1. Pancytopenia:
- primary process: aplastic anemia,
- secondary process:
- any infiltrative process
- sarcoid, lupus
- B12 deficiency (17% of people)
- acute alcohol
- overwhelming sepsis
- aplastic anemia
- hypersplenism
2. Anemia + thrombocytopenia:
- microangiopathic (TTP-HUS, DIC, HELLP)
- autoimmune
- hypersplenism
- HIV
3. Anemia alone
- RPI to differentiate between underproduction and overconsumption.
4. Hemolysis:
- Check coombs to diagnose autoimmune, look for schistocytes on smear to determine microangiopathic hemolysis
- Think of others: hereditary (sickle cell, g6pd) and acquired (hypersplenism, toxin, infection like malaria)
5. MCV
- not specific: cannot be used to rule out etiology.
- if its slightly elevated, reticulocytes are big, so many hemolytic anemias will cause slightly increased MCV
6. Iron deficiency anemia
- Causes PICA
- Can give trial of iron and measure H&H at 4-6 weeks, or measure retics in 7-10 days
- Iron sulfate - can cause nausea/constipation: to avoid, titrate up to 325 TID, take with food, try other forms of iron which are easier to digest but have lower bioavail so it will take longer.
- Blood loss is #1 cause (menstrual, GI)
- Inadequate intake (less bioavail from veggies than from meat, so vegetarians/vegans)
- Increased demand (pregnancy, rapid growth, epo use)
- Malabsorption (celiac, crohns, post-gastrectomy)
- Ferritin is the best test in patients without inflammation (in al patients, low ferritin rules IN iron deficiency, LR+51 for ferritin <15, LR+25 for ferritin <32).
- TIBC next best test, TIBC < 5% LR +10 for iron deficiency
7. Who needs a workup for iron deficiency anemia?
- All dudes
- Women over 50
- People at increased risk of colon cancer
- With malabsorption: 12% of patients with celiac dx present with iron deficiency
8. GI bleed:
- Even low dose aspirin can cause peptic ulcer dx
- GI AVMs can be easily missed on colonoscopy
- SBFT is not sensitive at all for GI bleed
- Video capsule is test of choice for looking @ small bowel, unless someone has a history of stricture.
9. Macrocytic anemia:
- Megaloblastic: B12, folate
- Non megaloblastic: alcohol, hypothyroid, liver disease
10. Microcytic anemia:
- Iron deficiency, thalassemia, sideroblastic anemia (defect in heme synthesis leads to accumulation of iron in mitochondria around nucleus of developing RBC instead of being incorporated into heme)