Anaemia - Sideroblastic (Microcytic)

Question 1

Definition

Answer 1

Defective Hb synthesis within mitochondria = ineffective erythropoiesis , often X linked inherited ALA synthetase def.

Question 2

Ineffective erythropoiesis leads to…

Answer 2

Increased iron absorption
Iron loading in marrow
Haemosiderosis (endocrine, liver + heart damage due to iron deposition)

Question 3

Aetiology CAPITAL

Answer 3

Congenital (x-linked)
Acquired e.g. idiopathic
Post chemo
Irradiation
Tb drugs
Alcohol
Lead excess

Question 4

Pathophysiology

Answer 4

A functional Fe deficiency - increased Fe+ but not used on Hb synth because trapped in mitochondria = IMPAIRED INCORPORATION OF IRON INTO HEME

Question 5

Diagnosis

Answer 5

FBC + Blood film = MICROCYTIC HYPOCHRMIC with RINGED SIDEROBLASTS (excess fe deposits, ineffective erythropoiesis and die in bone marrow), basophilic stippling (Increased basophilic granules) and Pappenheimer bodies
Fe studies =
- Increased serum Fe
- Increased transferrin sats
- Low Total iron binding capacity

Question 6

Treatment

Answer 6

Remove cause
Pyridoxine
Repeated transfusions for severe anemia.

Question 7

Signs and symptoms

Answer 7

Similar to haematochromatosis
- Skin hyperpigmentation: ‘bronze skin’
- Arthritic joints
- Testicular atrophy
- Features of chronic liver disease: e.g. hepatomegaly
- Features of congestive cardiac failure: e.g. peripheral oedema due to dilated cardiomyopathy
- Splenomegaly

Symptoms
- Arthralgia
- Diarrhoea
- Fatigue