Central fever

Introduction Central fever refers to fever caused by abnormalities in the body temperature regulation center caused by central nervous system diseases. Central fever is rare in various causes of fever, and its performance and treatment are also different from common fevers caused by various infectious and other causes. Therefore, in the clinical determination of central fever, first of all, except for infectious, drug-induced and other causes of fever. For moderately unacceptable increases in moderate body temperature, it cannot be easily considered as central fever.

Cause

The diseases that cause central fever are more common in cerebrovascular disease, brain trauma and brain surgery. They can also be found in brain tumors, epilepsy, alcohol withdrawal and acute high intracranial pressure.

1. Cerebrovascular disease: Central fever caused by cerebrovascular disease is more common with hemorrhagic disease, especially patients with medial hemorrhage breaking into the lateral ventricle and third ventricle, primary ventricular hemorrhage, cerebral hemorrhage and subarachnoid hemorrhage More common; anterior communicating aneurysm rupture damage the hypothalamic anterior region is also likely to cause central hyperthermia. The central hyperthermia caused by hemorrhagic cerebrovascular disease is caused by hemorrhage and peripheral edema directly affecting the thermoregulatory center, as well as the release of serotonin from the subarachnoid space and intraventricular cells to stimulate the hypothalamic thermoregulatory center. It has also been reported that subarachnoid hemorrhage can cause pathological changes in the hypothalamus. Of the 409 patients with cerebral hemorrhage, 20 had central fever, of which 12 died. Cerebral infarction is less common in patients with central fever, but it can occur in patients with large area cerebral infarction and pons cerebral infarction. It may be caused by edema around large area infarction affecting the hypothalamic and pons brain lesions. .

2. Brain trauma and brain surgery: Severe brain trauma and craniocerebral surgery involving the pituitary fossa, the third ventricle, and the posterior fossa can cause fever. In particular, in the past, after the resection of the tumor in the sellar region through the three-ventricle approach, complications such as central hyperthermia and gastric mucosal hemorrhage often occur. Central fever caused by brain surgery often occurs within a few days after surgery.

3. Epilepsy: An epileptic seizure of a tonic-clonic seizure can cause an increase in body temperature after the onset. It may increase the heat production due to the continuous contraction of muscles, and the seizures cause the neurons to be overexcited and discharge, causing transient dysfunction of the hypothalamic thermoregulatory center, leading to fever. It has been reported that 40 of 93 patients with epilepsy (43%) had fever after seizures, and 27 of them (29%) had no signs of infection after fever. After an epileptic seizure, fever started on average 5.37h, with an average duration of 21.78h.

4. Acute hydrocephalus: It is reported that acute hydrocephalus can cause high fever, and the body temperature returns to normal after ventriculo-peritoneal shunt. Acute hydrocephalus fever may be released by neuropeptides, central dopamine mediators, or hypothalamic compression.

5. Alcohol withdrawal: There are reports of long-term alcoholics, which produce central fever after withdrawal.

6. Cervical segment or upper thoracic segment lesions: Injury of the medial lateral column, as well as obstructing the body temperature regulation and reflection, can cause fever. However, the transverse injury of the neck segment generally does not cause fever.

7. Wolff et al. reported periodic hyperthermia syndrome with vomiting, hypertension, and weight loss, with increased glucocorticoid secretion. The mechanism of periodic hyperthermia syndrome is unclear, and chlorpromazine is effective in symptomatic treatment.

8. Malignant hyperthermia: Malignant hyperthermia is a rare autosomal hereditary disease that rapidly develops severely uncontrollable hyperthermia, myotonia, and acidosis during anesthesia. Patients may have hyperglycemia, blood calcium, and increased phosphorus, potassium and magnesium plasma, creatine kinase (CK) is significantly increased, severe cases may have myoglobinuria and renal failure. The disease can be associated with muscle diseases such as muscular dystrophy and central axis disease. If the diagnosis and treatment are not rapid after malignant hyperthermia, the mortality rate is very high. If the early treatment with the muscle relaxant, dantrolene, the mortality rate is reduced from 70% to 10%.

9. neuroleptic malignant syndrome (NMS): a rare serious complication of antipsychotics. The exact cause is unclear and may be related to central dopamine dysfunction. About 15% of people taking antipsychotics can have this sign. Any antipsychotic can induce NMS. NMS can occur from a few hours to a few months after treatment, but most often around 2 weeks. Fever and dyskinesia are the most important features. The dyskinesia is more common with Parkinson's, such as myotonia and static tremor and slow movement. It can also have dystonia and dance. About 70% to 80% have varying degrees of disturbance of consciousness and autonomic dysfunction, such as tachycardia, sweating, or changes in blood pressure. There may be dysarthria and difficulty swallowing. Consciousness disorders can range from paralysis to coma. The patient progresses rapidly from 1 to 3 days after onset, with an average of 2 weeks. Most patients can recover completely, but the mortality rate is 20%. It can be complicated by serious complications such as acute renal failure, acute myocardial infarction and pulmonary edema. About 10% can leave Parkinson's syndrome, dyskinesia, dementia and ataxia. The CK of the patient's blood can be increased, the white blood cell count can be significantly increased, and there can be abnormal liver function, decreased blood oxygen partial pressure, and acidosis.

an examination

Bilateral hypothalamic anterior lesions, especially lesions in the pre-pregnancy temperature-sensitive neurons, cause body temperature integration dysfunction, causing thermal dysfunction of the body's vasodilatation and sweat gland secretion, resulting in central hyperthermia. Due to the obstacle of heat dissipation, there is no physiological heat-dissipation reaction such as sweating, rapid breathing, rapid pulse increase and skin vasodilation during fever. The central fever has the following characteristics.

1. Suddenly high fever, body temperature can rise straight, reaching 40 ~ 41 ° C, continued high fever for several hours to several days until death; or body temperature suddenly dropped to normal.

2. The temperature of the trunk is high, the temperature of the limb is second, and the temperature on both sides can be asymmetric, with a difference of more than 0.5 °C.

3. Although the fever is high, the symptoms of poisoning are not obvious, and there is no trembling.

4. No facial and body skin flushing and other reactions, on the contrary can be expressed as dry skin, reduced sweating, cold limbs.

5. Generally not accompanied by pulse and respiratory increase with increasing body temperature.

6. There is no evidence of infection, generally not accompanied by increased white blood cells, or the total number is high, the classification has no change.

7. Due to the integration of dysfunction of body temperature, body temperature fluctuates with changes in external temperature.

8. Antibiotics and antipyretics (such as acetylsalicylic acid) are generally ineffective during high fever. This is because the body temperature regulation center is damaged, and the antipyretic drugs are difficult to affect them, so the clinical effect of cooling is not produced. However, it can be effective with chlorpromazine and cold compress.

Differential diagnosis

Infectious fever: various infectious diseases such as bacteria, viruses, fungi, spirochetes, malaria parasites, etc. act on the body temperature regulation center, body temperature central dysfunction or excessive heat production caused by various causes, heat dissipation is reduced, resulting in an increase in body temperature beyond normal The scope of the situation.

Unexplained fever: The concept of generalized unexplained fever refers to all fevers of unknown origin. However, in the clinic, the narrow concept of fever is also adopted, that is, fever of unknown cause. The fever lasted for more than 3 weeks, the body temperature was above 38.5 °C, and the diagnosis was not confirmed by detailed medical history, physical examination and routine laboratory tests.

Persistent fever: When the mouth temperature is higher than 37.3 ° C or the anus temperature is higher than 37.6 ° C, the change in one day exceeds 1.2 ° C, which is called fever. According to the level of fever, it can be divided into the following clinical classifications: low heat 37.4 ° C ~ 38 ° C moderate heat 38.1 ° C ~ 39 ° C high heat 39.1 ° C ~ 41 ° C ultra high heat 41 ° C or more, lasting more than 4 weeks, for continuous fever .

Relaxation heat: The body temperature continues to be above 39 degrees, and the fluctuation range is large. The body temperature fluctuation range exceeds 2 degrees within 24 hours, but both are above the normal level.

Excessive heat: The body temperature is constantly maintained at a high level above 39-40 ° C for several days or weeks. The temperature fluctuation range does not exceed 1 °C within 24 hours. Common in pneumococcal pneumonia, typhus and typhoid fever.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.