A 30-year-old businessman developed sudden onset of fever, sore throat, diarrhoea and myalgia. Over the next three days he noticed a widespread rash affecting his face, trunk, palms and soles. He was usually fit and well and had only consulted his GP once in the past 10 years for a typhoid vaccine before travelling to India. Over the past four months he had established business links with a company in Thailand and had visited the country on three occasions. His last visit to Thailand was eight weeks previously. He was married with two young children. He was not taking any medications and had no history of drug allergy.
On examination his temperature was 38.6°C. There was cervical lymphadenopathy. Inspection of the oral cavity revealed several painful ulcers affecting the tongue. The pharynx was oedematous and red with minimal tonsillar exudates. The chest was clear. Abdominal examination was normal. Investigations are shown.
Hb 13 g/dl WCC 11 109/l (neutrophils 6 109/l, lymphocytes 4 109/l) Platelets 130 109/l Monspot test Negative Sodium 135 mmol/l Potassium 3.8 mmol/l Urea 6 mmol/l Creatinine 80 mol/l Bilirubin 23 mol/l ALT 45 iu/l AST 49 iu/l
What is the diagnosis?
a. Acute HIV infection.
b. Secondary syphilis.
c. Acute hepatitis infection.
d. Infectious mononucleosis.
e. Acute CMV infection.
e. Acute CMV infection.
The main differential diagnosis is between infectious mononucleosis, CMV infection and acute HIV infection. All three are associated with sore throat, rash, fever and atypical lymphocytes. Mouth ulcers are usually absent in
EBV and CMV infection. Furthermore the rash in infectious mononucleosis is usually an idiosyncratic reaction to ampicillin whereas it is part of HIV seroconverson. The main clinical features differentiating infectious mononucleosis from acute HIV infection are tabulated below. The rash in CMV infection usually spares the palms and soles.
Differentiation between infectious mononucleosis and acute HIV infection Parameter Infections mononucleosis HIV infection Onset of symptoms Over a few days Abrupt Mouth ulcers Absent usually Often present Rash Usually secondary to ampicillin Part of HIV seroconversion Diarrhoea Unusual Common Tonsillar exudates Prominent Mild White cell count May be elevated Elevated or suppressed Atypical lymphocytes Frequent (90%) and numerous Present in 50% Transaminitis Common Common Thrombocytopenia Common Common