Megaloblastic Anemias

Question 1

What are some nutritional aspects of folate (probably not important)?

Answer 1

Intake is 200-250 micrograms a day, use about 100-150 a day, you store 10-12 and it is absorbed in the duodenum and jejunum

Question 2

When is folate at increased demand?

Answer 2

During pregnancy (5-10 times more), lactation increases loss; When RBC turnover increases during hemolytic diseases; exfoliative dermatitis; and drugs

Question 3

What are 3 things that impair Folic Acid absorption?

Answer 3

Tropical Sprue
Regional Enteritis
Resection of small intestine

Question 4

What 3 demographics have poor dietary intake of folate?

Answer 4

Elderly, poor, alcoholics

Question 5

What are the clinical features of megaloblastic anemias?

Answer 5

Insidious onset, mild jaundice, gossitis, angular stomatitis, weight loss, purpura

Question 6

What is the treatment for Folate Deficiency? What must you be careful for when treating?

Answer 6

Give 1mg/day of folic acid orally; must be careful that the diagnosis is right, if not certain give both B12 and folate to avoid neuropathy of B12 getting worse while blood changes improve

Question 7

What are our sources of B12 and how much do we need per day?

Answer 7

Animal products, milk, eggs, cheese; 1-2 micrograms per day, body stores are 2-3 mg’s

Question 8

What are the B12 deficiency gastric disorders?

Answer 8

Total gastrectomy, blind loop syndrome, and zollinger ellison syndrome

Question 9

What is zollinger ellison syndrome?

Answer 9

Gastric producing tumors in the pancreas, gastric secretion of large amounts of HCl, acid inactivates pancreatic proteases and prevents transfer from Cbl from R binders to IF

Question 10

What are the B12 intestinal disorders?

Answer 10

Ileal resection, Regional enteritis, Cbl malabsorption from hypthyroidism or drugs, tropical sprue

Question 11

What are other causes of B12 deficiency?

Answer 11

Pancreatic insufficiency (lack of pancreatic juices resulting in failure to inhibit R binder/Cbl complex and transfer to IF) and Dietary-rare Vegans

Question 12

What is neurologic disorder with B12 deficiency?

Answer 12

It happens early and involves parathesias of hands and feet, somulence and dementia, decreased vibritory and proprioception, loss of position sense. Late symptoms are spastic paralysis from demyelination (irreversible)

Question 13

What is the history of Pernicious anemia?

Answer 13

1855 - Addison - invariably fatal “idiopathic anemia”
1926 - Munot and Murphy - effect of liver feeding
1929 - Castle - intrinsic factor

Question 14

What is Pernicious Anemia?

Answer 14

An autoimmune disease with an insidious onset (like a ninja). Intrinsic factor secretion fails due to gastric mucosal atrophy. Onset after 40 yrs, prevalent in scandanavia

Question 15

What is the Pathogenesis of Pernicious anemia?

Answer 15

Gastric atrophy - CD4+ T cells whose receptors recognize H+/K+-ATMPase
Antiparietal cell antibodies in 90% of PA and 60% of atrophic gastritis
Intrinsic factor antibodies found in 50-70% of PA

Question 16

What are other AI diseases associated with PA? (7)

Answer 16

AI Thyroid Disorders
T1 Diabetes
Hypoparathyroidism
Addison Disease
Ulcerative colitis
Vitiligo
Acquired agammaglobulinemia

Question 17

What is the Schilling test?

Answer 17

I) Drink .5 microCi of radioactive cyanocobalamin, start 24 hour urine collection, at 2 hrs = 1000 micrograms of IM B1, measure radioactivity in 24 hour uring collection
II) Give 60 mg of hog intrinsic factor with radioactive B12
III) repeat after 14 days of antibiotics

Question 18

How do you treat B12 deficiency? What are the results?

Answer 18

Give IM B12, 1000 micrograms of B12 IM daily for 2 weeks then 100 micrograms monthly for life. Bone marrow resolves in 2-3 days and Hbg normal in 1-2 months.