I was a student of medicine in the University of Tehran from 1988 to 1995. I spent my internal medicine internship in the Imam Hospital Complex, which at the time was also called the 1000-Bed Hospital.

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![Imam Hospital Complex](http://gsia.tums.ac.ir/Images/UserFiles/66/image/imam_khomeini_hospital.jpg)
_Picture Credit: [Tehran University of Medical Sciences](http://gsia.tums.ac.ir/Images/UserFiles/66/image/imam_khomeini_hospital.jpg)_

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I have a lot of memories from those good old days, but the one I am going to tell you about is very conspicuous in my mind, because it is about a very interesting case.

So I was on duty (as a medical intern) in the Emergency Room with a few other interns and we had internal medicine residents and also neurology residents. It was a very busy day and a lot of patients were coming to the ER and the interns and the residents were really busy. You know, at that time, the public sector hospitals in Iran were very cheap (almost free) and patients from all over the country came to the 1000-Bed Hospital, which is a really big hospital.

There was this middle-aged man who had been referred by a neurologist from Karaj, another big city near Tehran. He was brought into ER by two men who carried him on a stretcher. He was obviously unable to move. There was an accompanying note from the neurologist who had referred the patient.

The note said that the patient had presented with paralysis (without neck stiffness) to the neurologist and he had done workup for stroke, including CT scan and had also performed a lumbar puncture to rule out meningitis and other infectious causes. He had also mentioned the possibility of a conversion disorder or hysterical paralysis. Our internal medicine residents called neurology residents and they ordered some workup which I really don’t remember now.

I was just a rookie intern, no doubt about that, but I was also fresh and that meant that I took was I had been taught seriously. I knew that the first step in evaluating a patient was taking a comprehensive history. The patient was unable to talk, but I started talking to his two companions. I asked about when the paralysis started and so on. Turned out the patient had had multiple episodes like this before. His age was not consistent with a diagnosis of stroke and he did not have predisposing risk factors like hypertension and so on. Besides, the paralysis had started with no apparent cause, without fever or any sign of infection.

I had recently read parts of [The Harrison's Principles of Internal Medicine](https://en.wikipedia.org/wiki/Harrison%27s_Principles_of_Internal_Medicine) (and even went on to translate the whole [Harrison's principles of internal medicine: companion handbook](https://books.google.com/books?isbn=0070709106) into Persian), it was evident for me that the patient’s history was not compatible with a diagnosis of stroke, meningitis, encephalitis, etc. On the other hand, it was totally consistent with a diagnosis of [hypokalemic periodic paralysis](https://en.wikipedia.org/wiki/Hypokalemic_periodic_paralysis). In this rare genetic disease, lowering of serum potassium levels due to daily activity and other factors causes a paralysis in muscles.

Long story short, I talked to our residents, we ordered the blood tests (actually we had already done that), and confirmed the diagnosis by finding a low potassium level. We added potassium chloride to the patient’s intravenous fluids and in no time he recovered fully from the paralysis and could sit and walk normally.