EmDocs - February 22, 2021 - By Brandon M. Carius
Reviewed by: Alex Koyfman and Brit Long
Background Pearls
Anemia is common, with some studies finding prevalence in up to one-third of the global population.
Much literature cites WHO anemia standards of a hemoglobin <12 g/dL in females and <13 g/dL in males, but baselines can vary between demographics.
Outward signs of anemia on initial evaluation (such as tachycardia and hypoxia) may be tempered by chronic compensatory mechanisms of increased plasma volume and RBC production.
Classification Pearls
Anemia can be subclassified between acute and chronic, although stringent time thresholds are not often mentioned. Other classifications include “blood loss” vs. “non-blood loss” anemia and sub-classifications based on RBC indices.
Assessment Pearls
Initial evaluation should focus on patient hemodynamics. When anemia is suspected, crystalloids should be avoided if possible.
Stable vital signs should not be used to exclude the diagnosis of anemia, given early onset with compensation in acutely anemic patients and long-term adaptation measures in those with chronic anemia.
Laboratory Evaluation Pearls
Anemia differential primarily utilizes MCV, however there is some overlap of etiologies between these categories and further laboratory evaluation is generally required.
While IDA is common, its presence should not be presumed to be isolated, and further evaluation is recommended for causes of occult bleeding.
Peripheral blood smears can help recognize specific RBC dysmorphia that can identify anemia etiologies.
Management Pearls
Outpatient management for anemic patients with stable vital signs centers on iron supplementation with encouraged follow-up. Vitamin C may help with absorption.
In patients with gastrointestinal comorbidities or who may not tolerate oral iron supplementation can be considered for IV iron ‘loading’ in the emergency department prior to discharge.
Emergent transfusion with O-negative whole blood should be used for the reproductive age female who is unstable and O-positive for all othersPreviously-universal transfusion thresholds of hemoglobin < 10 g/dL have been superseded by a 7 g/dL cut-off in most situations.”