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Zorluk: OrtaOrdering Laboratory Tests

A 54-year-old male construction worker visits his primary care provider complaining of a 6-month history of progressive fatigue, generalized weakness, and joint pain affecting his hands, wrists, and knees. He also mentions a recent, uncharacteristic decline in libido. His medical history is notable for type 2 diabetes mellitus diagnosed one year ago, which is currently managed with metformin. Vital signs are within normal limits. Physical examination reveals a firm, palpable liver edge 4 cm below the right costal margin and a diffuse, bronze-colored hyperpigmentation of the skin that is most prominent on his face and forearms. Joint examination demonstrates bony enlargement of the second and third metacarpophalangeal joints bilaterally without significant warmth, erythema, or synovial thickening. Which of the following is the most appropriate next step in laboratory evaluation?

  1. A
    Genetic testing for HFE gene mutations
  2. B
    Rheumatoid factor and anti-cyclic citrullinated peptide antibodies
  3. Serum transferrin saturation and ferritin levelsCevap
  4. D
    Early morning total and free serum testosterone
  5. E
    Magnetic resonance imaging of the abdomen

Cevap

Serum transferrin saturation and ferritin levels
This patient presents with a classic constellation of symptoms for hereditary hemochromatosis (HH), including new-onset atypical diabetes mellitus, hepatomegaly, bronze-colored skin hyperpigmentation, hypogonadism (evidenced by decreased libido), and a characteristic arthropathy involving the second and third metacarpophalangeal (MCP) joints. The most appropriate initial step in the laboratory evaluation of suspected HH is obtaining a serum transferrin saturation and a serum ferritin level. A transferrin saturation greater than 45% is highly sensitive for HH and warrants further confirmatory testing.

Adım Adım Çözüm

1
Identify the underlying clinical syndrome based on the patient's comprehensive presentation.
The patient exhibits new-onset diabetes, hepatomegaly, bronze skin hyperpigmentation, specific arthropathy (2nd and 3rd MCP joints), and hypogonadism.
This constellation of findings is the classic presentation for hereditary hemochromatosis, a disorder of systemic iron overload.
2
Determine the most appropriate initial diagnostic laboratory test for the suspected condition.
The initial screening test is an iron panel, specifically serum transferrin saturation and ferritin levels.
Non-invasive, cost-effective biochemical evidence of iron overload (transferrin saturation > 45%) is required before proceeding to confirmatory genetic testing or invasive biopsies.

Anahtar Kavram

The most appropriate initial laboratory evaluation for patients presenting with clinical signs of hereditary hemochromatosis (e.g., hepatomegaly, skin hyperpigmentation, new-onset diabetes, and MCP arthropathy) is measuring serum transferrin saturation and ferritin levels.
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