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PRACTICAL PEDIATRICS
A News Letter Devoted To Practical Pediatric Practice
Volume 4 Issue 6 Date June 2022
Editor in Chief :
BD Gupta
Ass Editor :
RK Maheshwari
Mohan Makwana
Anil Arora
Regional Editors
Pankaj Agrawal
Avinash Bansal
Anil Jain
PC Khatri
Priyanshu Mathur
Jai Singh Meena
Adarsh Purohit
Editorial advisory Board
Neeraj Gupta
Manoj Jangid
Rakesh Jora
Amarjeet Mehta
Lakhan Poswal
GS Sengar
Pramod Sharma
Anurag Singh
Kuldeep Singh
S Sitaraman
Fever in Pediatrics
Dr Rakesh Dudi
Fever is one of the oldest clinical indicators of a disease process in humans; in addition, it is one of the most common reasons for medical consultations worldwide. Human beings are homeothermic, meaning hereby that they maintain their body temperature within a limited range of ±2° F despite a wide variation in ambient temperature. Along with pulse rate and respiratory rate, body temperature is also one of the vital signs. Here we are recapitulating basics of fever like pathophysiology behind fever, various metabolic and physical changes observed during fever per se, and different classical patterns of fever which can be helpful in diagnosing the cause behind fever.
Fever in Pediatrics
Dr Rakesh Dudi
Introduction
Fever is one of the oldest clinical indicators of a disease process in humans; in addition, it is one of the most common reasons for medical consultations worldwide. Human beings are homeothermic, meaning hereby that they maintain their body temperature within a limited range of ±2° F despite a wide variation in ambient temperature. Along with pulse rate and respiratory rate, body temperature is also one of the vital signs. Here we are recapitulating basics of fever like pathophysiology behind fever, various metabolic and physical changes observed during fever per se, and different classical patterns of fever which can be helpful in diagnosing the cause behind fever.
Definition of Fever: Fever is defined as a rise in body temperature of 1°C (1.8 °F) or more above the mean at the site of temperature recording. For example, the range of body temperature at axilla is 34.7–37.4°C, with a mean of 36.4 °C, then 1°C above the mean would be 37.4 °C.
The following degrees of temperature at different body sites are accepted as fever:
- Core temperature ≥38.3 °C / 100.9°F
- Rectal temperature ≥38.0 °C / 100.4°F
- Oral temperature ≥37.6 °C / 99.7 °F
- Tympanic membrane ≥37.6 °C / 99.7 °F
- Axillary temperature ≥37.4 °C / 99.3 °F
The importance of this rise of body temperature by at least 1°C from the mean temperature lies in the diurnal variation observed in normal body temperature; body temperature reaches its highest level in late afternoon (4–6 pm) and lowest prior to awakening (4–5 am). This rhythm is regulated by hypothalamic light-sensitive suprachiasmatic nucleus (SCN) that responds to light entering the eyes. Diurnal temperature fluctuations are greater in children than in adults and are more pronounced during febrile episodes.
Pathophysiology of Fever: Fever is an interleukin-1 (IL-1)-mediated elevation of the thermoregulatory set point of the hypothalamic centre. In response to an upward displacement of the set point, an active process occurs in the body in order to reach a new set point. This is accomplished physiologically by minimizing heat loss by means of vasoconstriction, and by producing heat by shivering. Behavioral means of raising body temperature include seeking a warmer environment, adding more clothes, curling up in bed and drinking warm liquids.
Clinical Phases of Fever
- The Phase of Temperature Rise: This phase is characterized by discomfort and is the result of poor heat loss because of vasoconstriction, and increased heat production by mechanism of shivering. The patient feels chills, and the skin also feels cold to the touch.
- The Phase of Temperature Stabilization (Fastigium): During this phase the thermoregulatory set point is reset to a new level. Heat production and heat loss are balanced as in a normal healthy child, but at a higher hypothalamic set point. A flushed or pink appearance signifies that the fever has peaked. Once this phase is reached, the child usually feels comfortable without shivering, in spite of high temperature.
- The Phase of Falling temperature or Defervescence: It occurs either by lysis (falling gradually within 2–3 days to a normal level) or by crisis (falling within a few hours to a normal level). Sweating is observed during this phase. Defervescence by lysis is observed in typhoid fever and that by crisis is a feature of malarial fever treated with antimalarial, MISC (Multisystem Inflammatory Syndrome in Children) treated with MPS, and in Bronchopneumonia treated with appropriate antibiotic.
Constitutional Manifestations of Fever
The subjective perception of fever is generally absent in children, and fever is usually detected by the parents. Manifestations associated with fever vary considerably and depend on the child’s age, how acute and how high the fever is and on the nature of the disease that has caused the fever (bacterial, viral, or inflammatory).
Associated Symptoms: Chills/Rigor, myalgia, headache, nausea, anorexia, excessive sleep, fatigue, thirst, delirium and scanty urine (oliguria) are some of the symptoms which are usually observed in any febrile child irrespective of cause of fever and are called as Constitutional Symptoms.
Signs: Drowsiness, irritability, tachycardia, tachypnoea, increased blood Pressure, flushed face, and sometimes grunting.
Pathophysiology Behind Common Constitutional Symptoms:
- Chills or rigors, which characteristically herald the onset of high fever, occur because of release of large number of cytokines and prostaglandins causing rapid rise in body temperature by rapid muscle contraction and relaxation. Young children do not often have chills, or the chills are so subtle that they pass unnoticed.
- Headache and irritability associated with pyrexia usually go away with use of antipyretic drugs, but may persist in case of meningitis.
- Delirium – It is defined as acute onset disturbance of consciousness. Common causes of delirium are Encephalopathy, Encephalitis, drug use, and psychosis.
Associated Changes in Physical Parameters
- Tachycardia: Heart Rate (HR) increases by 10 beats/min for every 1°C rise in body temperature. (in Children >2months age)
- Tachypnoea: Respiratory Rate (RR) increases by 3-4 breaths/min for every 1°C rise in body temperature.
- Blood Pressure (BP): It may increase or decrease. Hypotension may occur despite hyper-dynamic circulation and increased cardiac output, which is due to redistribution of blood and vasodilatation.
- Glomerular Filtration Rate (GFR) usually falls leading to a fall in urine output. Proteinuria may be observed in many cases of fever, but is usually mild.
- Capillary refill time (CRT) in febrile children essentially remains the same as in those without fever (2–3 s). CRT has an important diagnostic value in identifying critically ill children with shock and dehydration. Mottled skin (livedo reticularis, cutis marmorata) is commonly seen which is an autonomic phenomenon caused by fluctuations in body temperature. This patchy skin discoloration is often also seen in healthy newborn infants and is harmless.
Metabolic Effects of Fever
- Increase in energy expenditure and Basal Metabolic Rate (13% for each °C rise in temperature)
- Increase in Oxygen consumption (10–12% for each °C rise in body temperature)
- Increase in insensible water loss (10% for each °C rise in body temperature)
- ↑ glucose production ↓ iron, zinc?
- ↑ amino acid release ↓ phosphorus
- ↑ C-reactive protein, ↑ haptoglobin, ↑ceruloplasmin
- ↑ hormones: Cortisol, ACTH, growth hormone, arginine,
- Negative nitrogen balance (loss of about 10 g daily with high fever)
- ↓ sodium
Etiology of Fever
Infection is the most common cause of fever. Besides, fever is also a common finding in many Non-infectious Diseases (collagen/vascular, malignancy, drug-induced, allergy/autoimmune, recent immunization and periodic fevers). Infection remains a likely diagnosis in a febrile child until proven otherwise. Febrile response is mediated by endogenous pyrogens (cytokines, IL-1, TNF and INF) in response to exogenous pyrogens, primarily micro-organisms or their direct products (toxins).
Fever in Non-infectious Diseases
- Malignancy: Fever in children with malignancy may be due to the disease (neoplastic fever) per se, or due to underlying serious bacterial infection. The diagnosis of neoplastic fever should only be considered after exclusion of any underlying infection.
- Rheumatological Disorders: Out of Rheumatological Diseases, children with juvenile idiopathic arthritis have the highest incidence of fever.
- Post-Vaccination: Fever following vaccination is fairly common and usually trivial. It is not a contraindication to further doses of vaccines.
Patterns of fever
Immense use of antipyretics and antibiotics in early stage of disease has made it difficult to use specific pattern of fever to diagnose the cause of fever. Thus, laboratory investigations are frequently required to establish the diagnosis. Patterns of fever include the type of onset (insidious or abrupt), variation in temperature degree during a 24-h period and during the entire episode of illness, cycle of fever and response to therapy. Several patterns may be seen in clinical practice, some of which have great clinical value. For example, characteristic fever pattern is seen in malaria which helps in its specific diagnosis.
- Continuous fever – It is characterised by persistent elevation of body temperature above normal, with a maximal fluctuation of 0.5°C during a 24-h period and does not touch the base line. This pattern is not usually associated with chills or rigor. Normal diurnal fluctuation in temperature is usually absent or insignificant. Example of this pattern is Typhoid or Enteric fever.
- Remittent fever – It is characterised by persistent elevation of body temperature above normal, with a fluctuation more than 0.5°C during a 24-h period, but does not touch the baseline. This is the most common type of fever in pediatric practice and is not specific to any disease. Example: most viral and bacterial infections.
- Intermittent fever– In this pattern, temperature returns to normal each day, usually in the morning, and peaks in the afternoon. This is the second most common type of fever encountered in clinical practice. Subtypes are quotidian, tertian and quartan
- Double quotidian fever– In this, two temperature spikes are recorded within a 24-hour period; for example, in Juvenile Idiopathic Arthritis (JIA).
- Undulant fever– It is characterized by a gradual increase in temperature, which remains high for a few days and then gradually decreases to normal level. Brucella may cause this type of fever.
- Prolonged fever describes a single illness in which duration of fever exceeds that expected for this illness, e.g. >10 days for a viral upper respiratory tract infection.
- Recurrent fevers (RF) are defined as three or more febrile episodes during a 6-month period, with symptom-free intervals of at least 7 days separating the episodes. Causes of RF are either infectious or non-infectious. Infections such as viral upper respiratory tract infections (URTIs) are by far the most common causes of RF in children. Young children commonly develop one to two episodes of URTI monthly, especially if they are attending a preschool nursery. Another example is malaria; in endemic area it is the one of the most common causes of RF. Other examples are listed in table below:
| Infectious causes | Non-infectious causes |
| Ø Viral (URTI, EBV)
Ø Bacterial (UTI, Brucella) Ø Fungal (Histoplasmosis) Ø Parasitic (Malaria, Toxoplasmosis) Ø Relapsing fever (Borrelia) |
Ø Immune-mediated (CD, SLE)
Ø Neoplasms Ø Drug fever Ø Periodic Fever Syndromes Ø Auto-inflammatory diseases |
- Pel-Ebstein fever- Fever is one of the most important presenting symptoms of Hodgkin’s lymphoma (HL), usually intermittent fever. Only a few patients with Hodgkin’s disease develop this pattern, but when present, it is suggestive of HL. The pattern consists of recurrent episodes of high fever, often reaching 40°C and lasting 3–10 days, usually a week, followed by an afebrile period of similar duration. The cause of this type of fever may be related to tissue destruction or associated hemolytic anemia.
- Relapsing Fever: Relapsing fever is the term usually applied to recurrent fevers caused by numerous species of Borrelia and transmitted by lice or ticks. The most well-known tick-borne disease is Lyme disease caused by burgdorferi.
Potential Complications of Fever
Complications directly related to fever are rare. Morbidity and mortality are closely linked to the severity of the underlying disease and not to the level of fever.
- Dehydration – Dehydration may occur due to increased body temperature and the therapeutic effects of drugs that promote sweating. Fever and infection increase the metabolic rate to more than 1.5 times the basal metabolic rate. For every 1°C rise of body temperature, there is a 10% rise in insensible water loss. Dehydrated children are prone to heat stroke, particularly if the child is excessively wrapped. It is essential to prevent this complication by offering oral fluids to the febrile child frequently and maintaining a comfortable thermoneutral surrounding temperature.
- Fever-induced Seizure (febrile seizure): 3 to 4% of genetically susceptible children younger than 5 years, experience fever-induced seizure (febrile seizure), which occurs when the temperature of a susceptible child rises rapidly.
- Delirium: Some young children experience delirium in association with a high degree of body temperature. This is a non-specific sign caused by viral as well as bacterial infections and medications. Delirium has an acute onset causing disturbance of consciousness and reduced focus. It requires immediate medical attention to exclude other serious causes such as encephalitis, psychosis or acute anxiety state. Delirium often recurs, causing considerable anxiety on the part of parents. Antipyretics will rapidly ameliorate symptoms caused by fever. Other conditions usually respond to haloperidol or risperidone.
- Hyperpyrexia: Hyperpyrexia is a rectal temperature of 41.1°C or higher. There is a significant association between such a degree of temperature and serious bacterial infections, such as meningitis. Apart from infection, hyperpyrexia up to 41.8°C has been reported in neonates presenting with intra-ventricular hemorrhage.
- Herpes simplex labialis (cold sore): It results from activation of a latent herpes simplex infection in association with febrile illnesses. It occurs less often in children than in adults and is more common with certain bacterial infections, such as pneumococcal or meningococcal infection.
Practical tips on “complications of fever”
- The principal complication of fever is dehydration, which can easily be prevented and treated by providing extra fluids to the child.
- Fever may be associated with lethargy and drowsiness caused in over 90% kids by a viral infection that lasts a few days.
- Fever is a symptom and not a disease. It is not dangerous. If there is morbidity or mortality, it is due to the underlying disease, not due to the fever directly.
- Febrile seizures occur only in genetically susceptible children and are usually not dangerous.
- Fever helps the body fight against infection; it is one of the important defense mechanisms.
- Fever does not damage the central nervous system. It also does not climb up relentlessly because it is well controlled by a hypothalamic center.
Is Fever Beneficial for a Child?
Fever has a long evolutionary history, which by itself supports the hypothesis that fever is an adaptive host response to infection. There is considerable evidence that fever promotes host defense against infection. Complications and mortality associated with high fever >40°C are closely related to the severity of the underlying disease, not to the level of fever. Fever is effectively controlled by the hypothalamic center and therefore does not climb up relentlessly.
If the febrile child is comfortable, there is little reason to support the practice of routine use of antipyretic medication. Therefore, parental education is critical in the management of the febrile child. It is also important to convey that antipyretics do not prevent febrile seizures. Up till now there is a conflict between research evidence supporting a positive role of fever and the demands of current practice that fever be abolished.
Situations whereby fever clearly worsens the prognosis of disease
- Acute stroke
- Severe sepsis
- Children with bronchiolitis
- Situations associated with limited energy supply or increased metabolic rate e.g. burn, cardiovascular and pulmonary diseases, prolonged febrile illness, young children, undernourishment and postoperative state
- Diseases associated with high fever (>40 °C)
Fever is a symptom of some disease process going inside the body of child which may or may not be infectious, sometimes it may be a physiological event like after excessive exercise or fatigue, or high ambient temperature. We as clinicians have to confirm the presence of fever first, then categorize it into physiological or pathological, identify the severity of illness leading to it and to identify the cause behind this which will eventually guide us to treat the cause and ameliorating the fever. Besides, counseling the parents, and addressing their anxieties and concerns is our added responsibility.
References
1.Kluger MJ, Ringler DH, Anver MR. Fever and survival. Science. 1975;188:166–8.
2.Bernheim HA, Kluger MJ. Fever: of drug-induced antipyresis on survival. Science. 1976;193:237–9.
3.Graham NH, Burrell CJ, Douglas RM, et al. Adverse effects of aspirin, acetaminophen, and ibuprofen on immune function, viral shedding and clinical status in rhinovirus-infected volunteers. Infect Dis. 1990;162:1277–82.
4.Doran TF, Angelis CD, Baumgarder RA, et al. Acetaminophen: more harm than good in chickenpox? J Pediatr. 1989;114:1045–8.
