Lung infiltrates complicate a common rash
Hector had come to the ER for evaluation of a pruritic, painful rash. The four-day-old rash had started on his face and in his mouth, extended to his chest and back, and then spread diffusely over his arms, legs, and feet. Fever and malaise had accompanied the eruption. For the past few days, he had suffered painful swallowing, pleuritic chest pain, nonproductive cough, and dyspnea.
At age 23, Hector was otherwise healthy. He took no medications and had no drug allergies. Family history was unremarkable. For the past 14 years, Hector had smoked one pack of cigarettes daily. There was no history of alcohol or IV drug use. He did not know which of the childhood immunizations he had received; he was reasonably certain he had never had the chickenpox.
1. EXAMINATION FINDINGS
Hector was fatigued and toxic in appearance. On examination, his temperature was 39ºC, BP 90/60 mm Hg, pulse 112 beats per minute, respiration rate 24 breaths per minute, oxygen saturation 92% (100% on a nonrebreather face mask). A prominent rash was visible on his scalp, face, cheeks, mouth, neck, chest, back, forearms, arms, legs, and feet. The rash was pruritic, centripetal, and most prominent on the face, scalp, and trunk. Most of the lesions were vesicular, superficial, and elliptical with slightly raised borders, somewhat reminiscent of a dewdrop. Some maculopapules and scant crusted lesions were also observed. Other physical findings included tachypnea, sinus tachycardia, bilaterally decreased breath sounds, and bibasilar crackles.
WBC count was 6,800/µL (neutrophils 32%, bands 17%, lymphocytes 41%, monocytes 10%), hemoglobin 15.3 g/dL, platelets 85,000/µL. Aminotransferases were mildly elevated; other serum chemistries were normal. Blood cultures were drawn on admission. Chest x-ray showed a fine reticulonodular pattern, more prominent in the lower lobes.
The history, physical, and radiographic findings were compelling for disseminated varicella, or chickenpox, complicated by varicella pneumonia, thrombocytopenia, and hepatitis. Hector was placed in a negative-pressure room in the ICU. Isolation with strict contact and respiratory precautions was implemented until the primary crusts disappeared. Diligent skin care was maintained to avoid secondary bacterial infection. IV acyclovir was started. Pruritus was treated with oral antihistamines, topical calamine lotion, and colloidal oatmeal baths. Acetaminophen was used as an antipyretic. Aspirin and all nonsteroidal anti-inflammatory drugs were avoided so as not to precipitate Reye's syndrome. Other supportive measures (IV fluids, electrolyte and hematologic monitoring, adequate nutrition, and pain control) were also administered.
Varicella is highly contagious, with a 90% attack rate among seronegative individuals. The infection is endemic in the general population but becomes epidemic among susceptible individuals during seasonal peaks (late winter and early spring). Children ages 5-9 years account for 50% of all cases. Approximately 10% of the U.S. population over age 15 is susceptible. An estimated 50,000 adults get chickenpox each year. Adults generally have more severe manifestations than children.
Preventive guidelines recommend that adults who have never had (or are unsure whether they have had) chickenpox be tested. Those who are seronegative should be vaccinated. Severe illness due to chickenpox is reduced by 95% for 10 years after vaccination.
The incubation period of chickenpox is 10-21 days. Patients are infectious approximately 48 hours prior to onset of the rash, during the period of vesicle formation (generally four to five days), and until all vesicles are crusted. Varicella is spread via respiratory secretions and by direct contact. Isolation with strict contact and respiratory precautions is essential while the patient is infectious.
Antiviral therapy is most effective when given within 48 hours of rash onset. Oral regimens (acyclovir, valacyclovir, famciclovir) are very effective. Immunoglobulins are necessary for persons with significant exposure to the patient during the infectious phase. Hospitalization for IV acyclovir is indicated for those with complications of chickenpox, such as varicella pneumonia or encephalitis, or for those who are immunosuppressed.
Varicella pneumonia is the most serious complication, developing in 20% of adults. The risk is increased by certain comorbidities and other factors, including pregnancy and the postpartum state, tobacco or corticosteroid use, presence of chronic obstructive pulmonary disease, immunosuppression, advanced HIV infection, transplantation (particularly bone marrow or solid organs), malignancy, or age older than 65 years. Onset occurs three to five days into the infection and is associated with tachypnea, cough, dyspnea, and fever. Cyanosis, pleuritic chest pain, and hemoptysis are frequent. Chest x-ray shows reticulonodular infiltrates and interstitial pneumonitis. IV acyclovir for 7-10 days and supportive measures comprise the cornerstone of management. Resolution of pneumonitis parallels improvement of the rash.
Secondary bacterial superinfection of the skin occurs often but can be prevented by meticulous skin care. Asymptomatic hepatic involvement is very common and is characterized by elevated levels of aminotransferases. Other complications include myocarditis, corneal lesions, arthritis, bleeding diatheses, nephritis, acute glomerulonephritis, aseptic meningitis, encephalitis, transverse myelitis, Guillain-Barré syndrome, and Reye's syndrome.