A 50-year-old white man has had increasing orthopnea and worsening pedal edema for the past 3 years. He complains of worsening arthritis involving his hands, knees, hips, and elbows. On physical examination, he has decreased range of motion of the lower legs, but no apparent joint deformities, warmth, or swelling. There is a brownish hue to his skin,
although it is winter, and he rarely goes outdoors. Laboratory findings show hemoglobin, 13.7 g/dL; hematocrit, 40.8%; MCV, 90 μm3; platelet count, 213,500/mm3; WBC count, 6690/mm3; Na+, 141 mmol/L; K+, 4.2 mmol/L; Cl−, 101 mmol/L; CO2, 24 mmol/L; glucose, 201 mg/dL; creatinine, 1.2 mg/dL; and calcium, 8.2 mg/dL. Which of the following underlying
diseases most likely explains these findings?
Diabetes mellitus type 1
Answer : D Hereditary hemochromatosis
The C282Y mutation in the HFE gene can be found in one of nine individuals of Celtic heritage and causes increased absorption of dietary iron.
In men about 40 years old, the increased iron stores lead to organ dysfunction, typically involving the heart (cardiomyopathy with congestive heart failure), pancreas (diabetes mellitus), skin (increased pigmentation), and joints (arthritis).
In women, increased iron loss through menses delays the onset of this disease for 20 more years.
A patient with β-thalassemia would have anemia, although the ineffective erythropoiesis leads to excessive iron absorption.
Although this patient has diabetes mellitus and an increased glucose level, diabetes mellitus type 1 does not explain all the findings, such as the arthritis.
Familial hypercholesterolemia could lead to coronary artery disease and heart failure, but it does not explain the patient’s diabetes or arthritis. Rheumatoid arthritis typically leads to joint deformities and mostly involves small joints.