In addition, this is not a misunderstanding as such, but there is anecdotally a very high incidence of the Ehlers-Danlos spectrum of disorders in people with PP, to the extent that patients with either disease should be asked about symptoms of the other. This has so far never been published. The coexistence of the 2 disorders obviously makes mobility and pain control more difficult for the patient.

Many patients with genetic PP report frequent and significant problems with many medications — multiple side effects, perhaps even more allergies than in others, but mostly reactions to very small doses of drugs, both therapeutically and adversely. It seems wise to start all people with PP on very small doses of any drug and then gradually increase the dose as tolerated.

The PP disorders are channelopathies of muscle fibers (and myocardium in Andersen-Tawil) and perhaps clinically in other tissues yet to be classified. PP is not a neurologic disease. Some patients wonder if they may be better served by being looked after by rare-disease physicians, or perhaps by metabolic specialists, rather than by neurologists. Perhaps a multispecialty medical team would be the ideal. But none of this is ever discussed openly. Perhaps we should discuss it.

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There are a variety of congenital anatomic anomalies reported in ATS. However, very few patients display all of them, and the changes may be very subtle but should specifically be looked for when making the diagnosis.

Most doctors and nurses know nothing about the PP disorders. This is forgivable as they are rare disorders — particularly ATS — but some doctors like to say that they know all about PP when in fact they don’t. This is unforgivable and dangerous. Please admit forgivable ignorance and ask for advice from an expert. And ask for information from the patient — many people diagnosed with rare disorders know more about them than their doctors do and are often cognizant of the up-to-date medical literature.

The symptoms in the genetic PP disorders are intermittent. That is why they are called “periodic” — or [they would be better referred to as] “episodic.” Between acute attacks, the person, particularly a younger patient, is likely to be fit and well with no abnormal physical findings. This clearly makes diagnosis more challenging. Even during an attack, there may be no physical signs apart from the subjective and objective flaccid paralysis. It is reported that tendon reflexes may be diminished or absent during paralysis.

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PP may be fatal. Over the 20-year history of the Periodic Paralysis International listserve, with a more or less stable membership at any one time of 250 clinically or genetically diagnosed members, we have lost over a dozen members directly to PP attacks, most in the prime of life — 5 within hours of surgery or during recovery. Perioperative care is a very risky time for patients with any of the Periodic Paralysis disorders. Dangers are especially with the use of anaesthetic agents, but many aspects of hospital care can provoke crises in PP patients. Periodic Paralysis International has published a literature search and practical guidelines for peri-operative care which can be found at

Muscle strength between attacks, which patients may rate as ”normal” and not recognize as weakness, is actually reduced from “healthy normal” by 15% to 17%. However, when you’ve never felt “healthy normal,” the reduction feels normal. Falls from weakness and subsequent broken bones are so common, we don’t even keep count.

Nearly 90% of patients report near-constant muscle pain, but half are told by their physicians that PP doesn’t hurt, and some have been initially denied a diagnosis because of muscle pain. Others continue to be denied appropriate analgesia — at worst, accused of drug-seeking behavior.

And the disease doesn’t go away at 40 — while attacks gradually become less precipitous, weakness settles in with age and becomes a constant companion, reducing strength and stamina with each passing year. This is the permanent muscle weakness that patients often fear. The percentage is high. Some patients’ muscles may atrophy, and some look perfectly normal, but they don’t work properly. Patients with PP need to begin receiving the same kind of aids and supportive services people with multiple sclerosis or other neuromuscular disorders get — for example, bracing to stabilize joints and prevent falls, power wheelchairs, and ramps.


  1. Baughan ASJ, Cavel-Greant D, Megalo J, Weber F. Anaesthesia and peri-operative care in the primary periodic paralysis disorders–part 1: A review of the literature. Accessed March 30, 2018.
  2. Baughan ASJ, Cavel-Greant D, Megalo J, Weber F. Anaesthesia and peri-operative care in the primary periodic paralysis disorders–part 2: Practical guidelines. Accessed March 30, 2018.