19b - Hypoproliferative Anemias Flashcards
What is pernicious anemia?
A decificney in vitamin B12 secondary to intrinsic factor (IF) abnormalities.
Most frequent cause of vitamin B12 deficiency.
Autoantibodies against IF are requiredfor diagnosis.
What are four lab findings seen with vitamin B12 deficiency?
- Low vitamin B12 levels
- Low reticulocyte count
- Auto-antibodies to IF or parietal cells (if pernicious anemia)
- Elevated methylmalonic acid
What are four causes of folate deficiency?
- Decreased intake (alcoholism, poverty)
- Increased requirements (growth, pregnancy, staes or high cell turnover like leukemia)
- Defective absorption (jejunal restriction or malabsorption)
- Folic acid antagonists
What are sources of folate? How is it stored?
Sources: green veggies and fortified flour
Storage: can deplete in months
What are clinical symptoms of folate deficiency?
Megaloblasticanemia
Neural tube defects: 300,000 children/yr
- spina bifida occulta causing anencephaly
- Important of supplementation
What are three lab findings seen with folate deficiency?
- Low serum folate levels
-
Low RBC folate levels
- Marker of folate status at time of RBC production
- May be decreased in VitB12 deficiency too
- Normal methylmalonic acid levels (this helps rule out B12 deficiency in which methyllamonic acid levels would be high)
How do you treat B12 or folate deficiency?
VitB12 or folate supplementation (oral or IM)
Do NOT treat vitB12 deficiency with folate!
- Anemia will reverse
- Neurologial manifestations will not.
A 30yo previously heathy woman presents to Dr. Allie Cotter, primary care extraordinaire, and complains of fatigue. She has recently become shortness of breathe with strenuous exercise. She is pale in no acute distress. Her labs are as follows: What would you expect her peripheral blood smear to look like?
Her MCV is 61 so she is macrocytic.
Her MCHC is low so it will be hypochromic.
Her hemoglobin is low which also indicates that the RBCs will have hypochromicity.
What is the most common cause of iron deficiency in young women? What about in the elderly?
Young women: menstrual cycle
Elderly: GI bleeds
What are five compensatory mechanisms in anemia?
- Increased 2,3-DPG
- Shunting of blood from non-vital to vital areas
- Increased CO
- Increased RR
- Increased red cell production
What three things should be on your ddx with microcytic, hypochromic anemia?
- Iron deficiency anemia
- Thalassemia
- Anemia of chronic disease
Where is the “functional” iron found in the body?
Component of heme (80%)
Component of myoglobin, cytochromes, and catalases (20%)
Where is the “storage” iron found in the body? What are the different forms that iron is stored in?
Stored iron is 15-20% of total iron
- It’s found in the liver, spleen, and marrow.
- Hemosiderin is the breakdown of ferritin
- Ferritin
(There are differences in sexes)
How common is iron deficiency? Who gets it?
MOST COMMON world wide nutritional disorder (4-5 billion people worldwide).
Infants, children, and women most susceptible. Also elderly with occult GI bleeding.
What are the clinical features of iron deficiency?
- Microcytic, hypochromic anemia
- Impaired cognition, work capacity
What are four causes of iron deficiency?
- Dietary (milk fed infants)
- Impaired absorption (duodenum)
- Increased requirement (pregnant)
- Chronic blood loss (GI in <50yo or mentrual bleed)
How is non-heme vs heme iron absorbed?
Heme iron is absorbed by the heme transporter while non-heme iron is reduced by the duodenal cytochrome B (using VitC) and then taken up by
What happens once heme iron and non-heme iron are taken up by intestinal epithelial cells?
They are transported to mucosal ferritin and then transported out into the peripheral blood and hephaestin oxidizes Fe2+ it into Fe3+.
In the peripheral blood it is bound by plasma transferrin.