Microcytic anaemia

Question 1

Define microcytic anaemia

Answer 1

Low haemoglobin associated with low MCV <80 fl)

Question 2

General aetiology of microcytic anaemia

Answer 2

Iron deficiency
Anaemia of chronic disease
Thalassaemia alpha/beta
Sideroblastic anaemia

Question 3

What is the aetiology of iron deficiency anaemia

Answer 3

Reduced absorption: malnutrition, coeliac, IBD, vegetarian diet

Loss: GI MALIGNANCY, peptic ulcer, IBD, menstruation

Increased requirement: Pregnancy, breastfeeding

Question 4

What is the aetiology of anaemia of chronic disease

Answer 4

Cytokine increase -> hepcidin increase -> iron taken into ferritin

Question 5

Aetiology of sideroblastic anaemia

Answer 5

X-linked
Secondary to alcohol, drugs (isoniazid, chloramphenicol), lead, myelodysplasia
Lead poisoning e.g. in scrap metal or smelting workers

Question 6

Epidemiology of microcytic anaemia

Answer 6

Global prevalence of anaemia is 33%
IDA is the most common cause
IDA more common in young children and pre-menopausal women
Thalassaemia high frequencies in CYPRUS, mediterranean etc.

Question 7

Presenting symptoms of microcytic anaemia

Answer 7

Fatigue, lethargy 
Malaise
Dypsnoea
Pallor 
Exacerbation of pre-existing angina

PICA: craving to eat ice or dirt (IDA)

Question 8

Symptoms and signs of lead poisoning

Answer 8

Anorexia
N+V
Abdominal pain
Constipation
Peripheral nerve lesions

Blue gumline
Peripheral nerve lesions
Encephalopathy
Convulsions
Reduced consciousness

Question 9

Signs of Microcytic anaemia

Answer 9

Pallor, brittle nails and hair, koilonychia
Glossitis
Cheilitis, angular stomatitis

Tachypnoea if severe

Question 10

Investigations for microcytic anaemia

Answer 10

FBC: Hb reduced, MCV <80
Iron studies
Blood films

Hb Electrophopresis: confirms thalassaemia or sideroblastic (stain blue-green with perl’s)

Question 11

What would you expect to see on the iron studies for IDA, ACD and thalassaemia

Answer 11

IDA - everything reduced except transferrin

ACD - everything reduced except ferritin, TIBC normal

Thalassaemia - everything normal

Question 12

What would you expect to see on the blood film for IDA, sideroblastic anaemia and lead poisoning

Answer 12

IDA - microcytic, hypochromic, anisocytosis, poikilocytosis, pencil cells

Sideroblastic - dimorphic with hypochromic microcytic RBC

Lead poisoning: basophillic stripping

Question 13

Investigations for IDA specifically

Answer 13

Find the cause: 
Full GI investigations (male, female >40, post-menopause, scanty menstrual loss) 
 - OGD
 - Duodenal biopsies
 - Colonoscopy 

Urinalysis: Urinary blood loss

tTG + IgA: Antibodies for coeliac

Question 14

Management for IDA

Answer 14

Oral iron supplements e.g. 200mg ferrous sulphate tablets 2 or 3x daily with food

Malabsorption or intolerance - parenteral iron supplements

Monitor Hb and MCV, aiming for Hb rise of 1 g/dL/week

Question 15

Management of lead poisoning

Answer 15

Remove the source
Dimercaprol
D-penicillamine
Ca2+ + EDTA

Question 16

Management of sideroblastic anaemia

Answer 16

Treat the cause
Pyridoxine for inherited forms
Blood transfusion and iron chelation

Question 17

Complications of microcytic anaemia

Answer 17

High output cardiac failure

Complications of the cause