Fever Flashcards
Above what temp is someone classed as having a fever?
What are the temperature raising responses? - 4
What are the temperature lowering responses? - 3
> 38
Vasoconstriction
Shivering
Piloerection
Increased metabolism
Vasodilation
Sweating
Increased ventilation
Why do we get a fever?
It is a normal response to infection, therefore, controlled hyperthermia.
Endogenous pyrogens - Cells in the body release fever-inducing cytokines such as TNF, IL-1, IL-6, IFN. What cells release these cytokines?
There can be uncontrolled hyperthermia due to what type of stroke?
What drugs could also cause this?
Prostaglandin E2 is activated which acts on thermoregulatory centres in the hypothalamus
Mononuclear cells Macrophages T-lymphocytes Kupffer cells endothelial cells tumour cells
Heat stroke, also known as sun stroke, is a type of severe heat illness that results in a body temperature greater than 40.0 °C (104.0 °F) and confusion. Other symptoms include red skin, headache, and dizziness.
SSRIs
Antipsychotics
Where can temp be measured?
This is only 65% sensitive. The only way to detect true fever is to measure the temp via ____ and ____.
Rectal
Oesophageal
Patterns of fever dependent on disease:
Continous:
- What lung infection will cause this?
- What cardiac infection will cause this?
Remittent:
- What does this mean?
- What cardiac infection will cause this?
Intermittent:
- What does this mean?
- What type of emergency could cause this?
- Abscesses can also cause this!!
Relapsing:
- What does this mean?
Thyroid disease causes a step-ladder rise to a plateau
Lobar pneumonia
Infective endocarditis
Continuously elevated temp with high spikes
Infective endocarditis
Normal temp with febrile spikes
Sepsis
Sub-type of intermittent fever, with spikes separated by days
LOOK AT PRESENTATION
DDx - night sweats:
What infections will cause this?
Why can antipsychotics and antidepressants cause night sweats?
What endocrine disease can cause this due to heat intolerance?
What does DM cause it?
TB Abscess Endocarditis Osteomyelitis HIV
SSRIs (selective serotonin reuptake inhibitors) increase serotonin levels of serotonin in the brain. Serotonin affects both the hypothalamus, which sets our core temperature at which sweating occurs, and the spinal cord which may lead to excessive sweating.
Thyrotoxicosis
Night sweats are often caused by low blood glucose, which can occur in people taking insulin or diabetes medications known as sulfonylureas. When your blood glucose drops too low, you produce excess adrenaline, which causes sweating.
Rigors:
What is it?
How do you know it is not a seizure?
What is this a sign of?
Uncontrollable limb shaking +/- teeth chattering
No loss of consciousness
A sign of severe infection, usually requiring hospital admission
Septic screen:
What bloods need to be done? - 3
What investigations should be done?
What can raise CRP/ESR apart from infection?
FBC
CRP
Blood culture
Urinalysis
Lumbar puncture
CXR
Autoimmune disease
Cancer
MI
Burns
Pyrexia of unknown origin:
How long does the fever have to last before being classed as PUO?
If fever is being investigated in hospital, how many days until it is classed as PUO?
Types:
- Classical
- What does nosocomial fever mean?
- Immunodeficient
- HIV
3 wks
3 days - uncertain diagnosis
It can also be over 3 outpatient appointments
Fever beginning in hospital >48 hrs after admission
NO INFECTION OR INCUBATION AT ADMISSION
Classic F/PUO:
Infection - typical causes?
Abscess
Infection endocarditis
TB
Complicated UTI
Connective Tissue
Young - Still’s/JRA
Adult
- RA
- Lupus
Elderly
- Giant cell arteritis
- Polymyalgia rheumatica (PMR)
Nosocomial FUO:
Causes?
Catheters/devices Thrombophlebitis - IV UTI/RTI Drug fevers C. diff ICU - ventilation, ET tubes, NG tubes Stroke - aspiration pneumonia
FUO in immunodeficiency:
Harder to localise things clinically and radiologically.
FUO in HIV:
Primary HIV infection (seroconversion illness) - leads to a fever so ALWAYS TEST FOR HIV
FUO in immunodeficiency:
Harder to localise things clinically and radiologically.
FUO in HIV:
Primary HIV infection (seroconversion illness) - leads to a fever so ALWAYS TEST FOR HIV
Approach to FUO:
History – just take a thorrough history in every domain - SYSTEMS REVIEW
Investigation very broad - look at presentation
Approach to FUO:
History – just take a thorrough history in every domain - SYSTEMS REVIEW
What can cause a fluctuating fever?
ABSCESS
