Fever-Types, Causes, Symptoms, Diagnosis and Treatment.
Definition:-Fever is a common medical condition and this medical condition is usually accompanied by an increase of body temperature above the normal level. A normal person has a body temperature at 98.6°F.or 36.5°C. The body temperature may vary up to 1°F throughout the day and this variation when goes up beyond one degree, the condition is called as fever. The fever is also referred as pyrexia. The regulatory set-point of body temperature is altered and eventually ends in fever which in turn triggers increased shivering and muscle tone.
Patient’s temperature should be taken to reveal possible fever. It should be remembered, however, that an elevated temperature does not always correspond to the gravity of the patient’s condition.
Primary causes of fever:-The fever can be caused by several reasons from common infection to serious cancers. But, however most of the fever are caused by infection such as flu, pneumonia or throat sore. Other causes may include extreme sunburn, exposure to hot environments and certain medications. In very rare cases the cause of the fever is unknown. Fever is also a body’s immune response that tries to neutralize infection. A person, who is having the increase in the temperature, feels cold and when a new temperature is attained, he again feels warmth. A common form of slight fever does not require any medications and antipyretic medication would do its best to comfort the patient.
About thermometer:-A patient’s temperature should be read with a maximum thermometer which reads the maximum temperature and it does not change after cooling. A narrowing in the capillary tube prevents the mercury from descending by gravitational pull in to the bulb unless the thermometer is shaken heavily. Shaking should be done gently as not to break the thermometer. Thermometer should be kept in a glass containing cotton wool. A disinfectant solution should be filled to half of the glass.
Types of fever:- A correct diagnosis can be established not only according to the degree of temperature elevation but also by its circadian variations(by the type of fever) and six major types of fever are classified.
1. Continuous fever (37.5-38.5°C) that persists for several days or weeks with circadian variation within 1°C. This fever is characteristic of lobar pneumonia, typhoid fever, urinary tract infection and brucellosis.
2. Remittant fever is another type in which the circadian variation is significant(usually 1.5 to 2°C). This fever is characteristic of tuberculosis, bronchopneumonia, and purulent infections.
3. Intermittent fever:- This fever is characterized by a sudden rise in temperature up to 39-40°C.and subsequent fall to normal temperature in a few hours. The temperature may rise again in 1-3 days. This type of fever is characteristic of malaria.
4. Hectic fever:- It is characterized by a rise in temperature to 39°C and over followed by a sudden fall during the same day to a normal or even subnormal temperature. This fever is characteristic of sepsis and severe forms of tuberculosis.
5. Inverted fever:- The morning temperature is higher than the evening one and this type of fever is characteristic of brucellosis, sepsis, and tuberculosis.
6. Irregular fever:- It occurs mostly in influenza, rheumatism, dysentery, tuberculosis, etc, temperature swings during the day are quite varied and indefinite in irregular fever.
In addition, there are two forms of temperatures and they are relapsing fever and undulant fever. Relapsing fever is characterized by alteration of pyrexia and apyrexia. It occurs in typhus recurrens. Undulant fever is characterized by a gradual rise in temperature over several days followed by its gradual fall. This fever occurs in brucellosis and lymphogranulomatosis. A fever lasting 15 days is called acute, and over 45 days, chronic.
Temperature may rise to various degrees. Temperature between 37-38°C are called subfebrile, 38-39°C moderately high, 39-40°C high, 40-41°C very high, and over 41°C hyperpyrexial temperature. Hyperpyrexial fever is attended by severe nervous disorders and endangers the patient’s life.
Periods of fever:- Three periods of fever are distinguished.
1. Rising temperature,2.maximum temperature,3.dropping temperature. The first period is characterized by a gradual or abrupt rise of temperature attended by chill, cyanosis (blueing) of the lips and the extremities, headache, and subjective indisposition. During this period the patient should be covered with a warm blanket and given hot tea. During the second period the patient develops headache, vertigo, dryness in the mouth, hyperaemia in the skin, and in serious cases even delirium and hallucinations. The patient should be given much liquid to drink because his loss of water is significant. If the patient develops delirium or hallucinations his bed should be provided with a protective network to prevent him from falling out of bed. A special post for a nurse should be arranged at his bed side. The third period varies. The temperature may decrease gradually, during the course of several days. This termination of fever is called lysis. The patient perspires slightly and his weakness is moderate. A rapid fall of temperature is called crisis. It is attended by intense perspiration and pronounced weakness. Arterial pressure often drops, the limbs become cold, and cyanosis develops. Preparations increasing arterial pressure should be given and the patient should be warmed with hot water bottles.
Hyperpyrexia,Hyperthermia:- Extreme elevation of body temperature during the course of fever is described as hyperpyrexia and the body temperature may rise up to 41.5°C(106.7°F). This condition may be attended by severe nervous disorders and endangers the patient’s life. Intracranial hemorrhage is the most common cause for hyperpyrexia.
Hyperthermia is a condition that has a high temperature, but it is not a fever. It may occur due to various causes including serotonin syndrome, malignancy and heatstroke.
Symptoms of fever:- A Fever may accompany anorexia, sleepiness, depression, lethargy,hyperalgesia and the patient is unable to concentrate. The symptoms of fever depends upon the causes and it may often attended by accelerated heart and respiration rates, and a fall in the arterial pressure. Patients complain of chills, shivering, warmness, excess sweating, head ache, dryness of mouth, thirst, runny nose, sore throat, aching joints and muscles, nausea, vomiting and absence of appetite. Due to the increased metabolic rate during fever, the amount of perspired liquid may be more than 8 liters a day. As a result of decreased appetite and liquid loss during a fever, the patient sometimes loses significant weight.
Differential diagnosis: Differential diagnosis should be made according to the specific symptoms that arise from a particular cause.
1. Various skin inflammations such as in abscess and boils.
2. Infectitious diseases- like in malaria, gastroenteritis and influenza.
3. Immunological diseases like sarcoidosis, lupus erythematosus and inflammatory bowel diseases.
4. Metabolic disorders like porphyria and gout.
Treatment:- Fever is recovered spontaneously in many incidents and they require no medical attention even. But, in some cases it turns to a life threatening condition, if untreated. Dehydration is the most common problem in fever due to loss of water by excessive perspiration. More amount of water or a rehydration solution is used to tackle the problem.
Acetaminophen is the common drug that is used to lower fever. It could be taken every four to six hours as directed by the physician.
Ibuprofen is another drug that could be best taken (400mg) every four to six hours to reduce the fever and it is best to be taken as directed by the physician.
Aspirin is the next drug in reducing the fever but it should not be used for children.