Written By: Sarah Donnelly & Hermeen Dhillon
Reviewed By: Chris Cochrane
Assess the risk of decompensation of anemic patients to decide if prompt transfusion or volume replacement is necessary.
Is the patient stable or unstable?
A patient is unstable if they are hemodynamically compromised. Think of things like tachycardia, hypotension SBP <90, MAP <65) – use your clinical judgement!
If unstable, they need Group O PRBCs ASAP.
- can use O+ve for males and post-menopausal females. Save the group O -ve blood for all other females
Group: identifying patients ABO blood type and Rh status
Screen: checks for other antibodies in the serum
Crossmatch: assesses how the patient’s blood reacts with the donor blood by mixing them together
When to transfuse?
- Hb <70 g/L for otherwise healthy individuals
- Hb <80 for patients with sepsis, ischemic heart or brain injury
A unit(250mL) of PRBC is expected to raise Hb by ~10 g/L
Do not exceed a transfusion beyond four hours to avoid risk of contamination, and usually the first 30 minutes of transfusion is done slower to watch for patient reaction.
In a patient with anemia, classify the anemia as microcytic, normocytic, or macrocytic by using the MCV or smear test result, to direct further assessment and treatment.
Mean Corpuscular Volume(MCV) <80 is Microcytic
T: halassemia, which is 2nd more common in Canada
A: naemia of chronic disease, 3rd most common
I: ron deficiency, most common cause
L: ead poisoning
S: ideroblastic anaemia
MCV 80-100 is Normocytic
- RBC Loss or Destruction
- Reticulocyte count should be elevated if normal bone marrow
- Low ferritin, as this is lost with the RBCs
- Source identification: FIT/FOBT, Urinalysis, DRE, Hx of melena
Triad is: anaemia, jaundice, splenomegaly
- elevated LDH
- elevated unconjugated bilirubin
- decreased haptoglobin
- positive DAT, if autoimmune
- Insufficient RBC Production
- Early iron deficiency anaemia, get a ferritin
- Anaemia of chronic disease, check a CRP
- Aplastic anaemia, CBC looking for pancytopenia, or bone marrow bx showing hypocellularity
- Chronic Kidney Disease
In all patients with anemia, determine the iron status before initiating treatment.
Do not initiate supplementation without determining ferritin.
Ferritin is most reliable, but occurs on a continuum and needs patient context to interpret.
- under 15ug/L is iron deficiency
- 15-30 is ‘probably’ iron deficiency
- over 30 makes iron deficiency unlikely
- over 100ug/L is considered normal
- over 600 suggests a workup for Fe overload
In a patient with iron deficiency, investigate further to find the cause.
- Bleeding as cause
- menorrhagia is most common among pre-menopausal women
- FIT/FOBT for occult GI bleed, or DRE, or patient history
- Dyspepsia, melena or haemoptysis
- Ask about haematuria or consister a urinalyisis
Think of where iron is absorbed “Dude Is Just Feeling Ill Bro” (this means duodenum)
- Iron deficient diet
Unexplained Fe deficiency needs workup, we don’t want to miss a Cancer.
Consider and look for anemia in appropriate patients. Such as those at risk for blood loss or in patients with hemolysis whether they are symptomatic or not, and in those with new or worsening symptoms of angina or CHF.
- conjunctival rim pallor: +ve LR 16.7!
- palmar crease pallor: +ve LR 7.9
- palmar pallor +ve LR 5.6
Patients at Risk of Anaemia
- those on anticuagulation
- those taking chronic NSAIDs, look for evidence of UGIB
- mechanical and bioprosthetic valces
Symptoms of Anaemia in these higher risk patients
- CHF exacerbations
- worsening angina
peripheral blood smear shows oval macrocytes and hypersegmented neutrophils (6-7 lobes)
- Folate or Vit B12 deficiency, get levels
- Medications such as Methotrexate, look for symmetric parasthesias, numbness and gait issues
- liver disease
- excess EtOH intake
- bone marrow failure, infiltration or suppression
- pseudo-macrocytosis due to haemolysis
Look for other manifestations of the deficiency in order to make the diagnosis of pernicious anemia when it is present.
This is due to an autoimmune attack on the parietal cells of the stomach, which produce intrinsic factor.
- GI: glossitis
- Neurologic: symmetric parasthesias, numbness, gait issues, weakness, ataxia
- Psychiatric: depression, irritability, cognitive slowing, dementia, psychosis, EPS
As part of well-baby care, consider anemia in high-risk populations or in high-risk patients
Infants are at risk of iron deficiency due to high Fe demands to grow into full size humans.
High risk kids for this include:
- those with chronic illness
- living in low socioeconomic status
- suboptimal iron intake, or prolonged bottle-feeding
- preterm delivery or birth weight under 2.5kg
- mothers with obesity or anaemia
- early cord clamping at delivery
- high cow’s milk intake
First Nations in Canada
Children in these communities are estimated to be at 10x risk of iron deficiency in children 4-18 months of age.
When a patient is discovered to have a slightly low hemoglobin level, look carefully for a cause as one cannot assume that this is normal for them.
Work up even mild anaemias thoroughly.
Classify by their MCV and go from there. Customizing your approach specific to your patient.
In anemic patients with menorrhagia, determine the need to look for other causes of the anemia.
Don’t stop at the first obvious aetiology in this population. These patients can also have bleeds elsewhere, haemolysis, deficiencies. They can also have cancers, and numerous causes for gynecological bleeds. You do NOT want to miss these by not completing the workup these women deserve.
Choosing wisely Canada Transfusion Medicine https://choosingwiselycanada.org/transfusion-medicine/
BC Guidelines Irone Deficiency Anemia https://www2.gov.bc.ca/assets/gov/health/practitioner-pro/bc-guidelines/iron-deficiency.pdf
Physical Exam for Anaemia, Evidence Based Physical Diagnosis Steven McGee pp75
Assessment for anaemia in well-baby care https://www.cps.ca/en/documents/position/iron-requirements
Check out Episode Five of the GenerEhlist CCFP 105 Topics Podcast on Anaemia! #MedEd #MedTwitter #FamilyMedicineRocks #FOAMEdTweet