Temperature recording and fever

Normal body temperature and its variations

Normal temperature regulation in the body

How will you record the body temperature ?

What is meant by fall by crisis or lysis in fever ?

What is chills and rigors?

What is periodic fever?

What is factitious fever ?

What are the causes of aseptic fever ?

What is drug fever?

What is hectic temperature ?

What is pyrexia of unknown origin (puo) ?

What are effect of fever on body?

Appearance of rash in a febrile patient

Causes of Herpes labialis (fever blisters) with pyrexia

Fever with patch or membrane in the throat

Relative bradycardia and relative tachycardia

What is febrile convulsion ?

What are the features of enteric fever in its first week?

What are the causes of hypothermia ?

What is meant by fall by crisis or lysis in fever ?

Fever can subside in the following ways

Crisis

Elevated body temperature settles down to the baseline value immediately after starting treatment. This may be accompanied by diaphoresis, diarrhoea or diuresis.

• Acute lobar pneumonia.
• Rheumatic fever
• Enteric fever with intestinal haemorrhage  or perforation.
• Adrenal crisis (seen in meningococcal meningitis).
• Septicaemic shock.

Lysis 

• Elevated body temperature settles down to normal in step ladder pattern in typhoid fever

What is pyrexia of unknown origin (puo) ?

It is also known as fever of unknown origin (PUO).

Definition of PUO (by Petersdorf and Beeson. 1961) 

• Fever higher than 101°F on several occasions.
• A duration of more than 3 weeks
• Failure to reach a diagnosis by 1 week of inpatient investigation or 3 out patient visit

Classification of PUO by Durack and Street 1991

• Classical PUO
• Nosocomial PUO (hospital-acquired).
• Neutropenic PUO (when neutrophil count is < 500/mnr1)
• HIV-associated (eg. tuberculosis, NHL,drug fever).

What are the diseases which may initially present as PUO 

1.Infections

Tuberculosis, SBE, subphrenic abscess, liver abscess, brucellosis,AIDS and fungal infections

2.Immune causes

Collagen vascular diseases,SLE, rheumatoid arthritis, polyarteritis

3.Factitious fever, drug fever, habitual hyperthermia

4.Malignancy

Lymphomas, leukaemias, multiple myeloma and carcinoma (specially of lungs liver,colon and kidney)

What is periodic fever?

There is periodic attack of fever alternating with a period of apyrexia.This is seen in 

• Pel Ebstein temperature in Hodgkin lymphoma
• Brucellosis.
• Relapsing fever.
• Malaria.
• Rat bite fever.
• Dengue etc.

Appearance of rash in a febrile patient

This article shows temporal association of rash and fever

1st day fever -Chicken pox 

Rash appear in the first day of fever  vesicles are seen mainly in trunk, all forms of vesicles are seen at a time, no umbilication of rash is noticed

2nd day-Scarlet fever 

Rash is seen over chest, neck, scapula; mainlv macular in nature

3rd day - Pox (smallpox) :

It is not seen now-a-days. Rash is peripheral distribution and comes in sequence, umbilication of vescicle are noticed

4th day -Measles

In measles maculo-papular rash over forehead,hairline near ears, face and trunk is seen

5th day -Typhus fever

Macular rash over shoulders, chest, extremities, palms and soles are noticed.

6th day- Dengue fever  

Morbilliform rash  over dorsum of hands and feel, trunk called as white islands in red sea

7th day - Typhoid or enteric fever .

There is rose spots over abdomen, flanks and back: rash is pale-pink in colour and fades on application of pressure

What are the life threatening infection with skin rash

• Meningococcemia
• Dengue hemorrhagic fever
• Rickettsial fever - Rocky Mountain spottcfever
• Septicemia-pseudomonas infection Ecthyma

Relative bradycardia and relative tachycardia

It is known that with every degree (1°F) rise of temperature, the pulse rate is increased by 10 beats/minute.

Relative bradycardia

In this condition, the increase in pulse rate is less than 10 beats/minute with per degree (1°F) rise of temperature.

For example, the pulse rate in relative bradycardia will be about 80/minute, when the temperature is increased by 2°F (actually it should be 92/minutc). 

This is is seen in :

• Any viral fever.
• First week of enteric fever.
• Sometimes in pyogenic meningitis.
• Brucellosis, psittacosis.
• The relative bradycardia in yellow fever is known as Faget's sign.

Relative tachycardia

The increase in pulse rale is more than 10 beats/minute with per degree (1°F) rise of temperature. For example, the pulse rate will be about 120/minute, when the tem-

perature is raised by 3°F (actually it should be 102/minute).

This is seen in :

• Acute rheumatic carditis.
• Tuberculosis.
• Diphtheritic myocarditis.
• Polyarteritis nodosa.

What are the causes of hypothermia ?

Hypothermia can be caused by

• Myxoedema coma.
• Prolonged exposure to cold (in street beggars, accidental or in mountaineering).
• Peripheral circulatory failure due to any cause.
• Enteric fever if associated with haemorrhage or perforation : commonly occurs in the 3rd week
• Panhypopituitarism, adrenal insufficiency.
• Myxedema coma
• Phenobarbitone poisoning
• Exposure to cold ,frost bite
• Alcohol intoxication
• Hypoglycemia
• Artificial hypothermia induced in open heart surgery.

Causes of Herpes labialis (fever blisters) with pyrexia

These are painful and tender vesicles on the outer surface of lips, and is commonlv observed in 

• Acute lobar pneumonia (often gives clue to the side affected and stages of pneumonia)
• Influenza.
• Malaria.
• Meningococcal meningitis.
• Weil's disease.
• Mycoplasma pneumoniae infection.
• AIDS.
• Herpes labialis may be normally seen in females during menstruation.

What is hectic temperature ?

In hectic fever there is a big swing in the body temperature and the temperature rises with chill and rigor, then it persists for few hours and suddenly falls with profuse sweating.

Common causes of hectic fever are :

1.Pent-up pus anywhere in the body

•  Lung abscess
•  Liver abscess
•  Empyema thoracis
•  Empyema of gall bladder
•  Subdiaphragmatic abscess

2.Septicaemia or pyaemia.

3.Rarely in advanced tuberculosis

Fever with patch or membrane in the throat

Fever with patch or membrane seen in the throat in the following conditions

• Acute follicular tonsillitis.
• Candidiasis.
• Diphtheria.
• Agranulocytosis.
• Infectious mononucleosis.
• Vincents angina.

What is chills and rigors?

Chill is a sensation of cold which occurs in most of the fevers.

The normal body temperature is maintained in health by the balance between the heat gain and heat loss by the body that is governed by the Hypothalamus 

Rigor is state of profound chill with piloerection (goose flesh) and is associated with teeth chattering and severe shivering.This shivering is called as rigor

Chills or rigors occur when the thermostat in the hypothalamus, is suddenly reset to a higher temperature due to presence of pyrogens in the body.The body temperature then tends to rise to the newly reset level in the thermostat by conserving heat in the body by the mechanism of cutaneous vasoconstriction and involuntary contraction of skeletal muscles, experienced as chills or rigors. 

When the higher temperature is reached, heat loss starts from the body and the cutaneous vessels dilate to dissipate the heat. Then patient feels hot and sweating starts.

Chills or rigors may be commonly seen with bacterial, rickettsial, protozoal, influenzal infections.

What are the causes of fever with chill and rigor ?

• Malaria.
• Urinary tract infection.
• Pentup pus anywhere in the body (lung abscess, liver abscess etc)
• Septicaemia or pyaemia.
• Cholangitis.
• Subacute bacterial endocarditis.
• Thrombophlebitis.
• Acute pyelitis.
• Acute lobar pneumonia.
• Intravenous fliud infusion or blood transfusion.
• Filariasis.

What is febrile convulsion ?

Young children often develop seizures during the febrile illness and these are short, generalised tonic clonic convulsions.

The characteristics features of febrile convulsions are

• Affects 2-5% of the population of young children.
• Age range of children is between 6 months to 5 years.
• Often there is a positive family history of febrile convulsion.
• Convulsions are not related to the degree of rise of temperature as they may occur even with moderate fever.
• Seizures may last for less than 5 minutes and this is generalised.
• It is not associaled with interictal EEG abnormalities or any neurologic deficit.
  

Management of febrile convulsion

• Management is done by tepid sponge bathing 
• Antipyretics 
• Diazepam (0.2-0.5 mg/kg. I.V).

Predictive factors for recurrence of febrile seizure are the following

• Young age of onset
• Low fever
• Family H/O febrile convulsion 
• Short duration of fever before convulsion.

What are the features of enteric fever in its first week?

Following are the features of enteric fever in the first week

• Step-ladder pattern of pyrexia.
• Frontal headache.
• Constipation.
• Anorexia, nausea, cough and epistaxis.
• Flushed face with toxic look.
• Angry looking tongue, central coating with red tip and margins
• Caecal gurgling.
• Relative bradycardia and rarely dicrotic pulse
• Appearance of rash on the 7th day (usually appears on 7th-10th day).
• The spleen may be just palpable, soft and tender spleen at the end of first week is seen

What is typhoid state ?

If the enteric fever is untreated it may enter into a toxemic phase towards the end of 3 week and is manifested as the following

• Semiconsciousness or unconsciousness.
• Low muttering delirium.
• Coma vigil - Patient lies with half-open eyes but ignorant of his surroundings
• Carphology manifested as picking of bed clothes
• Sub sultus tendinus this is the involuntary movement of the fingers and wrist
• Convulsions rarely.

What is factitious fever ?

Occasionally some patients purposefully show false elevations in body temperature. These patients are usually young women, often they are  attached to health professionals.

They produce rise in body temperature by the following means 

• They may infect themselves with bacteria
• Ingest thyroxine 
• Falsely register higher temperature (after immersing the thermometer in hot water).

The diagnosis is done by.

• Dissociation between pulse and temperature.
• Excessively high temperature (106°F).
• Absence of chills, sweats, tachycardia, tachvpnoea.
• Absence of normal diurnal variation in temperature.

What is drug fever?

Drug fever has the following clinical features.

• Drug induced fever is a prolonged fever and it may belong to any febrile pattern given below
• There is relative bradycardia and hypotension associated with this fever
• Pruritus, skin rash and arthralgia can occur
• It begins 1-3 weeks after the start of the drugs and this may persists 2-3 day's after the drug is stopped
• .Eosinophilia may be present.
  

Almost all drugs can produce fever.Important commonly used drugs producing fever are

Agents causing drug fever

• Sulphonamides.
• Iodides, bromides.
• Thiouracils.
• Barbiturates.
• Rifampicin (‘flu syndrome’)
• Phenolpthalein (used in laxatives).
• Quinidine.
• Phenytoin 

Digoxin does not cause drug fever.

What are the causes of aseptic fever ?

In aseptic fever the rise in body temperature is not due to infection.

Aseptic fever can occur secondary to the following causes 

• Heat stroke.
• Lymphoma, leukaemias or disseminated malignancy
• Collagen vascular disease eg, SLE. .
• Pontine haemorrhage.
• Thyroid storm.
• Acute myocardial infarction
• Drug fever eg. rifampicin or sulphonamides.
• Gout
• Crush injury.
• Radiation sickness
• Over-atropinisation.

What are effect of fever on body?

Fever can have effect on various systems in the body

Effect on cardiovascular system

With every 1°F rise of temperature above 100°F the following changes are observed 

1.The pulse rate increases by 10 

Relative bradycardia means there is no proportionate increase in the pulse rate with rise in temperature

This is seen in 

• Any viral fever.
• First week of enteric fever.
• Sometimes in pyogenic meningitis.
• Brucellosis and psittacosis

Relative tachycardia there is disprortionate increase in the heart rate compared to rise in body temperature

The rise is more than  10/degree F 

• Actute rheumatic carditis.
• Tuberculosis.
• Diphtheritic myocarditis.
• Polyarteritis nodosa.

2.High volume pulse and wide pulse pressure is seen in febrile patients because of vasodilatation

Effect of fever on respiratory system 

There is rise in respiratory rate by 4degree F with rise of temperature above 100 degree F

Tachypnea is seen especially in pneumonia

Effect of fever on central nervous system

• There is headache due to vasodilatation
• Febrile convulsion can occur especially in children
• Acute confused state and delirium  may be seen in febrile patients called and is called as toxic encephalopathy

Effect of fever on gastrointestinal system

These manifestations include anorexia. constipation and herpes labialis

These are especially seen in patients with pneumonia and malaria (rare in enteric fever),  

Effect of fever on skin

• Cutaneous manifestations are seen with fever 
• Miliaria is due to sweat retention rash
• Rash in exanthematous fevers link

Dehydration is common in febrile patients due to increased sweating, vomiting and decreased fluid intake.

Normal body temperature and its variations

Normal body temperature is 36.6 to 37.2 or 98 to 99 degree farenheit

What are the alteration in body temperature?

The normal diurnal variation is 1°F.The normal body temperature is more towards the evening as as a result of increased BMR and increased skeletal muscle activity. Rectal temperature is 0.6°C (1°F) higher than oral temperature. Oral temperature is 0.6°C (1°F) higher than temperature recorded in the axilla.

Maximum normal oral temperature

At 6.00 AM 37.0°C (98.6°F)

At 6.00 PM 37.6°C (99.6°F)

Normally the rectal temperature > oral temperature > axillary temperature.

Fever

It is an elevation of body temperature above the normal circadian variation as a result of the change in the thermoregulatory centre, located in the hypothalamus

What are the physiological variation of temperature?

In a menstruating females, the early morning temperature recording is subnormal in the two weeks preceding ovulation. At the time of ovulation, the temperature

increases  by about 0.6°C (1°F), and it persists till menstruation occurs because of the thermogenic property of progesterone.

With every 1°F rise of temperature, above 100°F the following alterations are noted 

• The pulse rate increases by 10, 
• The respiratory rate increase by 4, 
• BMR increase by 7. 
• Oxygen consumption increases by 13%.

How will you record the body temperature ?

You should always measure the body temperature as a part of initial clinical examination.

What are the preferred sites of recording of temperature?

• Oral cavity
•  Axilla
•  Rectal temperature

How to record the oral temperature?
1.Oral temperature is recorded by placing the clinical thermometer under the patients tongue the patient breathes through the nose with lips firmly closed for a period of one minute. This will reflects the body-core temperature.

Precautions while recording temperature

• Prior to measurement the patient should not take any oral feeds for 15 minutes, 
• You should wash the thermometer with antiseptic solution before taking the reeding
• Before taking the measurement mercury in the thermometer is gently shaken down

2.Axillary temperature is taken by placing the thermometer in the arm pit and measuring the temperature after 2 minutes the temperature is 0.5 to 1 F less than the oral temperature
3.Rectal temperature- This is the most reliable as well as accurate, and it is 0.5-1F higher than the oral temperature
The rectal temperature is recorded using  a special low-reading’ thermometer. It is stouter than the
usual clinical thermometer, this has  a rounded bulb (to reduce the risk of injury') and is graduated upto 90°F.
Thermometer  should be  kept at least for 2 minutes in the axilla or rectum and the rectal temperature >oral temperature>axillary temperature.

What are the alteration in body temperature?


                                     Degree Celsius             Degree Farenheit
• Normal temperature              36.6-37.2                       98-99
• Febrile                                    > 37.2                           >99       
• Hyperpyrexia                         > 41.6                           > 107
• Subnormal                             < 36.6                            < 98  
• Hypothermia                          < 35                              <95                                                                                                                                                                           

Which is the preferred site for temperature recording in infants ?
The  axilla or groin with thigh flexed over the abdomen .this is also convenient in an unconscious patient.

Which is the preferred  site for recording of temperature in adults ?
Oral temperature is the preferred site in adults .If the oral temperature is more than 99 degree F the patient is febrile
The patienl is febrile, when the axillary temperature is above 98.6 degree F or 37 degree celsius
Oral temperature is preferred because it does not change with sweating or vasoconstriction as the axillary temperature may vary.

What are the contraindications of taking oral temperature ?

• Infants and children.
• Mentally retarded. eg. Down's syndrome.
• During convulsions or history of recurrent fits.
• After taking tea. coffee or chewing tobacco : smoking.
• Inflammation within the oral cavity, eg. ulcer in the'mouth, impacted wisdom teeth
• During severe dyspnoea.
• Unconscious or restless patients.
• Trismus (tetanus, tetany).
• Paralysis of the tongue.
•  In mouth breathers.

When the rectal temperature is preferred ?

• In collapsed, comatosed or elderly patients.
• Cholera patients (surface temperature is subnormal but rectal temperature is raised)
• In algid malaria.

Why there is a kink in thermometer ?
This is to prevent the return of mercury column when the thermometer is taken out of the body.

Normal temperature regulation in the body

Normally heat is being continuously produced in the human body, and also is being lost continuously to the surrounding environment. The person is said to be in heat balance when the rate of heat production is equal to the rate of heat loss,But when there is a disturbance of equilibrium between the production and heat loss, then the body temperature may rise leading to fever, or temperature may fall leading to hypothermia.

What are the factors that determine the rate of heat?

Heat production is by the following mechanism 

• Basal metabolic rate of the body
• Muscle activity
• Effect of thyroid hormones
• Effect of epinephrine and norepinephrine.

What are the causes of heat loss from the body

• Radiation: Loss of heat can occur from the body in the form of infrared rays.
• Conduction: Heat is conducted from the body to the objects that comes in contact with it, e.g. chair, bed, etc.
• Convection: Heat is lost from the body by the air currents surrounding it.
• Evaporation: Evaporation of water (sweat) from the body surface serves as a very important protective mechanism in decreasing the body temperature which may rise due to environmental factors (that is in hot weather). 

In heat stroke, the sweating is impaired hence the body core temperature rises to dangerous levels.