Poliomyelitis is an acute viral infection that occurs with a predominant lesion of the gray matter of the brain, which causes the development of paresis and paralysis. Signs of polio can be detected in children under the age of 7, but the risk of contracting it, under certain circumstances, remains in adults.
A bit of history
Poliomyelitis is characterized by an acute infectious lesion of the spinal cord and brain stem, resulting in the development of paresis and paralysis, bulbar disorders. The disease poliomyelitis, the signs of which were known for a very long time, became widespread in the 19th and early 20th centuries. During this period, mass epidemics of this infection were recorded in the countries of America and Europe. The causative agent of poliomyelitis was discovered in Vienna in 1908 by E. Popper and K. Landstein, and the inactivated vaccines created by A. Sabin and J. Salk made it possible to significantly reduce the number of cases when signs of poliomyelitis were detected in children by the 50s of the last century.
The positive dynamics in the fight against this infection continues thanks to active immunization, frequent signs of polio remain only in some countries - Pakistan, Afghanistan, Nigeria, India, Syria - while in 1988 their number reached 125. The number of cases during this period decreased from 350 thousand cases (of which 17.5 thousand were fatal) to 406 cases identified in 2013. The countries of Western Europe, Russia and North America are now considered free from this disease, and signs of poliomyelitis are detected here only as sporadic cases.
Pathogen
Polio is a viral disease. It is caused by the poliovirus, which belongs to the enteroviruses. Three types of virus are identified (I, II, III). Types I and III are pathogenic for humans and monkeys. II can infect some rodents. The virus contains RNA, its size is 12 microns. Stable in the external environment - in water it can last up to 100 days, in milk - up to 3 months, up to 6 months - in the secretions of the patient. Ordinary des. means are ineffective, but the virus is quickly neutralized by autoclaving, boiling, exposure to ultraviolet light. When heated to 50 °C, the virus dies within 30 minutes. When infected during the incubation period, it can be detected in the blood, the first 10 days of the disease - in swabs from the pharynx, and very rarely - in the cerebrospinal fluid.
Transmission mechanism
The source of infection in polio can be like a patienta person and an asymptomatic virus carrier (in some cases, carriage may persist for three to five months after recovery). The virus is released into the external environment with the patient's feces and nasopharyngeal mucus. The following transmission routes are relevant for polio:
- contact;
- airborne;
- fecal-oral.
The most common route of transmission is fecal-oral - the virus enters the body through contaminated hands, cutlery, food, water. Also dangerous is the mucus secreted by patients from the nasopharynx from the 2nd day of the disease during the first 2 weeks.
The susceptibility of the virus is 0.2-1%, most of the cases are children under 7 years old. The peak incidence occurs in summer and autumn.
Risk factors
Factors contributing to the spread of infection include:
- lack of hygiene skills of the child;
- crowding;
- poor sanitary and hygienic conditions, including violation of the sanitary regime in children's institutions;
- frequent illnesses (more than 4 times a year) in a child;
- immunodeficiency states;
- low level of vaccination of the population.
Classification
Polio is classified according to the nature of the damage to the nervous system:
- non-paralytic forms- occurring without pronounced lesions of the nervous system - meningeal, abortive (visceral), inapparatus (asymptomatic and is a virus carrier that can only be determined by laboratory) forms;
- paralytic form.
In turn, the paralytic form is classified according to the location of the lesion. Highlight:
- spinal form - characterized by flaccid paralysis of the limbs, trunk, diaphragm, neck;
- pontine form - proceeds with complete or partial loss of facial expressions, sagging corner of the mouth on half of the face, lagophthalmos;
- bulbar - characterized by impaired speech, swallowing, respiratory and cardiac disorders;
- encephalitis - focal and cerebral symptoms;
- mixed form - pontospinal, bulbospinal, bulbopontospinal.
The flow distinguishes between mild, moderate, severe and subclinical forms.
Incubation period
The incubation period, when the first signs of poliomyelitis do not yet appear, lasts from 2 to 35 days. Most often, its duration is 10-12 days, depending on the individual characteristics of the child's body. At this time, through the entrance gate (they are the pharynx and digestive tract), the virus enters the lymph nodes of the intestine, where it multiplies. After that, it penetrates into the blood and the stage of viremia begins, during which the infection spreads throughout the body and affects the mostdepartments that are vulnerable to it. In the case of polio, these are the anterior horns of the spinal cord and myocardial cells.
Symptoms of the meningeal form
Meningeal and abortive forms are non-paralytic forms of poliomyelitis. The first signs of poliomyelitis in children with meningeal form always appear acutely. The temperature in a few hours rises to 38–39 °. There are symptoms characteristic of a cold - coughing, serous or mucous discharge from the nose. When examining the throat, hyperemia is noted, there may be plaque on the tonsils and palatine arches. Nausea and vomiting are possible at elevated temperatures. In the future, the temperature decreases and the child's condition stabilizes for two to three days.
Then the temperature rises again, and the signs of polio become more pronounced - drowsiness, lethargy, lethargy, headaches, vomiting appear. Meningeal symptoms appear: a positive symptom of Kerning (the patient lying on his back is bent at the knee and hip joint at an angle of 90 °, after which, due to muscle tension, it becomes impossible to straighten the knee joint), stiff neck muscles (the inability to lie on his back to reach his chest with his chin).
Abortive form
Signs of poliomyelitis in children with abortive form also begin to appear acutely. Against the background of high temperature (37, 5–38 °), malaise, lethargy, mild headaches are noted. There are small catarrhal phenomena - cough, runny nose, redness of the throat, there may be pain in the abdomen, vomiting. In the future, catarrhal tonsillitis, enterocolitis or gastroenteritis may develop. It is the intestinal manifestations that distinguish abortive poliomyelitis. Signs of the disease in children in this case most often consist in pronounced intestinal toxicosis like dysentery or cholera. There are no neurological manifestations in this form of polio.
Paralytic polio
This form of poliomyelitis is much more severe than the forms described above and is much more difficult to treat. The first neurological signs of polio begin to appear 4-10 days after exposure to the virus, in some cases this period can be extended up to 5 weeks.
The following stages are distinguished in the development of the disease.
- Preparalytic. Temperature rise to 38.5-39.5°C, headaches, cough, runny nose, diarrhea, nausea, vomiting are typical. On the 2-3rd day, the condition returns to normal, but then a new rise in temperature begins to 39 - 40 °. Against its background, there are severe headaches and muscle pains, convulsive muscle twitching, which can be seen even visually, impaired consciousness. This period lasts 4-5 days.
- The paralytic stage is characterized by the development of paralysis. They develop suddenly and are expressed in the absence of active movements. Depending on the form, paralysis of the limbs (usually the legs), trunk, and neck develop, but sensitivity, as a rule, is not disturbed. The duration of the paralytic stage varies from 1 to 2 weeks.
- Stagerecovery with successful therapy is characterized by the restoration of the functions of paralyzed muscles. At first, this process is very intensive, but then the pace slows down. This period can last from one to three years.
- At the stage of residual effects, the affected muscles atrophy, contractures form and various deformities of the limbs and trunk develop, which are so widely known as signs of polio in children. The photos presented in our review quite clearly illustrate this stage.
Spinal shape
It is characterized by an acute onset (the temperature rises to 40° and, unlike other forms, is permanent). The child is lethargic, adynamic, drowsy, but hyperexcitability is also possible (as a rule, its symptoms are more pronounced in very young children), convulsive syndrome. There are spontaneous pains in the lower extremities, aggravated by a change in body position, pain in the dorsal and occipital muscles. On examination, symptoms of bronchitis, pharyngitis, rhinitis are revealed. There are cerebral symptoms, hyperesthesia (increased reaction to various pathogens). When you press on the spine or on the projection of the nerve trunks, a sharp pain syndrome occurs.
On 2-4 days from the onset of the disease, paralysis occurs. In poliomyelitis, they have the following features:
- asymmetry - the lesion is of the type left hand - right foot;
- mosaic - not all muscles of the limb are affected;
- decrease or absence of tendon reflexes;
- decrease in muscle tone up to atony, but the sensitivity is not impaired.
Affected limbs are pale, cyanotic, cold to the touch. The pain syndrome leads to the fact that the child takes a forced position, which, in turn, causes early contractures.
Restoration of motor functions begins from the 2nd week of the disease, but this process continues for a long time and unevenly. Pronounced violations of tissue trophism, lag in the growth of limbs, joint deformities, and atrophy of bone tissue develop. The disease lasts 2-3 years.
Bulbar form
The bulbar form is characterized by an extremely acute onset. She has almost no preparalytic stage. Against the background of a sore throat and suddenly rising to high numbers (39-49 °), neurological symptoms occur:
- laryngeal paralysis - impaired swallowing and phonation;
- breathing disorders;
- disturbances in the movements of the eyeballs - nystagmus rotary and horizontal.
The course of the disease can be complicated by pneumonia, atelectasis, myocarditis. It is also possible to develop gastrointestinal bleeding, intestinal obstruction.
Pontine shape
The pontine form occurs as a result of the defeat of the facial, abducens, and sometimes the trigeminal nerves (V, VI, VII, pairs of cranial nerves) by the polio virus. This leads to muscle paralysisresponsible for facial expressions, and in some cases, chewing muscles. Clinically, this is expressed in the asymmetry of the muscles of the face, the smoothness of the nasolabial fold, the absence of horizontal wrinkles on the forehead, ptosis (drooping) of the corner of the mouth or eyelid, and its incomplete closure. Symptoms become more pronounced when you try to smile, close your eyes, or puff out your cheeks.
Treatment
There is no specific treatment for polio. When making a diagnosis, the patient is hospitalized in an infectious diseases hospital, where he is provided with physical and mental rest. In the preparalytic and paralytic periods, painkillers and diuretics are used, according to indications, anti-inflammatory drugs or corticosteroids are given. In case of dysfunction of swallowing - feeding through a tube, in case of respiratory failure - mechanical ventilation. In the recovery period, exercise therapy, massage, physiotherapy, vitamins and nootropics, spa treatment are indicated.
Prevention
Polio is one of those diseases that are easier to avoid than to treat. This can be done through vaccination. In Russia, all newborn children are vaccinated. Vaccination is carried out in several stages - at 3 and 4, 5 months, the baby is vaccinated with an inactivated vaccine. At 6, 18, 20 months, the procedure is repeated using a live vaccine. The last vaccination is carried out at the age of 14. And you should not skip it, because, despite the fact that it is believed that polio is dangerous only for babies, this is not so, and in case of illness, the signs of polio in adults arevery pronounced and dangerous character.
When an illness is detected, an important element of prevention will be the timely isolation of the patient, quarantine and observation of the contact group for 3 weeks, and personal hygiene.
Thus, we have considered in sufficient detail what signs of polio exist, and what needs to be done to avoid this serious illness.
