Chickenpox
Complications
Secondary bacterial infection:
Often group A strep, can be others. May even have further serious complications like nec fasc, TSS syndrome.
Encephalitis. Can occur during the early phase of the illness. Generally good prognosis. Conservative management (i.e. just let it get better by itself). Resolves within a month.
ATAXIA with cerebellar signs (cerebellitis), ~1 week after rash appears
NEW FEVER (fever initially settles and then recurs a few days later = likely 2ndary infection) or PERSISTENT fever after a few days
Purpura fulminans
Cerebellitis, aseptic meningitis, generalised encephalitis
Clinical features
Typical vesicular rash
Illness probably lasts about a week after rash appears, spikes in temperature that wiggle around 40 degrees
Incubation
Rash comes in crops for 3-5 days. Papules >> Vesicles >> Pustules >> Crusts (when fever has come down)
10-23 but median average is 2 weeks. Spread through close contact (15 minutes), respiratory droplets, direct contact with vesicular lesions
Highly infectious during viral shedding - from 2 days before rash appears until it has crusted over
200-500 lesions. Start on the trunk and spread to peripheries
New lesions should not occur after 10 days - suggest defect in cellular immunity
“dew drops on rose petals” appearance
Management
Treatment is symptom-based. No evidence for ORAL acicylovir
Immunocompromised children >> INTRAVENOUS acicylovir
Oral valaciclovir if no organ dissemination. Useful in adults with primary VZV infection (later in life it is worse)
Prophylaxis
Recommended for high risk immunosuppressed/compromised individuals - when they have come into contact with chickenpox infected. Give VZ IV Ig
Children who are immunosuppressed - cancer patients that have received chemotherapy - most viral infections do not pose threat APART from CHICKENPOX and MEASLES
Vasculitis in the skin and soft tissues. Cross reaction of antiviral Abs produced against coagulation factor (protein S) >> dysregulation of clotting, manigestation in the skin.
In the immunocompromised: severe progressive disseminated disease = mortality 20%
In pregnancy
In first 20 w if mother gets primary VZV (not previously immune) Foetus at risk of severe scarring of the skin and possibly ocular and neurological damage and digital dysplasia
Within 5 days of and 2 days after delivery - ,fetus is NOT PROTECTED by maternal antibodies and the viral dose is high. About 25% develop a vesicular rash. The illness has a mortality as high as 30%.
Exposed susceptible mothers can be protected with varicella zoster immune globulin (VZIG) and treated with aciclovir. Infants born in the high-risk period should also receive zoster immune globulin and are often also given aciclovir prophylactically.
Reye syndrome: nausea, vomiting, headache, excitability, delirium, and combativeness with frequent progression to coma
Aspirin use in fever identified as a risk factor for this - stopped using aspirin in children and the rates of Reye syndrome have gone down a lot
Consider varicella vaccination in immunocompromised patients? AVOID LIVE VACCINES. But VARIVAX (for 1yro plus is a live attenuated vaccine)