What Are Positive Symptoms?

Hypothermia refers to the state where the deep temperature of the human body (rectum, esophagus, and tympanum) is lower than 35 ° C. Hypothermia can directly or indirectly cause death. If the body temperature drops below 32 ° C, human organs will not be able to metabolize and work normally.

Basic Information

English name

hypothermia

Visiting department

Emergency Department

Common causes

Exposure to cold environment, drowning in cold water, disease, medicine

Common symptoms

Appearance, central nervous system, respiratory system, cardiovascular system, urinary system, digestive system, blood system, secretory system

Causes of hypothermia

External factor

The causes of hypothermia are divided into external and internal causes, the most important being external factors, that is, exposure to cold environments or drowning in cold water. In addition, inadequate heat supply, as well as wind and humid climate, can also increase body heat loss through convection and evaporation, respectively.

Internal factors

Internal causes are extremely important for patients with hypothermia, which can be divided into physiological and pathological causes, that is, the physiological dysfunction of body temperature regulation and the accompanying basic diseases and drugs that reduce heat energy are important causes of hypothermia in the elderly.

(1) Physiological reasons The temperature of the human body can be kept constant, and the production and dissipation of heat in the body is kept in balance through physiological adjustment. When the human body is in a cold environment, on the one hand, the body excites the sympathetic nerves through the hypothalamic body temperature regulation center, accelerates the heart rate, and constricts the skin blood vessels to preserve body heat; on the other hand, it promotes muscle chills (ie, reactions) and promotes the secretion of the thyroid and adrenals Function (late response) to increase heat production.

(2) Pathological causes More common are pathological causes, namely secondary hypothermia, and many important underlying diseases can be secondary hypothermia.

Clinical manifestations of hypothermia

Whether it is primary or secondary hypothermia, all systems and organs of the body can suffer varying degrees of damage, but clinical manifestations are often non-specific.

Appearance

Due to the mixed appearance of pale and cyanosis on the face, the patient's complexion was pale, sometimes with a specific pink color, which was suspected of carbon monoxide poisoning. Cold skin. Facial swelling, sluggish speech, and hoarseness can be misdiagnosed as myxedema. These symptoms disappeared when the patient's temperature returned to normal.

2. Central nervous system

Chills occur during mild hypothermia, the central nervous system presents ataxia, dementia, dysphonia or slowness, hallucinations, etc., and is often mistaken for "aging". When the body temperature is less than 32 , the chills disappear, the dullness is replaced by muscle tension, and delirium and lethargy appear. When the body temperature is <25 ° C, the patient is in a coma, the reflection disappears, the pupil sizes on both sides are different, and the response to light is weak.

3. Respiratory system

As body temperature decreases, breathing becomes slower and shallower, and ventilation becomes insufficient. The rales appearing at the base of the lungs are not entirely due to infection, but may be pulmonary edema. As a result of insanity, weakened cough reflexes, and cold irritation of the bronchial lungs, increased secretion and difficulty in sputum removal can lead to aspiration pneumonia, pulmonary edema, secondary infections, and atelectasis. During hypothermia, the hemoglobin oxygen departure curve shifts to the left, reducing the release of oxygen at the tissue level, increasing anaerobic metabolism and reducing respiratory ventilation, resulting in severe respiratory acidosis and eventually respiratory failure.

4. Cardiovascular system

Reduced cardiac output, hypotension, bradycardia, and atrial fibrillation are common. If tachycardia is present, hypoglycemia should be considered. Electrocardiograms often show varying degrees of conduction block, and can exhibit indoor conduction delays, as well as various forms of arrhythmia, including atrial fibrillation, atrial flutter, ventricular premature contractions, and ventricular autonomic rhythms. A more common ECG change is a small regular baseline swing that results from an increase in muscle tone that does not detect tremors. When the body temperature is less than 32 ° C, one-third of the patients may have a characteristic tortuous- "J" wave at the junction of the QRS wave terminal and the ST segment, which is particularly obvious on the left ventricular anterior lead, showing a positive wave. The right side is negative. Although it has no prognostic significance, it only appears in hypothermia. Ventricular fibrillation may occur at a body temperature of <28 ° C, which may eventually lead to cardiac arrest.

5. Urinary system

Patients with hypothermia may suffer from oliguria and acute tubular necrosis due to ischemia coupled with direct damage to the kidneys by cold. In the early stage, due to the decrease of renal tubular activity, "cold polyuria" may also occur, leading to hypovolemia and prerenal azotemia.

6. Digestive system

Acute pancreatitis and mumps often occur, the former often lacks signs, and only the serum amylase is elevated. If the upper abdomen is pressed hard, patients with atrophy should be suspected of the disease. Gastrointestinal dysfunction often occurs, peristalsis weakens, paralytic intestinal obstruction and gastrointestinal bleeding occur, and abdominal distension and bowel sounds weaken. When the liver function is impaired, the blood pH value decreases, and the liver's ability to detoxify is low.

7. Blood system

Blood is concentrated, blood viscosity is increased, platelets are reduced, and DIC can occur.

8. Endocrine system

Hyperglycemia can occur as a result of reduced insulin release and reduced effects resulting in reduced glucose utilization. Both thyroid and pituitary function are impaired to varying degrees.

Hypothermia test

Laboratory inspection

Most laboratory data of hypothermia are non-specific tests, including white blood cells, platelet counts, prothrombin time, fibrinogen, blood glucose, serum amylase, blood urea nitrogen, serum aspartate aminotransferase, aJ hydroxyl acid dehydrogenase (HBD ) And creatine phosphokinase (CPK), renal function, and arterial blood gas analysis. If you find thrombocytopenia, elevated levels of blood urea nitrogen, serum amylase, and other enzymes mentioned above, you should think of this disease. In addition, serum triiodothyronine (T ₃ ), thyroxine (T ₄ ), and thyroid stimulating hormone (TSH) levels can be diagnosed as hypothermia caused by primary myxedema by radioimmunoassay. The serum T ₃ and T ₄ levels of the disease decrease and TSH increases. The hypothermia caused by nonmyxedema cannot reach this level.

2. Other auxiliary inspections

Electrocardiograms often show varying degrees of conduction block, and can have indoor conduction delays.

3. Related inspections

T ₃ and T _{4 analysis of} thyroid stimulating hormone, urea, amylase, fibrinogen, creatine kinase, platelets, and blood gas.

Hypothermia diagnosis

A high degree of vigilance is required to make a timely diagnosis of hypothermia, because hypothermia is often misdiagnosed. Medical staff are alert to find and rule out fever, and negligently look for and rule out hypothermia. The diagnosis of hypothermia includes medical history, clinical symptoms, physical examination, and laboratory tests.

Treatment of hypothermia

1. Add warm clothing

In the winter season, even at home, you may feel cold, especially late at night, so it is important to add clothing at any time.

2. Reduce heat loss

Wearing wet clothes or immersing in water for a long time will cause the body's thermal energy to quickly lose, so even after exercise, the body will generate a lot of heat energy, but if you wear clothes soaked with sweat, it may cause loss Temperature phenomenon. In addition, you must do warm-up exercises before swimming, and immediately dry your body after swimming, and change to dry and warm clothes to prevent the body's thermal energy from being quickly consumed.

3. Improve the function of making energy in the body

In addition to maintaining warmth by external forces, raising the body temperature is the most active method. For example, maintaining exercise habits can enhance blood circulation and metabolic functions; maintaining nutritional balance, the body has enough energy to provide the required heat , Especially foods rich in vitamins E and C, such as blue-backed fish, yellow-green vegetables, beans, citrus, broccoli, green peppers, potatoes, etc. should be ingested; high-calorie foods can also help the body quickly temperature.