Concept of hyperpyrexia and hypothermia

the concept of hyperthermia and hypothermia and its management

1. The Concept of hyperpyrexia and hypothermia Maryam Majid Al Ezairej Collage of medicine RAKMHSU

2. Objectives The Concept of Hyperpyrexia The Concept of Hypothermia ECG findings in hypothermia

3. fever fever , also known as  pyrexia   is defined as having a  temperature  above the  normal range  due to an increase in the body's temperature  set-point . ] Temperature in the  anus  (rectum/rectal) is at or over 37.5–38.3 °C (99.5–100.9 °F ) Temperature in the mouth (oral) is at or over 37.7 °C (99.9 °F ) Temperature under the arm (axillary) or in the  ear  (tympanic) is at or over 37.2 °C (99.0 °F)

4. Hyperpyrexia Hyperpyrexia is an extreme elevation of  body temperature  which, depending upon the source, is classified as a  core body temperature  greater than or equal to 40.0 or 41.5 °C (104.0 or 106.7 °F ). Such a high temperature is considered a  medical emergency

5. Hyperthermia Hyperthermia  is elevated body temperature due to failed  thermoregulation  that occurs when a body produces or absorbs more  heat  than it dissipates. Extreme temperature elevation then becomes a  medical emergency Hyperthermia differs from  fever  in that the body's  temperature set point  remains unchanged

6. Etiology of hyperpyrexia Ne u r o le p tic mal i gna n t s y n d r ome Mal i gna n t h y p ert h erm i a Se r o t on i n s y n d r ome He a t s t r o k e

7. Sings and symptoms Ch i l l s , sh i v eri n g , and ri g o r s – Mechani s ms t o r ai s e bod y c o r e t empe r a tu r e F a t i gue Mala i se M y algias N i g h t s w e a ts Ano re x ia

8. Ai r w a y c o n t r o l , b r e a thi ng and ci r cul a t o r y support f o r un s t abl e p a ti e n t Mon i t or i n g a n d IV access shou l d b e o b t ai n e d in the f i e l d f o r un s t abl e p a ti e n ts o r p a ti e n ts with al t e r ed me n t al s t a tus Imme d i a t e t r e a tme n t r a r e ly r e q u i r ed In i ti a t e b r oa d- sp e ctrum a n ti b i ot ic t r e a tme n t immed i a t e ly f o r immuno c omp r om i se d p a ti e n ts and p a ti e n ts with un s t abl e v i t al s igns o r p r o f ound me n t al s t a tus chan g es

9. Antipyrtics – A c e t ami nophen , N S AIDs, o r s ali c yl a t es Gl u c o c ort i c o i ds M o s t f ebr i le p a tie n ts d o n o t r equ i r e a n ti p y r e tic medi c a ti o n othe r than f o r c o m f ort. S e l e c t ed p a ti e n ts r equ i r e mo r e a g g r ess i v e a n ti py r eti c i n t e r v e n ti ons P r egna n t w om e n P a ti e n ts w ith h i s t o ry o f s e i z u r e d i s o r de r s P a ti e n ts w i th s i g n i f ic a n t ca r d iac disea s e He m od y nami c al l y u n s t able p a ti e n ts P a ti e n ts w i th al t e r ed m e nt al s ta tus Emp iri c a n ti b i ot i cs f o r un s t abl e or i m m uno c omp r om i se d p a ti e n ts E x t er n al c o o li n g m echan i s m r a r el y i nd i c a t ed

10. Hypothermia Hypothermia is a medical emergency that occurs when the body loses heat faster than it can produce heat, causing a dangerously low body temperature below 95º F (35º C). Hypothermia is most often caused by exposure to cold weather or immersion in a cold body of water.

11. Presentation Mild hypothermia (32-35°C): - altered judgment, amnesia, and dysarthria. ↑ respiratory rate • Moderate hypothermia (28-32°C): -Oxygen consumption decreases, CNS depression hypoventilation, hyporeflexia , decreased renal flow, arrthythmias , and paradoxical undressing may be noted. Severe hypothermia (< 28°C) : - ventricular fibrillation and further depression of myocardial contractility. - Below 27°C, 83% of patients are comatose. - Pulmonary edema, oliguria, hypotension, rigidity, apnea, pulselessness , areflexia , unresponsiveness, fixed pupils, and decreased or absent activity on EEG

12. ECG findings in Hypothermia Prolonged PR, QRS, and QT intervals, and atrial or ventricular arrhythmias. Characteristic J (Osborne) waves are seen proportional to the degree of hypothermia.

13. Management- first Aid Remove wet clothing, use dry blankets or sleeping bags. • Initiate external rewarming with heat packs ( eg , hot water bottles, chemical packs) placed in the axillae, groin, and on the abdomen. •In dire circumstances, when heat packs are unavailable, rescuers can provide skin-to-skin contact with patients.

14. Management Prehospital management - prevent further heat loss, rewarm the body core temperature, and avoid precipitating ventricular fibrillation Bretylium (5 mg/kg initially) is recommended for any hypothermic patient manifesting significant new ventricular ectopy or frank dysrhythmia Warmed, humidified oxygen; heated intravenous saline; warmed blankets or heat lamps around a hypothermic patient. Cardiothoracic bypass has been successful for treating cases of accidental hypothermia with prolonged cardiac arrest. To be successful, bypass must be performed rapidly.

15. References Davidson Harrisons Textbook of Medicine

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