Pyrexia of Unknown Origin

Question 1

Pyrexia of Unknown Origin Definition

Answer 1

• Temperature greater than 38.3 on several occasions
• Accompanied by more than three weeks of illness
• Failure to reach diagnosis after one week of inpatient investigations

Question 2

Pyrexia of Unknown Origin Causes

Answer 2

• Most are unusual presentations of common diseases
• In adults, infections and cancer account for most
• Abscesses, TB, UTIs, Endocarditis, cholangitis, osteomyelitis
• HSV (e.g. CMV, EBV)
• HIV
• Parasites e.g. toxoplasmosis
• Lymphoma, leukaemia, RCC, solid tumours, malignant histiocytes
• Drug fever e.g. some antibiotics
• Connective tissue disease, vasculitis and granulomatous disease are the most common non-infectious causes

Question 3

Pyrexia of Unknown Origin Epidemiology

Answer 3

• A common problem
• GCA and PMR most frequent in elderly
• Still’s most common in younger