Microbiology Picture Quiz: Number 7: Answers

courtesy of Midgeley DJ
courtesy of Midgeley DJ
courtesy of Brook da Oger
courtesy of Brook da Oger

Have a look at these pictures from two different patients with the same clinical condition, and answer the questions below:


What is the likely clinical disease in these two patients?

Hand, Foot and Mouth syndrome. Sometimes the lesions do not always appear on all three areas. Sometimes the lesions appear in other areas also, such as the buttocks and peri-oral area.

Classically the lesions are papulo-vesicular, but sometimes vesicles are not present.

When the lesions only appear on the oro-pharynx, it is sometimes called “herpangina”


What are the likely causes of this condition?

Hand, foot and mouth disease is a clinical syndrome caused by enteroviruses. The most common enteroviruses causing this syndrome worldwide are Enterovirus 71 (EV71), Coxsackie A6 (CA6), Coxsackie A16 (CA16), and Coxsackie A10 (CA10).


How is it diagnosed in the laboratory?

In most cases the clinical diagnosis is obvious. If laboratory diagnosis is required then Enterovirus PCR can be attempted in either vesicle fluid, throat swab or stool. Only with vesicle fluid can a positive result be firmly attributed to the patients clinical symptoms and signs, and this is what I would recommend if available.

Enteroviruses can be isolated by viral culture, but this goes hand in hand with all the well known limitations of viral culture.

Enterovirus serology suffers from significant sensitivity and specificity problems and many laboratories no longer offer it.


What are the main complications of the condition?

Most cases of Hand, Foot and Mouth Disease are mild and self-limiting. However serious complications (and fatalities) can occur with clinical syndromes such as aseptic meningitis, encephalitis & acute flaccid paralysis. There may also be pulmonary oedema, possibly neurogenic in nature. These complications occur most commonly with EV71.


For a more in-depth look at Hand, Foot and Mouth Disease, here is a useful article



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