MKSAP(S) – Endocrinology & Metabolism (1)

MKSAP for Students 5 in the WHOLE

Item 1 [Basic]

A 48-year-old man comes to the office for a routine physical examination. The patient is asymptomatic but overweight. Although he has no pertinent personal medical history, he has a strong family history of diabetes mellitus. He currently takes no medications.
Results of physical examination are normal, except for a BMI of 29.
Results of routine laboratory studies show a fasting plasma glucose level of 158 mg/dL (8.8 mmol/L). These results are confirmed 2 days later.

Which of the following terms best describes his current glycemic status?
(A) Impaired fasting glucose
(B) Impaired glucose tolerance
(C) Metabolic syndrome
(D) Type 2 diabetes mellitus

Answer
Educational Objective: Diagnose type 2 diabetes mellitus.
This patient has type 2 diabetes mellitus. The diagnosis of diabetes mellitus can be established by a fasting plasma glucose level of at least 126 mg/dL (7.0 mmol/L), a random plasma glucose level of at least 200 mg/dL (11.1 mmol/L) and symptoms of hyperglycemia (for example, polyuria, polydipsia, or blurred vision), or a 2-hour oral glucose tolerance test (OGT T ) result of at least 200 mg/dL (11.1 mmol/L). In 2010, the American Diabetes Association endorsed a hemoglobin A1c value of 6.5% of greater as diagnostic of diabetes.
Impaired fasting glucose, impaired glucose tolerance, or both mark the transition from normal glucose tolerance to type 2 diabetes mellitus. Impaired fasting glucose is diagnosed when the fasting plasma glucose level is in the range of 100 to 125 mg/dL (5.6 to 6.9 mmol/L), and impaired glucose tolerance—an analogous prediabetic state—is diagnosed when the plasma glucose level at the 2-hour mark of an OGT T is 140 to 199 mg/dL (7.8 to 11.0 mmol/L).
For a diagnosis of the metabolic syndrome to be made, information about the patient’s blood pressure (≥130/85 mm Hg), lipid levels (triglyceride level ≥150 mg/dL [1.7 mmol/L]; HDL-cholesterol <40 mg/dL in men [1.0 mmol/L]), fasting plasma glucose level (≥110 mg/dL [6.1 mmol/L]), and waist circumference (>40 in [>102 cm] in men) is necessary. Insufficient data have been provided for this diagnosis.
Key Point
Type 2 diabetes mellitus is diagnosed when the fasting plasma glucose level is 126 mg/dL (7.0 mmol/L) or greater, the random plasma glucose level is 200 mg/dL (11.1 mmol/L) or greater, the plasma glucose level is 200 mg/dL (11.1 mmol/L) or greater after a 2-hour oral glucose tolerance test, or the venous hemoglobin A1c value is 6.5% or greater.
Bibliography
American Diabetes Association. Standards of medical care in diabetes—2010. Diabetes Care. 2010;33 Suppl 1:S11-61. [PMID: 20042772]

Item 2 [Basic]

A 68-year-old woman is re-evaluated after laboratory studies show a fasting plasma glucose level of 113 mg/dL (6.3 mmol/L). She has a family history of type 2 diabetes mellitus.
On physical examination, blood pressure is 142/88 mm Hg and BMI is 29. Other vital signs and examination findings are normal.
She undergoes an oral glucose tolerance test, during which her 2-hour plasma glucose level increases to 135 mg/dL (7.5 mmol/L).
Which of the following is the most appropriate treatment recommendation?
(A) Acarbose
(B) Metformin
(C) Ramipril
(D) Rosiglitazone
(E) Diet and exercise

Answer
Educational Objective: Treat prediabetes with diet and exercise.
The most appropriate treatment for this patient is diet and exercise. She has impaired fasting glucose (IFG), defined as a fasting plasma glucose level in the range of 100 to 125 mg/dL (5.6 to 6.9 mmol/L), and should begin a program of intensive lifestyle change, including 30 minutes of exercise most days of the week and a calorie-restricted diet, to achieve weight reduction on the order of 7% of body weight.
Diet and exercise is the recommended approach for patients with either IFG or impaired glucose tolerance (IGT), the prediabetic states. The relative risk reduction (RRR) in the incidence of diabetes in patients with IGT associated with intensive lifestyle change is 58%.
Pharmacologic therapy with glucose-lowering drugs is not indicated for this patient with isolated IFG. In pharmacologic studies of diabetes prevention, acarbose therapy resulted in only a 25% RRR, which is inferior to that obtained with diet and exercise.
Metformin therapy is associated with an RRR of 31%, which is also inferior to the 58% RRR obtained with diet and exercise. Metformin therapy may be considered in patients with both IFG and IGT , who constitute a higher risk group. This patient does not have IGT (fasting plasma glucose level of 140 to 199 mg/dL [7.7 to 11.0 mmol/L] at the 2-hour mark of an oral glucose tolerance test) and so should not receive metformin.
Modulators of the renin-angiotensin axis, such as ramipril and other angiotensin-converting enzyme inhibitors, do not contribute to diabetes prevention.
Rosiglitazone and pioglitazone have been associated with 62% and 81% RRRs, respectively, in the incidence of diabetes. These agents, however, are not endorsed for routine pharmacologic use in patients with prediabetes because of their costs and adverse effects, including edema, increased fracture risk in women, and possible increased cardiovascular morbidity.
Key Point
Patients with prediabetes should be advised to adopt a program of lifestyle change to prevent progression to type 2 diabetes mellitus.
Bibliography
Vijan S. Type 2 diabetes. Ann Intern Med. 2010;152(5):IT C31-15. [PMID: 20194231]

Item 3 [Advanced]

A 51-year-old man is evaluated for a 9-month history of chronic abdominal pain. He has a long-standing history of alcoholism and has been admitted to the hospital several times in the past 8 years for acute pancreatitis. He reports a 5.5-kg (12.1-lb) weight loss over the past year. He currently takes no medications.
Vital signs are normal; BMI is 23. Physical examination reveals a scaphoid-appearing abdomen with normal bowel sounds and diffuse abdominal tenderness to palpation without guarding.
A fasting plasma glucose level is 175 mg/dL (9.7 mmol/L), and a repeat fasting plasma glucose level is 182 mg/dL (10.1 mmol/L). Urine ketones are negative.
A CT scan of the abdomen reveals diffuse pancreatic calcifications.
Which of the following is the best categorization of this patient’s diabetes mellitus?
(A) Late-onset autoimmune diabetes of adulthood
(B) Secondary diabetes
(C) Type 1 diabetes
(D) Type 2 diabetes
(D) Begin pioglitazone
(E) Continue the diet and exercise for an additional 3 months

Item 4 [Basic]

An obese 44-year-old woman is evaluated for persistent hyperglycemia. For the past 3 months, she has followed a strict regimen of diet and exercise in an attempt to control her hyperglycemia. Home blood glucose monitoring has shown preprandial levels between 120 and 160 mg/dL (6.7 and 8.9 mmol/L) and occasional postprandial levels exceeding 200 mg/dL (11.1 mmol/L). She takes no medications.
Vital signs and physical examination findings are normal, except for a BMI of 30.
Laboratory studies show a serum creatinine level of 0.8 mg/dL (70.7 μmol/L); the urine is negative for microalbuminuria.
Which of the following is the most appropriate treatment?
(A) Begin exenatide
(B) Begin glimepiride
(C) Begin metformin
(D) Begin pioglitazone
(E) Continue the diet and exercise for an additional 3 months

Item 5 [Advanced]

A 78-year-old man is evaluated in the hospital for poor glycemic control before undergoing femoral-popliteal bypass surgery. He has been on the vascular surgery ward for 3 weeks with a nonhealing foot ulcer. The patient has an extensive history of arteriosclerotic cardiovascular disease, including peripheral vascular disease, and a 20-year-history of type 2 diabetes mellitus. His most recent hemoglobin A1c value, obtained on admission, was 8.9%. His diabetes regimen consists of glipizide. While in the hospital, his plasma glucose levels have generally been in the 200 to 250 mg/dL (11.1 to 13.9 mmol/L) range. He is eating well.
In addition to stopping glipizide, which of the following is most appropriate treatment for this patient?
(A) Basal insulin and rapid-acting insulin before meals
(B) Continuous insulin infusion
(C) Neutral protamine Hagedorn (NPH) insulin twice daily
(D) Sliding scale regular insulin

Item 6 [Advanced]

A 48-year-old man is evaluated for mild blurring of his central vision bilaterally. He has had type 1 diabetes mellitus for 24 years. The patient is referred for an immediate retinal examination, which reveals macular edema and new neovascularization.
Which of the following is the most appropriate next management step?
(A) Addition of aspirin
(B) Addition of atorvastatin
(C) Decrease in the insulin dosage
(D) Retinal photocoagulation

Item 7 [Basic]

A 67-year-old woman is seen for a follow-up visit. She has had several hypoglycemic episodes that have become increasingly frequent over the past 6 months. Her current medications are neutral protamine Hagedorn (NPH) insulin, 20 units, and regular insulin, 5 units, both injected before breakfast and supper. A review of her glucose log shows blood glucose readings ranging between 70 and 150 mg/dL (3.9 and 8.3 mmol/L) when fasting and 50 and 250 mg/dL (2.8 and 13.9 mmol/L) during the day. Her last measured hemoglobin A1c value was 7.8%.
Which of the following changes is most appropriate?
(A) Change to insulin glargine and insulin lispro
(B) Change to oral metformin and sitagliptin
(C) Decrease the dosages of NPH and regular insulin by 10%
(D) Increase her caloric intake

Item 8 [Basic]

A 20-year-old woman is brought to the emergency department by her college roommate. The patient is lethargic with rapid respirations. Her roommate reports that the patient has had a cough, fever, and chills for the 3 days. She has a 12-year history of type 1 diabetes mellitus. During the previous 24 hours, the patient has had poor oral intake and has not taken her insulin. Today she developed abdominal pain, nausea, and vomiting.
On physical examination, the patient is lethargic but arousable. Temperature is 35.5°C (96.0°F), blood pressure is 90/68 mm Hg, pulse rate is 120/min, and respiration rate is 28/min and deep. The cardiopulmonary examination is normal. Bowel sounds are diminished but present. Palpation elicits generalized tenderness, but no peritoneal signs are present. Other than lethargy, the neurologic examination is normal.
Which the following tests will establish the diagnosis?
(A) Serum glucose and electrolytes and urine ketones
(B) Serum glucose and potassium, complete blood count, and urinalysis
(C) Serum glucose, electrolytes, and ketones and arterial blood gases
(D) Serum glucose, phosphate, and potassium and arterial blood gases
(E) Serum ketones and carbon dioxide, complete blood count, and urine ketones

Item 9 [Advanced]

An 83-year-old obtunded woman is evaluated in the emergency department. She has a history of type 2 diabetes mellitus treated with insulin glargine. The patient developed nausea, vomiting, and diarrhea 2 days ago. Her oral intake was limited, and she did not receive her insulin. Today, the patient was found minimally responsive.
On physical examination, the patient responds only to noxious stimuli with groaning. Temperature is 35.9°C (96.7°F), blood pressure is 90/50 mm Hg, pulse rate is 120/min, and respiration rate is 14/min. She has dry mucous membranes, and her skin demonstrates prolonged tenting. Other than obtundation, the neurologic examination is normal.

  • Glucose 976 mg/dL (54.2 mmol/L)
    Blood urea nitrogen 46 mg/dL (16.4 mmol/L)
    Creatinine 2.1 mg/dL (185.6 mmol/L)
  • Electrolytes
    Sodium 132 meq/L (132 mmol/L)
    Potassium 4.8 meq/L (4.8 mmol/L)
    Chloride 98 meq/L (98 mmol/L)
    Carbon dioxide 22 meq/L (22 mmol/L)
    Osmolality 335 mosm/kg H2O
    Serum ketones Negative
    Arterial pH 7.33

Which of the following is the best next management step for this patient?
(A) Administer broad-spectrum antibiotics
(B) Bicarbonate replacement
(C) Insulin administration
(D) Intravenous fluid administration
(E) Potassium replacement

Item 10 [Basic]

A 23-year-old woman with type 1 diabetes mellitus is admitted to the hospital with a diagnosis of community-acquired pneumonia and lethargy. Before admission, her insulin pump therapy was discontinued because of confused mentation.
On physical examination, temperature is 37.5°C (99.5°F), blood pressure is 108/70 mm Hg, pulse rate is 100/min, and respiration rate is 24 min. There are decreased breath sounds in the posterior right lower lung. Neurologic examination reveals altered consciousness.

  • Blood urea nitrogen 38 mg/dL (13.6 mmol/L)
    Creatinine 1.4 mg/dL (123.8 μmol/L)
  • Electrolytes
    Sodium 130 meq/L (130 mmol/L)
    Potassium 5.0 meq/L (5.0 mmol/L)
    Chloride 100 meq/L (100 mmol/L)
    Bicarbonate 14 meq/L (14 mmol/L)
    Glucose 262 mg/dL (14.5 mmol/L)
    Urine ketones Positive
    Rapid infusion of normal saline is initiated.

Which of the following is the most appropriate next management step?
(A) Add insulin glargine
(B) Add neutral protamine Hagedorn (NPH) insulin
(C) Implement a sliding scale for regular insulin
(D) Start an insulin drip

Item 11 [Basic]

A 50-year-old man is evaluated during a routine physical examination. He is asymptomatic, has no medical problems, and takes no medications. He is a nonsmoker and drinks
two alcoholic beverages daily. His father, uncle, and a brother had myocardial infarctions between the ages of 55 and 60 years.
On physical examination, vital signs are normal. BMI is 28. On the skin examination, he has soft, nontender, yellow plaques measuring between 0.5 and 1 cm on his upper eyelids. The remainder of the physical examination results are normal.
Which of the diagnostic studies should be done next?
(A) Aminotransferase and alkaline phosphatase
(B) Serum ferritin
(C) Serum glucose and hemoglobin A1c
(D) Serum lipids
(E) Thyroid-stimulating hormone