Medicine Fever Part 1+2 .pdf

FEVER By dr. Mohammed Muhsin Jarallah Specialist in Clinical hematology/ bone marrow stem cell transplantation  Learning objectives Understand the normal body temperature setting physiology How does fever occur Differentiate between fever, hyperpyrexia and hyperthermia ...

FEVER By dr. Mohammed Muhsin Jarallah Specialist in Clinical hematology/ bone marrow stem cell transplantation  Learning objectives Understand the normal body temperature setting physiology How does fever occur Differentiate between fever, hyperpyrexia and hyperthermia  Physiology There is an excess of heat production originating from metabolic activity in the liver and muscles. · i = / Heat loss occurs through the skin, facilitated by sweating and through the lungs. · S fi iii There is a diurnal variation in the body temperature where there is 0.5C higher body temperature in the evening as compared to early morning body temperature. g - & MCQ 36.8C ±0.4C is the mean oral temperature in the morning. Rectal temperatures are generally 0.4C higher than oral readings.  Fever Body temperature is controlled by the ‫مهم‬ hypothalamus. Na 1,941 i osidas , The hypothalamus receives signals from peripheral nerves and the blood washing the region , both signal are integrated in the thermoregulatory center in the hypothalamus. %19 4 m Hypothalamus/ : SS 2.. & &.. In a neutral environment the metabolic rate would produce more heat to maintain a range of ‫مهم‬ (36.5-37.5)C & >  Fever 365-3751551-411 j 2 / Fever is an elevation of body temperature that exceeds the normal daily variation and occurs in conjunction with an increase in hypothalamic set point e.g. from 37C to 39C. & osy' - & set-up on Normally o · 2011 & setpoints set-points i is - +1 hypothalamus. 5 de s Joe 21 Fever /. 2 · 1 , pothalamic set-points ? I w In brief a core temperature of more than 38C A fever of more than 41.5C is called hyperpyrexia and this can occur in severe infections and more commonly in central nervous system bleeding.  Typical condition ‫ألي انسان عايش بالبصرة‬ E Hyperthermia is an uncontrolled increase in body temperature that exceeds the body ability to lose heat. 1,41515 Exogenous heat exposure and endogenous heat production can easily cause dangerously high internal temperatures e.g. working or exercise in hot environments can produce heat faster than peripheral mechanisms can lose it. On clinical basis how can you differentiate between fever and hyperthermia?  ‫مصخن بالفراش‬ ‫صامطته الشمس‬ fever hyperthermia Preceding events like infections, exposure to a high temperature Or inflammation environment The skin can be cold as a result of dry, hot skin, vasoconstriction, specially in peripheral Does not respond to antipyretics parts and it responds to antipyretics ‫خافضات الحرارة‬  ‫مولد الحمى‬ pyrogen that can cause fever Exogenous pyrogens like bacterial toxins Endogenous pyrogens like interleukin-1, interleukin-6 and tumour necrosis factor (TNF) Pyrogens act to change the body set-temperature, for example raising the set temperature from 37C to 39C  ‫منظم حرارة الجسم‬ once the temperature new limit is set by effect of pyrogens,..etc., there is heat preservation and increased heat production - 61 z. ii Heat preservation Heat production Vasoconstriction, first Increase the heat noticed in the peripheral production from muscles by parts Sig - &95. & 01 shivering ‫ارتعاش‬  Does fever has causes other than infection? Why do we feel body aches when we have fever? 1- Yes, fever can have causes other than infection , like - Autoimmune disease ( systemic lupus erythematosus, rheumatoid arthritis) - some drugs , particularly certain antibiotics and anticonvulsants ( drug induced fever as a side effect) - some cancer , especially when it effect the immune system like lymphoma 2- the chemical mediator especially prostaglandin that released from the inflammatory cells - also the muscles contraction (shivering) and muscle tension ( that occur during fever to increase body temperature to the new set point) may cause aches  Learning objectives illustrate each of them Approaching a febrile patient  Types of fever Acute lasting for a week or less Sub-acute > 1 week,