Pyrexia: Causes, Symptoms, Diagnosis, Treatment And Prevention

Max Lab

Oct 16, 2023

What is Pyrexia?

Also known as fever, pyrexia is the medical term for an elevated body temperature above the normal range, which is typically around 98.6°F (37°C). This increase in temperature is the body's response to various external factors. Some of the causes of pyrexia may include infections, inflammation, or other medical conditions. It is an essential part of the body's defense mechanism against pathogens.

One’s body temperature is regulated by a part of the brain known as the hypothalamus which is responsible for maintaining a relatively constant temperature. When the body detects the presence of harmful microorganisms, it releases chemicals called pyrogens. These pyrogens signal the hypothalamus to raise the body's temperature which activates the immune system and creates an environment less favorable for the growth of pathogens.

Types of Pyrexia

Pyrexia can be classified on the basis of its temperature and duration. Different types of pyrexia have varying causes and treatment plans.

On the Basis of Temperature

• Low-Grade Fever

Low-grade fever is characterized by a mild increase in body temperature, usually staying within the range of 100.4°F (38°C) to 101.3°F (38.5°C). While it may not cause significant discomfort, it can persist for an extended period. Low-grade fevers may be associated with chronic infections, inflammatory conditions, or even medications.

• Moderate Fever

Moderate fever is when the body temperature rises to a more noticeable level, ranging from 101.4°F (38.6°C) to 104°F (40°C). It often indicates a more active immune response to infections, and it may be accompanied by more pronounced symptoms, such as fatigue and sweating.

• High Fever

High fever is characterized by body temperatures exceeding 104°F (40°C). This level of fever is more serious and may be associated with severe infections, heat-related illnesses, or other underlying medical conditions.

• Hyperpyrexia

Hyperpyrexia is a severe form of fever where the body temperature rises to extremely high levels, often exceeding 106°F (41°C). This type of pyrexia requires prompt medical treatment. The causes of hyperpyrexia are often associated with underlying medical conditions such as Malaria, Enterovirus infections, or Intracranial Hemorrhage.

On the Basis of Duration

• Acute Fever

Acute fever is characterized by a sudden and rapid increase in body temperature. It often appears abruptly and may be accompanied by other symptoms like chills, headache, and muscle aches. It tends to resolve within a few days to a week as the body's immune system fights off the invading pathogens.

• Sub-acute Fever

Sub-acute fever falls between acute and chronic fevers in terms of duration. It lasts for a longer period, usually between one and three weeks. The causes of this type of pyrexia may include a more prolonged infection or autoimmune disease.

• Chronic Fever

Chronic fever is defined as persistent fever lasting for more than three weeks. The most common causes of this type of pyrexia may be certain underlying medical conditions such as tuberculosis.

Causes of Pyrexia

Initially, when a fever persisted above 100° F (38°C), for at least 3 weeks, it was known as pyrexia of unknown origin. With time, the causes have become clearer with the help of medical advancements and diagnostic techniques. The causes of pyrexia can be classified into infectious causes and non-infectious causes.

Infectious Causes of Pyrexia

• Tuberculosis
• Respiratory tract infections such as Bronchitis
• Viral and Bacterial infections
• Urinary tract infections
• Bone infections

Non-Infectious Causes of Pyrexia

• Reaction to drugs
• Brain fever or haemorrhages
• Bowel or bladder problems

Symptoms of Pyrexia

• Elevated body temperature
• Chills or shivering Sweating  
• Headache 
• Muscle aches
• Fatigue
• Loss of appetite
• Increased heart rate and breathing

These symptoms help in reaching an accurate diagnosis of pyrexia and determine a suitable treatment plan.

Diagnosis of Pyrexia

Diagnosing pyrexia involves a thorough medical evaluation.

• Physical Examination

A physical exam will help the doctor assess your overall health and look for signs of infection or inflammation.

• Temperature Measurement

Your body temperature will be measured using a thermometer. Elevated temperature is a key indicator of pyrexia.

• Laboratory Tests

Blood tests may be conducted to identify the underlying cause of fever.

Treatment of Pyrexia

The treatment of pyrexia depends on the underlying cause and the severity of the fever. Here are some common approaches: -

• Rest and Hydration

Get plenty of rest and drink fluids like water, herbal teas, or clear broths to stay hydrated.

• Fever-Reducing Medications

Over-the-counter drugs like paracetamol can help lower fever and alleviate discomfort. Follow the dosing instructions carefully.

• Cool Compresses

 Applying a cool, damp cloth to the forehead and body can provide temporary relief from fever.

• Antibiotics

If the fever is caused by viral or bacterial infections, antibiotics may be prescribed to treat the underlying infection.

Prevention of Pyrexia

Prevention methods of pyrexia often involve reducing the risk of underlying infections and maintaining overall health

• Vaccination

Staying up-to-date with vaccinations can prevent many infectious diseases that lead to fever.

• Hand Hygiene

Regularly washing hands with soap and water helps reduce the risk of infection.

• Food Safety

Properly handling and cooking food can prevent foodborne illnesses.

• Avoid Close Contact

During outbreaks of contagious illnesses, avoid close contact with infected individuals.

• Stay Hydrated and Eat Nutritiously

A well-balanced diet and adequate hydration support a healthy immune system.

Pyrexia, or fever, is a common bodily response to infections and various other medical conditions. Understanding the causes and symptoms of pyrexia is essential for timely diagnosis and appropriate treatment.