Fever of unknown origin

Question 1

What is pyrexia of unknown origin?

Answer 1

A temperature over 38.3 on several occasions lasting more than 3 weeks
1. Infections,
2. Malignancy,
3. Rhumatological

Question 2

What are some differential diagnosis for pyrexia of unknown origin?

Answer 2

Abscess - Localised pain and swelling,
Bacterial infections - Infective endocarditis, brucellosis, typhus, lyme disease
Parasitic and fungal infections - Malaria, schistosomiasis
Malignancy - weight loss, night sweats, fatigue. Lymphoma
Drug reactions - Accompanied by oesinophilia
Connective tissue disorder - Joint pain, skin rash and fatigue. Eg, SLE
Autoimmune inflammatory syndromes - Vasculitis, systemic autoimmune diseases, granulomatous diseases (sarcoidosis), autoinflammatory syndromes.

Question 3

What is brucellosis

Answer 3

Bacterial infection caused by brucella species. It presents with constitutional symptoms, arthralgia, joint pain and swelling, hepatomegaly and/or splenomegaly

Question 4

What are the investigations for fever of unknown origin?

Answer 4

• Bloods,
• Blood cultures,
• ECHO,
• Imaging - chest X-ray, MRI, CT
• LP,
• Tissue biopsy,
• Urinalysis