Polio - Symptoms

The inapparent form of poliomyelitis, which develops in almost 90% of cases, is a healthy virus carrier, with no symptoms of poliomyelitis, and the virus does not go beyond the lymphopharyngeal ring and intestines. The infection is judged by the results of virological and serological studies.

The following clinical forms of poliomyelitis are distinguished: abortive (without damage to the central nervous system), meningeal and paralytic (the most typical). Depending on the localization of the process, the following are distinguished: spinal, bulbar, contact, encephalitic and mixed (combined) variants of the paralytic form.

The incubation period for poliomyelitis lasts from 3 to 35 days, most often 7-12 days.

The abortive (catarrhal) form of poliomyelitis (the so-called "minor disease") is characterized by an acute onset and symptoms of poliomyelitis: a short-term increase in body temperature, moderate intoxication, headache, mild catarrhal inflammation of the upper respiratory tract, abdominal pain, sometimes accompanied by vomiting and loose stools without pathological impurities. It proceeds benignly and ends in recovery in 3-7 days. The diagnosis is based on epidemiological and laboratory data.

In the meningeal form, the disease begins acutely with a rise in body temperature to 39-40 °C, severe headache, vomiting, pain in the back, neck, and limbs. Meningeal symptoms of poliomyelitis are moderate, but may also be absent, despite changes in the cerebrospinal fluid. Typically, there are symptoms of tension of the nerve trunks (Neri, Lasegue, Wasserman) and pain during palpation along the nerve trunks. Horizontal nystagmus is often detected. A two-wave course of the disease is possible. The first wave occurs as an abortive form of the disease, and then after remission lasting from one to five days, a picture of serous meningitis develops. During a lumbar puncture, transparent cerebrospinal fluid flows out under increased pressure. Pleocytosis ranges from several dozen cells to 300 in 1 μl. Neutrophils may predominate in the first 2-3 days, followed by lymphocytes. Protein concentration and glucose levels are within normal limits or slightly elevated. Sometimes inflammatory changes in the cerebrospinal fluid may appear 2-3 days after the onset of meningeal syndrome. The course of the disease is benign: by the beginning of the 2nd week of the disease, the temperature normalizes, the meningeal syndrome regresses, and by the 3rd week, the composition of the cerebrospinal fluid normalizes.

Spinal (paralytic) poliomyelitis occurs in less than one in 1000 infected people. The development of paralytic forms of poliomyelitis can be provoked by immunodeficiencies, malnutrition, pregnancy, tonsillectomy, subcutaneous and intravenous injections, high physical activity in the early stages of the disease. The clinical picture is divided into four periods: preparalytic, paralytic, recovery, residual (period of residual effects).

The pre-paralytic period lasts 3-6 days. Poliomyelitis begins acutely, with general intoxication, fever (sometimes two-wave). In the first days of the disease, catarrhal symptoms of poliomyelitis are noted: rhinitis, tracheitis, tonsillitis, bronchitis. Dyspepsia is possible, more often found in young children. On the 2nd-3rd day, symptoms of CNS damage join. With a two-wave temperature curve, neurological symptoms appear on the second wave after a 1-2-day period of apyrexia. Headache, pain in the limbs and back along the nerve trunks, "cerebral" vomiting, hyperesthesia, meningeal symptoms, as well as symptoms of tension of the nerve trunks and roots of the spinal nerves occur. Patients are lethargic, drowsy, capricious. Changes in the autonomic nervous system are manifested by severe sweating. Muscle fibrillation and urinary retention are possible. By the end of the first period, the general condition improves, intoxication decreases, the temperature drops, but the pain syndrome intensifies and the disease passes into the paralytic period. Paralysis occurs on the 2nd-6th day of the disease, less often (in the absence of a preparalytic period) - on the first day ("morning paralysis"). Typically, rapid development of flaccid asymmetric paresis and paralysis of the muscles of the trunk and limbs, dysfunction of the pelvic organs for a short time - from several hours to 1-3 days. Muscle hypotonia, hypo- or areflexia, proximal localization of lesions and their mosaicism (due to the death of some nerve cells of the anterior horns of the spinal cord while others are intact) are characteristic. Symptoms of poliomyelitis depend on the localization of the nervous system lesion. Most often, the lumbar spinal cord is affected with the development of paresis and paralysis of the muscles of the pelvic girdle and lower limbs. With thoracic localization of the paralysis process, spreading to the intercostal muscles and diaphragm, cause respiratory disorders. Damage to the cervical and thoracic spinal cord manifests itself in paralysis and paresis of the muscles of the neck and arms (spinal paralytic poliomyelitis). Depending on the number of affected segments of the spinal cord, the spinal form can be limited (monoparesis) or widespread. Isolated damage to individual muscles while maintaining the functions of others leads to disruption of the interaction between them, the development of contractures, and the occurrence of joint deformations. The paralytic period lasts from several days to 2 weeks, after which the recovery period begins. The most noticeable restoration of impaired functions, the return of muscle strength occurs in the first 3-6 months. Subsequently, the pace slows down, but recovery continues for up to a year, sometimes up to two years. First of all, movements in the least affected muscles are restored, mainly due to the preserved neurons, further recovery occurs as a result of compensatory hypertrophy of muscle fibers that have retained innervation. If there is no positive dynamics within six months, the remaining paralysis and paresis are considered residual.The residual period is characterized by muscle atrophy, development of joint contractures, osteoporosis, bone deformation, in children - growth retardation of the affected limbs, with damage to the long muscles of the back - curvature of the spine, with damage to the abdominal muscles - abdominal deformation. More often, residual effects are observed in the lower limbs.

The bulbar form of poliomyelitis is characterized by high fever, severe intoxication, vomiting, and a serious condition of patients. The preparalytic period is short or absent. This form of the disease is accompanied by damage to the nuclei of the motor cranial nerves with the involvement of vital centers that control breathing, blood circulation, and thermoregulation. Damage to the nuclei of the IX and X pairs of cranial nerves leads to hypersecretion of mucus, swallowing disorders, phonation, and, as a consequence, to obstruction of the respiratory tract, impaired ventilation of the lungs, hypoxia, and the development of aspiration pneumonia. When the respiratory and vasomotor centers are damaged, the normal rhythm of breathing is disrupted (pauses and pathological rhythms), increasing cyanosis, abnormal heart rhythm (tachy- or bradyarrhythmia), and an increase and subsequent drop in blood pressure are noted. The following symptoms of poliomyelitis are observed: psychomotor agitation, confusion, and then stupor and coma. In stem forms with damage to the nuclei of the III, VI and VII pairs of cranial nerves, oculomotor disorders and facial asymmetry are revealed due to paresis of the facial muscles. The bulbar form often ends in death. If death does not occur, then in the next 2-3 days the process stabilizes, and from the 2nd-3rd week of the disease the condition of patients improves and complete restoration of lost functions occurs.

In case of isolated damage to the nucleus of the facial nerve, located in the area of the pons of the brain, a less severe pontine form develops. The pre-paralytic period, fever, general intoxication, meningeal symptoms may often be absent. When examining the patient, paresis or paralysis of the facial muscles of half the face, failure to close the eye slit (lagophthalmos), and drooping of the corner of the mouth are revealed. The course is benign, but persistent preservation of facial nerve paresis is possible.

A number of authors describe an encephalitic form of poliomyelitis, in which general cerebral symptoms of poliomyelitis predominate and scattered symptoms of loss are present. When various parts of the brain are affected, mixed (combined) forms of the disease are also distinguished - bulbospinal and pontospinal.

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Complications of Polio

In severe cases of the disease with damage to the diaphragm, accessory respiratory muscles, respiratory center, IX, X, XII pairs of cranial nerves, pneumonia, atelectasis and destructive lung lesions are observed, often leading to death.

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