This is merelythe feeling that you will pass out unless you he down rightaway.
Simultaneously, your surroundings maylook gray or your vision may fade.
There are many causes of syncope and near-syncope.
These include cardiac and neurological problems,certainmedications, and dehydration.
These causes are not nearly ascommon in diabetics asare sudden drops of blood pressure caused by autonomic neuropa thy or by inappropriate use of antihypertensive medications , espe cially diuretics ("water pills") and alpha-1 adrenergic antagonists, such as prazosinand terazosin.
When most of us stand from a seated,supine, or squatting position, the brain sends a message to the blood vessels in our legs to constrict reflexively and instantiy.
This prevents blood from poolingin the legs, which would deprive the brain of blood and oxygen.
If you've had high blood sugars for manyyears, the nerves that signal the vessels in the legs may conduct the message poorly (a sign of autonomic neu ropathy).
A drop in blood pressure upon standing, called postural, or orthostatic, hypotension, occurs when this pooling in the legs occurs.
For some,the heartmaybringblood pressure backup by increasing its rateand amount ofcontraction.Unfortunately,this does not occur for many diabetics with autonomic neuropathy.
Alternatively, if you eat a big meal, blood may concentrate in your digestive system, also depriving the brain.
The normal mechanisms that protect the brain from this shunting of bloodmaybe deficient if you have autonomic neuropathy.
It is in part to gauge potential for these reactions that I measure supine and standing blood pressures, and perform R-R interval studies on all my diabetic patients.
A recent study of medical (mosdy nondiabetic) outpatients in the United States suggests that 20 percent of individuals overthe age of 65 and 30 percent of those over age 70 have documentable postural hypoten sion.
Fordiabetics the incidence is probably much greater.
A common scenario for syncope or near-syncope involves the dia beticwho gets up in the middle of the night to urinate and keels over on the wayto the bathroom.
A simple wayto avoid this is to sit at the edge of the bed with feet dangling for a few minutesbefore standing.
Another syncopescenario involves the personwho goes to the toi let and passes out while tryingto produce a bowelmovement or uri nate.
Again, the reflexes that prevent shunting of blood away from the brain areblunted by autonomic neuropathy.
If syncope iscaused bytransient lowcerebral bloodpressure as are sult of autonomic neuropathy, one should lay the victim out flat and
How to Preventand Correct LowBloodSugars 343
elevate his feethigh abovehis head.He should return to consciousness almost immediately.
The symptoms of syncope are similarto those of moderate to se vere hypoglycemia.
In both cases, the brain is being deprived of a ba sic nutrient , oxygen in the case of syncope, glucose in the case of hypoglycemia.
Furthermore, postural hypotension canalso occuras a result of hypoglycemia.
Some symptoms of near-syncope include faintness, visual changes, and disorientation.
Whatever the cause of fainting or near-syncope, blood sugar must be checked to rule out hypoglycemia.
If blood sugar is normal, no amountof glucose will cure the problem.
People with recurrent pos turalhypotension will usually find reliefbywearing surgical stockings of 30-40 mm compression.
If these are inadequate, waist-high surgi cal pantyhose should be used.
TWO FINAL NOTES
If you've heard horror stories about the frequency and severity of se vere hypoglycemia in type 1diabetes, thepeople you've been hearing about are probably taking industrial doses of insulin to cover large amounts of dietarycarbohydrate.
On our regimen, this hazard is vir tually nil.Someone would have to make a major mistake, suchas tak ing an insulin dose twice, or not waiting the full 5 hours before correcting an elevated bloodsugar, forlife-threatening episodes to oc cur.
Many type 1 diabetics seek me out because of their frequent hy poglycemic episodes and not necessarily because of their high blood sugars.
Our regimen takes care of both.
Please don'tneglect to ask others to read thischapter.
When youare mostin needof help fortreating hypoglycemia, youmay be incapable of rendering it yourself.
So show this chapter to your close relatives, friends, and coworkers and ask them to read it.
It should increase their own confidence in coping with such situations, andthepotential pay off to you may be considerable.
21 How to Cope with Dehydration, Dehydrating Illness, and Infection
W h e n you experience vomiting, nausea, fever, diarrhea, or any form ofinfection, you shouldimmediatelycontactyour physician.
I can't really emphasize enoughthe importance of getting treatment and getting it fast.
To drive home this point, I'll share the following experience.
Some years ago, I got a call from a woman at about four o'clock on a Sunday afternoon.
She wasn't my patient, but her diabetologist was out of town for the weekend with no backup for emergencies.
He had nevertaught her what I teach my patients , the contents of this chapter.
She found my Diabetes Center in the white pages of the phone book.
She was alone with her toddler son and had been vomiting con tinuously since 9:00 a.m.
She asked me what she could do.
I told her that she must be so dehydrated that her only choice was to get to a hospital emergency room as fast as possible for intravenous fluid re placement.
While she dropped off hersonwithhermother, I called the hospital andtold them to expect her.
I gotacall 5 hourslater from an attending physician.
He had admitted her to the hospital because the emergency room couldn't help her.
Why not?
Her kidneys had failed from dehydration.
Fortunately, the hospital had a dialysis center, so they put her on dialysis and gave herintravenous fluids.
Had dialysis not been available, she would likely have died.
As it turned out, she spent five days in the hospital.
Clearly, a dehydrating illness is not something to takelightly, not a reason to assumeyour doctoris going to think you'reahypochondriac if you call every time you have one of the problems discussed in this
How to Cope withDehydration, Dehydrating Illness, andInfection 345
chapter. This is something that could kill you, and you need prompt treatment.
Why is it, then, that diabetics have a more serious time with dehy drating illness than nondiabetics? Clearly it has something to do with blood sugars.
DEHYDRATION'S VICIOUS CIRCLE
Ifyou are vomiting or have diarrhea, you've either been poisoned (un likely) or have an infectious illness.
If you have an infection, whether it's in your mouth, on your finger, or in your gastrointestinal tract, your blood sugar is most likely going to go up.
So you're starting off with elevated blood sugars just by virtue ofthe infection.
Ifyou vomit or have diarrhea, you are losing fluid from a region in the body that normally contains fluid.
That lost fluid is going to be replaced from the largest source of fluid in the body, the bloodstream.
It's not that you're going to bleed into your stomach , your GI tract is full of blood vessels that are there in part for the exchange of fluids.
That's how fluid is absorbed.
Your body naturally tries tomaintain abalance, sowhen fluid disap pears from one place, your body tries toreplace itusing water from your bloodstream.
But as your blood loses water, glucose isleft behind, and youend up with a higherbloodsugar concentration.
In addition, blood vessels area giantweb throughout the body, but unlike a web, the ves sels narrow as they travel outfrom the center, narrowing from inside the body to outside, from inside an organ to itssurface, and so on.At any given time, much oftheblood is inthese narrow, peripheral vessels.
If your bloodstream has lost significant amounts of fluid, as you would in a dehydrating illness, the periphery is notgoing tobeas well supplied as it would normally be.
It's like having a whole new insulin resistance simply because insulin andglucose aren't adequately reach ingthe narrower vessels.
Since less glucose will be delivered to the cells adjoining these vessels, yourblood sugar concentration will continue to climb.
Furthermore, the higher your blood sugars go, the more in sulin resistance you will experience.
The more insulin-resistant you are, thehigher your blood sugars are going to be.
Avicious circle.
To make the circle even more vicious, when you have high blood sugars, you urinate , andofcourse what happens then isthatyou get
346 Treatment
even more dehydrated and more insulin-resistant and your blood sugar goes even higher.
Now your peripheral cells have a choice, either die from lack of glucose and insulin or metabolize fat.
They'll choose the latter.
But ketones are created by fat metabolism, causing you to urinateeven moreto rid yourself of the ketones, taking you to a whole new level of dehydration.
This sequence of events can happen in a matter of hours, as it did with the woman just described.
Sothe name of the gameisprevention.
Howdo youprevent illness from causing dehydration?
Let's sayyou wake up in the middle of the night or in the morning and vomit or have a bout of diarrhea.
What do you do?
Callyour physicianand let him or her know, even if it's two o'clock in the morning, call your doctor.
Even if it turns out to be just something you ate and it's a tran sient episode, callyour doctor or his/her answering service.
We allgetsickfromtimeto time, but ifyou're on our diet and treat ment plan, and if you'rereasonably healthy, you shouldn't get sickany more frequently than the average person, and probably less fre quently than the average diabetic.
For diabetics, however, such illness can pose specialproblems.
As you know, sickness or infection can cause your blood sugar to increase, and injected insulin , even if you don't normally take in sulin , can help preserve beta cell function during illness (as well as help keep your blood sugar under control and thereby reduce de hydration).
One of the most pressing concerns for diabetics during illness is dehydration, which, as illustrated above, can lead to life- threatening consequences if not handled effectively and rapidly.
DIABETES AND DEHYDRATION: A DANGEROUS COMBINATION Common causes of dehydration include not onlymultiple episodes of diarrhea or vomiting, and fever and resulting perspiration; they also includefailure to drink adequate fluids, especially during hot weather or prolonged exercise, andvery high blood sugars.
You probably know that one of the hallmark symptoms of very high blood sugars is the combination of extreme thirst and frequent urination.
From what you've already read in this chapter, you should understand the equa tion.
Still, I think it's noteworthy enough to lay it out again for em phasis.
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