A 33 year old patient presents with fatigue to her family physician’s office. Her blood work is shown below. What is the differential for her blood findings and why?
|Hematocrit||0.249||(0.345 – 0.450)/L|
What is your differential diagnosis for a microcytic anemia?
- Anemia of chronic disease
- Iron deficiency anemia
- Lead poisoning
- Sideroblastic anemia
What ferritin value increases the likelihood of iron deficiency?
A ferritin of less than 18 ug/L has a likelihood ration of over 41 for iron deficiency anemia.
What is the gold standard for investigation?
A bone marrow biopsy.
Compare and contrast investigations differentiating iron deficiency anemia, anemia of chronic inflammation, and thallasemia.
|Condition||Serum Iron||TIBC||Iron Saturation||Ferritin|
An 18 year old female re-presents to the emergency department after 3 days of severe migraines. Her CBC is shown below. What other investigations are pertinent in her diagnosis?
Points of discussion: It is imperative that any diagnosis of microangiopathic hemolytic anemia be diagnosed immediately due to the inherent mortality risk with disorders such as TTP or DIC. Investigations include:
- Peripheral blood film to assess for fragmentation
- CBC, LDH, bilirubin, haptoglobin, reticulocyte count
- Group and screen, direct antiglobulin test
- Lytes, Cr, calcium panel (Ca, Mg, phosphate, albumin), liver enzymes
- PT, PTT, fibrinogen
- Add septic workup including stool sample in presence of diarrhea.
- Consider adding HIV, HCV, and autoimmune screen if suspicion of TTP
- ADAMTS13 screening if suspicion of TTP
- Beta HCG for all women of childbearing age
What is the management of TTP?
Points of discussion: This is a clinical diagnosis with a mortality of >90% without treatment. Do not wait for ADAMT13 testing to support a diagnosis.
- Immediate transfer to a plasmapheresis center
- Frozen plasma to be administered immediately to replete deficient ADAMTS13
- Daily plasmapheresis (Repletes ADAMTS13 and removes Antibody targeting ADAMTS13)
- Folic acid, iron (if deficient), role of prednisone and ASA is controversial
Consider the blood tests used when evaluating a patient with autoimmune hemolysis. How does a DAT work? What is your differential diagnosis for a DAT + hemolytic anemia?
Direct Antiglobulin Test: Detects the presence of an antibody (IgG) or complement (C3d) bound in vivo to red blood cells in a patient’s circulation.
Coombs reagent is a monospecific immunoglobulin against IgG or C3 bound to the RBC surface. Agglutination indicates a positive test.
- Auto Antibody
- Warm autoimmune hemolytic anemia (positive test to IgG)
- Cold autoimmune hemolytic anemia (positive to C3d)
- Paroxysmal Cold Hemoglobinuria
- Drug effect
- Allo Antibody
- Transfused blood, IVIG
- Stem Cell transplant
- Hemolytic disease of the newborn
- MM/Plasma Cell dyscrasia
A 36 year old female is post-op day 3 for a colectomy for ulcerative colitis. She is on oral iron replacement and feels well with a minimal need for analgesia. Her chart indicates that her heart rate was 110 bpm and there is an order for 2 units of packed red blood cells if the Hgb is <100g/L. You question the evidence behind such an order and call the surgical service covering her care.
Points of Discussion: What are the indications for transfusion? Is there any evidence that exists to help with when and how much blood should be transfused?
Indications for Transfusion
- Symptomatic anemia in a NORMOVOLEMIC patient
- Hb <70g/L
- Hb <80g/L in chronic transfusion patients
- Inappropriate if Hb >100g/L
- Atherosclerosis, unstable angina, other cardiac, pulmonary,↑ oxygen consumption, unpredictable bleeding
- DO NOT transfuse based solely on Hb
- Always use Hb in combination with clinical status and history
Discussion Point: The TRICC Trial was a RCT of transfusion requirements in critical care to determine whether a restrictive strategy of red-cell transfusion (i.e. transfuse once Hgb < 70g/L to maintain a Hgb between 70–90g/L) and a liberal strategy (transfuse to keep Hgb >100g/L) produced equivalent results in critically ill patients. Results compared the rates of death from all causes at 30 days and the severity of organ dysfunction.
|Category||Hb >100||Hb >70|
|30 day mortality||23%||19% (p=0.11)|
|Overall mortality*||28%||22% (p=0.05)|
|Age <55*||Worse||Better (less cardiopulmonary events: TACO, TRALI)
|Apache II <20*||16% mortality||8.7% mortality (p=0.03)|
*Illustrates statistically significant results
Hebert et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group. NEJM 1999;340:409-17