecting pneumonia when there is acute cough PLUS fever >4 days, new focal chest signs, dyspnea, or tachypnea. 2 This patient has none of these features.

Acute Asthma (Important to Consider)

The American College of Chest Physicians suggests that approximately one-third of patients presenting with acute cough are misdiagnosed with acute bronchitis when they actually have acute asthma, particularly if there have been at least two similar episodes in the past 5 years. 1 Ask specifically about:

• History of similar episodes
• Wheezing on examination
• Response to bronchodilators in the past
• History of allergies or atopy

Chronic Airways Disease

Lung function tests should be considered to assess the presence of chronic lung disease in patients with at least two of the following signs: wheezing, prolonged expiration, history of smoking, and symptoms of allergy. 3

Management Plan

Symptomatic Treatment (No Antibiotics)

Antibiotics should NOT be prescribed, as this is almost certainly a self-limited viral illness. 1, 2 Multiple randomized placebo-controlled trials consistently demonstrate that antibiotics do not reduce symptom duration or severity in uncomplicated acute bronchitis. 1

Recommended symptomatic treatment: 1, 2

• Analgesics: Acetaminophen or ibuprofen for sore throat and chest discomfort 1
• Throat lozenges: For sore throat relief 1
• Nasal decongestant: Pseudoephedrine if nasal congestion is present 1
• Cough management: If cough persists beyond 3-5 days and is bothersome, inhaled ipratropium bromide is the first-line cough suppressant (Grade A recommendation) 1
• Hydration and rest: Essential for recovery 1

Expected Clinical Course

Symptoms typically peak at days 3-6 and should begin improving thereafter. 1 Most uncomplicated viral URIs resolve within 5-7 days, though cough may persist for up to 3 weeks (post-infectious cough). 1 Transient bronchial hyperresponsiveness can last 2-3 weeks, occasionally up to 2 months. 1

Red Flags Requiring Re-evaluation

The patient should return if: 1, 2

• Symptoms persist >10 days without improvement
• Symptoms worsen after initial improvement
• Development of high fever (>4 days)
• Development of focal chest findings or significant dyspnea
• New concerning symptoms develop

Common Pitfalls to Avoid

• Do not assume chest tightness means pneumonia: Chest wall pain from coughing is extremely common in viral URTIs 2
• Do not order a chest X-ray based solely on chest pain and cough without fever or focal findings: This leads to unnecessary radiation exposure and cost 2
• Do not diagnose "acute bronchitis" unless you have ruled out the common cold first: The definitions overlap significantly, and "acute bronchitis" implies a bacterial cause to many patients, leading to inappropriate antibiotic prescribing in 65-80% of cases 2
• Do not prescribe antibiotics for prolonged cough alone: Even cough lasting up to 3 weeks is NOT an indication for antibiotics, as multiple randomized controlled trials demonstrate that antibiotics do not reduce cough duration in uncomplicated acute bronchitis 1