What is Anemia?
Abnormally low hgb concentration
<12 for women
< 11 in 1st tri
< 10.5 in 2nd tri
< 11 in third tri
<13 for men
What are the types of anemia?
Classified by RBC size:
- Microcytic (MCV < 80)
- Macrocytic (MCV > 100)
- Normocytic (MCV 80-100)
What Causes Microcytic Anemia?
- IDA - usually d/t chronic low volume blood loss (menorrhagia, GI bleeds/colon cancer). dietary insufficiency, pregnancy d/t increased metabolic demand
- thalassemia trait
What causes Macrocytic Anemia?
- Vit B12 deficiency - PPIs can decrease B12, iron absorption; metformin can decrease B12 absorption
- Folate deficiency
- Liver disease
- hypothyroid
What causes Normocytic anemia?
- anemia of chronic disease - reduced RBC production/lifespan d/t inflammation
hemolysis - anemia of chronic disease can contribute - sickle cell disease
- renal failure - CRF (reduced erythropoetin)
- ACUTE blood loss
What is the most common anemia
IDA
What is the etiology for IDA?
- slow, persistent blood loss (GI bleed, heavy menstrual periods)
- Inadequate dietary intake (not common)
- Metabolic demands in excess of intake - like in pregnancy
What lab values would lead to IDA?
MICROCYTIC/HYPOCHROMIC
Hgb: Low
Hct: Low
RBC: Low
MCV: Low (small size/microcytic)
MCHC: Low (pale/hypochromic)
RDW: increased (cells different sizes)
Reticulocytes: decreased
If above is on CBC –> next step ferritin for estimate of iron stores
Ferritin: low
TIBC: high
Serum FE: normal or low
What is the etiology of anemia of chronic disease?
- hypoproliferative anemia associated with underlying chronic disorders like infection, inflammatory disorders (lupus/RA), malignancy
- reduced production and repose to erythropoeitin, decreased RBC life span (CRF)
- Defect in iron reutilization
- Common in elderly/autoimmune
What are the lab values for anemia of chronic disease?
Normocytic, Normochromic, NL RDW
Hgb: Low
Hct: Low
RBC: Low
MCV: wnl
MCHC: wnl
RDW: wnl
Next step: ID cause/dictated by suspected cause (lupus, RA, CRF… ACUTE BLOOD loss also has these labs)
What is the etiology of Vit B12 deficiency anemia?
- Vit B12 deficiency alters DNA synthesis and maturation of RBCs
- Vit B12 deficiency develops secondary to lack or relative deficiency of intrinsic factor that leads to impaired vitamin B12 absorption (pernicious anemia) –> d/t autoimmune reaction involving gastric parietal cells OR hx of gastrectomy
- Secondary to nutritional deficiency of vitamin, vegan diet is at risk
-alcoholism
What are the lab values for vit B12 deficiency?
Macrocytic Normochromic
hgb: low
hct: low
rbc: low
MHC: high
MCHC: wnl
RDW high
Follow up labs: serum vit B12, RBC folate
vit B12 will be low
What is the etiology of folate-deficiency anemia?
- folate deficiency alters synthesis of DNA and RBC maturation
- folate deficiency can be caused by: malabsorption syndromes, increased demand (pregnancy), inadequate intake (alcoholics/elderly)
- certain drugs can inhibit folate absorption: antacids, H2 antagonists, PPIs, metformin
- MOST common megaloblastic anemia in pregnancy
What are the lab values for folate-deficiency anemia?
Macrocytic, Normochromic
hgb: low
hct: low
rbc: low
MCV: high
MCHC: wnl
RDW: high
Next steps: B12 and folate
- folate will be low
What is the etiology for sickle-cell anemia?
Chronic hemolytic anemia characterized by sickle-shaped RBCs
- autosomal recessive disorder where Hgb S develops instead of hgb A
- persons with ssd are homozygous for Hgb S
- prevalent in AA ancestry, also mediterranean
Labs:
hgb 7-9
mild leukocytosis
reticulocytosis
Hgb S 85-95% in SCD; 40% in trait
What is the etiology of beta thal/alpha thal?
through inherited genetic variation, small (microcytic), pale (hypochromic) cells that are all around the same size (NL RDW)
autosomal recessive
alpha thal: asian, african ancestry (AAA)
beta thal: african, mediterranean, Middle Eastern (BAMME)
What are the lab values of beta thal/alpha thal?
microcytic, hypochromic, RDW wnl
hgb: low
hct: low
RBC: ELEVATED (make extra RBCs because they are small and pale)
MCV: low (microcytic)
MCHC: low (hypochromic)
RDW: wnl - all new cells are the same size
Next steps: hgb electrophoresis for evaluation of hemoglobin variants
What are the causes of drug-induced macrocytosis, usually without anemia?
excess alcohol - most common (>/= 3 drinks/day for women, 5 for men))
Anti-epileptic drugs (carbamazepine, phenytoin)
methotrexate
Lab values for macrocytosis without anemia:
hgb: wnl
hct: wnl
mcv: increased (macrocytic)
MCHC: wnl
RBC: wnl
Treatment for macrocytosis without anemia?
Reversible when use of offending medication is discontinued… but usually not a reason to curtain the drug’s use, except for excessive alcohol intake
S/S of ALL anemia
fatigue, weakness, exertional dyspnea, lightheadedness, anorexia
PE: palor, tachycardia, tachypnea
S/S of specific to IDA
pica, HA
PE: nail changes (spoon shaped koilonychias); brittle nails, brittle/fine hair
S/S specific to B12 deficiency anemia
insidious onset
GI disturbances - anorexia, bloating, diarrhea
SORE tongue
neurologic: peripheral paresthesia, ataxia
loss of taste and smell
PE: smooth, beefy-red tongue (glossitis), hepatomegaly/splenomegaly, jaundice, ataxia (+ Romberg), hyperactive reflexes, peripheral loss of sensation, change in mental state
S/S specific to Sickle cell anemia
vaso-occlusive crisis: malaise, chills, pain esp in bones, abdomen, chest, lower legs, HA, epistaxis, vomiting, difficulty walking
PE: jaundice, cardiomegaly, renal disease
