MLSP 5213: W3 Anemias

What causes iron deficiency anemia

Chronic blood loss (GI bleed in adults, menstruation in young women), poor intake, malabsorption (celiac), increased demand (pregnancy).

Typical age groups for IDA?

Infants/toddlers: poor intake

Young women: menstruation

Older adults: occult GI malignancy (colon cancer until proven otherwise)

Key labs to diagnose IDA?

Low ferritin, low serum iron, high TIBC, high RDW, microcytic hypochromic RBCs.

Treatment for IDA?

Oral or IV iron plus identification of bleeding source.

What causes anemia of chronic disease?

Chronic inflammation; high hepcidin meaning iron trapped in macrophages.

Common patient populations for ACD?

Older adults with chronic infections, autoimmune disease, cancer, CKD.

How do iron studies for ACD differ from IDA?

Normal/high ferritin, low serum iron, low/normal TIBC.

Treatment for ACD?

Treat underlying condition; EPO if severe.

What causes thalassemia?

Genetic decrease in globin chain production (α or β chains).

Age of presentation of thalassemia?

Trait: childhood or incidental finding

Major forms: infancy (after HbF declines)

Hallmark lab clue for thalassemia?

Very low MCV with mild anemia, normal RDW, target cells.

Confirmatory test for thalassemia?

Hemoglobin electrophoresis.

Treatment for thalassemia?

None for trait; transfusions and iron chelation for severe forms.

Cause of acute blood loss anemia?

Trauma, GI bleed, obstetric hemorrhage

Lab pattern of acute blood loss: early vs later?

Early: normal Hb/MCV; Later: low Hb with high reticulocytes.

Treatment for acute blood loss anemia?

Control bleeding, volume replacement, transfusion if severe

What defines hemolytic anemia?

Premature RBC destruction exceeding marrow compensation.

Core lab findings of Hemolytic anemia?

high retics, high LDH, high indirect bilirubin, low haptoglobin

Cause of hereditary spherocytosis?

RBC membrane cytoskeleton defect (spectrin).

Typical age group of hereditary spherocytosis?

Childhood or adolescence.

Smear finding of hereditary spherocytosis?

Spherocytes (no central pallor).

Treatment of hereditary spherocytosis?

Splenectomy (corrects anemia, not membrane defect).

Cause of G6PD deficiency?

X-linked enzyme defect → inability to handle oxidative stress.

Common triggers of G6PD deficiency

Infections, sulfa drugs, antimalarials, aspirin, mothballs, fava beans.

Typical patient of G6PD deficiency

Males of African, Mediterranean, or Middle Eastern descent.

Smear clue of G6PD deficiency

Bite cells, Heinz bodies (special stain).

Treatment of G6PD deficiency

Avoid oxidant triggers; supportive care.

Cause of AIHA?

Autoantibodies against RBCs.

Age group of AIHA?

Adults; often secondary to autoimmune disease or malignancy.

Key diagnostic test of AIHA?

Positive direct Coombs test.

Treatment of AIHA?

Steroids, immunosuppression, splenectomy if refractory.

Cause of MAHA?

RBC fragmentation in damaged small vessels (DIC, TTP, HUS).

Smear finding of MAHA?

Schistocytes

Treatment of MAHA?

Treat underlying cause (plasma exchange for TTP).

Cause of aplastic anemia?

Bone marrow stem cell failure (drugs, radiation, viruses, idiopathic).

Typical age of aplastic anemia?

Biphasic: teens/young adults and older adults.

Lab pattern of aplastic anemia?

Pancytopenia, very low reticulocytes.

Treatment of aplastic anemia?

Bone marrow transplant, immunosuppression.

Why does kidney disease cause anemia?

Low Erythropoietin production.

Typical patient of anemia of renal failure?

Adults with chronic kidney disease.

Smear clue of anemia of renal failure?

echinocytes.

Treatment of anemia of renal failure?

Recombinant EPO, dialysis.

Cause of B12 deficiency?

Pernicious anemia, malabsorption, vegan diet.

Typical age of B12 deficiency?

Older adults.

Unique clinical clue of B12 deficiency?

Neurologic symptoms (paresthesias, ataxia).

Treatment of B12 deficiency?

Vitamin B12 replacement (IM or oral).

Cause of folate deficiency?

Poor diet, alcoholism, pregnancy.

Age group of folate deficiency?

Adults, pregnant patients, alcohol use disorder.

Key distinction of folate deficiency from B12 deficiency?

No neurologic symptoms.

Treatment of folate deficiency?

Oral folate supplementation.

Best single test to separate anemia causes?

Reticulocyte count.

Rule for treatment?

Never treat the number—treat the cause.