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Anemia, Emergency Medicine

Basics

Description

- Excessive blood loss (most common cause): - Trauma - GI bleed - Menstruation

- Hemolysis (increased RBC destruction, RBC lifespan <100 days): - Hypersplenism - Autoimmune hemolytic anemia - Mechanical trauma (prosthetic heart valves, vasculitis, thrombotic thrombocytopenic purpura [TTP], hemolytic uremic syndrome [HUS], or disseminated intravascular coagulation [DIC]) - Toxins - Infections (malaria, babesiosis) - Membrane abnormalities - Intracellular RBC abnormalities (G6PD, sickle cell anemia, or thalassemia)

- Decreased RBC synthesis: - Classified by measurement of RBC size - Hypochromic/microcytic: - Iron deficiency - Thalassemia - Sideroblastic - Chronic disease

- Cardiovascular: - Tachycardia, cardiomegaly, or murmurs - Postural hypotension

- Neurologic: - Neuropathy - Altered mental status

- Stool for occult blood - Electrolytes, BUN, creatinine, glucose: - Urinalysis: - Hematuria - Hemoglobinuria in hemolytic anemia

- Autoimmune hemolytic anemia: - Corticosteroids (prednisone 60 mg/day until response) - Immunosuppressive agents - Plasmapheresis - Splenectomy if splenic sequestration

- Drug-induced hemolytic anemia: Stop offending agent. - Anemia of chronic disease: Treat underlying disease. - Vitamin B12 deficiency: - Vitamin B12: 1,000 ╬╝g IM daily for 1 wk, then weekly for 1 mo, then monthly - Hematologic parameters normalize within 2 mo. - Neurologic symptoms present >6 mo may be permanent.

- Aplastic anemia - Antithymocyte globulin - Bone marrow transplantation: - Sickle cell anemia - Supportive care with oxygen, rehydration, analgesia - Treat precipitating cause.

  • Reduction below normal in the mass of RBCs
  • Measured by 1 or more of the major RBC components:Hemoglobin (Hgb): Concentration of the major oxygen-carrying component in whole bloodHematocrit (Hct): Percent volume of whole blood occupied by intact RBCsRBC count: RBCs contained in a volume of whole blood
  • Adult female: Hgb <12 g/dL or Hct <37%
  • Adult male: Hgb <14 g/dL or Hct <42%
  • Normal blood count values depend on age:Birth: Hgb 16.5, Hct 511 yr: Hgb 12, Hct 366 yr: Hgb 12.5, Hct 37Adult male: Hgb 14, Hct 42Adult female: Hgb 12, Hct 37
  • Hgb/Hct depend on oxygen pressure:Increased in neonates and people living above 4,000 ft
  • Hgb, Hct, and RBC count are concentrations:Dependent on RBC mass and plasma volumeValues decrease if RBC mass decreases or plasma volume increases.
  • Anemia is an indication of an underlying disorder or deficiency.

Etiology

  • Never a normal variant:May be the first manifestation of a systemic disorderAlways seek a cause.
  • Excessive blood loss (most common cause):TraumaGI bleedMenstruation
  • Hemolysis (increased RBC destruction, RBC lifespan <100 days):HypersplenismAutoimmune hemolytic anemiaMechanical trauma (prosthetic heart valves, vasculitis, thrombotic thrombocytopenic purpura [TTP], hemolytic uremic syndrome [HUS], or disseminated intravascular coagulation [DIC])ToxinsInfections (malaria, babesiosis)Membrane abnormalitiesIntracellular RBC abnormalities (G6PD, sickle cell anemia, or thalassemia)
  • Decreased RBC synthesis:Classified by measurement of RBC sizeHypochromic/microcytic:Iron deficiencyThalassemiaSideroblasticChronic diseaseNormochromic/macrocytic:HypothyroidismFolate deficiencyVitamin B12 deficiencyLiver diseaseMyelodysplasiaCertain leukemiasNormochromic/normocytic:Aplastic anemiaChronic renal failureMalignancyAdrenal insufficiencyHyperparathyroidismAlcohol abuseAcute blood loss

Diagnosis

Signs and Symptoms

Depends on: á

  • Rapidity of onset:Hypovolemia if acuteAsymptomatic if mild and chronic

History

  • Underlying disease
  • Severity and type of anemia
  • Fatigue
  • Decreased exercise intolerance
  • Shortness of breath
  • Dyspnea on exertion
  • Chest pain/angina
  • Syncope
  • Blood in stool/tarry black stools
  • Irregular or heavy menses
  • Easy bruising or history of excessive bleeding

Physical Exam

  • Cardiovascular:Tachycardia, cardiomegaly, or murmursPostural hypotension
  • Dermatologic:Skin:CoolPallorJaundicePurpuraTelangiectasiaPetechiaeEcchymosisSpoon-shaped nails (koilonychia)
  • Neurologic:NeuropathyAltered mental status
  • Bone (especially sternal) or joint pain (sickle cell disease)
  • Hepatomegaly, splenomegaly
  • Lymphadenopathy
  • Findings reflect underlying disease

Essential Workup

  • CBC
  • Vital signs/orthostatics
  • Determine if:BleedingIncreased RBC destructionBone marrow suppressionIron deficient

Diagnosis Tests & Interpretation

Lab

  • Type and crossmatch or type and screen
  • CBCRBC indices:Mean corpuscular volume (MCV; normal: 80-100 ╬╝m3)Mean corpuscular hemoglobin (MCH; normal: 27-34 pg/cell)Mean corpuscular hemoglobin concentration (MCHC; normal: 33-36%)Platelet countThrombocytosis suggests:Iron deficiencyMyeloproliferative disordersInflammationInfectionNeoplasmThrombocytopenia suggests:Bone marrow malignancyHypersplenismSepsisVitamin B12 or folate deficiencyAutoimmune disorders
  • Reticulocyte (retic) count:Normal 0.5-1.5% (retics/1,000 RBCs)Increased retic count: Increased erythropoietic response to continued blood loss or hemolysisStable anemia with low retic count: Impaired RBC productionActive hemolysis or blood loss with low retic count: Concurrent disorderLow retic count with pancytopenia: Aplastic anemiaLow retic count with normal WBC and platelets: Pure RBC aplasia
  • Reticulocyte index (RI): Retic count (%) Ś (patient Hct/normal Hct):RI <2% implies inadequate RBC production.RI >2% implies increased RBC production with excessive RBC destruction or loss.
  • WBC with differential and peripheral smear:Leukopenia with anemia suggests bone marrow suppression, hypersplenism, or deficient vitamin B12/folate
  • Stool for occult blood
  • Electrolytes, BUN, creatinine, glucose:
  • Urinalysis:HematuriaHemoglobinuria in hemolytic anemia
  • Workup strategy:Hypochromic/microcytic anemias:IronTotal iron-binding capacityTransferrin saturationFerritinMacrocytic anemias:FolateVitamin B12LFTThyroid function testsHemolytic anemia:Rapid fall in HgbReticulocytosisFragmented RBCsIncreased LDHIncreased indirect bilirubinDecreased serum haptoglobinCoombs positive
  • Special tests:Peripheral smear:Helmet cells/schistocytes-microangiopathic hemolysisTeardrop cells-myelofibrosisSpherocytes-autoimmune hemolysisLeukoerythroblastic pattern-bone marrow replacementBite cells-oxidative hemolysisRBC parasites-malaria or babesiosisTarget cells-liver diseaseBurr cells-uremiaSideroblasts-alcoholism or myelodysplasiaHowell-Jolly bodies-aspleniaHgb electrophoresis for sickle cell/thalassemiaIron, iron-binding capacity, transferrin saturation, ferritin:Iron deficiencyIron-decreasedIron-binding capacity-increasedTransferrin saturation-decreasedFerritin-decreasedChronic disease:Iron-decreasedIron-binding capacity-decreasedTransferrin saturation-decreased/normalFerritin-normal/increasedThalassemia:Iron-normalIron-binding capacity-normalFerritin-normalSideroblastic anemia:Iron-increasedIron-binding capacity-normalFerritin-increased

Diagnostic Procedures/Surgery

Bone marrow biopsy evaluates: á

  • Aplastic anemia
  • Myelodysplasia
  • Bone marrow malignancy
  • Myeloproliferative disorders

Differential Diagnosis

  • Acquired versus inherited anemia
  • Anemia of chronic disease
  • Blood loss
  • CHF
  • Dilutional anemia
  • Hemolysis
  • Malignancy
  • Nutritional deficiency/malabsorption
  • Toxic bone marrow suppression
  • Hemolytic anemia of the newborn:
  • Rh antibody crosses placenta when Rh-negative mother has Rh-positive child.
  • Physiologic or dilutional anemia in 3rd-trimester pregnancy:
  • 25% increase of RBC mass and 50% increase in plasma volume
  • Values for Hgb/Hct in healthy elderly are generally lower than in younger adults.
  • This lower "normal"Ł must be a diagnosis of exclusion.

Treatment

Pre-Hospital

Ongoing blood loss requires close assessment and rapid transport: á

  • Control bleeding to include wound packing and use of tourniquets if needed.
  • Two large-bore IVs

Initial Stabilization/Therapy

  • Airway, breathing, circulation (ABCs)
  • Oxygen
  • IV fluid resuscitation with 0.9% NS if ongoing loss/hypotension

Ed Treatment/Procedures

  • Depends on severity of anemia and acuteness of onset
  • Transfusion for hemorrhage with unstable vital signs not responding to crystalloid resuscitation.
  • Most anemias seen in ED are chronic and do not require immediate intervention.
  • Therapy for specific anemia:Iron deficiency:FeSO4: 300 mg PO TIDInvestigate underlying cause.Increased Hgb expected in 2-3 wkRenal failure:Endogenous erythropoietin is diminished.Replace with recombinant erythropoietinAutoimmune hemolytic anemia:Corticosteroids (prednisone 60 mg/day until response)Immunosuppressive agentsPlasmapheresisSplenectomy if splenic sequestrationDrug-induced hemolytic anemia: Stop offending agent.Anemia of chronic disease: Treat underlying disease.Vitamin B12 deficiency:Vitamin B12: 1,000 ╬╝g IM daily for 1 wk, then weekly for 1 mo, then monthlyHematologic parameters normalize within 2 mo.Neurologic symptoms present >6 mo may be permanent.Folate deficiency:Folic acid: 1 mg PO dailyAplastic anemiaAntithymocyte globulinBone marrow transplantation:Sickle cell anemiaSupportive care with oxygen, rehydration, analgesiaTreat precipitating cause.Leukemia:

Medication

  • Iron supplements
  • Erythropoietin for renal failure
  • Corticosteroids for autoimmune
  • Vitamin B12
  • Folic acid (B9)

Follow-Up

Disposition

Admission Criteria

  • Unstable vital signs
  • Ongoing blood loss
  • Symptomatic anemia-angina/dyspnea/syncope/neurologic symptoms
  • Need for transfusion
  • Need for aggressive evaluation
  • Severe anemiaInitial, unexplained Hgb <8 g/dLMajor difficulty in obtaining outpatient care for patients whose Hgb are significantly low or when comorbidity is present

Discharge Criteria

Discharge vast majority of stable patients for outpatient workup. á

Followup Recommendations

Newly diagnosed anemic patients need to be worked up: á

  • If stable for discharge from the ED, provide follow-up options for workup

Pearls and Pitfalls

  • Anemia is an indication of an underlying disorder or deficiency.
  • Severe or life-threatening cases require immediate correction via blood transfusion.
  • Most cases seen in the ED are chronic and do not require immediate intervention.

Additional Reading

  • Bryan áL, Zakai áN. Why is my patient anemic? Hematol Oncol Clin N. 2012;26:205-230.
  • Bunn áHF. Goldman: Goldmans Cecil Medicine. 24th ed. Philadelphia, PA: Saunders, an imprint of Elsevier Inc.; 2011.
  • Hoffman áR, Benz áEJ Jr, Silberstein áLE, et al. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Saunders, an imprint of Elsevier Inc.; 2012.
  • Recht áM. Thrombocytopenia and anemia in infants and children. Emerg Med Clin North Am. 2009;27:505-523.
  • Rizack áT. Special hematologic issues in the pregnant patient. Hematol Oncol Clin N. 2012;26:409-432.

See Also (Topic, Algorithm, Electronic Media Element)

  • GI Bleeding
  • Renal Failure
  • Sickle Cell Disease

Codes

ICD9

  • 280.0 Iron deficiency anemia secondary to blood loss (chronic)
  • 285.1 Acute posthemorrhagic anemia
  • 285.9 Anemia, unspecified
  • 283.9 Acquired hemolytic anemia, unspecified
  • 285.29 Anemia of other chronic disease

ICD10

  • D50.0 Iron deficiency anemia secondary to blood loss (chronic)
  • D62 Acute posthemorrhagic anemia
  • D64.9 Anemia, unspecified
  • D58.9 Hereditary hemolytic anemia, unspecified
  • D63.8 Anemia in other chronic diseases classified elsewhere

SNOMED

  • 271737000 Anemia (disorder)
  • 267530009 Acute posthemorrhagic anemia (disorder)
  • 413533008 anemia due to chronic blood loss (disorder)
  • 61261009 Hemolytic anemia (disorder)
  • 234347009 Anemia of chronic disorder (disorder)