Macrocytic anemia Abdul Waris Khan

Soepel: 3

Dept: Internal medicine

SOEPEL

• Subjective: A 33 years old male presents to ER with

complains of easy fatigueability, SOB, palpitations, and

headache.

• H/O presenting illness: the symptoms started 2 weeks

ago and it was gradual in onset.

• No past medical or family history

• Objective: pulse: 78 bpm, RR: 20, BP: 130/ 90

• pale, tachycardia

• Evaluation: anemia, sleep apnea, medication side

effects.

• Plan: CBC, blood film

• Elaboration: If anemia B12 and Folate supplements

Definition

• A macrocytic anemia is a class of anemia in which

the red blood cells (erythrocytes) are larger than their

normal volume (>96 fl)

• Normal 76-96 fl

• Pernicious anaemia (PA) is an autoimmune disorder in

which there is atrophic gastritis with loss of parietal cells

in the gastric mucosa with consequent failure of intrinsic

factor production and vitamin B12 malabsorption.

Clinical features

Signs of anemia

Lemon-yellow color in eyes

Glossitis

Angular stomatitis

Neuropathy

Symptoms (all non-specific)

■ Fatigue, headaches and faintness are all

very common

in the general population

■ Breathlessness

■ Angina

■ Intermittent claudication

■ Palpitations.

Signs

■ Pallor

■ Tachycardia

■ Systolic flow murmur

■ Cardiac failure.

Specific signs:

■ koilonychia – spoon-shaped nails seen in

iron deficiency anaemia

■ jaundice – found in haemolytic anaemia

■ bone deformities – found in thalassaemia

major

Haematological findings

■ Anaemia may be present. The MCV is characteristically > 96 fL unless there is a coexisting cause of

microcytosis when there may be a dimorphic picture with a normal/low average MCV.

■ The peripheral blood film shows oval macrocytes with hypersegmented polymorphs with six or more lobes

in the nucleus.

■ If severe, there may be leucopenia and thrombocytopenia.

Treatment

• Treatment depends on the type of deficiency.

Treatment of vitamin B12 deficiency

• Hydroxocobalamin 1000 μg can be given IM to a total of 5–6 mg over the

course of 3 weeks.

• 1000 μg is then necessary every 3 months for the rest of the patient’s life.

• it is now recommended that oral B12 2 mg per day is given, as 1–2% of an

oral dose is absorbed by diffusion and therefore does not require intrinsic

factor.

• In elderly patients the use of sublingual nuggets of B12 (2 × 1000 μg daily)

has been suggested to be an effective and more convenient option.

Treatment of folate deficiency

• Folate deficiency can be corrected by giving 5 mg of folic acid daily.

• Treatment should be given for about 4 months to replace body stores.

• Any underlying cause, e.g. coeliac disease, should be treated.

• Prophylactic folic acid (400 μg daily) is recommended for all women

planning a pregnancy to reduce neural tube defects.

• Women who have had a child with a neural tube defect should take 5 mg

folic acid daily before and during a subsequent pregnancy.

MACROCYTOSIS WITHOUT MEGALOBLASTIC

CHANGES

• A raised MCV with macrocytosis on the peripheral blood film can occur

with a normoblastic rather than a megaloblastic bone marrow.

• A common physiological cause of macrocytosis is pregnancy.

Common pathological causes are:

■ alcohol excess

■ liver disease

■ reticulocytosis

■ hypothyroidism

■ some haematological disorders (e.g. aplastic anaemia,

sideroblastic anaemia, pure red cell aplasia)

■ drugs (e.g. cytotoxics – azathioprine)

• In all these conditions, normal serum levels of vitamin

B12 and folate will be found.

References

• Kumar and Clark 7th edition