Viral infection in a child: Hand, foot and mouth disease Flashcards
Define hand, foot and mouth disease.
A common childhood viral infection that is most commonly caused by a coxsackievirus, characterised by low-grade fever, painful oral ulcers, and vesicles on the hands and feet.
The disease has no relation to foot-and-mouth disease, which affects cattle and other cloven-hoofed animals.
Explain the aetiology/risk factors for hand, foot and mouth disease.
The most common viruses implicated are a group of enteroviruses known as the coxsackieviruses. Coxsackie A16 infection is the most common cause, but A4 through to A7, A9, and A10 infections also occur. Enterovirus 71 (EV71) also causes this disease, but a more severe version. However, EV71 infection is uncommon in the US and Europe.
The enteroviruses are icosahedral non-enveloped viruses that are approximately 30 nanometres in diameter. The genome is made of a single-stranded linear molecule of RNA. Enteroviruses resist lipid solvents and tolerate a wide range of pH and temperature. They are inactivated at temperatures of >50°C (>122°F), but remain infectious at refrigerator temperatures.
Summarise the epidemiology of hand, foot and mouth disease.
The infection usually occurs as a sporadic event, but outbreaks do occur worldwide. Coxsackievirus infection is extremely contagious. It affects males and females equally and is most common in children <10 years of age.
However, infection in older children, adolescents, and adults can occur. Epidemics due to the more virulent strains of enterovirus 71 have occurred most often in East and South-east Asian countries such as Taiwan and Malaysia. These have resulted in severe cases with significant associated morbidity and mortality.
What are the presenting symptoms of hand, foot and mouth disease?
In most cases, the patient is <10 years of age and presents with a sudden onset of low-grade fever, loss of appetite, sore throat, cough, abdominal pain, diarrhoea, and general malaise. Arthralgia occurs occasionally.
This prodromal period may last for 3 to 4 days and is typically followed by sores appearing on the oral mucosa. Rash on the palms of the hands and soles of the feet and on the buttocks can follow within 1 or 2 days. The disease may cause all of the above signs and symptoms or just a few of them.
What are the signs of hand, foot and mouth disease?
Inflamed oropharynx, with scattered papules, macules, vesicles, or ulcers on the erythematous base present on the tongue, pharynx, buccal mucosa, gingiva, and occasionally the lips. Ulcers are 4-8mm in size and may be sharply marginated. There is usally an acral rash involving the palms and soles, with small oval or linear grey-white vesicopustules.
The vesicles are flaccid and thin-walled, with an erythematous halo. They may occasionally be painful or pruritic. They tend to ulcerate and become crusted. A maculopapular rash may be seen on the buttocks in infants and small children (but it does not usually ulcerate).
What are appropriate investigations for hand, foot and mouth disease?
Viral culture
FBC
PCR molecular assays
What is the management of hand, foot and mouth disease?
Analgesics and antipyretics+ topical anaesthetics+ adequate fluid and nutritional intake.
If patients are immunocompromised or have complications secondary to EV71 infection then hospitalisation and supportive treatment is warranted.
What are complications associated with hand, foot and mouth disease?
Volume depletion, secondary bacterial infection.
Enterovirus 71 (EV71)-related encephalitis or encephalomyelitis
EV71- related flaccid paralysis (polio-like syndrome)
EV71-related aseptic meningitis
EV71-related myocarditis
EV71-related pulmonary oedema and haemorrhage
Congential EV71 infection
Spontaneous miscarriage
What is the prognosis of hand, foot and mouth disease?
Spontaneous recovery with no complications is normal, and therefore follow-up is not usually required.
However, in clinical illness due to enterovirus 71, a recent study from Taiwan found that 4% of patients had long-term sequelae, and death occurred in 8% of patients.
