0.6-1.0°C

Lowest in morning, highest in late afternoon

37°C (if taken internally)

36.8°C (if taken orally)

>37.8°C orally

>38.3°C rectally

Hyperthermia= body's heat production exceeds heat loss. No reset of temperature regulation.

Fever= body resets thermostat to run hotter

Exogenous= things/events that stimulate the immune system to cause fever

Endogenous= inflammatory or pyrogenic cytokines (IL-1, IL-6, TNF, and Interferons) produced by phagocytic cells

1. Pyrogenic cytokines act on hypothalamic
endothelial cells

2. Stimulate production of PGE₂

3. PGE₂ attaches to glial cells and stimulates release of cyclic AMP

4. Cyclic AMP activates hypothalamus to increase body temperature

1. Fibrinogen

2. CRP

3. Serum amyloid A

4. Complement proteins

1. HR increases

2. water loss

3. Hyperventilation

4. Decrease in serum iron and zinc

1. enhanced immune function

2. enhanced neutrophil function

3. improved outcome in certain infections

4. inhibits growth of some pathogens (like Treponema pallidum)

5. Reduced pathogen growth in low iron

1. seizures in kids < 5 yo (treatment of fever doesn't prevent them either)

2. increased metabolic demand in ppl with already poor lungs or heart

3. can worsen encephalopathy and cause mental dysfunction in the elderly

4. Teratogenic in pregnancy (maybe)

Increases oxygen consumption

Can cause vasospasm of diseased coronary arteries and cause MI

Can get rebound hyperthermia

fever (>38.3°C) on several occasions and more than three weeks’ duration

uncertain despite appropriate investigations after at least three outpatient visits or three days in hospital

fever (>38.3°C) on several occasions in a hospitalized patient receiving acute care; infection not present or incubating on admission

uncertain after three days despite appropriate investigations, including at least two days incubation of  microbiologic cultures

 fever (>38.3°C) on several occasions; neutrophil count
<500/mm3 in peripheral blood, or expected to fall below that number within 1-2 days

uncertain after three days despite appropriate investigations, including at least two days incubation of  microbiologic cultures

fever (>38.3°C) on several occasions of more than three weeks’ duration as an outpatient or more than three days’ duration in hospital; confirmed positive HIV serology

uncertain after three days despite appropriate investigations, including at least two days incubation of  microbiologic cultures

Infectious

Neoplastic

Non-infectious inflammatory disorders

Other (granulomatous or other things)

Lymphomas

Leukemia (especially preleukemia phase)

Hypernephroma, Hepatoma

Tumor necrosis

Atrial myxoma

Giant Cell Arteritis (aka Temporal Arteritis)

- who gets it

- 4 symptoms

- 1 lab finding

- how to confirm diagnosis

Who: In elderly (>50 yo)

Symptoms: headaches, fever, proximal girdle soreness, possible blindness

Lab: ESR>50 (high)

To diagnose: temporal artery biopsy

Antibiotics

Anti-seizure drugs

intermittent fever with rigors

sometimes a rash (20%)

Eosinophilia 20%

Leukocytosis 20%

Factitious Fever

- who gets it (2)

- other illnesses associated

- 2 forms of it

Young women with training in healthcare

NO other illnesses (no psychiatric illness)

Fradulent or Self-induced

(is a form of Munchausen's Syndrome)

1 & 2. Lymphoma and Collagen Vascular Diseases (16% each)

3. Abscesses (13%)

4. Undiagnosed cause (9%)

5. Solid Tumor (8%)

6. Thrombosis or Hematoma (7%)

Usual cause of fever + chills

1. Screening stage (screening labs, H&P, and imaging)

2. Non-invasive evaluation stage (focused labs and imaging)

3. Invasive Stage (procedures, like biopsy)