Approach and management of pyrexia, PUO & hypothermia Flashcards
What is pyrexia?
Fever; a disease process characterized by an increase in body temperature.
What is hyperthermia?
Heat generation exceeding heat loss; can result in temperatures above 41.1°C.
What is the primary thermoregulatory center in the body?
Hypothalamus.
List some physiological responses to increased body temperature.
- Panting
- Vasodilation
- Cold seeking behavior
- Piloerection
- Shivering
- Curling up behavior
What triggers ‘true’ fever?
Infection leading to inflammation and the release of pyrogens.
What is the hypothalamic set point during fever?
Increased, rarely exceeding 41°C.
What historical period is associated with the evolution of fever?
Devonian period, approximately 360 million years ago.
What are the benefits of fever?
- Enhances white blood cell activity
- Induces acute phase proteins
- Scavenges free radicals
- Decreases viral excretion
What are the costs of fever?
- Increased energy expenditure
- Collateral damage to physiological processes
- Potential worsening of clinical signs
What is the goal temperature for treating hyperthermia?
39.5°C (103°F) within 60-90 minutes.
True or False: Antipyretics are effective in treating hyperthermia.
False.
What are the common causes of pyrexia?
- Infections (90% bacterial and viral)
- Drugs and vaccines
- Inflammatory diseases
What is the definition of fever of unknown origin (FUO)?
Fever that does not have an obvious cause and does not resolve spontaneously within the expected period for a self-limiting infection.
List the common causes of FUO.
- Immune mediated (30-40%)
- Neoplasia (20-30%)
- Infectious (15-20%)
- Others (7-12%)
- No diagnosis (20%)
What are acute phase proteins?
Part of the innate immune system that indicates inflammation, sensitive for detecting infection.
What is the role of COX enzymes in fever?
Convert arachidonic acid into prostaglandins, which help regulate the hypothalamic set point.
Fill in the blank: Fever is caused by the release of _______ from monocytes and macrophages.
pyrogens.
What are the side effects of NSAIDs in treating fever?
- Delays diagnosis
- Gastric ulceration
- Liver failure
- Renal failure
- Blood dyscrasias
What is the significance of monitoring response to therapy in fever?
Resolution of pyrexia helps determine treatment efficacy; may not reflect underlying disease.
What should be avoided in patients with severe pyrexia?
Antipyretics if the patient has an infection.
What are the diagnostic steps for prolonged fever?
- History
- Clinical examination
- Urinalysis
- Routine blood tests
- Radiography
- Fine needle aspirates
