ICL 4.1: Anemia Workup & Classification Flashcards
what is anemia?
decreased ability to carry oxygen due to low RBC count or low Hb concentration
what are the signs of anemia?
- pallor
- hemolytic: jaundice, brown urine, gallstones, ecchymosis
- iron deficiency: koilonychias, angular cheilitis
- B12 deficiency: gait disturbance
- lead poisoning: lead line
what are symptoms of anemia?
- dyspnea
- fatigue
- dizziness
- tachycardia
- leg cramps
- restless legs
- dementia
- paresthesia
symptoms depend on how quickly the anemia develops and the cardiac reserve of the patient
how do you classify anemia?
- by etiology
- loss of blood
- increased destruction
- decreased production - by morphology
- microcytic
- normocytic
- macrocytic
what is considered low Hb for men and women?
<13.5 g/dL for men
<12 g/dL for women
what is MCH?
mean corpuscle hemoglobin
Hb content in an RBC
low in IDA and thalassemia
what is MCHC?
mean corpuscular hemoglobin concentration
Hb concentration per RBC
low in IDA
high in spherocytosis
what is RDW?
variance in RBC size
high in IDA, MDS, hemoglobinopathies
what’s the bone marrow response to anemia?
increased reticulocytes in peripheral blood
what is reticulocyte index? what’s the formula?
correct for early bone marrow release
tells you if the bone marrow is responding properly to anemia
RI = corrected reticulocyte count/fudge factor
> 3-8: good response
< 3: poor response
ex. 7 g/dL Hb, 21 Hct with reticulocyte count 10%
corrected reticulocyte 10 x (21/45) = 4.6
reticulocyte index = 4.6/2.1 = 2.19
what is the corrected reticulocyte count?
% reticulocytes x (pt. Hct/normal Hct (45))
what does a reticulocyte look like on a blood smear?
special stain will show you the RNA that’s still in the reticulocyte
looks like a bunch of purple dots in the cell
this RNA wouldn’t be present in a mature RBC
what are Howell-Jolly bodies?
DNA
looks like one purple dot on an RBC
spleen
when do you see Howell-Jolly bodies?
when a person has had a splenectomy because the spleen is no longer clearing them out
can also see them in hemolytic anemias and megaloblastic anemias
when are Papenhelmer bodies seen?
iron deficiencies
hemolytic anemia
thalassemia
splenectomy
what do Pappenheimer bodies look like on a blood smear?
they look like just a couple little dots clumped together on the side of the RBC
what is basophilic stippling? when do you see it?
it’s RNA; pathological precipitation of ribosomes!
seen in thalassemia and lead poisoning
what does basophilic stippling look like on a blood smear?
like an RBC heavily covered in blue polka dots
what are Heinz bodies?
denatured hemoglobin
you need a special stain to see them!
when do you get Heinz bodies?
unstable hemoglobin
thalassemia
enzyme deficiencies like G6PD deficiency**
what do Heinz bodies look like on a blood smear?
just a few randomly scattered bigger polka dots in the RBC
what does Hemoglobin H look like on a blood smear and what is it?
denatured hemoglobin
looks like a uniformly covered RBC covered in polka dots but not super heavily covered
when are target cells present?
if macrocytic = liver disease
if normocytic = HbC disease
if microcytic = thalassemia
what are schistocytes? when do you get them?
RBC fragments, randomly shaped
seen in hemolytic anemias or mechanical destruction like with a heart valve
what are acanthocytes?
super spiky looking RBCs
usually seen in liver disease,
when are tear drop RBCs seen?
thalassemia
bone marrow has lots of fibrous stroma so the RBC is pushed out of the bone marrow and is tear drop shaped
what are echinocytes? when are they seen?
wavy sorta spiky looking RBCs
seen in pyruvate kinase deficiency
what are spherocytes? when are they seen?
solid, sphere shaped RBC
seen in immune hemolytic anemia and transfusion reaction
what are the types of RBC hemolysis?
intrinsic: problem with the RBC structure
extrinsic: antibodies of mechanical destruction
what causes decreased RBC production?
- lack of necessary building block (Fe, B12)
- lack of room to grow in bone marrow (due to malignancy)
- suppression of growth factors/cytokines from infections of drugs
what RBC features is used when we classify anemias by morphology?
RBC size
what causes microcytic anemias?
- lead poisoning
- pregnancy
what are the types of macrocytic anemia?
- megaloblastic
2. non-megaloblastic
what causes megaloblastic macrocytic anemia?
problems with RBC formation
- B12 deficiency
- folate deficiency
what causes non-megaloblastic macrocytic anemia?
- chronic alcohol use
- reticulocytosis
- liver disease
- hypothyroidism
what is B12 used for?
- homocysteine to methionine reaction
2. methylmalonylCoA to succinylCoA reaction
what does B12 deficiency cause?
decreased DNA synthesis
more megaloblasts in BM
hypersegmented neutrophils in peripheral blood
how do we absorb vitamin B12?
steps:
1. diet
- stomach: intrinsic factor
- terminal ileum absorption
- liver storage (supply lasts years)
what causes B12 deficiency?
- GI problems
- poor diet
- increased needs like pregnancy or hyperthyroidism
- stomach problems like loss of intrinsic factor or gastrectomy
- S.I. problems like bacterial overgrowth (blind loop syndrome) or fish tapeworm
- terminal ileum problems (loss of absorption) like crohn’s disease
how can you try to compensate for B12 deficiency?
give folate
but folate can’t compensate for neurological problems so make sure you’re giving both B12 and folate
compare RDW in IDA vs. thalassemia?
IDA: high
thalassemia: normal/low
compare RBC count in IDA vs. thalassemia?
IDA: low
thalassemia: increased
compare blood smear for IDA vs. thalassemia?
IDA: elliptocytes
thalassemia: basophilic stippling and target cells
how do you differentiate IDA vs. ACD?
TIBC and % saturation
increased in IDA
normal/decreased in ACD
where does fe absorption happen?
duodenum
if you have a normocytic anemia, what lab test will tel us if the bone marrow is responding appropriately?
reticulocyte count
what CBC parameter will help us differentiate between IDA and thalassemia?
RDW and RBC count
how can you use ferritin to distinguish IDA from ACD?
low in IDA
normal/high in ACD
BUT normal/increased ferritin does not rule out IDA
what CBC results do you usually see in hemolytic anemias?
- normal MCV
- elevated bilirubin
- elevated LDH
- decreased free haptoglobin
- hemoglo binemia/hemoglobinuria
- increased reticulocytes
- nucleated RBCs
what causes intrinsic hemolytic anemia?
- membrane issues (HS, PNH)
- enzyme issues (G6PD deficiency)
- Hb issues (HbSS)
what causes extrinsic hemolytic anemias?
- antibodies
- mechanical (heart valves)
- microangiopathic
what types of antibodies can be found in autoimmune hemolytic anemias?
- warm autoimmune
- cold agglutinins
- cold hemolysins
