Neonatal fever

Introduction to neonatal fever Increased body temperature is a common symptom in the neonatal period. The normal anus temperature is 36.2~37.8°C, the temperature under the armpit is slightly lower than the anus temperature, at 3637°C, when the neonatal sputum temperature exceeds 37.2°C or anus When the temperature exceeds 37.8 °C, it is called fever. The temperature is 37.5~38°C, which is called low heat, 38.139°C is called moderate heat, 39.141°C is called high heat, 41°C or above is called high fever, and the newborn is poorly tolerant to high heat. . When the body temperature exceeds 40 ° C for a long time, convulsions and permanent brain damage can occur. basic knowledge The proportion of sickness: 0.01% Susceptible people: infants and young children Mode of infection: non-infectious Complications: dehydration, hypernatremia, respiratory failure

Neonatal fever etiology

(1) Causes of the disease

1. Non-infectious fever: fever caused by non-infection in neonates is common.

(1) Excessive ambient temperature or excessive clothing: imbalance of body temperature regulation, in the thermal environment, especially when the indoor temperature in summer is close to 30 °C, the body temperature rises, 2 to 3 days after birth due to insufficient breast milk, intake of water Less, the ambient temperature is higher, dehydration heat can occur, and the winter clothes are covered by too much cap, which can cause hyperthermia and hyperthermia.

(2) Dissipation of heat: due to extensive ichthyosis, extensive dermatitis, no sweat adenosis or thermal obstruction caused by too thick and too thick, neonatal congenital ectodermal dysplasia, long-term fever.

(3) Disease effects: such as leukemia, intravascular embolism, burns, fractures, hematoma, absorption of blood in the abdominal cavity or chest, etc., in addition, if the child has nuclear jaundice (encephalopathy caused by excessive jaundice), intracranial hemorrhage (production injury) The sequelae can cause fever.

(4) Biological agents or drug reactions: such as serum, bacterins, allogeneic proteins or certain drugs (such as sulfonamides, barbiturates, etc.) are allergic.

2. Infectious fever Newborns are more likely to have neonatal infections, such as prenatal infection, premature rupture of the amniotic membrane, unclean vaginal examination, etc., more than 1 to 2 days after birth, fever occurs, postpartum infections occur mostly in life After about 1 week, common pneumonia, sepsis, umbilical inflammation, pustular or abscess.

Fever is a common problem in clinical practice. Pediatricians should first consider whether there is an infection. All kinds of pathogens such as bacteria, viruses, protozoa and other neonatal infectious diseases can cause fever. In severe infection, in neonatal body temperature. Often it does not rise.

(two) pathogenesis

1. Heat and heat are out of balance

(1) The function of the body temperature regulation center is imperfect: the body temperature regulation function of the newborn is not perfect, and the heat production and heat dissipation are easy to lose balance, so the body temperature is easy to fluctuate.

(2) Incomplete development of sweat glands: premature infants do not have perspiration function, body temperature rises with increasing ambient temperature, and full-term children use perspiration to maintain body temperature (sweating on the forehead), although neonates have sweat glands Tissue, but the development is imperfect, the response intensity to heat is only 1/3 of that of adults, and gradually increases after 10 days of birth. The sweat glands in premature infants are even worse, and they hardly sweat. In the hot environment, the body temperature is more likely to rise, less than the fetus. The sweat gland function of the same age is the same as the sweat gland function of the gestational age suitable for gestational age. The respiratory rate of the newborn does not increase significantly when sweating, suggesting that the amount of water evaporated from the respiratory tract is small, such as sweating is not enough to cause body heat loss. The body temperature rises.

(3) The ambient temperature is too high: when the ambient temperature is too high, the metabolic rate and oxygen consumption increase, and the non-dominant water loss increases. In the hot environment, the newborn is first the skin vasodilation, the blood flow velocity increases, and the radiation and convection are accelerated. Function, promote body heat dissipation, when the ambient temperature increases above 30 °C, or when the temperature rises to 37.2 °C, the newborn begins to sweat, sweat beads appear on the forehead, both sides of the horn, later in the chest, the inner thigh of the full moon Can also slightly sweat, if you do not pay attention to add water can cause dehydration and hypernatremia, blood concentration, red blood cell damage increased, and then cause hyperbilirubinemia, such as the increase in environmental temperature too fast, can make newborns every minute Reduced ventilation or apnea, respiratory failure, severe high fever can lead to death, survivors can cause brain damage.

2. Infection

The metabolites of various pathogens or their toxins act on the blood cells and the reticuloendothelial system, releasing an endogenous pyrogen, possibly prostaglandin E, acting on the thermoregulatory center in the anterior hypothalamus, causing fever, The body temperature rises.

Neonatal fever prevention

Pay attention to the body temperature, the neonatal living room temperature is 22 ~ 25 °C is appropriate, if the indoor temperature is too high, should try to lower the room temperature, should be indoor ventilation, ventilation, when the ventilation should be used to cover the quilt to prevent cold air from blowing directly to the disease On the body, prevent dehydration heat, open milk as soon as possible after birth, reasonable feeding, pay attention to disinfection and isolation, do a good job of neonatal skin, mucous membrane, umbilical care, to avoid neonatal infection.

Neonatal fever complications Complications dehydration hypernatremia respiratory failure

Neonatal tolerance to high fever is poor, dehydration can occur, causing hypernatremia, hyperbilirubinemia, when the body temperature exceeds 40 ° C and lasts for a long time, not only can cause convulsions, but also produce permanent brain Injury, residual sequelae of the nervous system, the ambient temperature is increased too fast, can reduce the ventilation of the newborn per minute or cause apnea, respiratory failure, severe high fever can lead to death, survivors can cause brain damage.

Neonatal fever symptoms common symptoms hyperthermia abnormal acute respiratory failure septicemia hypernatremia sputum perforation

1. High ambient temperature

In the hot environment, the newborn is first skin vasodilatation, and then begins to sweat. The sweat beads first appear on the forehead, and the two sides are in the horns. Later, in the chest and the inner thighs, if you do not pay attention to the water, you can cause dehydration and cause hypernatremia. Hyperbilirubinemia, such as an increase in ambient temperature, can reduce neonatal ventilation per minute or cause apnea, respiratory failure, severe high fever can lead to death, survivors can cause brain damage.

2. Neonatal dehydration fever

2 to 3 days after birth, the body temperature rises, irritability, crying, and the skin is flushed and urinary. After appropriate reduction of the ambient temperature or loosening of the package, the body temperature can be reduced to normal after more water is added.

3. Infection

Various infections cause elevated body temperature, in addition to fever, accompanied by symptoms of infection poisoning, such as low response, reduced feeding, low crying, gray complexion, etc., such as pneumonia, have anxious, cyanosis, suckling milk and Oral vomiting foam; if umbilical infection, you can find signs such as umbilical inflammation, with the original infection, different symptoms, signs, signs of nervous system infection, digestive system infection, urinary tract infection, sepsis, etc. In addition to the symptoms of fever and infection, the relevant clinical manifestations can be found in the relevant content.

Newborn fever check

Due to non-infectious factors such as high ambient temperature or improper feeding, there are often dehydration and hypernatremia, metabolic acidosis, etc. When there is blood concentration, the destruction of red blood cells increases. Therefore, the concentration of bilirubin is increased, and infection is caused. Infectious blood, if there is sepsis, blood culture is positive.

Routine chest X-ray, B-ultrasound, electrocardiogram, etc., except for lung infections, except for neurological diseases, etc., if necessary, do EEG, CT and other examinations.

Diagnosis of neonatal fever

Diagnostic criteria

When the temperature of neonates exceeds 37.2 °C or the temperature of the anus exceeds 37.8 °C, it is fever. The cause of fever should be further clarified. First of all, except for various causes of infection, according to medical history, clinical manifestations and laboratory tests, it is generally easy to diagnose, but First, the body temperature should be accurately measured.

The common parts for measuring the body temperature of the newborn are the anus, the abdomen skin and the armpit. The anus temperature is usually regarded as the deep body temperature. When the temperature of the anus is measured, the temperature probe insertion depth is 3 cm. The disadvantage of measuring the rectal temperature is that the intestinal perforation may occasionally occur. Very rare, such as the operation is cautious and gentle, completely avoidable. The advantage of measuring skin temperature is that it can detect early due to high temperature caused by the influence of ambient temperature, and has little interference to newborns; the disadvantage is that the probe is not easy to fix and is susceptible to ambient temperature. The effect is to fix the probe on the skin with double-sided tape and cover the reflective sheet. The advantage of the temperature is that the interference to the newborn is small, the external influence is small, and the advantages of rectal temperature and skin temperature are combined. Clinically, the temperature of the newborn is usually monitored as the body temperature of the newborn. The temperature is close to the deep body temperature. Under normal circumstances, the temperature is lower than that of the anus. If the body is stimulated by the cold, the brown fat is decomposed and the temperature is higher than the anus.

The interval between body temperature measurement depends on whether the body temperature of the newborn is stable and the method used. For example, the thermistor is used as the electronic thermometer of the probe. The temperature probe can be fixed in a part of the newborn body as a body temperature monitoring. On the screen, you can read the temperature reading. If you use the intermittent temperature measurement method, you should pay attention to the frequency. The commonly used mercury column glass thermometer is cheap and accurate. It should be designed for newborns with low temperature readings. It can be measured below 35 °C. Low body temperature.

Differential diagnosis

1. Fever caused by disease or environmental factors: fever caused by disease or environmental factors is sometimes difficult to distinguish, measuring the difference between deep body temperature and surrounding body temperature such as rectal temperature - finger (toe) temperature difference, help to distinguish, when the ambient temperature When it is too high, the blood vessels around the newborn expand, and the difference between the anus temperature and the surrounding body temperature is reduced; the fever caused by the disease, the surrounding blood vessels contract, and the limbs become cold, which increases the difference between the anus temperature and the surrounding body temperature, such as the difference between the deep temperature and the surrounding temperature is more than 1.6. °C, suggesting that fever is caused by disease.

2. Neonatal dehydration fever, should pay attention to the difference between perinatal bacterial or viral infection and fever caused by intracranial hemorrhage, dehydration fever is characterized by fever, irritability, crying, oliguria, skin flushing; the child is placed in a low temperature environment In the middle, the body temperature can be reduced to normal after adding water.

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