Polio: Description
In the past, polio (poliomyelitis, infantile paralysis) was a dreaded childhood disease because it can cause paralysis, even respiratory paralysis. In 1988, the World Health Organization (WHO) therefore launched a worldwide program to eradicate polio. Thanks to this program, no cases of polio occurred in Germany after 1990 (only some imported infections).
In other regions, such as Africa, however, outbreaks occur time and again when polio vaccinations are suspended for political and religious reasons, for example. Unvaccinated travelers can become infected there and bring the disease to Europe.
Polio: symptoms
The course of polio disease can vary: Four to eight percent of those affected develop polio disease without central nervous system (CNS) involvement, known as abortive polio. In rare cases, the infection subsequently spreads to the CNS: Two to four percent of those affected develop non-paralytic poliomyelitis. Very rarely, this develops further into paralytic poliomyelitis (0.1 to 1 percent of cases).
About six to nine days after infection with the polio virus, patients briefly develop nonspecific symptoms such as nausea, diarrhea, fever, stomach pain, sore throat, headache, and muscle aches.
Nonparalytic poliomyelitis (aseptic meningitis).
Some patients with abortive polio experience fever, muscle cramps, back pain, and a stiff neck about three to seven days afterward – signs that the disease has spread to the central nervous system.
In some patients with non-paralytic polio, symptoms initially improve. But after two to three days, fever reappears (biphasic = two-phase fever curve). In addition, flaccid paralyses develop rapidly or gradually. The paralyses are usually asymmetric and involve leg, arm, abdominal, thoracic, or eye muscles. Usually, the paralyses partially, but not completely, regress.
Rarely, speech, chewing or swallowing disorders with damage to the cranial nerve cells and central respiratory paralysis also occur (imminent danger to life!). Sometimes, inflammation of the heart muscle (myocarditis) develops, resulting in heart failure (cardiac insufficiency).
Polio: Causes and risk factors
In the early phase of infection, the polio pathogens can be transmitted via saliva (for example, when coughing or sneezing). However, transmission is primarily fecal-oral: patients excrete the pathogen in large quantities in their stool. Other people then usually become infected by consuming food and beverages that have been in contact with the infectious stool. Poor hygienic conditions favor this route of spread of the polioviruses.
A patient is infectious as long as he or she excretes the virus. The virus is detectable in saliva no earlier than 36 hours after infection. It can remain there for about a week.
Excretion of the virus in the stool begins two to three days after infection and usually lasts up to six weeks. People with weakened immune systems can even excrete the virus for months and years.
Polio: Examinations and diagnosis
In case of any suspicion of polio, a patient must be immediately taken to the hospital and kept isolated from other patients.
To diagnose poliomyelitis, the doctor will ask exactly about the course of the disease and about the previous medical history (anamnesis) – the patient himself or (in the case of sick children) the parents. Possible questions are:
- When did the first symptoms appear?
- Have you or has your child been abroad recently?
In pronounced cases, the physician may diagnose polio on the basis of symptoms alone. A characteristic feature of paralytic poliomyelitis is the biphasic course of the fever curve.
Polio: Laboratory tests
To confirm the diagnosis of polio, the physician also performs laboratory tests:
The polio pathogen can also be detected indirectly if specific antibodies against the virus are found in a patient’s blood.
Polio: Differential Diagnosis
Sudden flaccid paralysis can also be caused by Guillain-Barré syndrome. However, it is then usually symmetrical and may resolve within ten days. Also, accompanying symptoms such as fever, headache, nausea, and vomiting are often absent in Guillain-Barré syndrome.
If the disease progresses without paralysis, meningitis or encephalitis should always be ruled out as the cause.
Polio: Treatment
If polio is suspected, the attending physician must report this immediately to the responsible health authority and admit the patient to a hospital. There, the patient is isolated in a single room with its own toilet and is cared for under strict hygiene measures. The isolation remains in place until laboratory tests at the National Reference Center for Poliomyelitis and Enteroviruses (NRZ PE) have been able to rule out polio infection.
Polio: Hygiene measures
Consistent hygiene helps to prevent the spread of polio. This includes, above all, avoiding fecal-oral smear infection by regular hand washing and disinfection. Regardless of vaccination status, contacts should be vaccinated against polio as early as possible.
Polio vaccination
Only a complete vaccination can protect against polio. Learn more about polio vaccination.
Polio: Disease progression and prognosis
Paralysis can regress spontaneously up to two years after infection if the patient receives intensive physiotherapy. Mild damage remains in about a quarter of all patients with paralytic poliomyelitis, and severe damage in another quarter. Joint deformities, leg and arm length discrepancies, spinal column displacements and osteoporosis (bone atrophy) can also be late consequences of poliomyelitis.
Polio with CNS involvement: Post-polio syndrome
Years or decades after paralytic polio, post-polio syndrome (PPS) may occur: Existing paralysis worsens, and chronic muscle wasting occurs. Accompanying symptoms include pain and fatigue. Post-polio syndrome can manifest not only in those muscles that were originally affected by the infection, but also in new muscle groups.
