Outcome of varicella pneumonitis in immunocompetent adults requiring treatment in a high dependency unit

Objectives: The incidence of varicella infection is increasing in adults, where primary pneumonitis; is the main complication. Little information exists concerning treatment of those patients who require admission to a high dependency unit (HDU) facility. A study was performed to examine the risk factors for developing varicella pneumonitis (VP), to document disease progression and assess prognosis for patients with VP requiring HDU admission. Methods: A 10-year retrospective casenote review of patients admitted to the Regional Infectious Diseases Unit HDU. Varicella pneumonitis (VP) was defined as diffuse nodular shadowing on a chest X-ray (CXR) of a patient with a classical chickenpox rash. Severe pneumonitis was defined as an hypoxaemia index (pO2 in mmHG/FiO(2)) of less than 150 at any time during hospital stay. All patients were treated with intravenous acyclovir at a dose of 10 mg/kg. Results: A total of 33 patients were admitted to the HDU with VP over the study period, 30 were included in the study. Annual admission rates remained constant. Most patients (76.7%) had at least one recognised risk factor for severe VP: smoking 18/30, pregnancy 9/30, chronic lung disease 7/30. Twelve (40%) patients had severe VP, eight (26.7%) required assisted ventilation. The presence of greater than one risk factor (p < 0.02) was associated with progression to severe VP. There was one death: a 63-year-old man with a long history of chronic airflow limitation whose treatment had included domicillary long-term oxygen therapy. Nine (30%) patients developed secondary bacterial pneumonia. all recovered with appropriate antibiotic treatment. The period of stay in HDU for the majority of patients was short (mean 4.5 days). Conclusions: The prognosis for severe adult VP with current available treatment is good. The only predictor on admission for severe VP is the presence of more than one recognised risk factor for developing VP. (C) 2001 The British Infection Society.