Fever in the adult patient

Question 1

What percentage of infection are accounted for by the respiratory tract, the urinary tract and skin and soft tissue

Answer 1

80%

Question 2

Differentiate between fever and hyperthermia

Answer 2

Hyperthermia is due to the bodies inability to dissipate heat. Most cases of temperatures higher than 41.0C are a result of hyperthermia

Fever occurs when the normal range of temperature regulation is reset to a higher value.

Question 3

Discuss endogenous and exogenous causes of fever

How do toxins cause fever

Answer 3

Endogenous pyrogens include a variety of cytokines released by leukocytes in response to inflammatory infectious and neoplastic processes.

Exogenous pyrogens include a large number of bacterial and viral products and toxins

Toxins cause fever by inducing inflammatory cells to release endogenous pyrogens such as IL1, IL6 and TNFa which travel to the hypothalamus and cause production of prostaglandin E 2

Question 4

Discuss how the production of PGE2 causes fever

Answer 4

PGE2 raises the set point of the temperature range by a combination of effects, influding peripheral vasoconstriction, increased metabolic heat production, shivering and behavioral changes that conserve heat,

Question 5

Discuss modifiers of the PGE2 caused fever

Answer 5

Medications – any medication that inhibits COX will inhibit the production of PGE2 and the mounting of a fever. NSAIDS, Steroids

Malnutrition, elderly, immuno-suppression and chronic disease can also blunt this response

Question 6

Discuss the reason people feel cold during the initial phase of fever development

Answer 6

The initial step in the process of fever is resetting of the thermostatic set point in the hypothalamus to a high temperautre while the actual body temperature remains normal.

This mismatch of the themostate with the sensed body temperature causes the patient to feel chilled.

Question 7

Discuss a broad differential of infectious causes of fever (40)

Answer 7

Respiratory

• Critical diagnosis (bacterial pneumonia with resp failure)
• Emergent diagnosis( bacterial penumonia, peritonisllar abcess, retropharyngeal abcess, epiglotitis)
• Non emergent( otitits media, sinusitis, pharyngitis, bronchitis, influenza, TB)

CVS
-Emergent( endocarditis, percarditis)

GIT

• Critical (peritonitis)
• Emergent (Appendcitis, cholecytisits, diverticulitis, intrabdominal abcess)
• Non emergent (colittis, enteritis)

Genitoyurinary

• emergent (pyelo, tuboovarian, abcess, pid)
• non emergent (cystitis, epidymitis, prostatis)

Neuro

• Critical (menigitis, cavernous sinus, thrombosis)
• Emergent (encephalitis, brain abscess)

Skin and soft tissue
-emergent ( cellulitism infected decubitus ulcer, soft tissue abscess)

Systemic
-critical (sepsis/septic shock, meningococcemia)

Question 8

Discuss broadly non invective causes of fever

Answer 8

Critical

• Acute MI
• Pulmonary embolism,or infarction
• intracranial haemorrhage
• CVA
• neuroepletic syndrome
• Thyroid storm
• acute adrenal insufficiency
• transfusion reaction
• pulmonary odema

Emergent

• CCF
• Dehydration
• recent sieuzre
• sickle cell
• transplant rejection
• pancreatitis
• DVT

Non emergent

• drug reaction
• malignancy
• gout
• sarcoidosis
• chrons disease
• postmyocardiotomy syndrome