Division of General Internal Medicine and Geriatrics

Hospital Medicine

Revised 2015

Define Anemia

Describe both kinetic and morphologic approach to determining cause of anemia

Understand pertinent history, physical findings, and indicated studies

Recognize common types of anemia seen in clinical practice

Objectives

Exact cut-off values vary slightly by populations, but in

general, anemia is defined as

Hgb <13.5g/dL or Hct <41% in men

Hgb <12g/dL or Hct <36% in women

Keep in mind that Hgb and Hct are concentrations and dependent on volume status

Anemia

Erythropoiesis takes place within the bone marrow under

the influence of erythropoietin (EPO), a hormone produced in the kidney by cells that sense the adequacy of tissue oxygenation

Immature RBCs (reticulocytes) are formed and typically mature in the marrow for 2-3 days, then are released into the circulation, where they mature for an additional day

RBC circulates for 110-120 days, then is removed by macrophages

Under steady state, RBC production = RBC loss

RBC life cycle

Symptoms are due to decreased Oxygen delivery and, in

the case of acute bleeding, hypovolemia

Primary symptoms: DOE dyspnea at rest

fatigue

palpitations

If severe: lethargy, confusion, high output heart failure, MI

Hypovolemia: dizziness, syncope, shock

Symptoms

Causes of Anemia

Kinetic Approach

Decreased RBC production

Increased RBC destruction

Blood loss

Morphologic Approach

Based on measurement of RBC size Normocytic

Microcytic

Macrocytic

Iron def

Thalassemias

Sideroblastic (congenital, lead, EtOH, drugs)

AOCD

Copper def, Zinc poisoning (rare)

Microcytic (MCV<80)

Acute blood loss

IDA (early)

AOCD (infection, inflammation)

Chronic renal insufficiency

Hypothyroidism

Hypopituitarism

Bone marrow suppression (may also be macrocytic)

Normocytic (MCV 80-100)

Alcohol abuse

B12 deficiency

Folate deficiency

Myelodysplastic syndromes

Reticulocytosis (response to blood loss, hemolysis, etc)

Liver disease

Acute myeloid leukemias

Drug induced (eg, Hydroxyurea, AZT, chemo agents)

Macrocytic (MCV>100)

Take a good history!!

Look for chronic blood loss (dark stools, dyspepsia, abnormal menses, etc)

PMH, signs of infection or inflammatory diseases

Family history of blood disorders, inflamm dz, etc

Medications

Diet, EtOH use, Pica

Neurologic symptoms

Evaluation of the Patient with Anemia

Assess severity and find signs of organ or multisystem

involvement. Tachycardia, Postural hypotension

Dyspnea

Fever

Jaundice

Pallor

Petechiae, ecchymoses

Splenomegaly

Lymphadenopathy

Stool for occult blood

Physical Exam

Laboratory Evaluation

Look at other cell lines (WBC, platelets), RBC indices such as MCV, MCH

Reticulocytes Reticulocyte Production Index of >3 indicates a normal response;

<2 inadequate response

Hemolysis labs: Increased LDH, decreased Haptoglobin, increased indirect bilirubin

Iron studies, B12, Folate, LFTs, Cr, TFTs

Hgb electropheresis

Peripheral blood smear: schistocytes, tear drop cells, look for abnormal WBCs or platelets as well

Bone Marrow bx

Iron is needed in the marrow for heme synthesis RBC

production and maturation

Causes: blood loss (GI, menstrual)

Decreased supply: malnutrition, malabsorption

Increased need (pregnancy)

Microcytosis, anisopoikilocytosis (unequal RBC size, shape)

↓Iron, ↑TIBC (transferrin), ↓Transferrin saturation, and ↓Ferritin (<15)

Treatment: Reverse underlying cause, PO Iron (constipation, dark stools), IV Iron sucrose

Iron Deficiency Anemia (IDA)

Needed for DNA synthesis

Binds to intrinsic factor secreted by gastric parietal cells, then is absorbed in the ileum

Causes:

Malnutrition (alcoholics, vegans, elderly)

Malabsorption: Pernicious anemia (↓IF), sprue, Crohn’s, s/p gastric bypass

Glossitis, neurologic and psychiatric symptoms, sometimes pancytopenia

↓B12 (cobalamin), ↑homocysteine and methylmalonic acid

Hypersegmented neutrophils on smear

Treatment: 1mg B12 IM daily x 7d, then weekly x 4 weeks, then monthly for life if malabsorption (OK to use PO after stores replete in those with normal absorption)

B12 Deficiency

Small stores of folate in body, thus you can become deficient

relatively quickly (but can also be repleted quickly)

Causes:

Malnutrition, EtOH abuse, pregnancy, malabsporption, chronic hemolysis

Drugs: TMP, phenytoin, MTX

↓Folate, normal MMA, ↑homocysteine

It is reasonable to treat empirically with PO Folic Acid 1mg/day

Exclude B12 Deficiency before starting treatment as neurologic symptoms will progress

Folate Deficiency

Chronic infections, malignancy, collagen vascular diseases, HIV

Inflammatory cytokines decreases iron absorption and impairs iron utilization

Relative decrease in EPO production in response to low Hct

↓Transferrin (TIBC), ↓ or normal Iron, ↓ or normal %sat, ↑or normal Ferritin

Treatment:

Make sure iron stores replete

Can use ESA for goal Hgb 10-12g/dL (caution in malignancy)

Treat underlying disease

Anemia of chronic inflammation

Decreased renal cortical mass , decreased erythropoetin

Normochromic/normocytic

Peripheral smear may show Burr cells

ESA to achieve target Hbg levels 10 – 12

ESA can lead to HTN, Thrombosis, MI, CVA

Iron stores improve efficacy, Ferritin > 100

Anemia of Kidney Disease

Inflammatory Anemia vs IDA

Apply your understanding of clinical history and physical

exam before ordering extensive laboratory studies

Evaluating the blood smear will always provide important information

Anemia is never normal

Key Messages

MKSAP 16, Hematology and Oncology, pp 18 – 35.

Up to Date; Approach to the adult patient with Anemia; Schrier, Stanley, Jan 2013.

ESRD Network II, Medical Review Committee 2011 goals.

Pocket Medicine, 3rd ed. Edited by Marc Sabatine, 2008.

References

Original Version: Pam Charity, MD 2013

Revised 6/11/2015: Stefanie Erway, MD

Revision History