Anemia: Difference between revisions
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*Affects 1/3 of the world's population | *Affects 1/3 of the world's population | ||
*Most common causes are uterine and GI bleeding | *Most common causes are uterine and GI bleeding | ||
Severe anemia is defined as a hemoglobin level of 5 to 7 g/dL with symptoms of hypoperfusion including lactic acidosis, base deficit, shock, hemodynamic instability, or coronary ischemia<ref> Posluszny JA Jr, Napolitano LM. How do we treat life-threatening anemia in a Jehovah's Witness patient? Transfusion. 2014;54(12):3026-3034</ref> | |||
===Pathophysiology=== | |||
4 mechanisms: | |||
#Loss of RBCs by hemorrhage (e.g. GI bleed) | |||
#Increased destruction (SCD, hemolytic anemia) | |||
#Impaired production (iron/folate/B12 deficiency, aplastic/myelodysplastic anemia) | |||
#Dilutional (rapid IVF infusion) | |||
==Clinical Features== | ==Clinical Features== | ||
Revision as of 03:07, 16 August 2015
Background
- Affects 1/3 of the world's population
- Most common causes are uterine and GI bleeding
Severe anemia is defined as a hemoglobin level of 5 to 7 g/dL with symptoms of hypoperfusion including lactic acidosis, base deficit, shock, hemodynamic instability, or coronary ischemia[1]
Pathophysiology
4 mechanisms:
- Loss of RBCs by hemorrhage (e.g. GI bleed)
- Increased destruction (SCD, hemolytic anemia)
- Impaired production (iron/folate/B12 deficiency, aplastic/myelodysplastic anemia)
- Dilutional (rapid IVF infusion)
Clinical Features
General Anemia Symptoms
- Most patients begin to be symptomatic at ~7gm/dL
- Weakness, fatigue, lethargy, dyspnea on exertion, palpitations
- Skin, nail bed, mucosal pallor
- Widened pulse pressure
- Jaundice, hepatosplenomegaly (hemolysis)
- Peripheral neuropathy (B12 deficiency)
Differential Diagnosis
Anemia
RBC Loss
RBC consumption (Destruction/hemolytic)
- Hereditary
- Acquired
- Microangiopathic Hemolytic Anemia (MAHA)
- Autoimmune hemolytic anemia
Impaired Production (Hypochromic/microcytic)
- Iron deficiency
- Anemia of chronic disease
- Thalassemia
- Sideroblastic anemia
Aplastic/myelodysplastic (normocytic)
Megaloblastic (macrocytic)
- Vitamin B12/folate deficiency
- Drugs (chemo)
- HIV
Diagnosis
Acute Anemia
Assess for any signs of bleeding or trauma before considering other causes of chronic anemia.
Chronic Anemia
Microcytic Anemia (<81 fL)
- RDW high
- Ferritin low: Iron deficiency anemia
- Ferritin normal: Anemia chronic disease or sideroblastic anemia (e.g. lead poisoning)
- RDW normal
- RBC count low: Anemia chronic disease, hypothyroidism, Vitamin C deficiency
- RBC count nl or high: Thalassemia
Normocytic Anemia (81-100 fL)
- Retic count normal
- RDW normal: Anemia chronic disease, anemia of renal insufficiency
- RDW high: Iron, Vit B12, or folate deficiency
- Retic count high
- Coombs Positive: Autoimmune cause
- Coombs negative: G6PD, SCD, spherocytosis, microangiopathic hemolysis
Macrocytic Anemia (MCV>100 fL)
- RDW high: Vit B12 or folate deficiency
- RDW normal: ETOH abuse, liver disease, hypothyroidism, drug induced, myelodysplasia
Treatment
- Transfusions
- Consider if pt is symptomatic, hemodynamically unstable, hypoxic, or acidotic
- Most pts w/ Hb <6 will benefit from transfusion; most pts w/ Hb >10 will not
- Always draw labs necessary for diagnosis prior to transfusing
- 1 unit PRBCs should raise the Hgb by 1gm/dL
See Also
References
- ↑ Posluszny JA Jr, Napolitano LM. How do we treat life-threatening anemia in a Jehovah's Witness patient? Transfusion. 2014;54(12):3026-3034