macrocytic anaemia

Question 1

compare checking ferrtin levels with checking iron levels?

Answer 1

Checking ferritin level is better than checking iron level because feritin is IC and iron is EC so ion level would fluctuate and can even depend on the day-> ferritin gives a much better general view

however feritin is an acute phase protein-> HIGH IN INFLAMMATION-> not reliable if CRP is high

Question 2

define macrocytic anaemia?

Answer 2

Anaemia associated with a high MCV of erythrocytes (>100 fl in adults)

usually result of abnormal haemopoeisis -> red cell precursors continue to make Hb an dother cellular proteins but fail to divide normally

Question 3

what is meant by megaloblastic?

Answer 3

delay in maturation of nucleus-> cytoplasm continues to mature and cell continues to grow- unusually large and structurally abnormal, immature cells

OVAL MACROCYTES

Question 4

what are the causes of megaloblastic anaemia?

Answer 4

B12 or folate deficiency -> needed for DNA production and nuclear maturation

Drugs

Question 5

what are the causes of b12 deficiency?

Answer 5

Reduced absorption (e.g. post-gastrectomy, pernicious anaemia – autoimmune condition causing severe lack of IF, terminal ileal/small bowel resection or disease)

Reduced intake (vegans)

Abnormal metabolism (congenital transcobalamin II deficiency)

Question 6

what are the causes of folate deficiency?

Answer 6

Reduced intake (alcoholics, elderly, anorexia)

Increased demand (pregnancy, lactation, malignancy, chronic inflammation)

Reduced absorption (coeliac, tropical sprue)

Jejunal disease (e.g. coeliac disease)

Drugs (e.g. phenytoin)

Question 7

What drugs cause megaloblastic anaemia?

Answer 7

Methotrexate (dihydrofolate reductase inhibitor)

Hydroxyurea

Azathioprine

Zidovudine

Question 8

what are the causes of non- megaloblastic macrocytic anaemia?

Answer 8

Alcohol excess or Liver disease – ROUND macrocytes

Myelodysplasia

Multiple myeloma

Hypothyroidism (e.g. hashimotos)

Aplastic anaemia

Haemolysis (shift to immature red cell form - reticulocytosis)

Drugs (e.g. tyrosine kinase inhibitor)

Pregnancy

Question 9

summarise the epidemiology of macrocytic anaemia?

Answer 9

More common in ELDERLY FEMALES

Pernicious anaemia is the MOST COMMON cause of B12 deficiency in the West

Question 10

what are the presenting symptoms of macrocytic anaemia?

Answer 10

Non-specific symptoms of anaemia:

• Tiredness
• Lethargy
• Dyspnoea

Family history of autoimmune disease

Previous GI surgery

Symptoms of the CAUSE (e.g. weight loss, diarrhoea)

Question 11

what are the categories for the signs of macrocytic anaemia?

Answer 11

sign of anaemia

signs of pernicious anaemia

signs of B12 deficiency

folate deficiency symptoms

Question 12

what are the 3 main signs of anaemia?

Answer 12

pallor

tachycardia

breathlessness

Question 13

what are the signs of pernicious anaemia?

Answer 13

mild jaundice

glossitis

angular stomatitis

weight loss

Question 14

what are the signs of b12 deficiency on physical examination?

Answer 14

Peripheral neuropathy

Ataxia

Subacute combined degeneration of the spinal cord

Optic atrophy

Dementia

Positive Babinski’s, absent ankle reflex, increase knee reflex

Neuro symp

• numbness
• Paraethesia
• reduced sense of taste
• muscle weakness
• depression

Question 15

what are the symptoms of folate deficiency?

Answer 15

symptoms related to anaemia

Diarrhoea

Headache

Loss of appetite and weight loss

Question 16

what are the investigations for macrocytic anaemia?

Answer 16

bloods

blood film

schilling test

Bone marrow biopsy ( rarely needed)

Question 17

Describe bloods in B12 deficiency?

Answer 17

FBC

• High MCV
• Pancytopaenia in megaloblastic anaemia
• Different degrees of cytopaenia in myelodysplasia
• Exclude reticulocytosis

LFT

• High bilirubin (due to ineffective erythropoiesis or haemolysis)

ESR

TFT

Serum vitamin B12

Red cell folate

Anti-parietal cell (90%) and anti-intrinsic factor antibodies (40-60%)

Serum protein electrophoresis - looking for a dense band in myeloma

Question 18

Describe the blood film in macrocytic anaemia?

Answer 18

Large erythrocytes

In megaloblastic anaemia:

• Megaloblasts
• Hypersegmented neutrophil nuclei
• Target cells if liver disease

Question 19

what is the schilling test?

Answer 19

Method for testing for pernicious anaemia

B12 only absorbed when given with IF

Question 20

Generate a management plan for macrocytic anaemia

Answer 20

Pernicious Anaemia

• IM hydroxycobalamin (version of vitB12) for life

1. If no neurological defect-> IM hydroxycobalamin 1mg 3x/week for 2 weeks then 1mg/3 months
2. If neurological defect present-> 1mg every other day until no further improvement then 1mg/2 months

B12 deficiency – life-long therapy

• Rarely but may need a blood transfusion
• Dietary supplements – PO cyanocobalamin or IM 1000mg of hydroxocobalamin every 3 months

Folate Deficiency

• Oral folic acid
• If B12 deficiency is present, it must be treated before the folic acid deficiency as B12 is needed for folate to enter cells
• In pregnancy, prophylactic folate is given from conception until 12 weeks to prevent spina bifida

Question 21

what are the complications of macrocytic anaemia?

Answer 21

Pernicious anaemia –> increased risk of gastric cancer

Pregnancy - folate deficiency increases the risk of neural tube defects

Question 22

Summarise the prognosis for patients with macrocytic anaemia

Answer 22

Majority are treatable if there are no complications