Pneumonia, Pneumococcal

Key Features

Essentials of Diagnosis

• Productive cough, fever, rigors, dyspnea, early pleuritic chest pain

• Consolidating lobar pneumonia on chest radiograph

• Lancet-shaped gram-positive diplococci on Gram stain of sputum

General Considerations

• The most common cause of community-acquired pyogenic bacterial pneumonia

• Predisposing factors

  • Alcohol use disorder

  • Asthma

  • HIV infection

  • Sickle cell disease

  • Splenectomy

  • Hematologic disorders

Clinical Findings

Symptoms and Signs

• High fever, productive cough, occasional hemoptysis, and pleuritic chest pain

• Rigors may occur initially but are uncommon later in the course

• Bronchial breath sounds are an early sign

Diagnosis

Laboratory Tests

• Diagnosis requires isolation of the organism in culture, although the Gram stain appearance of sputum can be suggestive

• Sputum and blood cultures, positive in 60% and 25% of cases of pneumococcal pneumonia, respectively, should be obtained prior to initiation of antimicrobial therapy in patients who are admitted to the hospital

• A good-quality sputum sample (< 10 epithelial cells and > 25 polymorphonuclear leukocytes per high-power field) shows gram-positive diplococci in 80–90% of cases

• A rapid urinary antigen test for Streptococcus pneumoniae, with sensitivity of 70–80% and specificity > 95%, can assist with early diagnosis

Imaging

• Chest radiograph shows findings of consolidation, often with a lobar distribution, infiltrates, pleural effusion

Treatment

Medications

• Initial antimicrobial therapy of pneumonia is empiric pending isolation and identification of the causative organism (Table 9–8)

OUTPATIENT

• Amoxicillin, 750 mg twice daily orally for 7–10 days

• Cephalosporins may also be used

  • Cefpodoxime, 200 mg orally twice daily

  • Cefdinir, 300 mg twice daily

• Alternatives include

  • Azithromycin, one 500-mg dose orally on the first day and 250 mg orally for the next 4 days

  • Clarithromycin, 500 mg twice daily orally for 7 days

  • Doxycycline, 100 mg twice daily orally for 7 days

  • Levofloxacin, 750 mg orally for 5–7 days

  • Moxifloxacin, 400 mg orally for 7–14 days

• Outpatients with high-risk comorbid conditions (such as pulmonary disease, diabetes, cardiac disease, or alcohol use disorder) may benefit from broader combination therapy (eg, amoxicillin/clavulanate or cephalosporin plus doxycycline or a macrolide), unless a fluoroquinolone is chosen for monotherapy

INPATIENT

• Ceftriaxone, 1 g every 24 hours intravenously

• Azithromycin or doxycycline are typically added for coverage of atypical organisms

• For a highly penicillin-resistant strain, one of the following may be used:

  • Vancomycin, 1 g every 12 hours intravenously

  • Levofloxacin, 750 mg intravenously or orally once daily

  • Moxifloxacin, 400 mg intravenously or orally once daily

• Total duration of therapy is not well defined but 5–7 days is appropriate for patients who ...