What is the next best step in managing an 87-year-old man with a 3-day history of productive cough, fever, headache, and general malaise, who has developed confusion and lethargy, with a temperature of hyperthermia and a normal chest radiograph?

Management of Elderly Patient with Respiratory Symptoms and Altered Mental Status

A spiral CT scan of the chest is the most appropriate next step in this patient's management. 1

Clinical Assessment and Reasoning

This 87-year-old man presents with:

• 3-day history of productive cough, fever, headache, and malaise
• Recent onset confusion and lethargy (past 24 hours)
• Fever (38.3°C/101.0°F)
• Decreased breath sounds in right base with rhonchi
• Somatic dysfunction at ribs 6-10 on the right with right hemidiaphragm restriction
• Normal chest radiograph
• Normal urinalysis
• Normal head CT (showing only age-related atrophy)

Despite the normal chest radiograph, this clinical picture strongly suggests a lower respiratory tract infection, specifically pneumonia, with associated delirium. The American College of Radiology and Infectious Diseases Society of America guidelines emphasize that while chest radiography is essential for diagnosing pneumonia, it may occasionally be negative in early pneumonia 1.

Why Spiral CT Scan of the Chest is Indicated

1. Normal Chest X-ray with Persistent Clinical Suspicion: The ACCP guidelines recommend that when clinical findings do not match radiographic results, further investigation with chest CT should be considered 2. In this case, the patient has clear clinical signs of lower respiratory infection despite a normal chest radiograph.

2. Altered Mental Status: The patient's confusion and lethargy suggest a severe infection affecting his mental status. The BTS guidelines indicate that when patients show signs of severe infection (including confusion), more aggressive diagnostic approaches are warranted 2.

3. Diagnostic Limitations of Chest X-ray: Chest radiography has limited sensitivity for detecting early or subtle pulmonary infiltrates, particularly in elderly patients 2. Spiral CT has superior sensitivity for detecting pulmonary pathology not visible on standard radiographs 3.

4. Localized Clinical Findings: The decreased breath sounds in the right base with rhonchi and the right-sided somatic dysfunction strongly suggest a localized pulmonary process that may be better visualized with CT imaging.

Differential Diagnosis

The patient's presentation suggests several possibilities:

1. Community-acquired pneumonia - Most likely diagnosis given the fever, productive cough, and localized chest findings, despite normal chest X-ray
2. Pulmonary embolism - Can present with cough, fever, and altered mental status in elderly patients
3. Bronchitis with secondary delirium - Possible but less likely given the severity of mental status changes
4. Aspiration pneumonitis - Common in elderly with altered mental status

Why Other Options Are Less Appropriate

• Carotid ultrasonography: Not indicated as the head CT is normal and there are no focal neurological deficits suggesting carotid disease
• Electroencephalography: Not the first-line test for altered mental status with clear infectious symptoms
• Flexible bronchoscopy: Too invasive as an initial diagnostic test when non-invasive imaging can provide diagnostic information
• MR angiography of intracranial circulation: Not indicated with a normal head CT and clear respiratory symptoms

Management Algorithm

1. Obtain spiral CT scan of the chest to identify potential infiltrates not visible on chest X-ray
2. Collect blood cultures and sputum samples before initiating antibiotics 1
3. Begin empiric antibiotic therapy immediately after obtaining cultures, without waiting for CT results 1
   • For community-acquired pneumonia in elderly patients, consider a respiratory fluoroquinolone or β-lactam plus a macrolide 1, 4
4. Monitor oxygen saturation and provide supplemental oxygen if needed to maintain SaO2 >92% 2
5. Assess severity using validated tools (such as CURB-65) once pneumonia is confirmed 2
6. Consider ICU transfer if the patient develops signs of severe pneumonia (persistent hypoxia, progressive hypercapnia, severe acidosis) 2

Important Considerations

• Elderly patients often present atypically with pneumonia, with confusion being a common presentation rather than typical respiratory symptoms
• Delirium in elderly patients with infection is associated with higher mortality and requires prompt diagnosis and treatment
• Repeat imaging may be necessary if the spiral CT is negative but clinical suspicion remains high 1
• Follow-up chest imaging should be considered at 6 weeks if symptoms persist, especially in patients over 50 years of age 2

This approach prioritizes rapid diagnosis of a potentially life-threatening condition while avoiding unnecessary invasive procedures or delays in appropriate treatment.