Uncommon viral infections

Question 1

Uncommon viral infections

Measles

Measles

• Incidence has declined dramatically since immunisation was introduced; a recent small increase has resulted from the fall in immunisation uptake
• Clinical features: fever, cough, runny nose, conjunctivitis, marked malaise, Koplik spots, maculopapular rash
• Complications: common if malnourished or immunocompromised; major cause of death in developing countries.

Answer 1

Clinical features:

• Encephalitis occurs in about 1 in 5000, about 8 days after the onset of the illness. Initial symptoms are headache, lethargy and irritability, proceeding to convulsions and ultimately coma
• Subacute sclerosing panencephalitis (SSPE) is a rare but devastating illness manifesting, on average, 7 years after measles infection in about 1 in 100 000 cases
• The disorder presents with loss of neurological function, which progresses over several years to dementia and death

Treatment
Treatment for measles is symptomatic. Children who are admitted to hospital should be isolated. In immunocompromised patients, the antiviral drug ribavirin may be used. Vitamin A, which may modulate the immune response, should be given in developing countries.

Question 2

Uncommon viral infections

Mumps

Answer 2

Clinical features:

• incubation period is 15–24 days. Onset of the illness is with fever, malaise and parotitis,
• but in up to 30% of cases, the infection is subclinical.
• Only one side may be swollen initially, but bilateral involvement usually occurs over the next few days.
• Examination of the parotid duct may show redness and swelling.
• Occasionally, parotid swelling may be absent. The fever usually disappears within 3–4 days

Viral meningitis and encephalitis:

Lymphocytes are seen in the CSF in about 50%, meningeal signs are only seen in 10%, and encephalitis in about 1 in 5000. The common clinical features are headache, photophobia, vomiting and neck stiffness.

Orchitis:

This is the most feared complication, although it is uncommon in prepubertal males. When it does occur, it is usually unilateral. Although there is some evidence of a reduction in sperm count, infertility is actually extremely unusual. Rarely, oophoritis, mastitis and arthritis may occur

Question 3

Uncommon viral infections

Rubella (German measles)

Answer 3

• Mild disease in childhood, occurs in winter and spring, important infection, as it can cause severe damage to the fetus
• incubation period is 15–20 days, spread by respiratory route, frequently from a known contact.
• The prodrome is usually mild with a low-grade fever or none at all
• maculopapular rash is often the first sign of infection, appearing initially on the face and then spreading centrifugally to cover the whole body

Lymphadenopathy, particularly the suboccipital and postauricular nodes, is prominent. Complications rare in childhood but include arthritis, encephalitis, thrombocytopenia and myocarditis. Clinical differentiation from other viral infections is unreliable. The diagnosis should be confirmed serologically if there is any risk of exposure of a non-immune pregnant woman. There is no effective antiviral treatment. Prevention therefore lies in immunisation

Question 4

Prolonged fever

Answer 4

Most childhood infections are acute and resolve in a few days. If not, the child needs to be reassessed for complications of the original illness, e.g. a secondary bacterial infection, or the source of infection may not have been identified, e.g. urinary tract infection. Often, the child has developed another unrelated febrile illness. Assessment of prolonged fever also needs to be made for prompt recognition of Kawasaki disease to avoid complications

Question 5

Kawasaki disease

Kawasaki disease
Mainly affects infants and young children

• The diagnosis is made on clinical features – fever >5 days and four other features of non-purulent conjunctivitis, red mucous membranes, cervical lymphadenopathy, rash, red and oedematous palms and soles or peeling of fingers and toes
• ‘Incomplete’ (formerly called ‘atypical’) cases can occur, especially in infants, so a high index of suspicion should be maintained in a febrile child
• Complications – coronary artery aneurysms and sudden death
• Treatment – intravenous immunoglobulin and aspirin.

Answer 5

• Kawasaki disease (KD) is a systemic vasculitis, it is an important diagnosis as aneurysms of the coronary arteries are a devastating complication. Prompt treatment reduces their incidence
• Mainly affects children of 6 months to 4 years old, with a peak at the end of the first year, more common in Japanese, to a lesser extent, Afro-Caribbean ethnicity, than in Caucasians
• No diagnostic test, diagnosis is made on clinical findings. In addition to the classic features, affected children are irritable, have high fever that is difficult to control, and may also have inflammation of their BCG vaccination site
• high inflammatory markers (C-reactive protein, ESR, white cell count), with a platelet count that rises typically in the second week of the illness
• coronary arteries are affected in about one-third of affected children within the first 6 weeks of the illness. This can lead to aneurysms which are best visualised on echocardiography