Fever and PUO

Question 1

What are the mechanisms of Heat loss, Heat conservation and heat production?

Answer 1

Heat loss - Peripheral vasodilation, sweating and reduced physical activity

Heat conservation - Peripheral vasoconstriction, piloerection and warmth seeking behaviour -

Heat production Shivering, T3/4, GC, catecholamine release

Question 2

What is the classification of fever?

Answer 2

Early morning oral temperature >37.2C Oral temperature 37.8 any time of day *Oral temp

Question 3

Describe the febrile response

Answer 3

an adaptive mechanism in mammals. This increases the temperature switches on a range of processes (immunological ,endocrine and physiological) that are involved in defending against infectious agents. Optimum temp if 39.5C

Question 4

What is Rigor?

Answer 4

Rigor is a mark of high fever (39-40C) a feeling of intense cold and uncontrollabe shivering. There is piloerection-erection and pallor of the face and limbs (vasocontriction to shunt blood centrally). Exhaustion usually follows a fever with rigor.

Question 5

Describe Fever of short duration

Answer 5

Infection is the most common cause

• Symptoms
  
  • Runny nose
  • Cough
  • Diarrhoea
  • Urine symptoms
• Many are self limiting but some are not
  
  • Meningococcaemia
  • F.Malaria
  • Bacterial meningitis
  • Post splenectomy sepsis
  • Toxic shock
  • necrotising soft tissue infection (Group A strep)
  • Heand and neck space infection
  • Febrile neutropaenia
  • Acture staph aureus endocarditis
  • Severe pneumonia
• People at risk = Recent OS travel, splenic patients, neutropaenic pts, elderly, diaebetic, IV drug users
• Symptoms of such illness
  
  • Rapid onset
  • Rigors
  • Severe muscle pains
  • Imparied consciousness
  • Vomitting
  • Severe headache
  • Rash
  • Jaundice
• Management
  
  • Investigate
  • Blood: FBE, CRP, renal and liver function
  • Culture: blood urine
  • CXR: for pneumonia

Question 6

What is the cause and management of Prolonged fever?

Answer 6

3-5d of fever. Can still be due to infectious causes (but much less so) less localising symptoms

• Epidemiology
  
  • Occupational/animal exposure –> Coxella burnetti (Q fever)
  • Country - TB
  • Travel - Falciparum, vivax or ovale; Liver abscess can present 6-12 months afterward
  • Contact with toddlers - CMV the most common cause of fever in parents of young kids; get contamination during changing nappies
  • Risk for bacterial endocarditis (murmur, prosthetic valve, pacemaker, IV drug user)
• What to do next? look for more symptoms
  
  • Slight cough/crackles in lung
  • Enlarged LN/Spleen (lympadenopathy, splenomegaly)
  • Thyroid tenderness/temporal artery tenderness
  • Arthalgia/arthritis/rask - joint symptoms may be old world viruses
• Management
  
  • FBE
    
    • Atypical lymphocytosis (EBV, CMV, acute HIV)
    • Neutrophillia
    • Exclude malaria if OS travel in last few years
  • ESR - non-specific, high if prolonged bacterial infection or vasculitis. very high if autoimmune
  • CRP - very high (>200) suggests bacterial infection/inflammation
  • LFTs - usually non specific
  • CXR - atypical pneumonia (psittacosis, mycoplasma, legionella)

Question 7

Desribe Pyrexia of unknown origin

Answer 7

Prolonged illness 2-3wks, fever 38.3 on several occasions with no Dx

Question 8

What to do when someone has PUO?

Answer 8

Start from the basics!

1. Onset and duration
2. Seek localising symptoms
3. Estabolish severity
   
   1. Night sweats? unintentional weight loss?
4. Is there really fever?
5. Obtain info and review all results
6. Look for clues - PHx, FHx, medications
7. Country of origin
8. Travel Hx
9. Occupation, animal exposure
10. Sexual Hx and IV drug use

Question 9

What are the differential diganosis for PUO?

Answer 9

20% of PUO are bacterial infections

Subactue bacterial endocarditis (viridians strep) - Transoesophageal echocardiogram can be used

TB - Fever and weight loss

Intra-abdo abscess - apendix, liver abscess

HIV related infection (Cryptococcus, MAC)

Other? EBV, CMV, Brucella, Q fever, Psittacosis, malaria

CT Disorders

Polymyalgia rheumatica - presents with high ESR (200-300)

Giant cell arteritis (temporal artertis) - tender temporal arteries

Vasculitis - Polyarteritis nodosa

Still’s disease

SLE

Acute thyroiditis

Granulomatous disease - Sarcodosis, Crohn’s, idiopahtic granulomatous hepatitis

Maligncies

Lymphoma

Acute leukemia

Renal cell carcinoma

Hepatoma

Rarely GI malignancies

Atrial myxoma

mets

‘Benign pyrexias’

Drug fever

Facititious fever

Question 10

What investigations are needed for PUO?

Answer 10

Repeat + review basic blood including cultures

MSU - look for glomerular RBC

ANA (anti-nuclear antibody) RH, ANCA (anti-neutrophil cytoplasmic antibody)

Serum ferretin (iron studies)

LDH, b2-microglobulin

HIV serology - EBV, CMB, Brucellosis, Q fever, psittacosis, bartoella, syphillis

Mantoux

Question 11

What should you be aware of with acute fever?

Answer 11

Normal WWC and CRP on DAY 1 (If it doesn’t go up doesn’t mean its not bacterial, needs time)

and

Improvement with panadol and IV fluids

Question 12

What does EBV cause in children?

Answer 12

Glandular fever

Question 13

How does CMV present in children and adult?

Answer 13

Adults who have not been infected before present as fever, sweats and aches.

Asymptomatic in toddler.

Commonest cause of prolonged fever in young adults with kids