Chapter 128. Pneumococcal Infections (Part 4) Physical Findings Patients with pneumococcal pneumonia usually appear ill and have a grayish, anxious appearance that differs from that of persons with viral or mycoplasmal pneumonia. Temperature, pulse, and respiratory rate are typically elevated. Elderly patients may have only a slight temperature elevation or may be afebrile. Hypothermia may be documented instead of fever and is associated with increased morbidity and mortality. Pleuritic chest pain may cause diminished respiratory excursion (splinting) on the affected side. Dullness to percussion is noted in about half of cases, and vocal fremitus is increased over the area of consolidation. Breath sounds may be bronchial or tubular, and crackles are heard in most cases if enough air is being moved to generate them. Flatness to percussion at the lung base, absent fremitus, and lack of the expected degree of diaphragmatic motion suggest the presence of pleural fluid, which raises the possibility of empyema. The finding of a heart murmur—certainly if new—raises concern about endocarditis, a rare but serious complication. Hypoxia or the generalized response to pneumonia may cause the patient to be confused, but the appearance of confusion should also raise concern about meningitis. Obtundation or neck stiffness should lead to an immediate consideration of this complication. Radiographic Findings In patients sick enough to be hospitalized, pneumococcal pneumonia is limited to one lung segment in one-fourth of cases and to one lobe in another one- fourth, with multilobar disease in the remaining one-half. Air-space consolidation is the predominant finding and is detected in 80% of cases (Fig. 128-1). Air bronchogram (visualization of the air-filled bronchus against a background of alveolar consolidation) is evident in fewer than half of cases and is more common in bacteremic than in nonbacteremic disease. Rarely, pneumococcal pneumonia leads to a lung abscess. Although some pleural fluid may actually be present in half of cases, ≤20% of patients have a sufficient volume of fluid to allow aspiration, and in only a minority of these patients is empyema documented. Figure 128-1 A retrocardiac infiltrate in a patient with pneumococcal pneumonia. Right-lower-lobe consolidation is apparent in posterior-anterior (left) and lateral (right) views of the chest. General Laboratory Findings Anemia (hemoglobin level, <10 g/dL) is documented in 25% of cases. The peripheral-blood white blood cell (WBC) count exceeds 12,000/µL in the great majority of patients with pneumococcal pneumonia. A low WBC count (<6000/µL) is found in 5–10% of persons hospitalized for pneumococcal pneumonia and is strongly associated with fatal disease. The serum bilirubin level is modestly elevated in one-third of cases; hypoxia, inflammatory changes in the liver, and breakdown of red blood cells in the lung are all thought to contribute to this increase. A serum albumin level of <2.5 g/dL in 30% of cases may indicate predisposing malnutrition or may be the result of sepsis. About 20% of patients have serum sodium concentrations of ≤130 meq/L, and another 20% have serum creatinine concentrations of ≥2 mg/dL. Abnormalities of pleural fluid in empyema are reviewed in Chap. 251. Differential Diagnosis S. pneumoniae is the most common cause of so-called community-acquired pneumonia, but patients who present with this syndrome may actually have infection due to a broad array of microorganisms. The extensive list includes (but is not limited to) the following: H. influenzae or Moraxella catarrhalis in persons with little to predispose them other than chronic or acute inflammation of the airways; Staphylococcus aureus, especially in persons who take glucocorticoids, who have influenza, or who have major anatomic disruption of the airways; Streptococcus pyogenes; Neisseria meningitidis; anaerobic and microaerophilic bacteria in persons who may have aspirated oropharyngeal contents; Legionella; Pasteurella multocida in dog or cat owners; gram-negative bacilli, especially in persons who have severely damaged lungs and are taking glucocorticoids; viruses, especially influenza virus (in season), adenovirus, or respiratory syncytial virus; Mycobacterium tuberculosis; fungi, including Pneumocystis (depending on epidemiologic factors and HIV infection status); Mycoplasma; Chlamydia pneumoniae, especially in older adults; and Chlamydia psittaci in bird owners. Many older men with lung cancer present with pneumonia, as do persons who have acute-onset inflammatory pulmonary conditions of uncertain etiology or those with pulmonary embolus and infarction. The breadth of this list vividly illustrates the deficiency of empirical therapy for community-acquired pneumonia (Table 128-3). Many of these diseases require evaluation, and the increasing availability of specific therapy makes a precise etiologic diagnosis desirable. Table 128-3 Causes of a Pneumonia Syndrome Leading to Hospitalization of Adults in Houston, Texas a Common Less Common Streptococcus pneumoniae Moraxella catarrhalis Haemophilus influenzae Staphylococcus aureus Lung cancer Pulmonary infarction Mycobacterium tuberculosis Klebsiella pneumoniae Pneumocystis Cryptococcus, Histoplasma Influenza (seasonal) Respiratory syncytial virus Microaerophilic and anaerobic mouth flora Pseudomonas aeruginosa Legionella species Nontuberculous mycobacteria Chlamydia pneumoniae Nocardia species Hamman-Rich syndrome, others a Pneumonia was defined as a syndrome consisting of fever, increased cough, sputum production, and an abnormal pulmonary shadow on chest x-ray. . Chapter 128. Pneumococcal Infections (Part 4) Physical Findings Patients with pneumococcal pneumonia usually appear ill and have a grayish,. in only a minority of these patients is empyema documented. Figure 128- 1 A retrocardiac infiltrate in a patient with pneumococcal pneumonia. Right-lower-lobe consolidation is apparent. 12,000/µL in the great majority of patients with pneumococcal pneumonia. A low WBC count (<6000/µL) is found in 5–10% of persons hospitalized for pneumococcal pneumonia and is strongly associated