Polio

Poliomyelitis [from the Greek. polio (gray), myelos (brain)] is an acute infection caused by poliovirus. Symptoms of poliomyelitis are nonspecific, occasionally aseptic meningitis without paralysis (non-paralytic poliomyelitis), and less often paralysis of various muscle groups (paralytic poliomyelitis). The diagnosis is clinical, although laboratory diagnosis of poliomyelitis is possible. Treatment of poliomyelitis is symptomatic.

Synonyms. Epidemic infantile paralysis, Heine-Medina disease.

ICD-10 codes

• A80. Acute poliomyelitis.
  • A80.0. Acute paralytic poliomyelitis associated with the vaccine.
  • A80.1. Acute paralytic poliomyelitis caused by a wild imported virus.
  • A80.2. Acute paralytic poliomyelitis caused by wild natural virus.
  • A80.3. Acute paralytic poliomyelitis is different and unspecified.
  • A80.4. Acute non-paralytic poliomyelitis.
  • A80.9. Acute poliomyelitis, unspecified.

What causes poliomyelitis?

Poliomyelitis is caused by a poliovirus that has 3 types. Type 1 most often leads to paralysis, but is less often epidemic. Only man is the source of infection. Dispatched with direct contact. Asymptomatic, or small, infection refers to the paralytic form as 60: 1 and serves as the main source of spread. Active vaccination in developed countries will eliminate polio, however, cases of the disease occur in regions where vaccination is not fully completed, for example in sub-Saharan Africa and South Asia.

The poliomyelitis virus enters the mouth in a fecal-oral way, affects the lymphoid tissue as a result of primary viremia, and a few days later develops secondary viremia, culminating in the appearance of antibodies and clinical symptoms. The virus reaches the central nervous system with secondary viremia or perineural spaces. The virus is found in the nasopharynx and in feces in the incubation period and when there are symptoms of poliomyelitis, persists 1-2 weeks in the throat and more than 3-6 weeks in the feces.

The most severe lesions take place in the spinal cord and brain. Components of inflammation are produced with a primary viral infection. Factors predisposing to severe neurological damage include age, recent tonsillectomy or intramuscular injections, pregnancy, impaired B lymphocyte function, overwork.

What are the symptoms of poliomyelitis?

Symptoms of polio may be large (paralytic and non-paralytic) or small. Most cases, especially in young children, are small, when within 1-3 days subfebrile fever, malaise, headache, tickling in the throat, nausea are observed. These symptoms of poliomyelitis appear 3-5 days after contact. Neurological symptoms do not happen. Most often, poliomyelitis develops without previous minor signs, especially in older children and adults. Poliomyelitis has an incubation period that lasts 7-14 days. Symptoms of poliomyelitis include aseptic meningitis, deep muscle pain, hyperesthesia, paresthesia, with active myelitis - urinary retention and muscle spasm. Develops asymmetric flaccid paralysis. The earliest signs of bulbar disorders are dysphagia, nasal regurgitation, and nasal voices. Encephalitis develops rarely, and even less often, respiratory failure.

Some patients develop post-poliomyelitis syndrome.

How is polio diagnosed?

Nonparalytic poliomyelitis is characterized by the fact that in the cerebrospinal fluid the normal level of glucose, slightly increased protein and cytosis is 10-500 cells / μl, predominantly of lymphocytes. Diagnosis of poliomyelitis is based on the isolation of the virus from the oropharynx or feces or the buildup of antibody titers.

Asymmetric progressive limp flaccidity or bulbar palsy without loss of sensory sensitivity in febrile patients or in fever in non-immunized children or young people almost always indicates paralytic poliomyelitis. Rarely, such a picture can be caused by coxakiviruses of groups A and B (especially A7), various ECHO viruses, enterovirus type 71. West Nile fever also causes progressive paralysis, which is clinically indistinguishable from paralytic poliomyelitis caused by polioviruses; Epidemiological criteria and serological tests help in differential diagnosis. Guillain-Barre syndrome causes progressive paralysis, but fever is usually absent, muscle weakness is symmetrical, sensitive disorders occur in 70% of patients, and the protein of cerebrospinal fluid is increased against the background of normal cell contents.

How is polio treated?

Typically, polio treatment is symptomatic, including rest, analgesics, antipyretic drugs if necessary. The possibilities of specific antiviral therapy are being studied.

With active myelitis, one should remember the possibility of developing complications associated with prolonged bed rest (for example, deep vein thrombosis, atelectasis, urinary tract infections), and with prolonged immobilization, contractures. Respiratory failure may require artificial ventilation with a careful toilet of the bronchial tree.

Treatment of postmyelite syndrome is symptomatic.

How to prevent poliomyelitis?

All children at an early age should be vaccinated against poliomyelitis. The American Academy of Pediatricians recommends vaccination at 2, 4, 6-18 months with a booster dose of 4-6 years. Immunity is produced in more than 95%. It is preferable to use the Salk vaccine than the live attenuated oral Sabin vaccine; the latter causes paralytic poliomyelitis with a frequency of 1 case per 2 million 400 thousand doses and is not used in the US. With Salk vaccine, severe reactions are not associated. Adults are not vaccinated. Nonimmunized adults traveling to endemic foci should receive a primary vaccination with Salk vaccine, two doses are given separately at the 4th and 8th week, the 3rd dose at 6 or 12 months. One dose is given immediately before the trip. Those who received vaccination earlier should receive only one dose of the Salk vaccine. Immunosupermeted persons should not be given Sabin's vaccine.

What is the prognosis of poliomyelitis?

With non-paralytic forms of poliomyelitis, complete recovery is observed. In paralytic forms, about 2/3 of patients have residual phenomena, manifested as muscle weakness. Bulbar paralysis is resolved more often than peripheral. The mortality rate is 4-6%, but it rises to 10-20% in adults or in patients with developed bulbar paralysis.

Post-poliomyelitis syndrome is a muscle weakness and a decrease in tone, often associated with weakness, fasciculitis and atrophy, which develop years and decades after paralytic poliomyelitis, especially in elderly patients and in those with severe illness. Damage develops in previously affected muscle groups. The reason may be related to the further death of the cells of the anterior horns of the spinal cord as a result of the aging of the neuronal population affected by the polio virus infection. Poliomyelitis with severe lesions is rare.