Hematology & oncology Clinical Case / MCQS / Uworld for Usmle step 2 / case 3

 Hematology & oncology Clinical Case  / MCQS / Uworld for Usmle step 2 / case 3 with answer and explanation and references and Educational objective

A 42-year-old woman comes to the physician with bilateral knee pain that severely limits her mobility. She also complains of diffuse morning joint stiffness that takes several hours to improve. She has been taking over-the-counter ibuprofen and aspirin but has experienced little relief of symptoms. She has no other medical problems and does not use tobacco, alcohol, or illicit drugs. Her vital signs are within normal limits. Physical examination shows tenderness and swelling of multiple metacarpophalangeal joints, as well as both wrists and knees. Laboratory results are as follows:

Hemoglobin                             8.4 g/dL

Serum iron                               30 µg/dL (normal 50-150 µg/dL)

Total iron-binding capacity     230 µg/dL (normal 250-460 µg/dL)

Ferritin                                     300 ng/mL (normal15-200 ng/mL )

 

Which of the following is the most appropriate next step in management of this patient's anemia?

 

A. Cyanocobalamin supplementation . B. Erythropoietin . C. Folic acid supplementation . D. Iron supplementation . E. Methotrexate . F. Packed red blood cell transfusion . G. Splenectomy .

 

Answer : E

Explanation:

Iron studies in microcytic anemia
Cause	MCV	Iron	TIBC	Ferritin	Transferrin saturation (lron/TIBC)
Iron deficiency	↓	↓	↑	↓	↓
Thalassemia	↓↓	↑	↓	↑	↑↑
Anemia of chronic disease (inflammation)	Normal / ↓	↓	↓	Normal / ↑	Normal / ↓

MCV = mean corpuscular volume; TIBC = total iron binding capacity.

This patient has inflammatory arthritis, which is most consistent with early rheumatoid arthritis. She has moderate anemia with low serum iron and total iron-binding capacity (TIBC) consistent with anemia of chronic disease (ACD). Other characteristic laboratory findings of ACD include normochromic normocytic red blood cells, mildly decreased transferrin saturation, and normal to elevated ferritin. In contrast, iron-deficiency anemia features elevated TIBC and low ferritin. Erythropoietin levels are variable, but ACD patients usually have a low reticulocyte count relative to anemia severity, suggesting impaired red blood cell production. ACD pathophysiology is thought to involve iron trapping within macrophages, leading to reduced serum iron concentrations and poor iron availability for hemoglobin synthesis. Decreased erythropoietin production and poor marrow response to erythropoietin may also play a role.

 

ACD is commonly associated with chronic inflammatory diseases (eg, infections, cancer, autoimmune disorders) but can also be observed in heart disease, diabetes mellitus, and acute inflammation. Treating the underlying inflammatory disorder will often improve the anemia. Common agents used in rheumatoid arthritis treatment include methotrexate, hydroxychloroquine, and tumor necrosis factor inhibitors (eg, infliximab, etanercept).

Erythropoietin or darbepoetin treatment may benefit ACD patients unresponsive to underlying inflammatory disorder treatment (Choice B). Packed red blood cell transfusions are rarely required but can be considered after all other treatment interventions have failed (Choice F).

 

(Choice D) Serum iron concentrations are low in ACD patients. However, iron supplementation is not beneficial due to impaired iron utilization in ACD.

 

(Choices A and C) B-complex vitamins (pyridoxine, folic acid, cyanocobalamin, nicotinic acid) are not deficient in ACD; supplementation will not improve the anemia of ACD.

 

(Choice G) Hereditary spherocytosis is treated via splenectomy; this can be occasionally used for treating immune thrombocytopenic purpura and chronic idiopathic myelofibrosis with refractory anemia. However, splenectomy will not improve this patient's anemia.

 

Educational objective:

 

Anemia of chronic disease is a disorder of iron utilization that most commonly occurs in the setting of chronic inflammation. It is characterized by a normocytic anemia with decreased serum iron, decreased total iron-binding capacity, decreased iron saturation, and normal/elevated serum ferritin. Treating the underlying inflammatory disorder will often improve the anemia.

 

References: 1.   Anemia of chronic disease. New link : 2.   Anemia of chronic disease.

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