Blast Off!

Every Month: a Review of Major Teaching Points

Back to The Launch Pad

Countdown

A Power Program for Student Review

A Review of Teaching Highlights from Last Month

The 6-Month Program

  1. Biophysics Of Obesity
  2. Obesity...Cholesterol...Heart...Stroke
  3. Obesity...The Metabolic Syndrome
  4. Obesity...Insulin Resistance...Diabetes
  5. Diabetes Complications: Glycoproteinopathies
  6. Obesity...Feeling Sick and Liverish
Begin Countdown

Last month’s Teaching Patient Focus (on Twitter)…was: Insulin Resistance and Diabetes…and it’s reviewed for your convenience in this Countdown….

Liver cells are full of machinery that wears out quickly. Each cell lives only a few months, before being replaced. So your liver is renewed throughout life more often than you experience a change in season. It works steadily on many metabolic functions…like keeping the blood sugar level where it should be…but can become quietly dysfunctional, once choked with fat.

The liver receives nutrients from digestion which it processes for distribution in the blood. Its major work load comes up through the portal vein, a large blood vessel deep in the abdomen about as thick as your thumb. The vein delivers nutrients from the gut, and insulin from the pancreas, an organ lodged deep behind the gut. When working normally, the liver sweeps insulin up out of the portal vein, and out of the circulation. When overloaded by fatty acids, however, such livers allow excess insulin to circulate out into the blood.

Insulin’s job is to deliver glucose and amino acids into responsive tissues, like muscle and fat, usually after a meal. They resist being overfed, so the insulin effect is dampened, metabolic transfers are delayed, and Insulin Resistance exists. There’s no clinical effect on the blood sugar at this stage but resistance exists and leads to a slowing of metabolic processes. Trouble is brewing.

An early clinical expression of Insulin Resistance is a blood sugar rising too high after a meal. Digestive and metabolic processes do  continue but at slower rates. Nutrient transfers are less brisk. Such patients feel well, perhaps less energetic, but their routine lab tests are normal.

Eventually the delay becomes measurable, and was put to clinical use decades ago by development of the Glucose Tolerance Test. Under standardized conditions a glucose drink is given to people in the fasting state who then display a ‘normal’ blood sugar curve, or a ‘diabetic’ curve.

A positive Glucose Tolerance Test (sometimes called ‘chemical diabetes’) is in truth, early diabetes. It is not pre-diabetes. In such patients blood sugars after meals are best kept low with a diet that spreads their carbohydrate intake evenly over the day.

The ability of the pancreas to compensate for the resistance and overproduce insulin is eventually defeated. Blood sugars progressively go higher, and fail to return to normal, even after an overnight fast. Glucose begins to spill into the urine (at levels above 180). The patient usually now has developed symptoms and signs of classic diabetes: thirst, frequent urination, tissue wasting, debility, coma and must be treated or will go on to death.

Diabetic keto-acidosis can develop if diabetes is not recognized and treated with insulin. Fat is being burned to excess, producing combustion products called ketone bodies. They depress consciousness and provoke hyperventilation, two hallmarks of diabetic coma. Insulin and fluids are lifesaving.

Once blood chemistries are restored to normal, new diabetics must manage their daily affairs in a way that avoids blood sugars going too low or too high. Too low a sugar can lead to loss of consciousness because the brain needs glucose to function. Too high a blood sugar, while is less dramatic, causes tissue damage over months and years. It affects especially the eyes, nerves and kidneys. Known as the complications of diabetes, they constitute this month’s series of teaching patients (on Twitter).

The diabetic state most commonly seen these days is a progression of these disabilities…it begins with Insulin Resistance from the fatty liver of visceral obesity…then progresses to fatigue and a high blood sugar…soon spilling into the urine. It could end in coma and death, where insulin is life-saving. More commonly seen these days are low-grade elevations of the blood sugar over months and years, setting the stage for the Complications of Diabetes…see this month’s Twitter ‘Tuts’.

BLAST OFF