Pernicious Anemia: Easy revision with flashcards
Pernicious anemia is an important exam topic, commonly tested in Internal Medicine, Hematology, and Gastroenterology. This post makes it easy to revise this important exam topic through flashcards.
Tip: Please try to answer in your head first before looking at the answer in the post. This way you will be able to retain information for a longer period.
What is pernicious anemia & what is its pathology?
Pernicious anemia is an autoimmune condition affecting gastric parietal cells.
Pathology: There is atrophic gastritis due to autoantibodies in this condition. This results in a lack of intrinsic factor secretion from the gastric parietal cells. Dietary B12, therefore, remains unbound and cannot be absorbed by the terminal ileum.
How much B12 is absorbed in the absence of lack of Intrinsic factor?
In the absence of intrinsic factor, only less than 1% of dietary vitamin B12 is absorbed.
Is there any gender predilection in this disease?
The incidence of pernicious anemia is 1.6 times higher in females.
What is its usual age of onset?
Pernicious anemia usually presents in > 40 years of age.
What are the associations of pernicious anemia?
Pernicious anemia can be associated with other autoimmune diseases in a patient. These include autoimmune thyroid disease, vitiligo, Addison’s disease, and hypoparathyroidism.
Carcinoma of the stomach is also about 3-fold more common in pernicious anemia.
What are the investigations done in pernicious anemia?
CBC will reveal anemia, with raised MCV.
If pernicious anemia is severe, white Cell Counts and platelets may also be reduced.
Peripheral blood film- hyper-segmented neutrophils can be found.
Reticulocytes – As red cell production is impaired, reticulocytes may also be low despite dyserythropoietic hemolysis.
Serum B12 levels will be low.
Bone marrow biopsy will show megaloblasts.
Gastric biopsy will reveal atrophic gastritis.
Specific tests for Pernicious anemia include:
– Intrinsic Factor antibodies. These antibodies are specific for pernicious anemia but have a lower sensitivity. The finding of anti-intrinsic factor antibodies in the context of B12 deficiency is diagnostic of pernicious anemia, without a need for any further investigation.
– Parietal cell antibodies. It has higher sensitivity but lower specificity. This is because these can be found in 90% of patients, but may also present in 20% of normal females, over the age of 60.
What is the treatment of pernicious anemia?
Treatment is with the replacement of Vitamin B12.
1 mg Cyanocobalamin is given IM for 6 doses, 2 or 3 days apart. It is followed by lifelong maintenance therapy of 1 mg, every 3 months.
In the presence of neurological involvement, a dose of 1 mg on alternate days is given, until there is no further improvement. It is then followed by maintenance as mentioned before, that is every 3 months for life.
Also, have a low thresh-hold to do upper GI endoscopy in the wake of increased risk of gastric Ca.
How is the response to treatment detected?
Response to treatment is noted with rising in reticulocyte count that peaks within 5–10 days. The hemoglobin will rise by 10 g/L every week until normalized.
Sensory neuropathy may take 6–12 months to correct, but long-standing neurological damage may not improve.
Is there any pitfall(s) in the treatment?
The response of the marrow and resultant increased erythropoiesis is associated with a fall in plasma potassium levels and rapid depletion of iron stores. Monitor potassium level and replace if necessary. Also, if an initial bone marrow response is not maintained and the blood film is dimorphic (mixed microcytic and macrocytic cells), the patient may need additional iron therapy.
Was this post useful? Please give your precious feedback in the comments section below.
