Fever is defined as a rectal temperature ≥38°C (100.4°F), and a value >40°C (104°F) is called hyperpyrexia. Body temperature fluctuates in a defined normal range (36.6-37.9°C [97 9-100.2°F]) rectally) so that the highest point is reached in early evening and the lower point is reached in the morning.
Etiology/Causes
Causes of fever can be categorized into 4 main categories:
- Infectious
- inflammatory
- Neoplastic
- Miscellaneous
Types Of Fever:
Self-limited viral infections (common cold, influenza, gastroenteritis) and uncomplicated bacterial infections (otitis media, pharyngitis, and sinusitis) are the most common causes of acute fever. The pattern of the fever can provide clues to the underlying etiology. Viral infections typically are associated with a slow decline of fever over 1 week, whereas bacterial infections are often associated with a prompt resolution of fever after effective antimicrobial treatment.
Intermittent fever is an exaggerated circadian rhythm that includes a period of normal temperatures on most days; extremely wide fluctuations may be termed septic or hectic fever.
Sustained fever is persistent and does not vary by >0.5°C (0.9°F)/day.
Remittent fever is persistent and varies by >0.5°C/day.
Relapsing fever is characterized by febrile periods separated by intervals of normal temperature.
Tertian fever occurs on the 1st and 3rd days (malaria caused by Plasmodium vivax).
Quartan fever occurs on the 1st and 4th days (malaria caused by Plasmodium malaria)
Biphasic fever indicates a single illness with two distinct periods (camelback fever pattern): poliomyelitis is the classic example.
Factitious fever or self-induced maybe caused by intentional manipulation of the thermometer or injection of pyrogenic material.
Clinical Features
Children might complain of feeling hot or cold display facial flushing, and experience shivering. Fatigue and irritability may be evident. Parents often reports that the child looks ill or pale and has a decreased appetite. There are some predictable features. For example, fever with petechiae in an ill -appearing patient indicates the high possibility of life threatening conditions such as meningococcemia. Changes in heart rate, most frequently tachycardia, accompany fever, Normally heart rate rises by 10 beats/min per 1°C (1.8°F) rise in temperature for children >2 months old.
Degree Ofillness:
When to worry about a child when having fever:
- Mild to Moderate
All infants aged 4 weeks or more with temperature <38.9°C without cardiopulmonary disease or a complicated nursery stay and who have a reliable caretaker,
Mental status: smiles and not irritable, alerts
No signs of dehydration and good peripheral perfusion pink, warm extremities
No signs of respiratory distress
Absolute band count <1500/L, WBC5000-15,000
When diarrhea is present, <5 WBC/high-power field in stool and no blood in stool
- Severe
Infants aged more than 4 weeks or infants with temperature more than 38.9°C or infants having cardiopulmonary disease or a complicated nursery stay regardless of degree of fever or who lack a reliable care taker.
Mental status: irritable but consolable, poor eye, contact (lethargic), feeds poorly
Signs of dehydration or poor perfusion: mottled cool extremities
Respiratory rate >60, retractions, grunting
Absolute band count equal or greater 1500/L
WBC <5000 ог > 15,000
When diarrhea is present, ≥ WBC high-power field in stool or blood in stools
- Very Severe
Mental status: irritable and not consolable, unresponsive, too week to feed and seizures
Shock ,pale with thread pulse
Apnea, cyanosis, respiratory failure
Evaluation Of Acute Fever:
Thorough history: onset, other symptoms, exposures (daycare. school, family, pets, playmates), travel, medications, other underlying disorders, immunizations
Physical examination: complete, with focus on localizing symptoms
Laboratory studies on a case-by-case basis:
- Rapid antigen testing
- Nasopharyngeal: respiratory viruses by polymerase chain reaction
- Throat: group A streptococcus
- Blood: Complete blood count, blood culture, C-reactive protein, sedimentation rate, procalcitonin
- Urine: urinalysis, culture
- Chest radiograph or other imaging studies on a case-by-case basis
Management
Treating fever in self-limiting illnesses for the sole reason of bringing the body temperature back to normal is not necessary in the otherwise healthy child.
Fever with temperatures <39°C (102.2°F) in healthy children generally does not require treatment.
Other than providing symptomatic relief, antipyretic therapy does not change the course of infectious diseases. Encouraging good hydration is the 1st step to replace fluids that are lost related to the increased metabolic demands and insensible losses of fever. Antipyretic therapy is beneficial in high-risk patients and patients with discomfort. Hyperpyrexia (>4I°C [105.8°F]) indicates high probability of hypothalamic disorders or central nervous system hemorrhage and should be treated with antipyretics. The most common antipyretics are acetaminophen, 10-15 mg/kg/dose every 4 hr, and ibuprofen in children >6 month old at 5-10 mg/kg/dose every 8 hr.
Physical measures such as tepid baths and cooling blankets are not considered effective to reduce fever. Evidence is also scarce for the use of complementary and alternative medicines interventions.
