Eight-month prospective study of 14 patients with hospital-acquired severe acute respiratory syndrome

Abstract

Objective: To define the clinical characteristics and clinical course of hospital-acquired severe acute respiratory syndrome (SARS).

Patients and methods: This 8-month prospective study of 14 patients with hospital-acquired SARS in Taipei, Taiwan, was conducted from April through December 2003.

Results: The most common presenting symptoms in our 14 patients with hospital-acquired SARS were fever, dyspnea, dizziness, malaise, diarrhea, dry cough, muscle pain, and chills. Lymphopenia and elevated serum levels of lactate dehydrogenase (LDH) and C-reactive protein (CRP) were the most common Initial laboratory findings. Initial chest radiographs revealed various pattern abnormalities and normal results. Five of the 14 patients required mechanical ventilation. The need for mechanical ventilation was associated with bilateral lung involvement on the initial chest radiograph and higher peak levels of LDH and CRP. Clinical severity of disease varied from mild to severe. At 8 months after disease onset, patients with mild or moderate SARS had normal findings or only focal fibrosis on chest high-resolution computed tomography. However, bilateral fibrotic changes remained in the 4 patients who had recovered from severe SARS, 1 of whom had mild restrictive ventilatory impairment. One patient with severe SARS died; she was elderly and had other comorbidities. Five additional patients had reduced diffusing capacity.

Conclusion: The clinical picture of our patients presenting with hospital-acquired SARS revealed atypical pneumonia associated with lymphopenia, elevated serum levels of LDH, rapid clinical deterioration, and lack of response to empirical antibiotic therapy. Substantially elevated levels of LDH and CRP correlated with severe illness requiring mechanical ventilatory support. In those receiving mechanical ventilation, pulmonary function was only mildly reduced at 6 to 8 months after acute illness, consistent with the natural history of acute respiratory distress syndrome due to other causes.

FIGURE 1

Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to diagnose the severe acute respiratory syndrome (SARS) coronavirus in patient 3. The PCR products were observed through 1.5% agarose gel electrophoresis. As shown in the S1 column, RT-PCR was done with the serum from this patient on hospital day 8, and results were positive; product size was 368 base pairs (bp). However, the same procedure was repeated with the serum from this patient on hospital day 50, and results were negative, as shown in the S2 column. This finding indicated that the virus was present in the blood during the initial phase but had disappeared in the late phase of disease.

FIGURE 2

Images of patient 3 who had severe acute respiratory syndrome complicated by acute respiratory distress syndrome. Left, Chest radiograph on day 8 reveals bilateral consolidation and infiltrates (endotracheal tube was placed for mechanical ventilation). Middle, Chest radiograph performed 6 months after hospital discharge shows residual fibrotic infiltrates in the lower lung zones. Right, High-resolution computed tomography performed 6 months after hospital discharge reveals patchy ground-glass opacities and fibrotic infiltrates. Results of pulmonary function testing showed mild restrictive ventilatory impairment with a total lung capacity of 71%, forced expiratory volume in 1 second of 67%, and diffusing capacity of lung for carbon monoxide of 52%.

FIGURE 3

Serial radiographic studies of patient 5, a 30-year-old nurse from Hospital B, who had severe acute respiratory syndrome complicated by acute respiratory distress syndrome. Upper Left, Chest radiograph on admission shows bilateral consolidation and infiltrates involving the right upper lung, right lower lung, and left lower lung. Upper Middle, Chest radiograph on hospital day 2 shows progression of infiltration associated with development of severe hypoxia; mechanical ventilation was needed. Upper Right, Chest radiograph on hospital day 25 shows gradual resolution of consolidation and lung fibrotic infiltrates. Lower Left, Chest radiograph 3 months after disease onset shows near-normal findings, except for mild fibrotic lesion in left lower lung. Lower Middle and Lower Right, High-resolution computed tomography performed 3 and 6 months, respectively, after hospital discharge shows ground-glass opacities in the bilateral lower lung and fibrotic infiltrates in the left lower lung. Compared with 3-month scan, the 6-month scan shows that the area of ground glass was smaller but denser and reveals a fibrotic lesion. At 6-month follow-up, results of pulmonary function testing showed a total lung capacity of 82%, forced expiratory volume in 1 second of 53%, and diffusing capacity of lung for carbon monoxide of 39%.