Polio

Introduction to polio Polioyelitis (hereinafter referred to as polio), also known as polio, is an acute infectious disease caused by poliovirus. Clinical manifestations include fever, sore throat and limb pain, and some patients may experience flaccid paralysis. In the epidemic, there are many cases of concealed infection and innocent sputum. The incidence of children is higher than that of adults. Before the vaccination, especially in infants and young children, it is also called polio. The main disease is in the gray matter of the spinal cord. There are sequelae. basic knowledge The proportion of illness: 0.002% Susceptible people: more infants and young children Mode of transmission: spread through feces Complications: electrolyte disorder hyponatremia myocarditis hypertension pulmonary edema shock atelectasis pneumonia rheumatoid arthritis kidney stones

Causes of polio

(1) Causes of the disease

The poliomyelitis virus is a genus of enteroviruses of the picornavirus family. Under the electron microscope, the virus has a small spherical shape with a diameter of 24 to 30 nm, which is round granular and contains a single ribonucleic acid. The nucleic acid content is 20% to 30%, and the viral nucleocapsid is composed of 32 shell particles. Each microparticle contains four structural proteins, namely VP1 to VP4. VP1 has a special affinity with human cell membrane receptors, and is pathogenic to the virus. Related to toxicity.

resistance:

Poliovirus is insensitive to all known antibiotics and chemotherapeutic drugs and can tolerate general concentrations of chemical disinfectants such as 70% ethanol and 5% phenol bath soap, 0.3% formaldehyde, 0.1 mmol/L hydrochloric acid and (0.3 ~0.5)×10-6 residual chlorine can be quickly inactivated, but it can be protected in the presence of organic matter. It can be completely inactivated by heating to 56 °C for 30 minutes, but it can be stored for several years in the frozen environment at 4 °C. It can be stored in the refrigerator for several weeks. It can survive for several days at room temperature. It is sensitive to ultraviolet light, dryness and heat. It can survive for several months in water, feces and milk. Magnesium chloride can enhance the resistance of the virus to temperature, so it is widely used. For the preservation of live attenuated vaccines.

Antigenic properties:

Using serum neutralization test, it can be divided into three serotypes, I, II and III. Each serotype virus has two type-specific antigens, one is D (dense) antigen, which is present in mature virion and contains D. The virus of the antigen is sufficiently infectious and antigenic; the other is C (coreless) antigen, which is present in the front shell of the virus. The virus containing the C antigen is an empty shell particle lacking RNA, non-infectious, and the virus is neutralized. Under the action of the antibody, D antigenicity can be converted into C antigenicity, and the ability to reinfect the cells is lost. The heat-inactivated virus loses VP4 and ribonucleic acid, and becomes a virus particle containing C antigen. The precipitation reaction and complement binding test are applied. The natural D antigen and the heated C antigen can be detected.

Body factors:

Humans are the natural host and storage host of poliovirus. Both monkeys and orangutans are susceptible animals. The virus binds to cell surface specific receptors and is taken into cells, replicating in the cytoplasm, and releasing inhibitors. Host cell RNA and protein synthesis.

The natural poliovirus is called the wild strain. The virus strain that has been attenuated in the laboratory is called the vaccine strain. The vaccine strain can only cause sputum when directly injected into the monkey central nervous system, but not for human nerve cells. Toxicity, vaccine strain viruses, especially type III viruses, can be mutated to a virulent intermediate strain when transmitted in a population. The most reliable method for identifying wild strains and vaccine strains is nucleic acid sequence analysis.

Other enteroviruses (Coxsackie and Echoviruses) originally present in the intestine can interfere with the oral vaccine strain virus, making it unable to settle on the intestinal mucosa and enter the blood circulation, thereby reducing its immune system. The ability to produce antibodies.

(two) pathogenesis

The pathogenesis of polio can be divided into two phases. The first phase is similar to the pathogenesis of other enteroviruses. The virus first in the lymphoid tissues of the pharynx and intestines, including the tonsils, the ileum, the deep lymph nodes, and the deep lymph nodes of the pharynx. The mesenteric lymph nodes multiply to a certain extent, and then enter the blood circulation to cause the first viremia. The virus re-grows through the bloodstream to the systemic mononuclear macrophage system, and then causes the second viremia, in the light or frustrated type. In this case, the infection ends here, and in the case of viremia, the virus can reach the meninges and cause aseptic meningitis.

In animal experimental infections, the virus can be detected in the blood on the second day and continue until the symptoms appear and the neutralizing antibodies are detected in the blood. After oral administration of OPV, the free virus is present in the blood on the 2nd to 5th day. Virus immune complexes can be detected in the blood for several days.

In a typical case, entering the second phase of the pathogenesis, the virus can reach the central nervous system with blood flow, causing extensive necrosis of the brain and spinal cord gray matter. In the experimental infection of the monkey, the poliovirus can reach the central axis along the axons of the peripheral nerve. The nervous system, but in the experimental infection of patients and orangutans, viremia occurs before sputum, and the virulence of the virus strain is also an important factor in the occurrence of convulsions.

In children who have undergone tonsectomy, poliovirus can spread to the brain along nerve fibers exposed by surgery, causing bulbar paralysis.

During the epidemic, the factors that cause the body's resistance to decline, such as cold, fatigue, local injury, surgery, various vaccinations and pregnancy, can promote the occurrence of sputum, and the injection of irritating substances during vaccination can promote the spread of the virus along the nerve.

Poliovirus selectively invades certain nerve cells, and the anterior horn cells of the spinal cord are the most prominent. The process of intracellular replication of the virus directly leads to damage or complete destruction of the cells, which causes the lower motor neuron sputum, and the virus does not directly invade. Muscle, peripheral nerves and muscle changes are secondary to the destruction of nerve cells.

Pathological changes include both neuronal damage and inflammatory response. Neuronal damage manifests as cytoplasmic Nissl bodies and chromatin dissolution until complete necrosis of cells disappears. Inflammation is secondary to destruction of nerve cells, including focal Infiltration of inflammatory cells around the blood vessels, inflammatory cells are mainly lymphocytes, accompanied by lobular granulocytes, plasma cells and microglia, inflammation and edema can oppress adjacent nerve cells, resulting in temporary loss of function, in recovery During the period, the inflammation subsided, and a large number of necrotic areas of nerve cells formed cavities and glial fibrosis. The muscle fibers innervated by the damaged nerves atrophied and distributed in the shape of islands in normal muscle fibers.

In addition to the most prominent anterior horn of the spinal cord, the central nervous system lesions can affect the entire gray matter, posterior horn and dorsal root ganglia of the spinal cord. The lesions are multifocal and scattered. The cervical lesions and the lumbar segments are more severely damaged. It is the damage of the lumbar region that causes paralysis of the lower extremities, and scattered inflammatory lesions on the pia mater.

Brain lesions can affect the brain, midbrain, medulla, cerebellum and brainstem. Among them, the reticular formation, vestibular nucleus, cerebellar condyle and cerebellar nucleus are most often involved. Except for the anterior central motion zone, the cerebral cortex is generally not affected. influences.

In addition to the nervous system, there are lymph nodes and intestinal lymphoid hyperplasia and inflammatory lesions, myocardial interstitial may have leukocyte infiltration, but myocardial necrosis is rare.

Polio prevention

The polio vaccine has a good immune response.

(1) Autoimmune

The earliest use of inactivated polio vaccine (Salk vaccine), the effect of protecting susceptible people after intramuscular injection is positive, and because it does not contain live vaccine, it is also very safe for immunodeficiency. In some countries, inactivated vaccine alone. It also achieves the remarkable effect of controlling and almost eliminating polio, but the immunity caused by inactivated vaccine is short-lived, requires repeated injections, does not cause local immunity, and the preparation price is expensive. However, in recent years, the preparation has been improved. In the second month, the fourth month, inoculation three times in the 12th to 18th months, 99% of the vaccinates can produce three types of antibodies for at least 5 years.

(two) passive immunization

If the child has not been vaccinated, pregnant women, medical staff, immunocompromised, tonsillectomy and other local operations, if close contact with the patient, early injection of gamma globulin, pediatric dose of 0.2 ~ 0.5ml / kg, or placenta Globulin 6 ~ 9ml, once a day for 2 consecutive days, immunity can be maintained for 3 to 6 weeks.

(3) Isolating patients

At least 40 days from the onset of the disease, the first week should emphasize the isolation of the respiratory tract and the intestine. The excretion is blocked and disinfected with 20% bleaching powder. The utensils are soaked in 0.1% bleaching solution or boiled, or exposed to sunlight. For two days, the ground is disinfected with lime water. The contact person is soaked in 0.1% bleaching powder clear solution with hands or disinfected with 0.1% peracetic acid. The susceptible person who is in close contact should be inspected for 20 days.

(4) Doing daily hygiene

It is very important to do a good job in environmental sanitation, eliminate flies, and cultivate health habits. During the epidemic, children should go to many places in the crowd to avoid excessive fatigue and cold, postpone various preventive injections and urgently needed operations, so as not to cause depression. The type of infection becomes a sputum type.

Polio complications Complications electrolyte disorder hyponatremia myocarditis hypertension pulmonary edema shock lung atelectasis rheumatoid arthritis kidney stones

Common complications

(1) Water, electrolyte disorder: patients with respiratory muscle spas often cause water and electrolyte disturbance when using artificial respirator for a long time. High fever, sweating, vomiting, diarrhea, inability to eat and blood gas changes can cause serious biochemical disorders, excessive fluid replacement. Causes edema and hyponatremia.

(2) Myocarditis: The virus can directly invade the myocardium, causing ECG T wave, ST segment and PR interval changes, seen in 10% to 20% of cases.

(3) Hypertension: can be caused by the following factors: 1 hypoxia; 2 due to the involvement of the inferior colliculus, leading to persistent hypertension, which in turn causes retinopathy, convulsions and changes in consciousness.

(4) pulmonary edema and shock: the pathogenesis is unknown, often at the end of the death case.

(5) Digestive tract perforation and hemorrhage: acute dilatation of the stomach and duodenum, cecal perforation, duodenum, acute ulcer of the stomach and esophagus, multiple erosions of the entire gastrointestinal tract accompanied by major bleeding and intestines Paralysis and so on.

(6) Atelectasis and pneumonia: common in severe bulbar palsy (the IX and X brain nerve involvement) or spinal cord paralysis caused by respiratory muscle spasm or swallowing tendon, can be aggravated by tracheotomy, common pathogens For Staphylococcus aureus or Gram-negative bacteria, it is often resistant to common antibiotics, and chemoprevention is also ineffective.

(7) urinary tract infection: often associated with indwelling catheter, chemotherapy and tidal drainage is usually ineffective, due to long-term bed and calcium mobilization often lead to kidney stones and infection, drink more water, limit calcium-containing food, acidify urine, use water Salicylic acid preparations and early activities can reduce the incidence of stones.

(8) Arthropathy: In the recovery period of sputum cases, a syndrome similar to rheumatoid arthritis can occur, which is characterized by redness, swelling, pain and tenderness of the large joints.

2. Risk factors for the onset and complications

(1) Age, gender and pregnancy: the incidence of this disease is equal for boys and girls, but the incidence of boys is higher than that of girls. The incidence of this disease is higher in women, but the incidence of sputum is equal. The rate is higher and the condition is more serious, which may be related to the suppression of immunity during pregnancy.

(2) Immunization defect status: In the United States, about 14% of cases of polio-type polio occur in those who are vaccinated with OPV and their contacts, most of which are simple B-cell immunodeficiency or severe mixed immunodeficiency syndrome, and more OPV serotypes. For type II, in patients with congenital immunodeficiency, OPV-related sputum cases are 10,000 times higher than normal children. The incubation period of this case is longer (30-120 days after oral administration of OPV), the course of disease is longer, and the sputum period can reach several weeks. There may be chronic meningitis, accompanied by mixed convulsions of the upper and lower motor neurons, basal ganglia lesions, and the virus is excreted from the feces for a long time.

(3) strenuous exercise: in the early stage of sputum, strenuous exercise and fatigue can increase the incidence and severity of sputum.

(4) Injection and trauma: limbs that have been traumatized by injection or fracture, surgery and other causes are prone to paralysis. This correlation has been confirmed by experimental infections in animals. The reason is not related to nerve dissemination, but Reflex expansion of the corresponding part of the spinal cord is associated with hematogenous dissemination.

(5) tonsillectomy: those who have had tonsillectomy in the near or long term, the risk of medullary poliomyelitis is 8 times higher than that of people with tonsils. In recent resection, the virus may be along the IX and X of the lesion. The nerve endings of the brain are spread to the medulla; the long-term resection may be related to the loss of the immune barrier of the tonsils and the rapid spread of the virus.

(6) Genetic factors: sputum poliomyelitis occurs in some families, and its members have successively developed this disease after many years. The reason cannot be explained by intra-family transmission, but suggests that the role of genetic factors is at the cellular level. The susceptibility to poliovirus is governed by the 19th chromosome gene of humans. In addition, there is evidence that the dominant (h leukocyte antigen) HLA antigen affects the occurrence of sputum.

Symptoms of poliomyelitis common symptoms spinal anterior horn lesions abdominal pain sore throat single eyelid tendon meningitis diarrhea muscle contracture quadriplegia reflex

The incubation period is 3 to 35 days, generally 7 to 14 days. It can be divided into four types: asymptomatic, frustrated, innocent and sputum.

1. Asymptomatic (ie, latent infection)

It accounts for 90% to 95% of all infected people. It is asymptomatic after infection, but the virus can be isolated from the pharynx and feces. Four times the specific neutralizing antibody can be detected in duplicate sera separated by 2 to 4 weeks. increase.

2. Setback

About 4% to 8% of all infected people, clinical manifestations of fever, fatigue, headache, lethargy, sore throat, nausea, vomiting, constipation and other symptoms, without central nervous system involvement symptoms, this type of clinical manifestations lack specific Sex, had observed the following three syndromes: 1 upper respiratory tract inflammation, varying degrees of fever, pharyngeal discomfort, cold symptoms, pharyngeal lymphatic congestion, edema; 2 gastrointestinal disorders, nausea, vomiting, diarrhea Or constipation, abdominal discomfort, may have moderate fever; 3 flu-like symptoms, fever and flu-like symptoms, the above symptoms last about 1 to 3 days, that is, recovery, in the early stage can be separated from the pharynx, feces and blood In poliovirus, specific neutralizing antibodies and complement-binding antibodies can be detected from serum during the recovery period.

3. Innocent type

This type is characterized by prodromal symptoms, meningeal irritation and cerebrospinal fluid changes. The prodromal symptoms are similar to the frustration type. Meningeal irritation occurs after a few days. Patients have headache, neck pain, back pain, vomiting, and neck and back rigidity. Kernig (Kernig) and Brunzinski (Brudzinski) sign positive, tripod sign (the patient stretched back to support the body when the patient was sitting up in bed) and Hoyne sign (patient in supine position) When the shoulder is raised, the visible head is tilted back. It can also be positive. The cerebrospinal fluid examination is consistent with the change of aseptic meningitis (the white blood cell count and protein content are slightly elevated, the sugar and chloride are normal, and the culture is sterile) There is no neurological and muscular function changes throughout the course of the disease. This type is clinically indistinguishable from aseptic meningitis caused by other viruses. It needs to be confirmed by virology or serological examination. The patient usually takes 3 to 5 days. Antipyretic, but meningeal irritation can last for 2 weeks.

4. Type

This type only accounts for 1% to 2% of all infected people. It is characterized by the clinical manifestations of innocent type, plus the lesions involving the gray matter of the anterior horn of the spinal cord, brain or cranial nerves, which can be divided into spinal cord according to the lesion. Type, medullary type, brain type, mixed type 4, the most common type of spinal cord, this type is divided into the following five stages (Table 1).

(1) Prodromal period: The symptoms in this period are similar to those in the frustration type. In children, the above respiratory tract inflammation is dominant. In adults, it is systemic muscle, bone pain and skin hypersensitivity. After 1 to 2 days of fever, 4 to 7 days later. The abdomen period, then re-heating, into the pre-temporal period, biphasic fever is mainly seen in 10% to 30% of children, this period is equivalent to the second viremia stage, cerebrospinal fluid is still normal, most Cases, including adult cases, lack a prodromal period and enter the pre-temporal period.

(2) Early stage: The characteristics of this period are fever, headache, vomiting and muscle pain, sputum, fever throughout the whole stage, but the body temperature is not very high, headache spreads to the neck and back, and can radiate to the two thighs, due to muscle Pain caused by limited movement and muscle spasm, often caused by the illusion of sputum, occasional skin dysfunction, allergies or muscle involuntary sputum, in addition to the above-mentioned tripod sign and Hoyne sign, Laségue sign (knee joint straightening The pain caused by flexion of the hip joint is also often positive. About half of the patients have neck stiffness and Kernig sign positive, and cerebrospinal fluid changes, indicating that the virus has entered the central nervous system and caused meningitis. Patients may have a transient loss of consciousness or Drowsiness, abdominal pain, constipation, typhoid and urinary retention, this period usually lasts 3 to 4 days, even as short as 36h or as long as 14 days, rare cases can lack this stage and directly enter the flood season.

(3) sputum period: When fever and myalgia are at the peak, sudden convulsions occur, or gradually increase from convulsions. At the same time, the meningeal irritation sign gradually subsides, and the sacral neuron properties of the genus are manifested as sputum reflexes. Disappeared, decreased muscle tone, vasomotor dysfunction, muscle atrophy, EMG has evidence of spinal anterior horn lesions, sputum usually peaks within 48 hours, lighter no longer develops, severe cases continue to increase within 5 to 10 days The pain is asymmetrical and can affect any group of muscles. It can be expressed as a single sputum, double sputum, paraplegia or quadriplegia. In children, unilateral lower extremity spasm is the most common, followed by bilateral lower extremity spasm, and in adults, limbs. Hemorrhoids, paraplegia, bladder dysfunction and respiratory muscle spasm are more common, and males are more serious than females. This period lasts for 2 to 3 days, usually after the body temperature drops to normal.

1 spinal cord type: when the neck enlargement of the spinal cord is impaired, the neck muscles, shoulder muscles, upper limbs and tendon tendons may appear. When the thoracic segment of the spinal cord is involved, neck muscles, intercostal muscles, upper abdominal muscles and In the case of spinal muscle spasm, dyspnea may occur in both cases. When the lumbar enlargement of the spinal cord is involved, muscle paralysis of the lower limbs, lower abdomen and lower back may occur. In the first 2 weeks after the occurrence of sputum, local pain often occurs and recovery is entered. disappear slowly.

In the early stage of sputum, the abdominal wall and cremaster reflex can disappear for a short time (or throughout the course of the disease), usually without the pathological reflex of the cone system, early skin hypersensitivity, but the feeling does not disappear, the severe disease has autonomy Neurological dysfunction, such as tachycardia, high blood pressure, sweating, and coldness of affected limbs, etc., when the trunk muscles are paralyzed, the head cannot be vertical, can not sit up and turn over, etc., and the diaphragm and intercostal tendon behave as breathing. Difficulties, superficial breathing, cough, weakness, speech interruption, etc. Physical examination can be found that the thoracic expansion is limited (intercostal tendon) and the abdomen is not convex and concave when inhaling, and X-ray can be seen on the diaphragm when inhaling. An abnormal phenomenon of lifting (tendon spasm), urinary retention or urinary incontinence occurs in bladder tendon, intractable constipation can occur when the intestines and abdominal muscles are not automatically discharged, and local abdominal wall and abdominal wall reflex can be seen in abdominal muscle spasm disappear.

On the 5th to 6th day of the sputum, as the body temperature gradually subsided, the sputum stopped developing, but in about 10% of cases, the sputum can continue for up to 1 week after the fever.

2 medullary sputum: medullary sputum accounts for 5% to 35% of sputum type, about 85% of cases have a history of tonsillectomy within 1 month before onset, and the incidence of simple medullary type does not exceed 10% of sputum cases It is more common in children. In adults, the medullary type is often accompanied by spinal cord symptoms. The following symptoms can be caused by different lesions in the brain stem.

Cerebral neural crest: common in the X and VII damage to the cranial nerve, but other cranial nerves such as IX, XI, XII, III, IV, VI pairs can also spread, cranial nerve spasm is mostly unilateral, the first X has a nasal sound when the cranial nerve occurs, the nasal diet is refluxed by the nose, the oropharyngeal secretions and the diet accumulate in the pharynx, the breathing is difficult, the pronunciation is difficult, etc., the VII pairs of cranial nerves appear facial paralysis, the IX pairs of cranial nerve spasm When swallowing is difficult, eating cough, XI is more difficult to swallow when cranial nerves are paralyzed. There are still symptoms such as neck weakness, shoulder drooping, head tilting forward and backward, etc. XII may also cause difficulty in swallowing when the cranial nerve is invaded. There are still tongue extensions to the affected side, as well as chewing, pronunciation and other obstacles. The third and sixth nerves can cause eye muscle spasm, drooping eyelids and so on.

Respiratory central damage: When the reticular tissue on the outside of the ventral surface of the medulla is damaged, respiratory disturbances may occur, such as weak and irregular breathing, double inhalation, intermittent interval of breathing, apnea, etc., and the most significant time of hypoxia (pulse velocity) The pulse rate of children's cases can reach 200 times/min. The heart rate is irregular, and the blood pressure rises and then gradually decreases. The patient is initially restless, and after entering the coma with confusion, even convulsions can occur.

Central damage of vascular motion: Circulatory failure may occur when the reticular tissue inside the medulla is damaged. The patient is flushed at the beginning, tachycardia or tachycardia, followed by blood pressure, weak pulse, arrhythmia, cold extremities, Skin blemishes, etc., heart beats stop before breathing, patients often have irritability, convulsions, coma and other symptoms due to lack of oxygen, and even convulsions.

3 brain type: patients can be expressed as encephalitis alone, or with medullary or spinal cord type, diffuse encephalitis manifested as disturbance of consciousness, high fever, convulsions, tremors, convulsions, coma, tonic spasm, etc., focal Encephalitis manifests as a symptom of brain localization. In the recovery period, there may be reading disorders, clonic or epileptic seizures.

4 mixed sputum: combined with the clinical manifestations of spinal cord hernia and medullary sputum, may have various combinations of limb paralysis, cranial nerve spasm, respiratory center damage, vascular motion center damage.

(4) Recovery period: 1 to 2 weeks after the acute phase, the limbs gradually recover, and the muscle strength is gradually enhanced, generally starting from the distal end of the limb. The following limbs often start from the toes, followed by the ankle and thigh, and the tendon reflex With the recovery of voluntary movement, it gradually became normal, and the diseased limb recovered faster in the first 3 to 6 months. Although there is still progress after that, the speed is slowed down, and the light has recovered very much after 1 to 3 months. Well, severe illness often takes 6 to 18 months or more to recover.

(5) sequelae: Some affected muscle groups are difficult to recover due to nerve damage, resulting in persistent sputum and muscle contracture, and can cause limbs or trunk (due to imbalance of muscle groups) deformities, such as lordosis or undercut , horseshoe foot inversion or eversion, etc., bone development is also hindered, thus seriously affecting the growth and development of children.

Polio examination

Blood routine

The total number of white blood cells and the percentage of neutrophils were mostly normal. The number of white blood cells in a few patients increased slightly, (10-15)×109/L, the percentage of neutrophils also increased slightly, and the erythrocyte sedimentation rate of 1/3 to 1/2 patients. Increase.

2. Cerebrospinal fluid examination

In the prodromal period, the cerebrospinal fluid is generally normal, and the number of cells in the pre-temporal period is often increased, usually between (50-500)×106/L. Even the percentage of neutrophils may increase, but the lymphocytes are mainly in the future, and the protein is Early can be normal, gradually increased, chloride normal, normal or slight increase in sugar, the second week after the emergence of the number of cells, the number of cells decreased rapidly, more than the third week after the recovery has returned to normal; but the protein content often continues to increase, It can reach 1~4 g/L, and it will return to normal after 4-10 weeks. This protein cell separation may help the diagnosis of this disease. The cerebrospinal fluid of a very small number of patients can always be normal.

3. Virus separation

The virus is isolated from the feces, and positive results can still be obtained within a few weeks after the onset of the disease. The specimen can be collected by an anal swab and stored in Hanks liquid containing antibiotics. Multiple tests can increase the positive rate, and can be collected within 1 week of the disease course. Throat swabs are preserved by the same method. Blood samples can be separated by aseptic method or anticoagulated with heparin. The virus can be isolated from the blood 2 to 5 days before the onset of sputum. The isolated virus is usually inoculated into monkey kidney by tissue culture. In the human embryonic kidney or Hela cell line, the cytopathic effect is observed first, and then the specific antiserum is used for the neutralization test. The whole process takes about 2 to 4 days, and the case of meningitis can be isolated from the cerebrospinal fluid. However, the positive rate is low. The virus isolated in China is mostly type I. In some epidemics, type II can also account for a high proportion. In developed countries or areas where the incidence of this disease is very low, attention should be paid to isolate vaccine-associated viruses, but The identification of wild strains and vaccine-associated viruses needs to be done in higher-level laboratories.

4. Immunological examination

Collect as many sera as possible, the first one is collected as soon as possible after onset, and the second dose is 2 to 3 weeks later, cerebrospinal fluid or serum anti-poliovirus IgM antibody positive or IgG antibody titer is 4 times higher, Diagnostic significance, neutralizing antibody is the most diagnostic, and can be classified, it begins to appear at the onset, the disease peaks 2 to 3 weeks, and can be maintained for life, so a single serum IgG antibody positive can not identify the past and the recent Infection, the complement binding test is less specific, but the operation is simpler than the neutralization test. The antibody with negative antibody in the recovery period can rule out the disease. In recent years, viral cDNA is used for nucleic acid hybridization and RT-PCR for detection of viral RNA, all of which have rapid diagnosis. effect. Invading the myocardium, the electrocardiogram showed T wave, ST segment and PR interval abnormalities.

Diagnosis and diagnosis of polio

In the epidemic season, if there is a susceptible person who comes into contact with the patient, sweating, irritability, hyperesthesia, sore throat, neck and back pain, rigidity, and paralysis reflex disappear, and the disease should be suspected. The prodromal period should be differentiated from general upper respiratory infections, influenza, and gastroenteritis. Patients with pre-eclampsia should be differentiated from various viral encephalitis, purulent meningitis, tuberculous meningitis and epidemic encephalitis. The presence of flaccid paralysis contributes to the diagnosis.

diagnosis

1. Epidemiological data

In the summer and autumn, the disease should be especially vigilant. The local epidemic situation and vaccination history have important reference value for the diagnosis of this disease.

2. Clinical manifestations

In children with fever, sweating, irritability, lethargy, severe headache, neck and back pain, hypersensitivity or abnormality, sore throat without obvious inflammation, should seriously consider the diagnosis of polio, if the child has a nape The tonic and gastrocnemius muscles are obviously painful, and the tendon reflexes are converted from normal or phlegm to weakened or disappeared, muscle strength is weakened, and the child can't sit up and turn over. The diagnosis of polio is more suspicious, when irregular distribution of flaccid paralysis or When the bulbar hernia occurs, the clinical diagnosis is basically established.

3. Laboratory inspection data

Positive findings of cerebrospinal fluid, such as lymphocytosis and normal sugar and chloride, cell protein separation, etc., are helpful for diagnosis, but the frustration and innocence can not rely solely on clinical manifestations for diagnosis, and can only rely on laboratory tests. Be diagnosed.

Differential diagnosis

(1) Infectious multiple radiculitis

Or Guillain-Barre's syndrome is more common in older children, with a fever, no fever or low fever, mild inflammation of the upper respiratory tract, gradual flaccid paralysis, ascending, symmetrical, often accompanied Feeling the obstacle. Cerebrospinal fluid has the characteristics of increased protein and few cells. Recovery is faster and more complete, with few sequelae.

(2) Familial periodicity

Less common, no heat, sudden convulsions, symmetry, rapid, and can be spread throughout the body. The blood potassium is low at the time of attack, and it recovers quickly after potassium supplementation, but it can recur. There is often a family history.

() peripheral neuritis

It can be caused by diphtheria neuritis, intramuscular injury, lead poisoning, vitamin B1 deficiency, and herpes zoster infection. The medical history and physical examination can be identified, and there is no change in cerebrospinal fluid.

(4) Other viral infections that cause contempt

Such as Coxsackie, Echo virus infection, etc., clinically difficult to identify, such as chest pain, rash and other typical symptoms, to help identify. Diagnosis depends on virus isolation and serological examination.

(5) Epidemic encephalitis

Should be identified with the brain type of the disease. JE occurs mostly in summer and autumn, and the onset is urgent, often accompanied by mental disorders. Neutrophils are predominant in peripheral blood and cerebrospinal fluid.

(6) False sex

Infants and young children due to injury, fractures, arthritis, vitamin C lack of subperiosteal hematoma, may have limited limb activity, should be carefully examined and identified.

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