Fever is defined as a body temperature above the normal range due to an increase in the body's temperature set point. There are different types of fevers classified by their temperature patterns, including continuous, intermittent, remittent, and hyperpyrexia (extreme fever over 106.7°F). Fever has many potential causes, including infections by viruses, bacteria, parasites, and fungi, as well as non-infectious conditions like autoimmune diseases, cancers, and metabolic disorders. Treatment focuses on reducing fever through conservative measures like rest, fluids, and antipyretic medications like acetaminophen and ibuprofen.

1. FEVERS
By FOTSO BENNIS Mounir
Medical student at Belarusian State Medical University
Faculty of General Medicine

2. DEFINITION
Fever, also known as pyrexia and febrile response, is defined
as having a temperature and also causing body to over
heat due to an increase in the body's temperature set-
point. There is not a single agreed upon upper limit for
normal temperature with sources using values between 37.5
and 38.3 °C (99.5 and 100.9 °F),

3. TYPES OF FEVER
The pattern of temperature changes may occasionally hint at the diagnosis:
• Continuous fever: Temperature remains above normal throughout the day and does not fluctuate more
than 1 °C in 24 hours, e.g. lobar pneumonia, typhoid, meningitis, urinary tract infection, brucellosis,
or typhus. Typhoid fever may show a specific fever pattern (Wunderlich curve of typhoid fever), with a slow
stepwise increase and a high plateau. (Drops due to fever-reducing drugs are excluded.)
• Intermittent fever: The temperature elevation is present only for a certain period, later cycling back to
normal, e.g. malaria, kala-azar, pyaemia, or septicemia. Following are its types
• Quotidian fever, with a periodicity of 24 hours, typical of Plasmodium falciparum or Plasmodium knowlesi malaria
• Tertian fever (48-hour periodicity), typical of Plasmodium vivax or Plasmodium ovale malaria
• Quartan fever (72-hour periodicity), typical of Plasmodium malariae malaria.
• Remittent fever: Temperature remains above normal throughout the day and fluctuates more than 1 °C in 24
hours, e.g., infective endocarditis.
• Pel-Ebstein fever: A specific kind of fever associated with Hodgkin's lymphoma, being high for one week and
low for the next week and so on. However, there is some debate as to whether this pattern truly exists.
• A neutropenic fever: also called febrile neutropenia, is a fever in the absence of normal immune system
function. Because of the lack of infection-fighting neutrophils, a bacterial infection can spread rapidly; this
fever is, therefore, usually considered to require urgent medical attention. This kind of fever is more
commonly seen in people receiving immune-suppressing chemotherapy than in apparently healthy people.
• Febricula is an old term for a low-grade fever, especially if the cause is unknown, no other symptoms are
present, and the patient recovers fully in less than a week.

5. HYPERPYREXIA
Hyperpyrexia is a fever with an extreme elevation of body temperature greater
than or equal to 41.5 °C (106.7 °F). Such a high temperature is considered a medical
emergency as it may indicate a serious underlying condition or lead to significant
side effects. The most common cause is an intracranial hemorrhage. Other possible
causes include sepsis, Kawasaki syndrome, neuroleptic malignant syndrome, drug
effects, serotonin syndrome, and thyroid storm. Infections are the most common
cause of fevers, however as the temperature rises other causes become more
common. Infections commonly associated with hyperpyrexia
include roseola, measles and enteroviral infections. Immediate aggressive cooling
to less than 38.9 °C (102.0 °F) has been found to improve survival. Hyperpyrexia
differs from hyperthermia in that in hyperpyrexia the body's temperature
regulation mechanism sets the body temperature above the normal temperature,
then generates heat to achieve this temperature, while in hyperthermia the body
temperature rises above its set point due to an outside source.

6. DIFFERENTIAL DIAGNOSIS
Fever is a common symptom of many medical conditions:
• Infectious disease, e.g., influenza, HIV, malaria, Ebola, infectious mononucleosis, or gastroenteritis, Lyme
disease
• Various skin inflammations, e.g., boils, or abscess
• Immunological diseases, e.g., lupus erythematosus, sarcoidosis, inflammatory bowel diseases, Kawasaki
disease, Still disease, Horton disease, granulomatosis with polyangiitis, autoimmune hepatitis, Relapsing
polychondritis
• Tissue destruction, which can occur in hemolysis, surgery, infarction, crush
syndrome, rhabdomyolysis, cerebral bleeding, etc.
• Reaction to incompatible blood products
• Cancers, most commonly kidney cancer and leukemia and lymphomas
• Metabolic disorders: gout, porphyria
• Inherited Metabolic disorder: Fabry disease
• Thrombo-embolic processes, e.g., pulmonary embolism or deep venous thrombosis
• Persistent fever that cannot be explained after repeated routine clinical inquiries is called fever of unknown
origin.

7. MANAGEMENT
Fever should not necessarily be treated. Most people recover without
specific medical attention. Although it is unpleasant, fever rarely rises
to a dangerous level even if untreated. Damage to the brain generally
does not occur until temperatures reach 42 °C (107.6 °F), and it is rare
for an untreated fever to exceed 40.6 °C (105 °F).

8. CONSERVATIVE MEASURES
Some limited evidence supports sponging or bathing feverish children
with tepid water. The use of a fan or air conditioning may somewhat
reduce the temperature and increase comfort. If the temperature
reaches the extremely high level of hyperpyrexia, aggressive cooling is
required. In general, people are advised to keep adequately
hydrated. Whether increased fluid intake improves symptoms or
shortens respiratory illnesses such as the common cold is not known.

9. MEDICATIONS
Medications that lower fevers are called antipyretics. The
antipyretic ibuprofen is effective in reducing fevers in children. It is more
effective than acetaminophen (paracetamol) in children. Ibuprofen and
acetaminophen may be safely used together in children with fevers. The
efficacy of acetaminophen by itself in children with fevers has been
questioned Ibuprofen is also superior to aspirin in children with
fevers. Additionally, aspirin is not recommended in children and young adults
(those under the age of 16 or 19 depending on the country) due to the risk
of Reye's syndrome.
Using both paracetamol and ibuprofen at the same time or alternating
between the two is more effective at decreasing fever than using only
paracetamol or ibuprofen. It is not clear if it increases child comfort.A