Pyrexia of unknown origin

Question 1

A 5 month old boy is brought to the ED with fevers to 39 degrees and vomiting. He has not had any diarrhoea in the last 48 hours. He has no localising features on examination but appears unwell. There is no one in the family who is unwell.

Answer 1

Impression
Fever of unknown origin, particularly concerned as the patient is <1yr and has not completed all immunisations, and appears unwell from bedside assessment.

Wide range of differentials to consider, both infective and non-infective.

Want to rule out life-threatening differentials including
- infective: Meningitis (bacterial, viral, fungal), GIT (Abscess, infection, etc), sepsis, other (UTI, Chest, skin, etc)
- non-infective: malignancy, drug reaction, autoimmune (Kawasaki disease), pyrexia of unknown origin (diagnosis of exclusion)

Goals
- assess if patient is septic utilising A to E, call for senior assistance
- conduct targeted and thorough Hx/Ex/Ix, to identify cause and rule out life-threatening presentations
- definitive Mx determined by my clinical assessment

Question 2

Fever of unknown origin - Assessment

Answer 2

Assessment
- Call for senior help
- MERT if clinically unstable

A - Likely intact, risk of aspiration with vomiting, ?secure with NGT if ongoing, administer antiemetics, resp adjuncts if compromised, intubate pending GCS
B - RR, SP02
C - 2xIVC, bloods (VBG, FBC, UEC, LFT, cultures, rest of septic screen); administer fluids, empirical ABx guided by clinical presentation
D - AVPU
E - temp, exposure for skin rashes, sites of wound infection

Question 3

Fever of unknown origin - history

Answer 3

History
would want to take a history concurrently, collateral;
- sx: vomiting vs reflux, nausea, irritability, feeding problems, bowel changes, urine changes, etc
- RISKS: recent travel, no immunisations, sick contacts, local disease outbreaks

Question 4

Fever of unknown origin - examination

Answer 4

Examination
- general appearance + vitals
- systems review
- Neuro exam (AVPU),
- meningitis: fontanelles, neck stiffness, focal neuro signs, non-blanching rashes

Question 5

Fever of unknown origin - Investigations

Answer 5

Investigations
would be guided by clinical impression and findings on Hx/Ex
key
- septic work-up + VBG

• Bedside: Urinalysis
• Bloods: FBC, CRP, cultures, UEC, LFT
• Imaging: CXR, MRI Brain
• other: +/- LP for meningitis

Question 6

Fever of unknown origin - Management

Answer 6

Management
- given fevers and vomiting, likely for admission under paeds for further investigations and monitoring.

Supportive
- gain vascular access
- IV fluids and electrolytes as required
- antipyretics, analgesia, antiemetics

Definitive
- depends if HD stable or unstable, manage as per sepsis protocol if clinically indicated
- Empirical ABx if still no focus identified, otherwise treat targeting the particular focus of infection
o Gent + Ceftriaxone +/- Vanc