GP - Anaemia Flashcards
What is aplastic anaemia?
Characterised by:
- Pancytopenia (reduced RBC, WBC and platelets)
- Hypoplastic bone marrow (few blood cells vs aplastic which is no cells)
Peak incidence = 30-yrs old
What are the features of aplastic aneamia?
Features:
- Normochromic, normocytic anaemia
- Leukopenia (lymphocytes relatively spared)
- Thrombocytopenia
- Can be the presenting features of acute lymphoblastic or myeloid leukaemia
What can cause aplastic anaemia?
- Idiopathic
- Infections: parvovirus, hepatitis
- Congenital: Fanconi anaemia, dyskeratosis congenita (DKC)
- Drugs: cytotoxics, chloramphenicol, sulphonamides, phenytoin, gold
- Toxins: benzene
- Radiation
What are some ‘Red-flag’ questions for suspected anaemia?
- Indigestion or vomiting - upper GI cancer can present with anaemia + these symptoms
- Blood loss anywhere - urine, on wiping front/back passage, in stool, in sperm, vaginal bleeding, haematemesis, haemoptysis
- Diet - diet low in red-meat / vegetarian / vegan can cause iron-deficiency anaemia
- Change in bowels (loose/constipated) - a symptom of bowel cancer can be anaemia
- Medications - NSAIDs can increase risk of peptic ulcer and GI inflammation –> causing anaemia
What are the normal ranges for haemoglobin in men and women?
- Men = 130 - 180 g/L
- Women = 115 - 165 g/L
What are some causes of Microcytic Anaemia?
Causes of Microcytic anaemia (< 80 fL):
- Iron-deficiency anaemia
-
Thalassaemia
- In beta-thalassaemia minor, the microcytosis is disproportionate to the anaemia
- Congenital sideroblastic anaemia
-
Anaemia of chronic disease
- more commonly a normocytic, normochromic picture
- Lead poisoning
What are the main categories of anaemia?
- Microcytic = < 80 fL
- Normocytic = 80-100 fL
- Macrocytic = > 100 fL
New onset microcytic anaemia in a pt > 60-yrs requires investigation for what?
2WW referral to invetigate for colorectal cancer
What are some causes of normocytic anaemia?
-
Anaemia of chronic disease
- Can be microcytic but more commonly normocytic
- Chronic kidney disease (CKD) - deficiency of erythropoietin
- Aplastic anaemia (pancytopenia)
- Haemolytic anaemia (↑ reticulocytes)
-
Acute blood loss
- Hb doesn’t drop immediately in blood loss as the concentration of Hb doesn’t actually fall
- Sickle Cell anemia
What are some causes of macrocytic anaemia?
Megaloblastic bone marrow:
- Vitamin B12 deficiency
- Folate deficiency
Normoblastic bone marrow:
- alcohol
- liver disease
- hypothyroidism
- reticulocytosis (increased immature RBCs)
- myelodysplasia (cancers in which immature blood cells don’t mature)
- pregnancy
- drugs: cytotoxics
What is Megaloblastic anaemia?
Anaemia (of macrocytic classification) which results from inhibition of DNA synthesis during RBC production
- DNA synthesis impairment –> cell cycle can’t progress from G2 growth stage to mitosis –> results in continued cell growth without division (macrocytosis)
- Often due vitamin deficiency:
- Vitamin B-12 deficiency
- Folate deficiency
What are some causes of hereditary haemolytic anaemia?
RBC membrane defects:
- hereditary spherocytosis
- hereditary elliptocytosis
Metabolism defect:
- G6PD deficiency
Haemoglobin defects:
- Sickle cell anaemia
- Thalassaemia
What are some causes of Acquired haemolytic anaemia?
Immune causes:
- Autoimmune - warm / cold antibody type
- Alloimmune - tranfusion reaction, haemolytic disease of newborn
- Drugs - methyldopa, penicillin
Non-immune causes:
-
Microangiopathic haemolytic anaemia (MAHA) - TTP / HUS, DIC, malignancy, pre-eclampsia
- Microangiopathy - refers to microvascular disease
- Prosthetic cardiac valves
- Paroxysmal nocturnal haemoglobinuria (PNH)
- Malaria
- Drugs - Dapsone (Abx often used for; leprosy, dermatitis herpetiformis, pneumocystis jirovecii pneumonia)
What is Fanconi anaemia?
Autosomal recessive - impaired response to DNA damage
Features:
- aplastic anaemia
- increased risk of acute myeloid leukaemia
- ~80% develop bone marrow failure by 20-yrs
- skeletal abnormalities e.g. short stature
- skin hyperpigmentation e.g. cafe au lait spots
What is pernicious anamia?
Pernicious anaemia is a type of B-12 deficiency anaemia, resulting from an autoimmune condition against gastric parietal cells or intrinsic factor → ↓ B-12 absorption
Epidemiology:
- F > M
- Commoner in middle age - old age
- Increased risk of gastric carcinoma
Associated with other autoimmune conditions:
- Thyroid disease
- Addisons
- RA
- Vitiligo