What is polio? | Infectious diseases | NCLEX-RN | Khan Academy

What is polio? | Infectious diseases | NCLEX-RN | Khan Academy

– Poliomyelitis, also known as Polio, is caused by the Polio virus. Now the Polio virus causes a
debilitating muscle disorder. And this is caused by damaging neurons that extend from the
central nervous system. Now, the central nervous system is composed of the brain
and the spinal cord. Now these neurons that
extend from the spinal cord innervate, or provide
tone and responsiveness, to the muscles of the body, so the muscles of the arms are innervated, and the muscles of the legs are innervated by motor neurons. Now Polio affects these motor neurons, causing damage to them and disability. And as you can see over here, this man with the cane actually was afflicted by
polio when he was younger, and has faced the consequences
of the motor neuron damage. His muscles in his right
leg have atrophied, or in other words they’ve
lost their muscle tone, and they’ve kind of shriveled up. Because without any input
from the motor neurons, they just shrivel up. Now another way to think of neurons are like electrical wires that provide electricity to your home. If you shut off these electrical wires, obviously your home will no
longer have any electricity, and so you can’t power your home with the energy that you
need from these wires. The motor neurons act in the same way, and you can no longer power
your muscles from these neurons after the Polio virus
damages these motor neurons. And so that’s what
happened to this man here. Now another prominent figure in history that was diagnosed with the Polio virus was Franklin Delano Roosevelt, FDR. The 32nd President of the United States. He was infected in 1921, which left him permanently damaged from the waist down. But interestingly enough, FDR didn’t want to show the general public his ailment, so there are
actually very few pictures of FDR in a wheelchair. Now though he was diagnosed with Polio, it’s now actually believed
that he was misdiagnosed, and that his symptoms
were actually caused by something called Guillain-Barré syndrome. This would mean that
his diagnosis of Polio may have been one of the
most prominent misdiagnoses in history. Now there’s a few reasons that we believe he may have been afflicted
by Guillain-Barré syndrome, and that’s for two distinct reasons. Most commonly, Polio affects children. Particularly children who are less than six months of age. So FDR contracting Polio when he’s 39 is not very likely. And second of all, Polio
causes something called asymmetric paralysis. Asymmetric paralysis. The muscles are damaged in
a somewhat random process. So having both legs damaged
equally is unlikely. I mean think about it. The Polio virus might affect
the neurons on this side, but the neurons providing
energy to his left leg may not be damaged. And so you might actually
see what happened to our guy over here, where his right leg is primarily affected. Franklin Delano Roosevelt,
both his legs were affected. And this is called symmetric paralysis. And Guillain-Barré
syndrome is known to cause this symmetric paralysis. So how does Polio infect a person, or specifically, most likely a child under the age of six months? So the virus usually comes in and enters through the mouth and actually starts, goes
down and starts replicating in the throat. So it starts increasing in number. And it can also travel down into the stomach and the intestines. And it might replicate in
the intestines as well. Once the Polio virus
has increased in number, somehow, and we’re not
actually 100 percent sure how, it gets into the central nervous system, into the spinal cord, where it can damage the motor neurons that provide energy to the muscles. Now not everybody who contracts Polio has this degredative damage
to their motor neurons. In fact, 90 to 95 percent of
people who are acutely infected are asymptomatic, so they
don’t have any symptoms. Asymptomatic. Whereas about five to
ten percent of people get only mild symptoms. Mild symptoms. So what are the mild symptoms? Well, these are symptoms
that you generally see, or can see, with any virus. You might get fever, headache, fatigue. So this is really from your immune system trying to thwart the virus, trying to fight it off. So a patient might also
have some throat pain, and this is due to
replication in the throat. The patient may also experience abdominal pain, stomach pain, or nausea, or vomiting. And that’s from the
replication that occurs in the intestine. Patients that have these mild
symptoms generally recover, and don’t experience the muscle weakness. In fact, only about a
half a percent of people who are infected acutely by the virus experience muscle symptoms. And these muscle symptoms
may include weakness, atrophy, or in other words, the muscles shrivel up due to under use, since the motor neurons
are damaged by the virus. Low muscle tone, and muscle twitching, which can occur by abnormal firing by some of the neurons
that may still be providing innervation to the muscles. Now you might think, wait, only half a percent of people face this motor neuron damage and muscle paralysis? That seems like such a small number. Well, let’s put it into a
little bit of perspective. If we take a look at a
football stadium of about maybe 100,000 people here, about 90,000 people may be asymptomatic. Only about 5,000 to 10,000 people will actually have symptoms. So maybe this group of people right here. And the people that
experience muscle weakness, maybe all of the members of the band and all of the members,
the players, the coaches, of both teams will be affected. Now still this may not seem like a lot in comparison to all the other people who are asymptomatic, who
aren’t feeling any symptoms. But the disease can spread very easily from person to person, which leads to more and more people being affected by the Polio virus. So though it’s a small amount of people, the damage can be very severe. In fact, we think about maybe the arms and the legs, right, you’re not able to walk or move your arms. But what happens if the
muscles that are used in respiration, in
breathing, are paralyzed? What if these muscles are damaged? Then patients can no longer
breathe on their own. So this can be very debilitating, and fatal if it affects
the respiratory muscles. But what other muscles do
we not commonly think about? Well, there’s also muscles in our throat. And our heart is a muscle. There’s actually nerves that extend from the lower part of the brain. It’s also known as the brain stem. This area has some neurons
that control speech as well as the functioning of the heart. So if we go ahead and take a view of the underside of the brain, you can see, right here’s the brain stem, and there’s all these nerves that extend from this part of the
central nervous system. And these are known as the cranial nerves. So nerves that might be affected are the glossopharyngeal,
cranial nerve nine, the vagus nerve, cranial nerve 10, the accessory nerve, cranial nerve 11, and the hypoglossal
nerve, cranial nerve 12. So these are motor neurons
that can be damaged as well. So what are some of the
symptoms you might see? The glossopharyngeal nerve assists in allowing you to swallow. So patients may have
difficulty swallowing. The vagus nerve controls
movement of the throat. So I wouldn’t be able
to talk to you right now without the vagus nerve. The vagus nerve innervates
other parts of the body as well, including the muscle known as the heart. So a patient who has their
cranial nerves affected should have close
cardio-vascular monitoring. Their heart should be
monitored very carefully. And then finally the accessory, this controls shoulder movement, and the hypoglossal
controls tongue movement. So you see, not only the muscles of the arms and the legs are affected, but also some patients can get this Bulbar Palsy, which is the name for this cranial nerve defect. So when these cranial nerves are affected, so a patient might have
difficulty talking, difficulty swallowing, and have heart problems as well, difficulty actually maintaining their heart’s function, this cranial nerve paralysis is known as Bulbar Palsy. And “bulb” just refers to the brain stem, it’s the bulb of your brain. And “palsy” means paralysis. So there you go. Nerves from the brain stem are paralyzed, Bulbar Palsy. Finally, after the initial infection, and the patient has
had some muscle damage, years later, a patient
may get something called Post-Polio syndrome. Post-Polio syndrome occurs years after the initial infection, it’s slow, and you get
progressive muscle wasting, so these muscles that may already be weak can get weaker and weaker. Now the prevalence of this
is not entirely clear. It doesn’t occur to all patients who end up getting the muscle weakness. But we do know that some of these patients get this onset of deterioration and dysfunction of the muscles years after the initial infection.

36 Replies to “What is polio? | Infectious diseases | NCLEX-RN | Khan Academy”

  1. KhanAcademy is absolutely foolproof. I am happy that i've found this for my nclex study. easy to understand, unbelievably helpful!!

  2. what is all about in my case.. because when I was 2 year old. I've been into that thing called polio. I was like bone and skin only due to always vomiting and bowels and high fever… but after few days or week I was suddenly getting better.. but now I really noticed my legs and arms are very small or thin.. the bones of my knees are too obvious and my skin showed too thin that my veins are shown too.. and this is the reason why I can't able to wear shorts because of these veins and small legs… and even in my arms looks like a man who always at the gym… but other than that I am fine.. I keep doing some exercises or running but there are no changes at all.. if I got full after eating, my stomach only will expand or shown bloated.. but my legs and arms are not getting better than usual… what was all the reason about it…?

  3. my gandpa got polio in 1941 or 42 when he was 15 or 16 and he died some were from 2009 to 2013 and he live var far from me and i was born in 2000 so i realy did not get to see him mush he start a dehidraing shop and Machining shop

    Boerhaave correlates paralysis with exposure to mercury fumes
    British physician Michael Underwood provides first clinical description
    Cooke associates paralysis with inhaling or swallowing mercury, arsenic or lead
    Emerson reports that the vital statistics for Philadelphia record more than 8,000 deaths from diseases of the nervous system in a decade, out of a population of 226,693.
    Turner blames the "dry belly-ache" of the Caribbean, which sometimes includes paralysis and is sometimes fatal, on lead poisoning
    Jacob Heine describes polio's clinical features and the involvement of the spinal cord
    Colton documents a patient who becomes paralyzed a week after swallowing arsenic
    First use of arsenical insecticide
    Vulpian produces paralaysis in a dog with lead
    Barrel spray pump first appeared on American market. Quantity of poison left on fruit due to pesticide applications judged insignificant.
    Mills reports 7 cases of paralysis resulting from consumption of a poisoned pumpkin pie. One young man became paralyzed fully 9 days after eating the pie.
    First outbreaks of paralytic shellfish disease reported in districts around the North Sea of Europe
    Starr points out that alcoholic spirits, but not wine and beer, sometimes produce paralysis. Distillation is a common cause of lead poisoning
    First polio epidemic in Sweden (43 cases)
    Lead arsenate first proposal as insecticidal spray
    132 cases in first US outbreak in Vermont
    Putnam states that it is generally accepted that polio has a toxic cause, although different toxins may produce slightly different symptoms. He rejects an infectious cause
    Caverly blames an epidemic in Vermont on "a specific poison". There was no evidence pointing towards contagion
    Stieglitz produces paralysis in 36 animals with lead poisoning
    Onuf reports a painter with paralysis in both legs. Until the 1920s most paints were lead based
    Cause of an epidemic of arsenic poisoning among British beer drinkers went undiscovered for 6 months. Symptoms included motor paralysis.
    Epidemic of arsenic poisoning around Manchester, England. It affected beer drinkers for six months until the cause was found.
    Phillippe and Gauthard report a case of anterior poliomyelitis from lead poisoning
    First severe polio epidemic in Sweden (886 cases)
    Emerson reports that, in an epidemic of polio in Massachusetts, that no breastfed baby was paralyzed
    First use of arsenates in dust form
    Landsteiner & Popper inject materials from the spinal column of a boy who died of polio into a monkey causing a similar disease. This is accepted as definitive proof of infectious causation
    Collins and Martland report poliomyelitis in a man using potassium cyanide as a silver polish
    Flexner & Lewis were able to create paralytic symptoms by passaging polio spinal cord material from a human through a series of monkeys
    Three years of polio in Sweden (6,764 cases)
    Paradichlorobenzene recommended in US for clothes moths and carpet beetles
    Large epidemic of polio in the New York City area (over 9,000 cases resulting in 2243 deaths). Nationwide there were about 27,000 cases and 6,000 deaths
    1916 June–1916 October
    Polio epidemic in New York and surrounding states with 8,900 cases and 2,400 deaths
    Franklin Delano Roosevelt comes down with polio when on vacation on the Bay of Fundy
    First commercial use of airplanes for applying insecticides
    Aycock and Eaton state that "Our present knowledge permits only speculation concerning the mode of infection"
    First outbreak of paralytic shellfish disease in California.. Also the largest ever number of poliomyelitis cases in this state (1,298)
    Zinc-based lithopone overtakes white lead as the primary paint pigment
    Paralysis occurs two weeks after an operation on three members of one family, perhaps caused by the anaesthetic
    Charles Armstrong of the USPHS sprays picric acid and alum solution into the noses of 4,600 Alabamans, to no avail
    Maurice Brodie's vaccine from ground up spinal cords of monkeys injected with polio virus is revealed to have caused at least one death and three cases of paralysis in humans and other scientists did not find that it protected monkeys from polio virus injections
    Polio-like intranuclear inclusion bodies found in children dying of lead poisoning.
    Lumsden states "On epidemiological grounds alone, it appears conceivable that poliomyelitis is not caused by a living microorganism or a virus but by a toxin."
    The polio-vaccinologist Sabin states "We possess no knowledge of the actual portal of entry into the human body"
    Insecticidal properties of DDT discovered by JR Geigy SA in Switzerland
    McKhann states "The portal of entry of the virus has not been definitely established"
    DDT Introduced to the UK and the US
    "DDT…became a [British] war priority of the highest order, ranking with penicillin and radar, and nothing was allowed to stand in its way."
    Lillie et al show that DDT can produce degeneration of cells in the spinal cord
    Mass production of DDT begins in the UK and US
    Stomach contents of fish from polluted rivers produced weakness in monkeys after a few days. The material had been sterilized to eliminate infectious agents. Emulsion of spinal cord of this monkey produced paralysis of the left leg when injected into another monkey.
    First year DDT used for pest control in the United States
    A Public Health Service study of the Detroit-Windsor area is launched under the 1909 boundary treaty in response to Canadian complaints about pollution from Detroit
    US Public Health Industrial Hygiene Medical Director, J.G. Townsend, notes the similarity between parathion poisoning and polio and believes that some polio might be caused by eating fruits or vegetables with parathion residues
    Years of London Smog before the Clean Air Act
    EQ-53 formulation of DDT released for use mothproof clothes by washing them
    Nearly two million US children participate in vaccine field trials.
    1954 April 26
    First of 440,000 trial inoculations using the Salk vaccine. 210,000 got a placebo.
    1955 April 12
    Salk vaccine pronounced safe and effective by Thomas Francis, who had previously employed Salk at his lab
    1955 April 23
    Jonas Salk awarded US Medal of Merit from President Eisenhower
    1955 April 25
    First paralysis from Salk vaccine reported
    1955 April 27
    First of 204 vaccine-associated cases of polio reported. About 75% were paralytic. 11 died.
    1955 April 28
    Cutter vaccine recalled after 380,000 children vaccinated with it, but many paralyzed or killed
    Of 67 high priority people (under 20 and pregnant women) only 25 million had the full three shots of vaccine, 22 million had 2, 11 million had one and 9 million remain unvaccinated
    Dr. Bernard Greenberg testifies that changes in the definition of polio in 1955 significantly reduced the number of cases
    Sabin vaccine made with live attenuated virus was preferred in most locations to the Salk vaccine
    US Switches to Sabin live polio vaccine
    1962 July
    First reports of paralysis shortly after receiving the Sabin (attenuated live polio virus) vaccine
    Lead poisoning due to moonshine is declining but remained an important cause of fatal lead poisoning through a 1979-1998 survey
    Outbreak of Acute Flaccid Paralysis (AFP) in Paraguay linked to Organophosphate pesticides
    25% of Moonshine samples seized by the US Bureau of Alcohol, Tobacco and Firearms would cause dangerous blood lead levels in heavy drinkers (more than one liter per day)

  5. I have built multiple wheelchairs for patients with Post-Polio syndrome. And what I have noticed is most patients have paralysis in their lower extremities.

  6. was watching this, and had all the symptoms for mild symptoms, so is it possible my immune system is fighting off polio ? xD

  7. And now the anti vaxxers are helping this dreadful virus to return so thanks and I hope to God you un vaxed kid gets it and is one of the 1% who has to spend the rest of his life in a iron lung because you deserve it for being so stupid.

  8. My dad had polio disease and from the story I heard from him it all started when he was 4 and because he lived in a small village in Hakkari (a small city that no one lived on that time and no one still lives there) it was hard to find a doctor and everyone immediately thought he was going to die but he didn’t and they found doctors that can help him and when they got the medicine that he needs… the nurse was giving him the medicine and without realizing the medicine touched his bone so one his leg stopped growing and that’s the time where they literally thought he was going to die everyone was sad because even if the medicine worked for some reason everyone thought he was about to die 1 but of course he didn’t die (I’m not sure if this is what exactly happened because these stuff happened a long time ago like 40-45 years ago he is 50-51 now) he is still alive and happy he has a happy family with 4 kids and the last one is me Eda just a normal 12 year old kid^-^

  9. This was an "Oliver Sachs Level" of a very, very gifted and knowledgeable person's awareness of peoples' general intelligence, combined with their penchant for "emotional aspects" being entertaining. This hit all the notes. I wanted to understand the scientific/medical aspects of this disease, but I wanted it to be explained in an anthropological/historical/news-conscious/emotional way.

    This was perfect.

  10. In order to relieve symptoms of polio take an eyebrow tweezers and remove the hair follicles of the body until the polio victims well being and abilities are restored start with hands, feet, and wrist.
    God bless you,

    Ron Erickson

  11. Hi. I'm scared because there's a polio outbreak now in my country. I'm currently turning 15 years old in October. Can I ask? Am I susceptible for polio? And can polio leave your body after several days after you got infected?
    Edit: I mean, can I get well after having a polio? Or is it a lifetime paralysis, like forever disabled?

  12. I have this problem on my right hand , what can be done to recover from it , i m 25 now , is there any possible treatment available for this ? What are the source of this virus ??? Please answer these questions and i would really like any peice of advice on it please please reply…

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