Temperature Related Disorders NORMAL BODY TEMPERATURE : In health 96.5 F(35.8 C) – 99 F(37.2 C) In general an oral temp. > 99 F in a person at bed rest is regarded as probable indication of a disease RECTAL TEMPERATURE : Is F above the oral temp. CORE TEMPERATURE : Is the deep temperature of body SHELL TEMPERATURE : Superficial temp. is +/- 7 F < Core Temp.

Contnd….. COMFORT ZONE : Winter F Summer F  Diurnal variation in body temp : Early in the morning F Between 6-10 P.M F At 4 A.M F The febrile patterns of most human diseases tend to follow this normal diurnal variation

Contnd… MEASUREMENT OF BODY TEMP. : Standard oral mercury thermometer measures oral temp. which may not reflect true core temp. Rectal thermometer is a better device to measure the true core temp. of the body

Control of the Body Temp. NEGATIVE FEED BACK MECHANISM : Rise in central temp. initiates mechanisms for loosing heat A fall in central temp. initiates mechanisms for heat production & heat conservation By varying the vol. of blood flow to the surface of the body heat loss is regulated There is constant loss of heat from the body by evaporation of fluids In addition sweating is the most effective natural means of combating Heat Stress

Contnd…… As long as sweating continues, human can withstand remarkably high temp. provided NaCl and water are replaced  ACCLIMITIZATION : It is the ability of physiological mechanism to adjust itself to un-usual conditions Can be achieved by 2-3 hours daily exercise under hot weather conditions for 1-2 weeks

Contnd……. ADJUSTMENT OF BODY TEMPERATURE INCLUDES : Peripheral Vasodilatation Total secretion of sweat increases but the salt loss in sweat decreases Conservation of salt is brought about by : Increased production of Aldosterone by Adrenal glands Action of increased ADH on Urinary Tubules Increased Respiratory rate Increased Pulse rate & Cardiac output

Heat Cramps These are characterized by brief, intermittent & often excruciating cramping pain in muscles subjected to extensive work INCIDENCE : Athletes, Firemen, Miners, Farmers CLNICAL PICTURE : TREATMENT : PREVENTION :

Heat Syncope Vigorous physical activity for > 2 Hours Coetaneous Vasodilatation Systemic & Cerebral Hypertension Sudden Unconsciousness CLINICAL PICTURE : Dizziness, Nausea, Blurred vision, Excessive sweating, Pale complexions TREATMENT :

Heat Exhaustion Vigorous & prolonged activity in a hot environment leads to dehydration & NaCl depletion C.V. changes, CNS symptoms and Hyperventilation Incidence is common in elderly individuals taking diuretics TREATMENT :

Heat Stroke Heat Exhaustion may lead to Heat Stroke if sweating ceases High fever (core temp.>106 F) Absence of sweating (skin is hot & dry) Pulse initially strong later on becomes weak B.P. increases initially but falls later Cerebral dysfunction  INCIDENCE :  TREATMENT :

Contnd……  PRICKLY HEAT (MILIARIA) : Blockage of sweat glands within the Prickle cell layer of Epidermis leads to leakage of sweat into Epidermis

Disorders due to Cold  INCIDENCE : Hikers, Climbers, Persons with poor general physical condition, Mentally retarded, persons suffering from any systemic illness, Accidental victims, Elderly people living in insufficiently heated houses in winter are more vulnerable.

Cotnd….. COLD URTICARIA : Familial or acquired hypersensitivity to cold & may develop Urticaria upon even a limited exposure to a cold wind  SYSTEMIC HYPOTHERMIA : Reduction of core temp. below 35 C (95 F) Constriction of superficial blood vessels Skin behaves like a blanket Increased metabolic production

Contnd…… CLINICAL FINDINGS : Drowsiness, Weakness, Confusion, Pulse & B.P. may be un-obtainable Death may result due to ventricular fibrillation TRETMENT : Warm bed, Warm bath, Warm packs, Warm blankets CPR in severe cases Warm I / V fluids Oxygen therapy

Hypothermia of Extremities When the skin temp. falls to  25 C : Decreased tissue metabolism Decreased circulation Vasoconstriction Area becomes cyanotic

Contnd……. When the skin temp. falls to :  15 C Marked decrease in tissue metabolism Dissociation of Oxyhaemoglobin  - 10 C Freezing (frost bite) occurs Tissue death due to….. Ischemia & thrombosis in smaller vessels

Contnd…… CHILBLAIN : Red itchy skin lesions usually on extremities Due to exposure to cold Without actual freezing of the tissues TRENCH FOOT(Immersion Syndrome):  TREATMENT : Same as for Systemic Hypothermia Surgical intervention may be required when tissue is damaged or dead.