Pneumonia in the Pregnant Patient: A Synopsis

, and , Division of Pulmonary and Critical Care Medicine, Winthrop University Hospital, Mineola, NY

Disclosures

Medscape General Medicine. 1999;1(3) 

In This Article

Other Pneumonias Complicating Pregnancy

As mentioned earlier, viral and fungal pneumonias also complicate pregnancy. Influenza viruses are of the myxovirus class, type A, B, or C. Most epidemics in humans are due to type A. The alterations in cell-mediated immunity seen in pregnancy make viral and also fungal and tuberculous infections more virulent in the pregnant woman than in her nonpregnant counterpart.[5] The Asian flu epidemic of 1918 demonstrated this phenomenon dramatically -- infection with the virus carried a maternal mortality of 30%, rising to 50% if pneumonia was also present.

Influenza Pneumonia

Clinically, influenza infection presents in the pregnant woman as it does in the nonpregnant host: with coryza, fever, chills, malaise, and usually a cough. These symptoms may be self-limiting, but if they persist for 5 days, complications must be anticipated. Pneumonia may be one such complication (usually a secondary bacterial pneumonia, but there may be viral infection of the parenchyma). The autopsy findings of victims of the 1957 flu epidemic revealed that pregnant women who died were likely to have viral pneumonia, whereas nonpregnant women who succumbed were more likely to have suffered secondary super-infection with bacterial pneumonia caused by S aureus, pneumococcus, and H influenzae.[41]

Primary influenza pneumonia can evolve into fulminant respiratory failure in the pregnant woman, leading to high FIO2 requirements and rapidly appearing bilateral patchy fluffy infiltrates. Antibiotic therapy must be rapidly instituted. Choices are as outlined in the previous section on bacterial pneumonia, but if viral pneumonia seems more likely, oral amantadine may be added.

Influenza pneumonia in pregnancy has been managed with oral amantadine and inhaled ribavirin. Amantadine acts by inhibiting the release of viral nucleic acids and is effective against influenza A. While this agent is not embryotoxic, it is excreted in the breast milk and is therefore only indicated for the highest-risk patients. Clinical data on ribavirin are more limited, but this agent is effective against influenza A and B. No data, however, are available on ribavirin in the setting of coexistent pregnancy and pneumonia.

Varicella Pneumonia

Varicella infection is also seen in pregnancy. The most serious maternal consequence of varicella infection is pneumonia. In the nonpregnant host, varicella pneumonia carries a mortality of 11% to 17%, compared with mortality rates of 35% to 40% in pregnancy.[4,46.] While infection with the varicella-zoster DNA virus usually leads to a benign self-limiting illness in children, in pregnancy, it may have devastating consequences. The disease is more common and more severe in pregnancy; however, studies have not shown increased mortality rates. Varicella pneumonia is most likely to complicate the final trimester, and infection is much more serious and confounding if it occurs at this time.[16,23,11]

Clinically, varicella presents as a fever and rash with malaise. In this setting, pneumonia onsets within 2-5 days, accompanied by dyspnea, pleuritic pain, and cough. Oral mucosal ulceration may also be present -- an important presenting symptom which should raise the physician's index of suspicion -- and severity of illness ranges from coryza-like symptoms to life-threatening respiratory failure requiring mechanical ventilation and positive-end expiratory pressure (PEEP). Classically, the chest radiograph shows miliary nodular infiltrates bilaterally; a late sequela is pulmonary calcification.

Aggressive therapy -- in terms of early hospitalization and antibiotics - is mandated. Acyclovir has been extensively used and has been found safe in pregnancy.[14,21,22,46,47,48,49,50]

There is no definitive evidence that the addition of acyclovir changes clinical outcome. Haake and coworkers[15] assessed the effect of early acyclovir on the course of varicella pneumonia (initiated within 36 hours of hospital admission) and found a reduction in fever and tachypnea and an improvement in A-a (Alveoli-arterial oxygen difference) gradient -- but whether this changes mortality is not known.

Fungal Pneumonia

Fungal pneumonia also deserves consideration in the pregnant patient. This form of pneumonia is rare in the pregnant host and reports in the medical literature are limited. Dissemination occurs more rapidly in this setting, particularly when the infection is acquired in the final trimester.[31] Maternal mortality and fetal loss may be lessened with appropriate treatment; amphotericin and ketoconazole have been used but the optimal therapy at this time is unknown. Supportive care, as always, is paramount.

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