Respiratory · Year 1 · from Respiratory
Case 1: Community-Acquired Pneumonia (Streptococcus pneumoniae)
Clinical Image
Source: Wikimedia Commons - Lobar Pneumonia X-ray - CC BY-SA 4.0
Case Presentation
A 58-year-old man with a history of hypertension and diabetes presents with 3 days of fever, productive cough with rust-colored sputum, and right-sided pleuritic chest pain. He reports sudden onset of shaking chills on the first day of illness. He has no recent travel or sick contacts. On examination, he appears ill and is febrile to 39.4C. Vital signs show heart rate 105 bpm, blood pressure 128/78 mmHg, respiratory rate 24/min, and oxygen saturation 92% on room air.
Chest examination reveals dullness to percussion, increased tactile fremitus, bronchial breath sounds, and egophony ("E to A" change) over the right lower lobe. These findings indicate lobar consolidation.
CURB-65 score: Confusion (no) = 0, Urea greater than 7 mmol/L (BUN 24 mg/dL, yes) = 1, Respiratory rate greater than 30 (no) = 0, Blood pressure less than 90 systolic (no) = 0, Age 65 or older (no) = 0. Total score = 1, suggesting outpatient treatment may be appropriate, but given his comorbidities and hypoxemia, hospital admission is warranted.
Chest X-ray shows dense consolidation of the right lower lobe with air bronchograms, the classic appearance of lobar pneumonia. Sputum Gram stain reveals numerous neutrophils and gram-positive diplococci. Blood cultures and sputum culture are obtained. Procalcitonin is elevated at 4.2 ng/mL, supporting bacterial etiology.
The patient is admitted and treated with IV ceftriaxone plus azithromycin (to cover typical and atypical pathogens). Blood cultures grow Streptococcus pneumoniae. The lobar consolidation pattern with air bronchograms reflects the pathologic stages of pneumococcal pneumonia: congestion, red hepatization, gray hepatization, and resolution. His fever resolves within 48 hours, and he is transitioned to oral antibiotics and discharged on hospital day 4 to complete a 5-day total antibiotic course.
Key Learning Points
- Streptococcus pneumoniae is the most common cause of community-acquired pneumonia
- Classic presentation: acute onset, high fever with rigors, productive cough with rusty sputum, pleuritic pain
- Physical findings of consolidation: dullness, increased fremitus, bronchial breath sounds, egophony
- CURB-65 score guides disposition: 0-1 outpatient, 2 consider admission, 3+ inpatient/ICU
- Lobar consolidation with air bronchograms is classic radiographic finding