Practice questions answers Pathology of endocrine pancreas I

Practice questions answers

Pathology of endocrine pancreas I

© Jun Wang, MD, PhD

1. D. The patient has typical presentation of diabetes (polydipsia, polyuria and weight loss), high blood glucose and low C peptide. In a young patient, this is most compatible with type I diabetes. Graves disease usually does not have hyperglycemia, but should have other presentations of thyrotoxicosis. Diabetic ketoacidosis has lower arterial pH. One of the diagnostic criteria for hyperosmolar hyperosmotic syndrome is blood glucose > 600 mg/dl. In addition, hyperosmolar hyperosmotic syndrome is more commonly seen in older population with type II diabetes. Type II diabetes usually has normal or elevated level of insulin and C peptide.

2. C. The key pathological process for type I diabetes is autoimmune injury of beta cells. Alpha cell proliferation is seen in patients with elevated level of glucagon and usually has elevated levels of insulin. Amyloid deposit and damage of islet is seen in type II diabetes. Beta cell hyperplasia and hyperfunction is associated with elevated levels of insulin and C peptide, and hypoglycemia, not hyperglycemia. Exogenous insulin causes hypoglycemia.

3. A. See discussion in question 2.

4. B. Exaggerated clinical presentations of diabetes and evidence of acidosis in a patient with type I diabetes is likely to be diabetic ketoacidosis, that may be associated with concomitant infection or other stresses. Acute myeloid leukemia (AML) and related neoplasms have immature myelocytes. Hyperosmolar hyperosmotic syndrome may have trace amount of ketone, but usually no evidence of acidosis. Hypoglycemia is the most common acute complication of diabetes mellitus, but is characterized by low blood glucose, not high. Sepsis is diagnosed when blood culture is positive for microorganisms.

5. E. The most important confirmative test for diabetic ketoacidosis is urine ketone analysis. Blood osmolality may be increased in many different disorders, including hyperosmolar hyperosmotic syndrome. Bone marrow biopsy and flow cytometry are more useful in hematopoietic disorders. Urine culture is useful for UTI, but not diabetic complications.

6. C. Diabetic ketoacidosis is associated with excessive fatty acid metabolism. Abnormal neutrophilic function is usually associated with immune deficiencies, with history of recurrent infections since childhood, but usually not a direct cause of increased ketone. Bacterial endotoxin, loss of plasma proteins and pulmonary malfunction are usually NOT directly associated with ketone acidosis, although they may trigger diabetic ketoacidosis in a patient with type I diabetes.

7. E. Pregnancy status may exaggerate the presentations of preexisting type II diabetes. Diabetic ketoacidosis has more prominent clinical presentations including nausea, vomiting, shallow rapid breathing, and elevated ketone in urine. Diabetic nephropathy has proteinuria. Gestational diabetes is defined as onset of glucose intolerance/diabetes during pregnancy. One of the diagnostic criteria for hyperosmolar hyperosmotic syndrome is blood glucose > 600 mg/dl.

8. D. Gestational diabetes is associated with placental production of hormones that may result in elevating blood glucose. Amyloid deposit and damage of islet is seen in type II diabetes. Autoimmune injury of islets is seen in type I diabetes. Glomerular inflammation is seen glomeronephritis, usually with hematuria.

9. C. The recommended screening test for gestational diabetes is one hour non-fasting glucose challenge test of 50 g glucose, and blood glucose level higher than 140 mg/dl an hour after taking 50-g glucose orally, is considered positive. Arterial blood gas is used to detect imbalances of acid/base, O₂/CO₂. Urine culture is used to detect infection.

10. A. A 100-g oral glucose tolerance test is performed once the screening test is positive. The diagnosis of gestational diabetes is made if at least two to the four plasma glucose levels are met or exceed: fasting (95 mg/dl), 1 h (180 mg/dl), 2 h (155 mg/dl) and 3 h (140 mg/dl). HbA1c is a test for chronic hyperglycemic status and will not reflect current blood glucose changes.

11. B. See discussion in question 10.

12. E. Gestational diabetes is a risk factor for type II diabetes.

13. B. One of the risk factors for type II diabetes is obesity. The diagnosis of diabetes is made if fasting plasma glucose is higher than 125 mg/dl, random plasma glucose greater than 200 mg/dl, HbA1c level greater than 6.5%, or a 2 hour plasma glucose greater than 200 mg/dl after 75 g oral glucose challenge. This patient has no evidence of ketoacidosis, or heart attack for ABG, urine ketone analysis or EKG. Liver function test will not yield useful information for the diagnosis of diabetes, that this patient most likely has.

14. C. The test results do not meet the criteria for diabetes, see discussion in question 13. It fits the diagnostic criteria for impaired glucose tolerance/prediabetes. The diagnostic criteria for impaired glucose tolerance/prediabetes include fasting plasma glucose between 100 and 125 mg/dL, 2-hour plasma glucose between 140 and 199 mg/dL following a 75-gm glucose OGTT, and/or HbA1C level between 5.7% and 6.4%. Diabetic nephropathy has proteinuria and the patient should have long history of diabetes. One of the diagnostic criteria for hyperosmolar hyperosmotic syndrome is blood glucose > 600 mg/dl.

15. E. This patient has many risk factors for type II diabetes, and is confirmed by an elevated non-fasting blood glucose level at 250 mg/dl (threshold: 200 mg/dl). Diabetic nephropathy has proteinuria. Hyperosmolar hyperosmotic syndrome has a blood glucose > 600 mg/dl. The diagnostic criteria for impaired glucose tolerance/prediabetes include fasting plasma glucose between 100 and 125 mg/dL, 2-hour plasma glucose between 140 and 199 mg/dL following a 75-gm glucose OGTT, and/or HbA1C level between 5.7% and 6.4%. Type I diabetes is usually seen in younger population.

16. E. One of the risk factors for type II diabetes is obesity. Autoimmune injury of islets and genetic defects are seen in type I diabetes. Cigarette smoking and history of hypertension are not considered significant risk factors for diabetes.

17. D. Markedly elevated blood glucose (>600 mg/dl) without acidosis in a patient with type II diabetes is most compatible with hyperosmolar hyperosmotic syndrome. Hypertensive kidney disease does not cause hyperglycemia. Diabetic ketoacidosis has lower arterial pH and elevated ketone in urine. Diabetic nephropathy has proteinuria and is more likely a chronic process without sudden onset of neurological symptoms. Urinary tract infection has white cells in urine and tend to be positive for urine cultures.

18. A. The key pathogenesis for hyperosmolar hyperosmotic syndrome is hyperglycemia caused osmotic diuresis and subsequent dehydration, and prerenal kidney dysfunction.

19. D. See discussion in question 18.

Back to practice questions 1, pathology of endocrine pancreas

Back to pathology of endocrine pancreas

Back to pathology of endocrine system

Back to contents