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Flashcards in Anaemia Deck (19):
1

Main causes of anaemia

Decreased production

Increased destruction

2

Causes of decreased production of RBCs

Dx = Low reticulocytes

BM problem

Haematinics - Iron, Vitamin 12 and folate

Anaemia of chronic disease

Kidney disease

3

Causes of increased RBC destruction

Haemolysis

Thalassaemia

Blood loss

4

Causes of microcytic anaemia

Iron deficiency

Thalassaemia

Anaemia of chronic disease
Myelodysplasia
Sideroblastic anaemia
Hyperthyroidism
Heavy metal poisoning

5

Iron homeostasis

Normal body = 3-4gms of iron
2gms in red cells
Rest is bound in proteins or stored

Need 20mg/day for erythropoiesis
1-3mg/day absorbed and rest is recycled

No regulated system of excretion - soughing of enterocytes and menstrual loss

6

Iron cycle

ABSORPTION:
Non-Haem Fe
- Duodenal entercytes abserob Fe2 through apical membrane DMT1
- Excreted by ferroportin from enterocyte into the plasma

Haem Fe
- Unknown pathway but more bioavailable

STORAGE:
Stored in hepatocytes, spleen and BM

TRANSPORT:
Transferred in plasma bound to transferrin

7

Regulation of iron absorption

HEPCIDIN:
- Binds ferroportin and induces its degradation
- --> decreases iron absorption
- Acute phase reactant
- Regulated by HFE, TfR2, HJV, hypoxia and EPO

Transcriptional control of DMT-1 and ferroportin
- Induced by hypoxia

8

Causes of iron deficiency anaemia

GIT Bleeding:
- Gastric ulcers
- Malignancy
- Diverticulitis

Menstruation
Diet
Other:
- Coeliac
- Gastric bypass
- Pregnancy
- PCRV
- GIT parasites

9

Diagnosis of cause of iron deficiency anaemia

Film - microcytic hypochromic red cells

Iron studies - high transferrin, low transferrin saturation and ferritin

Investigate for source of blood loss

10

Management of iron deficiency anaemia

Iron replacement therapy:
- Oral, IM or IV

Monitor Hb and reticulocyte count for response

Treatment failure:
- Non compliance
- Ongoing losses
- Malabsorption
- B12/folate deficiency
- ACD
- THALASSAEMIA

11

Anaemia of chronic disease

Multifactorial disease
Common causes - infection, neoplasia, inflammation

Inflammation --> IL-1, IL-6, TNF-alpha --> increased hepcidin

Reduced reticulocytosis, reduced RBC lifespan, and abnormal Fe homeostasis

Treat underlying disease
Fe replace
EPO

12

Causes of macrocytic anaemia

Megaloblastic erythropoiesis:
- B12 deficiency
- Folate deficiency
- Antifolate drugs - MTX, trimethoprim
- Anti-DNA synthesis drugs - AZA, hydroxyurea, zidovudine, chemotherapy

Reticulocytosis
- Haemolysis
- Bleeding

Others:
- BM pathology - Aplastic anaemia, MM, MDS
- Liver disease
- Copper deficiency
- Downs

13

Vitamin B12 absorption and metabolism

From animal products
Ingested as cobalamin - released from food by pepsin and acid
Bound by transcobalamin
Pancreatic enzymes release cobalamin --> binding by intrinsic factor
B12-IF complex absorbed in terminal ileum

Transcobalamin transports in the body

Stored in the liver

14

Role of Vitamin B12 in the body

1. Reduces homocystiene to methionine in the cytoplasm --> various metabolic pathways including nucleic acid synthesis

2. Used in the TCA cycle in mitochondria - MM-CoA --> Succinyl-CoA

15

Causes of Vitamin B12 deficiency

Pernicious Anaemia
- AID --> loss of parietal cells --> loss of intrinsic factor
- Test IF antibodies and Parietal cell antibodies

Diet
Intestinal pathology:
- Coeliac
- Ilieal resection
- Sprue

Gastrectomy

16

Diagnosis of B12 deficiency

Macrocytic anaemia
Glossitis, angular stomatitis
Increased melanin
Neurological findings

Cobalamin assay

17

Role of folate in the body

Required for DNA and RNA synthesis

Only from the diet
Absorbed in the small intestine

18

Causes of folate deficiency

Diet

Haemolysis
Pregnancy
Chronic inflammation
Malabsorption
Drugs - MTX, Trimethoprim

19

Diagnosis of folate deficiency

Fatigue, lethargy, sore tongue, headaches, diarrhoea, irritability

Blood film
Red cell folate