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Zorluk: OrtaMedical History Evaluation

A 72-year-old man is evaluated in the neurology clinic for a 6-month history of progressive weakness in his legs, unsteadiness, and numbness in his hands and feet. He reports that his symptoms began gradually, but he now requires a cane to ambulate. His medical history is significant for hypertension, osteoarthritis, and severe periodontitis that resulted in full dental extractions 5 years ago. His current prescription medications include hydrochlorothiazide and acetaminophen. On neurological examination, he exhibits spasticity in the lower extremities, 4/5 strength bilaterally in hip flexion and ankle dorsiflexion, and hyperreflexia at the knees. Sensation to vibration and proprioception is markedly decreased at the toes and ankles. Romberg test is positive. Laboratory studies reveal a hemoglobin of 10.2 g/dL, mean corpuscular volume of 108 fL, absolute neutrophil count of 1,100/mm³, normal thyroid-stimulating hormone, normal serum vitamin B12, normal serum folate, and normal methylmalonic acid levels. Which of the following historical elements is most important to elicit to determine the underlying cause of this patient's presentation?

  1. Daily application of large amounts of denture adhesive pasteCevap
  2. B
    Adherence to a strict vegan dietary pattern without vitamin supplementation
  3. C
    Previous employment in a battery manufacturing facility
  4. D
    History of a tick bite followed by an expanding erythematous rash
  5. E
    Chronic, heavy consumption of alcoholic beverages

Cevap

Daily application of large amounts of denture adhesive paste
The correct answer identifies that questioning the patient about over-the-counter denture adhesive use is essential. This patient presents with the classic triad of subacute combined degeneration (SCD), macrocytic anemia, and neutropenia. While this presentation is virtually pathognomonic for vitamin B12 deficiency, his normal B12 and methylmalonic acid levels definitively exclude it. The most common alternative cause for this exact clinical and hematologic picture is acquired copper deficiency. A frequent, yet overlooked historical trigger for copper deficiency is zinc toxicity. Chronic ingestion of large amounts of zinc-containing denture adhesive leads to the up-regulation of metallothionein within intestinal enterocytes. Metallothionein has a higher affinity for copper than for zinc; it binds dietary copper and traps it within the enterocytes, which are subsequently sloughed off into the gastrointestinal tract, leading to profound systemic copper deficiency. Therefore, eliciting a history of heavy denture adhesive use is the critical next step in establishing the diagnosis.

Adım Adım Çözüm

1
Analyze the patient's clinical presentation.
The patient exhibits a macrocytic anemia, neutropenia, and neurologic signs of subacute combined degeneration (spasticity, hyperreflexia, and profound loss of vibration/proprioception).
Identifying this classic syndromic triad narrows the differential diagnosis primarily to vitamin B12 deficiency and copper deficiency.
2
Evaluate the laboratory findings in the context of the differential diagnosis.
Normal levels of vitamin B12, folate, and methylmalonic acid are present.
Normal vitamin B12 and methylmalonic acid levels definitively rule out vitamin B12 deficiency, pointing strongly to acquired copper deficiency as the etiology.
3
Synthesize the remaining diagnosis with the patient's medical history to identify the trigger.
The patient had full dental extractions 5 years ago, implying current denture use. Chronic use of zinc-containing denture adhesive causes copper deficiency.
High enteral zinc up-regulates metallothionein in enterocytes. Metallothionein preferentially binds copper, trapping it in the enterocytes which are subsequently shed into the gut lumen, blocking systemic copper absorption.

Anahtar Kavram

Copper deficiency closely mimics vitamin B12 deficiency, presenting with subacute combined degeneration, macrocytic anemia, and neutropenia. A classic historical trigger is chronic excessive ingestion of zinc-containing denture adhesive.
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Medical History Evaluation

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