Pernicious Anemia (B12 Deficiency)

Question 1

What is the definition?
How long does it take to develop?
Which patients is it seen in ?

Answer 1

Cause of vit B12 deficiency
Takes years to develop
Older Px
Higher in vegans

Question 2

Causes of B12 deficiency

Answer 2

Pernicious anemia (mc - Abs vs parietal + IF cells)
Malnutrition (insufficient diet)
Pregnancy, crohns (affect ileum), gastrectony

Question 3

Pathology

Answer 3

Parietal cells in stomach produce intrinsic factor (IF), needed for B12 absorption in the ileum

B12 typically binds to transcolbamin 1 in saliva (protects vs stomach acid), then binds to IF in duodenum + absorbed as B12-IF complex at ileum

Anti parietal + IF Abs = low IF therefore low B12-IF complexes = low B12 absorption

Question 4

Symptoms

Answer 4

General Anemia
+ lemon yellow skin
Angular stomatitis + glossitis
Neurological symptoms- symmetrical parasthesia (pins & needles), muscle weakness

Question 5

Why would a patient experience Neurological symptoms?

Answer 5

B12 deficiency causes demyelination
Key DDx to folate deficiency

Question 6

Why does a patient experience stomatitis and glossitis?

Answer 6

B12, folate & Fe = haematinics
Nutrients needed for haematopoesis
Deficiencies in these cause those Sx

Question 7

Diagnosis

Answer 7

FBC + blood film = macrocytic anemia
Megaloblasts

Decreased serum B12

Anti IF Abs (very specific for pernicious anemia; DIAGNOSTIC but not present in all Px) & Anti parietal Abs

Question 8

The megaloblasts in pernicious anemia are described as?

Answer 8

Hypersegmented nucleated neutrophils - 6+ lobes)

Question 9

Treatment for pernicious anemia

Answer 9

Dietary advice (eggs, salmon)
B12 supplements (PO hydroxycolbamin)