Pregnancy itself does not appear to predispose to pneumonia. Jin and colleagues (2003) reported the antepartum hospitalization rate for pneumonia in Alberta, Canada, to be 1.S per 1000 deliveries-almost identical to the rate of 1.47 per 1000 for nonpregnant women. Likewise, Yost and associates (2000) reported an incidence of 1.S per 1000 for pneumonia complicating 7S,000 pregnancies cared for at Parkland Hospital. s discussed, at least hlf are caused by viruses. A fourth are bacterial, and S pneumoniae causes half of the latter. Over the past few years community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a common pathogen that may cause necrotizing pneumonia (Mandell, 201S; Moran, 2013). Occasionally, Legionnaires disease is encountered (Close, 2016).
FIGURE 51-3 Chest radiograph in a pregnant woman with right lower lobe and left upper lobe pneumonia. Rounded right basilar and let apical infiltrates are consistent with the diagnosis.
Typical symptoms of pneumonia include cough, dyspnea, sputum production, and pleuritic chest pain. Mild upper respiratory symptoms and malaise usually precede these symptoms, and mild leukocytosis is usually present. Chest radiography is essential for diagnosis (Fig. SI-3). Radiographical findings do not accurately predict the etiology, and as discussed, the responsible pathogen is identiied in fewer than half of cases. According to the Infectious Diseases Society of America (IDSA) and the American horacic Society (A TS), tests to identiy a specific agent are optional (Mandell, 2007). hus, sputum cultures, serological testing, cold agglutinin identiication, and tests for bacterial antigens are not routinely recommended. The one exception to this may be rapid serological testing for inluenza A and B (Sheield, 2009).
Although many otherwise healthy young adults can be safely treated as outpatients, at Parkland Hospital we hospitalize all pregnant women with radiographically proven pneumonia. Another option is outpatient therapy or 23-hour observation, which is reasonable with optimal follow-up. At least for nonpregnant patients, the pneumonia severity index (PSI) and the CURB-6S scoring system are used as a guide to admission (Mandell, 201S). Neither has been studied in pregnancy. Given that, risk factors shown in Table 5a1-3 should prompt consideration for hospitalization.
With severe disease, admission to an intensive or intermediate care unit is advisable. Approximately 20 percent of pregnant women admitted to Parkland Hospital for pneumonia require this level of care (Zeeman, 2003). Severe pneumo
TABLE 51-3. Criteria for Severe Community-Acquired Pneumoniaa
Leukopenia: WBC <4000/-LL
Thrombocytopenia-platelets < 1 OO,OOO/-LL aCriteria of the Infectious Diseases Society of America/
American Thoracic Society.
Pao/Fio2 = partial pressure oxygen in arterial blood/ fraction of inspired oxygen; WBC = white blood cell. Adapted from Mandell, 2007.
nia is a relatively common cause of acute respiratory distress syndrome (ARDS) during pregnancy, and mechanical ventilation may become necessary (Chap. 47, p. 919). Indeed, of the 51 gravidas who required mechanical ventilation in the review by Jenkins and coworkers (2003), 12 percent had pneumonia.