W29-L5: Fever, Pyrexia of unknown origin Flashcards
What is the diagnosis of Pyrexia of unknown origin?
- Prolonged illness (2-3 weeks duration)
- Fever (above 38.3C) on several occasions
- No diagnosis after intelligent investigations
What regulates body temperature?
Anterior hypothalamus
What is the definition of fever?
- Early morning oral temperature > 37.2C
* Oral temperature > 37.8C any time of day
What is the febrile response?
A rise in core temperature “switches on” a range of immune, endocrine and physiological mechanisms
What can produce a fever?
multiple factors not just bacteria and viruses can activate macrophages to produce a fever
What is special about gram negative bacteria and fevers?
can have endotoxins that
can act directly on brain and have rapid
onset of fever
What is a rigor?
Feeling of intense cold that causes uncontrollable shivering
What is your temperature during a rigor?
temperature goes up after rigor, normal during rigor as you are trying to increase it
What is a sign of Meningococcaemia?
purple spots over limbs
What are some warning bells for acute fever?
Rapid onset, rigors, severe muscle pains, vomitting, headache and impaired conscious state
Why are normal WCC and CRP on day 1 not always normal?
it takes time for immune system to increase WCC and CRP in response to infection
What are the differential diagnoses for PUO?
Infections, connective tissue disorders and malignancies
What are some infections that can cause PUO?
Subacute bacterial endocarditis (viridans strep), HIV related, TB
What are some connective tissue diseases that can causes PUO?
Polymyalgia rheumatica, SLE, acute thyroiditis
What malignancies can causes PUO?
Lymphoma, acute leukemia, renal cell carcinoma
