Clinical course, progression, and laboratory features of SARS
| Clinical features | Laboratory findings and pathological features | |
|---|---|---|
| Onset | Fever, chills, myalgia, dry cough and other constitutional symptoms. Approximately 20% of patients have diarrhoea | Lymphopenia, increased level of LDH. Chest radiographs may be normal |
| Week 1 | Progressive pneumonia and increasing oxygen dependency | Active viral replication phase: respiratory secretion, stool and urine positive for SARS associated coronavirus. Chest radiographs and CT scan of thorax show progressive air space consolidations |
| Week 2 | Gradual improvement (75%) or recurrence of fever, shifting radiological infiltrates with further deterioration/ARDS (25%) and death (8–15%) | Immune response phase: severe lung damage possibly related to immunopathological dysregulation. Necropsy of fatal cases showed diffuse alveolar damage, hyaline membrane formation, and desquamation of pneumocytes |
| Week 3 onwards | Gradual recovery of most patients (>80%) or death (8–15%) | SARS associated coronavirus still detectable from respiratory secretions (47%), stool (67%), and urine (21%) in recovered patients19 |