I’m so pleased to have Sarah Sundin back. I’ve missed having her here over the last several months as I’m sure you have as well. This week, she’ll be guest blogging about historical polio, the disease, and the polio immunization.
Welcome back, Sarah!
Polio Part 1—The Disease
For months, Helen had lain in the county polio ward. No matter how hard she’d concentrated, her legs wouldn’t do what she asked from them, demanded from them, pleaded from them.
In my novel, Blue Skies Tomorrow, which takes place during World War II, Helen Carlisle deals with many repercussions of a childhood bout with polio. Thanks to vaccination, polio is quickly being forgotten, but it was a dread threat in the first half of the twentieth century. If you write fiction set in this time period, it helps to be familiar with this much-feared disease.
Today I’ll discuss the disease, on August 24th, I’ll discuss treatment, and on August 26th, the vaccines.
Poliomyelitis, also known as infantile paralysis or polio, is caused by an RNA virus and only occurs in humans. It’s transmitted by the fecal-oral or oral-oral route. From the gastrointestinal tract, the virus can travel to the spinal cord, where it leads to inflammation of the gray matter. Spinal or cranial motor neurons die, which causes paralysis of the affected muscles and eventually atrophy of those muscles from lack of use. During recovery, other neurons in the vicinity can sometimes grow extra “buds” to re-inervate those muscles.
Although polio has been known since ancient times, it rarely caused paralysis or death. Due to poor sanitation, most children were infected at a very young age when they were still protected by maternal antibodies, and therefore, had asymptomatic or mild infections. However, as sanitation improved, children didn’t become infected until they were older, and the disease increases in virulence with the age of the patient. The first major epidemic in the United States occurred in Vermont in 1894. Epidemics occurred most years, with severe epidemics in 1916 and 1952. The 1952 epidemic was the worst, with 58,000 cases and 3000 deaths.
Epidemics were most common in July, August, and September. Due to the fecal-oral and oral-oral transmission route, people avoided swimming pools, ponds, drinking fountains, and crowds during the summer. Children who had previous tonsillectomies were at significantly increased risk, not only of contracting polio but of contracting more dangerous forms.
About 95 percent of those infected had no symptoms at all, and another 5 percent had only mild flu-like symptoms—fever, headache, nausea, fatigue, and muscle weakness. Less than 1 percent of those infected developed paralytic polio. Within a week of the development of symptoms, patients experienced neck and back stiffness, asymmetrical muscle weakness and pain, sensitivity to touch, a “pins and needles” sensation, and a sudden onset of paralysis. Paralysis became complete within two to three days of onset.
Spinal polio was the most common form of paralytic polio and occurred when the motor neurons in the spinal cord were afflicted. Patients experienced weak and floppy muscles, then paralysis often accompanied by painful spasms. Because sensory neurons were not affected, patients still felt pain, temperature changes, and itching. This form of polio was rarely fatal. About half of patients recovered fully, one quarter experienced minor long-term disability, and a quarter experienced severe disability.
About 2 percent of cases of paralytic polio affected the cranial nerves, leading to difficulties in swallowing, speaking, and breathing. This was fatal in about half of cases if mechanical ventilation was not available.
The most dangerous form of polio represented about 1 percent of cases. These patients had paralysis of the diaphragm as well as arms or legs. Respiratory involvement led to death in about half the patients if mechanical ventilation was not used.
Patients presenting with high fever, fatigue, and nausea were asked to touch their chins to their chest, since a stiff spine was an early sign. Usually diagnosis was made due to sudden falls and paralysis, and was confirmed with a lumbar puncture (spinal tap).
Recovery and Complications
Muscle strength often began to return within one month of illness, and improvement usually in 6-8 months. Any paralysis remaining after 18 months would rarely resolve.
Complications often resulted from imbalanced muscles. When the muscle on one side of the joint was paralyzed and the other wasn’t, the joint became distorted, leading to syndromes such as “foot drop,” and “back knee.” If a child was paralyzed on one side early in development, often one leg would grow longer than the other, leading to a lurching limp. Due to residual muscle weakness, polio survivors are at greater risk for bone fractures, and at higher risk from complications due to those fractures. Later in life they’re at higher risk of osteoporosis.
In the 1970s a new syndrome began to be recognized in former polio patients. New muscle weakness and fatigue in formerly affected muscles appeared after decades of strength. This Post-Polio Syndrome is now known to affect 25-50 percent of people who had childhood polio. The severity of weakness is directly related to the severity of the original acute illness.
Poliomyelitis was a major cause of death and disability through the 1950s and caused great fear for children and parents. Be very thankful for vaccination.
Sarah Sundin is the author of the Wings of Glory series from Revell: A Distant Melody (March 2010), A Memory Between Us (September 2010), and Blue Skies Tomorrow (August 2011). She has a doctorate in pharmacy from UC San Francisco and works on-call as a hospital pharmacist.