Date: Tue, 5 Jan 1999 12:27:13 -0500
From: "Eddie Bollenbach"
Subject: Re: [PPM] Para or Non Para
There are several arbitrary clinical diagnostic categories for acute polio infection. I say arbitrary because the diagnostic category infers that the virus only damaged certain tissues to a certain degree. All of the diagnostic categories assume a person is damaged only to the extent designated by the category. This overlooks the reality that polio damage occurs across a spectrum, continuously. So, as violet melds to blue then green then yellow and on to red, a polio diagnosis of one type may damage the body more than is commonly assumed.
These are the common categories for acute polio infection:
Sub-Clinical polio: The person is unaware of infection and gains active (sometimes lifelong) immunity to infection from that strain. Most people, prior to the development of the vaccine, obtained immunity this way. This is one reason why the disease expresses itself as a childhood disease. Many adults obtained immunity from earlier sub-clinical infection.Currently, people with non-paralytic polio are having a hard time getting diagnosed with PPS. Research criteria for studying polio included the need to study patients who had paralytic polio with residual weakness. These criteria have spilled over into the clinical area so that some physicians feel you cannot have PPS unless you have had paralytic polio and evidence of it by residual paralysis in at least one limb.
Abortive Polio: Symptoms include primarily gastrointestinal upset. Illness ends abruptly (aborts). Virus can be isolated from throat washings and stool. Infection is cut short by the host's defenses before it can enter the Central Nervous System. Since it is believed that this is so, and that there is no nerve damage, PPS should be unlikely. However, if the diagnosis of neurological involvement was missed it is possible to have nerve damage.
Non-Paralytic Polio: The virus enters the Central Nervous System to damage brain and spinal cord motor neurons. However, external signs and symptoms include headache, stiff neck, muscle cramping etc. There is no flaccid* (soft muscle) paralysis. Flaccid paralysis is indicative of severe nerve damage and the orphaning of skeletal muscle fibers by disconnection from motor nerves. If we find that in PPS one can have progressive weakening in muscles unaffected by polio ---which is one of the descriptive criteria for PPS--- to my mind there is no reason why PPS should not arise from non-paralytic polio. In non-paralytic there is no flaccid paralysis---just like in muscles unaffected by the original polio in paralytic polio. I would expect a decreased frequency of PPS for non-paralytic polio survivors. Such a study would be interesting because it might help us understand how PPS occurs.
*"FLACCID - Muscles that are weak, soft, and flabby; lacking tone."
Paralytic Polio: Virus enters the Central Nervous System and damages the neurons to the extent that muscles become flaccid. 15% mortality if brain stem involvement results in respiratory failure. Only some muscles are usually flaccid. Others, not flaccid, can be thought of as being non-paralytic (in a sense).
But, clinically, as I mentioned above, it is inconsistent to assert that previously unaffected areas can become weak in PPS, while at the same time insisting that PPS cannot occur in non-paralytic polio.
Contact Professor Edward P. Bollenbach
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