Anemias Flashcards
At IPV, pt has Hgb 8 and normal MCV, ferritin and iron. What is differential ddx?
Normocytic anemia and normal iron stores. Hemoglobinopathies (Thalassemia, sickle cell anemia), anemia of chronic disease (classically microcytic).
What additional testing? Hemoglobin electrophoresis (looks for structural abnormalities). Want to know the distribution of her hemoglobin chains, proportion of hemoglobin A2 and hemoglobin F.
How do you diagnose thalassemia? Genetic testing.
If testing idenfifies alpha-thal (–/aa), how would you counsel her? She has alpha-thal minor. Implications for fetus depending on partner’s genetic testing (also needs hemoglobin electrophoresis).
What is alpha thalassemia?
What is gestational thrombocytopenia?
Onset any point in pregnancy, most common in mid second to 3rd tri, most Plts >75K
Asymptomatic and no hx bleeding
No hx thrombocytopenia outside of pregnancy
Return to normal within 1-2 months after birth
Incidence of fetal or neonatal thrombocytopenia in setting of gTP is low.
What are causes of thrombocytopenia in pregnancy?
- Consumptive process like ITP, TTP-HUS, pancytopenia
- gTP
- systemic conditions (DIC, TTP/HUS, splenic sequestration)
- HDP (PEC, HELLP)
- primary immune thrombocytopenia
- secondary immune thrombcytopenia (APLS, SLE, infectious like HIV, HCV, drug-induced from heparin, antibiotics).
How do you classify immune thrombocytopenia in pregnancy?
Fetal NAIT (neonatal alloimmune thrombocytopenia): maternal destruction of fetal platelets due to maternal alloimmunization to fetal plt antigens w/ transplacental transfer of platelet-specific ab and plt destruction. Can affect 1st pregnancy. For subsequent pregnancies, check maternal anti-HPA1a Ab levels.
How would mom present: healthy mom, neonate w/ profound thrombocytopenia (petechiae, ecchymosis, hemorrhage after venipuncture) - most serious complication is fetal intracranial hemorrhage.
What finding can you see on US in fetus w/ NAIT: fetal intracranial hemorrhage (can see in 50% of cases on US).
ITP: diagnosis of exclusion, isolated thrombocyotpenia <100K. blood smear - platelet clumping. Severe ITP <50K.
How do you differentiate between most common causes of thrombocytopenia in pregnancy?
ITP and gTP most common in 1st and 2nd trimesters. ITP tx=steroids. If Plts 100-150, usually gTP. If Plts <100, likely ITP. in 3rd tri, consider PEC, TTP, HUS, DIC, AFLP.
What is TTP-HUS?
associated renal and neurological sx (FAT-RN), HUS seen after infection. tx=plasmapharesis.
What is management of GTP?
When do you transfuse platelets?
No increased risk of maternal bleeding. Reasonable to do qtrimester. Postpartum repeat in 1-3 months.
transfuse if Plts <50K before c-section.
When do you treat ITP?
Treat with prednisone if Plt <30 or pt has symptomatic bleeding. At time of delivery, consider risk associated w/ delivery, epidural anesthesia. Need Plts of 70 for epidural and 50 for CS.
Start prednisone at low dose 10-20mg/day, give for at least 3 weeks then taper. Response within 3 days-2 weeks.
If steroids not effective, give IVIG. 1g/kg as one-time dose. Response within 1-3 days.
- fix platelets 1 week prior to delivery.
What if steroids and IVIG fail? Splenectomy but avoid during pregnancy. If awful, can do 2nd trimester.
How much does transfusion of platelets increase Plt count? 30K.
- avoid forceps, vacuum, FSE.
What is ITP?
How do you evaluate possible NAIT?
Labs w/ HPA type and zygosity of both parents and confirm maternal antiplatelet antibodies.
How do you manage? Avoid operative vaginal delivery, early IVIG, can do PUBS after 32w, to assess fetal platelet response to therapy. CS if fetal platelets <50.
What is anemia in pregnancy?
Hct or Hgb <5%
1st tri: 33%/11
2nd tri: 32%/10.5
3rd tri: 33%/11
Hct affected by high altitude, smoking (raise it) and black race (lowers it by 2%)
What are classifications of anemia?
Acquired: deficiency, hemorrhagic, chronic disease, hemolytic anemia, aplastic anemia
inherited: thalassemia, sickle cell, inherited hemolytic.
Causes: decr RBC production vs. incr RBC destruction.
- most common causes: blood loss, IDA. then folate/B12/hemolytic
Workup: CBC, ferritin, iron levels. Maybe hub electrophoresis and genetic testing.
What is IDA?
most common cause microcytic anemia
- 1000mg Fe needed.
foods w/ high iron: beef, turkey, shrimp, beans, lentils.
causes of decreased iron absorption: dairy, coffee, tea, spinach, GI malabsorption.
Causes of IDA:
- short interval preg, HMB
Ddx: Ferritin < 30.
What are clinical consequences of IDA and what is treatment?
Fetal: LBW, PTB, incr perinatal mortality
Maternal: PPD
Treatment: oral FE 325mg ferrous sulfate. IV iron if anemia doesn’t respond.
- Transfusion antepartum if severe (Hgb <6) to prevent fetal death.
What is microcytic anemia?
MCV>100
- megaloblastic (folic acid, B12 deficiency or pernicious anemia) vs non-megaloblastic (alcoholism, liver disease, aplastic anemia, hypothyroid)
- low B12 common (gastric bypass, Crohn’s).
- folate requirements 400 mcg/d
Tx folate deficiency: diet and 1mg folic acid daily.
B12 deficiency: 1mg B12 IM monthly.
