UWORLD Chapter 35: Anemia

What 3 lab values are decreased in anemia?

RBCs, hemoglobin, and hematocrit

What are reticulocytes?

immature RBCs

What are erythrocytes?

red blood cells

What are causes of anemia?

- impaired RBC production

- increased RBC destruction

- acute or chronic blood loss

- nutritional deficiencies

- CKD

What are complications of anemia?

fatigue, weakness, SOB, exercise intolerance, headache, dizziness, and/or pallor

What is microcytic vs macrocytic anemia?

microcytic = low MCV (<80)

macrocytic = high MCV (>100)

What is the likely cause of microcytic anemia?

iron deficiency

What are likely causes of normocytic anemia?

Acute blood loss, malignancy, CKD, bone marrow failure (aplastic anemia), hemolysis

What are likely causes of macrocytic anemia?

Vitamin B12 or folate deficiency

What lab tests are used to evaluate causes of anemia?

MCV, iron studies, Vitamin B12, folate, reticulocyte count

What is the most common type of anemia

iron deficiency anemia

What labs are included in an iron study?

serum iron, serum ferritin, total iron binding capacity, transferrin saturation

What are causes of iron deficiency?

low iron intake

blood loss (heavy menses, PUD)

decreased iron absorption (high gastric pH, GI disorders, gastric bypass)

increased iron requirements (pregnancy, lactation, infants)

What are the lab values usually seen with iron deficiency anemia?

low Hgb, reticulocyte count, serum iron, ferritin, and TSAT, MCV<80

increased TIBC

What is the treatment and counseling points for iron deficiency anemia?

- Iron (1 tablet everyday or every other day)

- take on empty stomach (1 hr before or 2 hrs after meals) for best absorption

- Avoid H2RAs and PPIs, separate from antacids

- Sustained release or enteric coated formulations cause less GI upset

What is the treatment goal of iron deficiency anemia?

increase in Hgb by 1g/dL every 2-3 weeks, continue treatment for 3-6 months or until iron stores return to normal

How much elemental iron is in ferrous sulfate?

20% (so ferrous sulfate 325 x 0.2 = 65 mg elemental iron)

What are boxed warnings of oral iron?

Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under age 6 years. In the case of accidental overdose, go to emergency room or call a poison control center immediately (even if asymptomatic)

What is the side effects of oral iron?

constipation (dose related), dark and tarry stools

What is the antidote for iron overdose?

Deferoxamine (Desferal)

What is the elemental iron percentage in ferrous gluconate?

12%

What is the elemental iron percentage in ferrous sulfate?

20%

What is the elemental iron percentage in ferrous sulfate (dried)?

30%

What is the elemental iron percentage in ferrous fumarate?

33%

What are drug interactions with oral iron?

- chelation: tetracyclines, dopamine, FOS, levothyroxine, INSTIs

- increased absorption: ascorbic acid

- decreased absorption: phosphate, calcium, zinc, antacids, H2 blockers, PPIs

Who is IV iron restricted for

CKD on HD

CKD receiving ESAs

Unable to tolerate PO

What is the brand name of iron sucrose?

Venofer

What is the brand name of ferumoxytol?

Feraheme

What are the boxed warnings of IV iron?

Iron dextran and ferumoxytol: serious and sometimes fatal anaphylactic reactions

Iron dextran: all patients should be given a test dose prior to first full therapeutic dose

What is a safety warning with all IV iron formulations?

hypersensitivity reactions

What are causes of macrocytic anemia?

alcohol use disorder, low intake of vitamin B12 and/or folate, decreased GI absorption, longterm use of PPIs, H2RAs, and/or metformin

What is pernicious anemia?

Autoimmune destruction of parietal cells in the stomach, leading to loss of intrinsic factor and thus inability to take up vitamin B12. Treatment is lifelong B12 IV replacement

What are symptoms of B12 deficiency?

neurologic dysfunction: cognitive impairment, peripheral neuropathy (can be irreversible)

What type of B12 is recommended first line?

injections

what are symptoms of folate deficiency?

ulcerations of the tongue and oral mucosa