Episode Five: Anaemia

Written By: Sarah Donnelly & Hermeen Dhillon
Reviewed By: Chris Cochrane


Objective One:
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.

Objective Two:
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

  1. RBC Loss or Destruction

    1. Bleeding
      1. Reticulocyte count should be elevated if normal bone marrow
      2. Low ferritin, as this is lost with the RBCs
      3. Source identification: FIT/FOBT, Urinalysis, DRE, Hx of melena
    2. Haemolysis
      Triad is: anaemia, jaundice, splenomegaly
      1. elevated LDH
      2. elevated unconjugated bilirubin
      3. decreased haptoglobin
      4. positive DAT, if autoimmune
  2. Insufficient RBC Production
    1. Early iron deficiency anaemia, get a ferritin
    2. Anaemia of chronic disease, check a CRP
    3. Aplastic anaemia, CBC looking for pancytopenia, or bone marrow bx showing hypocellularity
    4. Chronic Kidney Disease
Objective Three
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.

Ferritin Interpretation

  • 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
Objective Four
In a patient with iron deficiency, investigate further to find the cause.
  1. Bleeding as cause
    1. menorrhagia is most common among pre-menopausal women
    2. FIT/FOBT for occult GI bleed, or DRE, or patient history
    3. Dyspepsia, melena or haemoptysis
    4. Ask about haematuria or consister a urinalyisis
  2. Malabsorption
    Think of where iron is absorbed “Dude Is Just Feeling Ill Bro” (this means duodenum)
  3. Iron deficient diet

Unexplained Fe deficiency needs workup, we don’t want to miss a Cancer.

Objective Five
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.

Physical Exam

  • conjunctival rim pallor: +ve LR 16.7!
  • palmar crease pallor: +ve LR 7.9
  • palmar pallor +ve LR 5.6
The ears, eyes, nose and throat | Basicmedical Key
Top is normal, bottom is pallorous

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

  1. bleeding
  2. SoB
  3. pallor
  4. jaundice
  5. CHF exacerbations
  6. worsening angina

Macrocytic Anaemia

Megaloblastic anaemia
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

Non-Megaloblastic Anaemia

Causes include:

  • liver disease
  • excess EtOH intake
  • hypothyroidism
  • bone marrow failure, infiltration or suppression
  • pseudo-macrocytosis due to haemolysis
Objective Six
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.

Symptoms include:

  • GI: glossitis
  • Neurologic: symmetric parasthesias, numbness, gait issues, weakness, ataxia
  • Psychiatric: depression, irritability, cognitive slowing, dementia, psychosis, EPS
Objective Seven
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.

Objective Eight 
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.

Objective Nine
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.

Sources Used

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 #FOAMEd

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