Physician Assistant Exam: High Blood Glucose
Make sure you review high blood glucose for the Physician Assistant Eam (PANCE). In people with uncontrolled diabetes mellitus, the blood glucose levels can be super duper high, even >= 1,000 mg/dL. High blood sugars due to uncontrolled diabetes mellitus are usually related to either diabetic ketoacidosis or hyperosmolar hyperglycemic nonketotic coma. These emergency medical conditions require a high level of care, often in the intensive care unit.
Diabetic ketoacidosis (DKA) is usually a complication of type 1 diabetes. The person has an insulin deficiency, and without insulin, the body goes into a ketotic, catabolic, acidemic state. This condition can be life-threatening.
One way to think about diabetic ketoacidosis is to separate the various components:
Diabetic: Blood sugar > 250 mg/dL, although it’s usually a lot higher
Keto: Positive serum acetone and positive urine ketones
Acidosis: Bicarbonate level < 15 mEq/L and a pH < 7.3
Here are some key points concerning diabetic ketoacidosis:
Symptoms of diabetic ketoacidosis can be confusion and lethargy, especially at higher blood glucose levels. Another common symptom is abdominal pain.
Sometimes the cause of DKA is more than just a missed dose of insulin. Also look for a medical condition that could’ve put someone into diabetic ketoacidosis. Think of the three i’s: infection, inflammation, or infarction.
Because diabetic ketoacidosis is commonly seen in type 1 diabetes, which is a state of insulin deficiency, insulin needs to be started with a bolus and followed by continuous infusion to help correct the ketosis and acidosis.
Someone who has diabetic ketoacidosis needs intravenous fluids, usually intravenous saline with insulin, because the person is likely to be volume depleted.
Potassium and phosphorous need to be adjusted and replaced during the treatment for diabetic ketoacidosis, because insulin pushes potassium and phosphorous into the cell. This requires frequent monitoring of the blood glucose, potassium, and phosphate levels.
Which of the following is true concerning diabetic ketoacidosis?
(A) Management initially consists of normal saline with intravenous insulin.
(B) Hyperglycemia is most commonly due to insulin resistance.
(C) The insulin drip is changed to subcutaneous dosing when the blood sugar normalizes.
(D) Hypophosphatemia can also be seen initially.
(E) Diabetic ketoacidosis never occurs in type 2 diabetes mellitus.
The answer is Choice (A). This question tests how well you understand the nuances of managing DKA. When you first encounter someone with DKA, the management includes initiating an insulin infusion and isotonic saline. This is the opposite of the treatment for HHNK.
You can initially see hyperkalemia and hyperphosphatemia, usually due to an insulin deficiency and hyperglycemia: Insulin isn’t present to push potassium and phosphorus into cells, and high blood sugars can pull potassium out of cells. Concerning Choice (B), diabetic ketoacidosis most often occurs in type 1 diabetes, which is due to an insulin deficiency.
Type 2 diabetes is caused by insulin resistance and beta-cell burnout. Choice (C) isn’t true because the insulin drip is converted to a subcutaneous insulin regimen when the anion gap normalizes, not when the blood sugar normalizes. This point is critical to remember in diabetic ketoacidosis: It’s an anion-gap acidosis. Even if the blood sugar has normalized, usually the intravenous insulin infusion stays until the anion gap is normalized.
Although diabetic ketoacidosis is a state of insulin deficiency and nine times out of ten is seen in type 1 diabetes, the right physiologic stressors can, on rare occasions, cause diabetic ketoacidosis. So although it’s rare, diabetic ketoacidosis can happen in type 2 diabetes.
People usually think of hyperosmolar hyperglycemic nonketotic coma as a complication of uncontrolled type 2 diabetes. You need to look for an underlying cause. What was the stimulus that put the person into this state in the first place? Remember the three i’s and apply them here: infection, inflammation, and infarction. Here are some key points concerning HHNK:
Blood glucose levels can be high in diabetic ketoacidosis, but they’re often higher in HHNK, usually >= 500 mg/dL.
You usually don’t see an acidosis with HHNK.
HHNK happens to older people, whereas diabetic ketoacidosis happens more often to younger people. Commonly, HHNK is seen predominantly in those with type 2 diabetes, whereas diabetic ketoacidosis is seen in those with type I diabetes.
In diabetic ketoacidosis, you think of giving insulin first and then volume. But in HHNK, you think the opposite: Give fluid first (usually normal saline to start), and if that doesn’t bring down the blood glucose level, then you think about giving insulin.
Hypoglycemia can be a significant problem. Realize that hypoglycemia can be more than just a side effect of insulin or medication therapy. Other medical conditions are also related to low blood sugar levels.
The two big types of hypoglycemia you need be aware of are fasting hypoglycemia and postprandial hypoglycemia:
Fasting: Causes of fasting hypoglycemia include adrenal insufficiency, liver disease, and even kidney disease. Not only can liver disease be a cause of hypoglycemia, but so can alcohol use. The administration of diabetic medications, including insulin, is also in the differential etiology.
Postprandial: If hypoglycemia is detected after a meal, think about a problem with the GI tract. Look for gastroparesis, and ask whether the patient has ever had gastric surgery. Look for other potential GI problems, including malabsorption.
Whipple’s triad is three signs that can alert the clinician that a person’s diaphoresis, tremulousness, and/or shakiness may be due to hypoglycemia. This triad suggests that an insulinoma may be present. Although insulinomas are rare, test-makers like asking about this particular triad on tests. The triad goes like this:
The patient demonstrates diaphoresis, tremulousness, and/or shakiness, alerting the clinician that hypoglycemia may be present.
While the person is having the symptoms, a blood glucose level is checked to verify that hypoglycemia is present at the same time as the symptoms.
Normalizing the blood glucose normalizes the person’s symptoms.