A 2 year old developmentally normal boy presented to the paediatric admissions unit, with a three day history of a rash. The rash was over his right shoulder, arm, and back. He was systemically well, and had had chickenpox twice previously. On examination he was well, there were red, raised, crusty vesicles on his right chest wall, back and upper arm, as illustrated in figure 1.

QUESTION

What is the spot diagnosis in figure 1.

Answer

The rash was diagnosed as herpes zoster, he was prescribed a 10 day course of oral aciclovir and discharged home.

Two days later he represented to the paediatric admissions unit. He was unwell, with a one day history of high fever, vomiting, and lethargy.

On examination he was feverish at 40°C, poorly perfused, capillary refill time of four seconds. There was no neck stiffness, photophobia or other rash except for the “shingles”. He required 40 ml/kg of normal saline (0.9%) fluid boluses. He had a full septic screen, and was given intravenous ceftriaxone and intravenous aciclovir.

QUESTION

What would be the differential diagnoses on this second presentation?

Answer

The differential diagnoses would be:

• Bacterial meningitis, for example, N meningitides, S Pneumoniae.

• Septicaemia.

• Varicella meningitis/encephalitis.

• Viraemia.

QUESTION

What investigations would you perform to differentiate these diagnoses?

Answer

A case of suspected meningitis or septicaemia, should have a blood culture, throat swab, EDTA sample for polymerase chain reaction amplification (PCR), …