Definition
A.Anemia is characterized by a lower than normal number of red blood cells (RBCs) and/or level of hemoglobin causing decreased oxygen-carrying capacity.
Incidence
A.Iron deficiency is the most common cause of anemia worldwide with women and children most often affected.
B.Other causes of anemia vary based on age, gender, and geographical region. Anemias in high income North American countries, including the United States, are most frequently the result of gastrointestinal hemorrhage, hemoglobinopathy, and chronic kidney disease.
C.Approximately 240,000 ED visits in the United States result in anemia as the primary hospital discharge diagnosis.
Pathogenesis
A.Anemia can be a consequence of bleeding, hemolysis, or inadequate bone marrow function, or nutritional deficiency.
B.Blood loss anemia results in a loss of iron containing RBCs. Hemolysis results in destruction of RBCs but iron is retained in the body.
C.Microcytic anemia is characterized by RBCs of reduced size. While most commonly associated with iron deficiency, microcytic anemia can be associated with anemia of chronic disease (ACD), thalassemia, and sideroblastic anemia.
D.Macrocytic anemias are characterized by greater than normal mean corpuscular volume. Causes are most often associated with vitamin B12 and folate deficiency; antimetabolite drugs, including methotrexate; and other causes that interfere with cell metabolism.
E.Pernicious anemia is associated with vitamin B12 deficiency caused by the absence of intrinsic factor, a glycoprotein secreted by parietal cells needed for absorption of vitamin B12. Absence of intrinsic factor may be congenital, but is most often caused by an autoimmune-mediated atrophic gastritis.
F.Normocytic anemia, characterized by normal size RBCs, may be associated with ACD, hemolysis, acute blood loss, and volume overload. In the acute care setting, hemolysis may be associated with hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), disseminated intravascular coagulation (DIC), or heart valve abnormalities.
Predisposing Factors
A.Use of nonsteroidal anti-inflammatory drugs (NSAIDs).
B.Peptic ulcer disease.
C.Chronic kidney disease.
D.Uterine fibroids/menorrhagia.
E.Family history of thalassemia, sickle cell disease, or hereditary spherocytosis.
F.Recent blood transfusion.
G.Nutritional deficiency.
H.Alcohol abuse.
I.Cancer.
J.Connective tissue diseases.
K.Chronic infection such as HIV or tuberculosis (TB).
L.Pregnancy.
M.Intestinal disorders including diverticulosis, inflammatory bowel disease, or celiac disease.
Subjective Data
A.Common complaints/symptoms.
1.Signs and symptoms of anemia may vary depending on the severity, speed of development, age, and comorbidities of the individual. Tissue hypoxia and the pathologic process contribute to complaints.
2.Fatigue, weakness, headache, shortness of breath, palpitations, and angina may occur.
3.Decreased oxygen to the brain often results in confusion, visual changes, and fainting.
4.Chronic blood loss may not cause symptoms until hemoglobin drops below 8 g/dL.
B.Common/typical scenario.
1.Other signs and symptoms.
a.Pale skin, nail beds, conjunctiva, and mucous membranes result from shifting of blood away from cutaneous tissues.
b.Flow-type systolic murmurs may be associated with altered blood viscosity. High output heart failure and ventricular hypertrophy may occur with severe anemia, especially individuals with established heart disease.
c.Hemolytic anemia may be associated with increased bilirubin causing jaundice, splenomegaly, and dark-colored urine.
C.Family and social history.
1.Onset and duration of symptoms.
2.Family history of blood disorder.
3.Associated abdominal pain.
4.Changes in diet, bowel habits.
5.Menstrual history including timing and amount of bleeding.
6.Medication history.
D.Review of systems.
1.Head, ear, eyes, nose, and throat (HEENT): Ask about premature graying of hair or burning sensation of tongue.
2.Neurology: Ask about numbness or tingling sensations.
3.Genitourinary: Ask about urine color.
4.Gastrointestinal: Ask about stool color, any blood in stool, abdominal pain, or cramping.
5.Ask about dietary habits or unusual habits such as pagophagia.
6.Dermatology: Ask about any rashes or redness of skin.
7.Psychiatric: Ask about fatigue.
Physical Examination
A.Check vital signs including pulse, respirations, and blood pressure.
B.Oral mucosa may be cracked or dry; tongue may be thickened and smooth with vitamin deficiency.
C.Cardiac examination, noting rate, rhythm, and presence of murmurs.
D.Lung examination, noting rate and adventitious sounds.
E.Abdominal examination, noting evidence of bleeding, distension, peristalsis, abnormal bowel sounds, tenderness, and masses.
F.Rectal examination, noting presence of blood in stool.
G.Skin and mucous membrane examination, noting petechiae, bruising, or pallor of skin, nail beds, and mucous membranes including conjunctiva.
H.Neurological disturbances may be associated with long-standing vitamin B12 deficiency; peripheral neuropathy, alterations in deep tendon reflexes, impaired vibratory sensation, alterations in balance, and impaired mental status may be present.
Diagnostic Tests
A.Complete blood count (CBC) including RBC indices.
B.Reticulocyte count.
C.Hemoglobin electrophoresis.
D.Coombs test (antiglobulin test).
E.Serum ferritin.
F.Serum iron.
G.Vitamin B12 level.
H.Folate level.
I.Haptoglobin.
Differential Diagnosis
A.Acute blood loss.
B.Chronic blood loss.
C.Hemolysis.
D.Aplastic anemia.
E.Leukemia.
Evaluation and Management Plan
A.General plan.
1.See Figure 12.1 for overview of anemia evaluation.
2.Treatment of anemia is based on identifying and eliminating or ameliorating the cause.
3.The severity of the anemia and its accompanying symptoms determine treatment.
4.Transfusion is often indicated if/when hematocrit drops to 27% or less.
5.Risks associated with transfusion include fluid overload, transfusion reaction, and iron overload, which must be taken into consideration.
6.Iron deficiency may be treated with increased intake of dietary iron and supplemental iron. Dietary sources are frequently insufficient and oral and/or intravenous supplementation are often required.
7.ACD may require treatment when patients become symptomatic with use of medication to stimulate erythropoiesis such as erythropoietin alpha and darbepoietin alfa.
B.Patient/family teaching points.
1.Nutritional deficiencies of iron, vitamin B12, and folic acid should be corrected with changes to diet.
2.If taking ferrous sulfate, patients should avoid tea and coffee, which can affect absorption of the drug.
C.Pharmacotherapy.
1.Treatment of anemia is to correct the underlying condition and supplement with ferrous sulfate until anemia is corrected and for several months after it is corrected.
2.Ferrous sulfate 325 mg three times a day is the standard pharmacological treatment.
3.Vitamin C 500 units per day can promote absorption of ferrous sulfate.
4.Patients with severe anemia from chronic kidney failure, chemotherapy, or HIV can benefit from epoetin injections.
a.Dose of epoetin will depend on the severity of anemia, but typically starts at 50 to 100 units per kilogram administered subcutaneously three times per week. Patient will require adequate iron stores prior to starting epoetin injections.
D.Discharge instructions (If standard accepted guidelines exist please use discharge template).
1.Patients are not routinely admitted for anemia unless they are hemodynamically unstable.
2.Discharge planning for a patient who is found to be anemic in the hospital would be to follow-up with the primary care provider for a further evaluation and workup of anemia in nonacute setting.
Follow-Up
A.Once iron stores have been replenished, there is no need to retest iron studies unless there is evidence of a change in the patient’s symptoms or physical examination.
B.Follow-up to identify the cause of the anemia is discussed in the following.
C.Conditions that are unresolved warrant follow-up.
D.ACD often requires ongoing treatment and follow-up under specialist care depending on the cause of the underlying disease.
E.Patients with aggressive forms of thalassemia should be under care of a hematologist.
F.Patients with vitamin B12 deficiency require ongoing care for monitoring B12 levels and monitoring of liver function if taking parenteral therapy.
G.Follow-up for patients with folic acid deficiency should consist of periodic monitoring of CBC and serum folate levels.
Consultation/Referral
A.Iron deficiency associated with occult blood loss often requires referral to a gastroenterologist for upper endoscopy and/or colonoscopy as well as additional testing to identify the source of bleeding.
B.In the case of menorrhagia, referral for follow-up gynecologic care may be needed. Follow-up care of individuals with ACD is dependent on the underlying cause.