A family physician has a short break between seeing patients in her busy clinic. Looking over her survey, she wants to identify which patients need to be referred for screening colonoscopy.
Which of the following patients should be screened for colon cancer?
Correct Answer D:
As of 2014, colorectal cancer is the second most common cause of cancer death in males, and third most common cause of cancer death in females. Screening can take the form of a screening colonoscopy, flexible sigmoidoscopy, fecal occult blood testing, barium enema, and CT colonography ("virtual colonoscopy"). The most preferred test is the colonoscopy for its accuracy, and because it allows direct visualization and biopsy of lesions.
Screening colonoscopy guidelines include the following:
→ A 47-year-old hypertensive female with no personal or family history of colon cancer (choice A) is incorrect. She does not need screening for another three years. Hypertension does not alter the screening schedule.
→ A 30-year-old diabetic male with a family history of colon cancer in his father at the age of 45 (choice B) does not need screening until age 35 (10 years before onset in family member).
→ A 40-year-old male with Peutz-Jeghers syndrome and no family history of cancer and negative colonoscopy 1 year ago (choice C) would not require the colon cancer screening. Surveillance for gastric and small-bowel polyposis should begin at age 8-10 years and continue at 2-year intervals.
→ A 60-year-old male with a history of colon cancer resection 2 years ago and a colonoscopy 1 year ago (choice E) does not need a colonoscopy for another two years. Patients with previous colon cancer resection receive screening colonoscopy at 1, 3, and 5 years after resection.
Key point:
A hemoglobin A1C of 7.0% would correspond to which one of the following mean (average) plasma glucose levels?
Correct Answer B:
A hemoglobin A1c (HbA1c) of 6.0% correlates with a mean plasma glucose level of 126 mg/dL or 7.0 mmol/dL. A calculator to convert HbA1c levels into estimated average glucose levels is available at http://professional.diabetes.org/eAG.
A rough guide for estimating average plasma glucose levels assumes that an HbA 1c of 6.0% equals an average glucose level of 120 mg/dL. Each percentage point increase in HbA1c is equivalent to a 30-mg/dL rise in average glucose. An HbA1c of 7.0% is therefore roughly equivalent to an average glucose level of 150 mg/dL, and an HbA1c of 8.0% translates to an average glucose level of 180 mg/dL.
The relationship between A1C and eAG is described by the formula 28.7 X A1C – 46.7 = eAG
Early in September, a family physician sees his diabetic patient after 5 month. The patient is not feeling well and random blood glucose is 11.2 mmol/L. Hemoglobin A1C (HbA1c) is 7.8%.
One month's average blood glucose probably contributed most to HbA1c in this patient.
Which one is it?
Correct Answer A:
The average blood sugar of month prior to measurement, August (choice A), probably contributed most to hemoglobin A1C (HbA1c) in this patient. The average life span of red blood cells is 120 days or four months. Of the circulating red cells in this patient at the time of measurement of HbA1c, very little is produced more than 120 days ago (April and earlier), a small proportion is produced between 90 and 120 days (May) ago, a slightly larger proportion is produced 60 and 90 (June) days ago and the largest proportion is produced within the 30 days or last month (August). It follows that glycated hemoglobin produced in the prior month contributes to about 50% of circulating HbA1c.
A 60-year-old Chinese female asks you about being tested for osteoporosis. She is postmenopausal and has never used hormone therapy. She does not consume dairy products because she has lactose intolerance. She is on no medications, is otherwise healthy, and has no history of falls or fractures. Her mother had osteoporosis and vertebral compression fractures. Her BMI is 20 kg/m².
Which one of the following tests would be best to determine whether this patient has osteoporosis?
This patient has several risk factors for osteoporosis: Asian ethnicity, low body weight, positive family history, postmenopausal status with no history of hormone replacement, and low calcium intake. The best diagnostic test for osteoporosis is a central dual-energy X-ray absorptiometry (DXA, previously DEXA) of the hip, femoral neck, and lumbar spine (choice A).
→ Quantitative CT (choice C) is accurate, but cost and radiation exposure are issues.
→ Peripheral DXA (choice B) and calcaneal sonography (choice D) results do not correlate well with central DXA.
→ Measurement of biochemical marker (choice E) s is not recommended for the diagnosis of osteoporosis.
Which one of the following patients is unlikely to benefit from vaccination against hepatitis A?
Correct Answer E:
Each of the individuals listed is at increased risk for hepatitis A infection or its complications, except for the Indian immigrant. Hepatitis A is so prevalent in developing countries such as India that virtually everyone is infected by the end of childhood, and therefore immune. Infection with hepatitis A confers lifelong immunity, so an adult from a highly endemic area such as India has little to gain from vaccination.
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