Friday, March 2, 2012

About Pain

Recently, I have had an episode of severe pain caused by a kidney stone in ureter (that propels urine from the kidneys to the bladder).  The pain was so intense that I was woken up in the middle of the night and after half an hour, I had to asked to be taken to the emergency room.  According to some statistics, there are more than 1 million incidents of kidney stone reported each year in U.S.  and one in ten people will experience such an episode at least once in their life time.

Of course, every one of us has had experienced pain of varying degrees in our lives.  Pain, while unpleasant, is a necessary mechanism to protect oneself to survive in the world.  Can you imagine the consequence of not feeling the pain when you are being burned, broke your leg, or sprain your ankle?  (By the way, I am limiting myself here to the discussion of physical pain which is already complicated enough.)

Yet, until 500 hundred years ago, pain was not well-understood.  Many well-respected scholars thought it was subjective and postulated it has something to do with external and spiritual world.  Some went as far as proclaiming it as a punishment by God.

With the advances of science, we now understand pain a lot more.  Significant discoveries have been and continued being made about the mechanisms of the sensing of pain and how to help relief and manage certain pains.  The basic model now tells us that there are millions of nerve endings with sensory neurons called nociceptors that can detect pain for skin, joints/bones, and body organs. When the received stimuli that are related to pain (including nerve damage) reach certain thresholds, particular neurons will signal and register the pain in the anterior cingulate gyrus of the brain and trigger appropriate responses.

Intuitively, pain has many dimensions and characteristics.  Obvious attributes include duration (short, long and continuous, and chronic), character (sharp, dull, throbbing), etc.  There are vivid verbal descriptions of experiences of distinct level of the intensity of pain too.  Among the severe pains, apparently it is true that pain can be so intense that one looses consciousness because of it, be it due to accident or torture.  Pain can also be so excruciating and have no obvious end to it that the thought of death is preferred to prolonged pain is real for many.  Severe pain with the hope of an end to it can still impair one’s judgment and potentially make one behave irrationally.  I would consider the pain caused by the kidney stone belong to this category.  First time in my life, I had reached the point of feeling so desperate that I was ready to plead for a powerful pain killer that would take my pain away immediately!

So what can we do about pain?  Pain killers come to mind immediately that is what most of us have done from time to time.  Over the counter pain killers come in various brand and packaging with ingredient such as aspirin, acetaminophen (e.g. Tylenol), ibuprofen (e.g., Advil, Motrin) and naproxen (e.g. Aleve).  These drugs all belong to the family of non-opioid analgesics that work to inhibit an enzyme known as cyclooxygenase (COX), a catalyst for the production of prostaglandins that causes pain, inflammation and fever.  Depending on where the inhabitation takes place (in central vs. peripheral nerve systems), some pain killers are more effective for headache and others are more effective for muscle or joint pains.  Except for acetaminophen, others examples above are NSAID (Non-Steroidal Anti-Inflamatory Drug) that can also reduce inflammation.  They all provide temporary reliefs for minor pains and are considered fairly safe albeit with some possible negative side effects. 

To manage more severe pains, potent and stronger pain killers are often prescribed by trained physicians.  Various opioid analgesics like morphine, hydrocodone and oxycodone come to mind.  They are either found in, or derived from, or synthesized from opiate alkaloids in natural opium poppy plants.  Remember the Opium Wars (the First Opium War from 1839 to 1842 and the Second Opium War from 1856 to 1860) between the British Empire and the Qing Dynasty of China that marked the beginning of the modern China?  Yes, Opium Wars woke up China from its deep isolation and ignorance.  Yes, the wars were triggered by the ban of opium and the seizures of the opium supplies of British and American merchants by Qing Government. 

As one of the world’s oldest known drugs, opioid works by binding to opioid receptors in our central and peripheral nervous systems and gastrointestinal tract.  The net effect is reduced the perception of pain, the decreased reaction to pain and an increase our pain tolerance.  It does have adverse side effects if not used properly.  It is addictive and often abused because of the euphoria it can produce.  But for medical use to treat acute and severe pains, it works magicv!   I was given some morphine through IV (Intravenous therapy) together with Zofran, an anti-nausea/vomiting drug to alleviate possible side effect of morphine.  Within a short time, I no longer feel any pain or discomfort (no, I did not reach euphoria)!  That was actually pretty much the end of my short kidney stone episode.  Two weeks later, the 3 mm long trouble making kidney stone was out of my body on its own without difficulty. 

In all, two things I learned from this painful experience.  I used to brag about my pain tolerance and tease those who take strong pain medications.  No more!  I have to admit that a little morphine brought me back from the hell of pain in the midst of my kidney stone episode.  I was able to breathe and talk normally not long after the IV.  Secondly, now I can honestly say I appreciate women’s worst physical pain.  The emergency room female doctor who treated me told us that pain due to kidney stone is considered comparable to that of giving a child birth.  The price I paid for this knowledge was no more sympathy from my wife.

Talk to you soon!

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