Immunology & Haematology Small Conditions Flashcards
A type of macrocytic anaemia in which the bone marrow produces unusually large, structurally abnormal, immature red blood cells
Causes, presentation, diagnosis, management
Megaloblastic anaemia
Causes: B12 deficiency (pernicious anaemia*/GI disease) Folate deficiency (dietary/GI)
Presentation: “lemon yellow” tinge, pancytopenia (B12)
Diagnosis: macrocytic, ↓B12/folate
Management:
B12 i/m injection (loading dose, then 3 monthly)
Oral folate replacement
((*pernicious anaemia = autoimmune against intrinsic factor –> malabsorption))
Commonest cause of anaemia worldwide
causes, presentation, diagnosis, management
Iron deficiency anaemia
Causes: bleeding, diet, malabsorption, pregnancy
Presentation: koilonychia, atrophic tongue, angular stomatitis, general features of anaemia
Diagnosis: hypochromic microcytic, ↓ serum ferritin
Management: correct cause!, oral iron (IV if intolerant), blood transfusion (if chest pain at rest - risk of MI)
Anaemia due to defective iron utilisation
causes, diagnosis
Secondary anaemia/ anaemia of chronic disease
Causes: identifiable underlying disease
- infection
- inflammation
- malignancy
Diagnosis:
normochromic normocytic, normal reticulocyte count
OR hypochromic microcytic, normal serum ferritin
Anaemia due to accelerated red cell destruction and compensation by bone marrow
causes, diagnosis, management
Haemolytic anaemia
Causes:
congenital anaemias,
extravascular haemolysis = autoimmune haemolytic anaemia
intravascular haemolysis = non immune causes (severe infection, DIC, mechanical e.g. artificial valve, HUS, transfusion reaction)
Diagnosis: normochromic normocytic, ↑reticulocyte count*
direct antiglobulin test (+ve if immune mediated)
Management: folic acid (supports marrow function)
correct cause: steroids if autoimmune, splenectomy (remove site of destruction)…
Consider transfusion
*due to bone marrow compensation
Congenital anaemia caused by defects in structural proteins –> spherical RBCs that are removed by the reticuloendothelial system
Inheritance, presentation, treatment
Hereditary Spherocytosis
Inheritance: autosomal dominant
Presentation: anaemia, neonatal jaundice, splenomegaly, pigment gallstones
Treatment: folic acid, transfusion, splenectomy if severe
3 categories of causes of congenital anemia
Defects in red cell membrane
(e.g. hereditary spherocytosis)
Defects in metabolic pathways
(e.g. G6PD deficiency, pyruvate kinase deficiency)
Defects in haemoglobin (haemoglobinopathies)
(e.g. sickle cell disease, thalassaemias)
Congenital anaemia caused by a metabolic pathway deficiency leaving cells vulnerable to oxidative damage
Inheritance and presentation
G6PD (glucose 6 phosphate dehydrogenase) Deficiency
inheritance: X-linked
Presentation: anaemia, neonatal jaundice, splenomegaly, pigment gallstones
Haemolytic crisis triggered by infection/acute illness, foods (fava beans), drugs (antimalarials, aspirin, vitK)
((confers protection against malaria))
Congenital anaemia caused by a metabolic pathway deficiency leaving cells rigid
presentation
presentation
Pyruvate kinase deficiency
Presentation: anaemia, jaundice, gallstones
A group of congenital anaemias characterised by mutations or deletions in globin chain production –> chronic haemolysis and anaemia
Thalassaemias
A type of thalassaemia caused by absence of beta chains in the globin protein
inheritance, presentation, diagnosis, management
Beta Thalassaemia Major
Inheritance: autosomal recessive (carriers = thalassaemia trait)
Presentation: severe anaemia (present at 3-6 months old), bone deformities, growth retardation, splenomegaly
Diagnosis: “hair on end” appearance of skull on x-ray (expansion of ineffective bone marrow)
Management:
chronic transfusion support (4-6 weekly)
+ Iron chelation therapy (prevents death from iron loading)
or bone marrow transplantation = curative
((life expectancy <10yrs if untreated/irregular transfusions))
A type of clot usually secondary to atherosclerosis
composition, risk factors, presentation, management
Arterial thrombus
Composition: mainly platelets “white clot”
Risk factors:
age, obesity, smoking, sedentary lifestyle, hypertension, DM, hypercholesterolaemia
Presentation:
Coronary thrombus = MI/unstable angina
Cerebral TE = stroke/TIA
Peripheral TE = limb ischaemia
Management:
lifestyle modification + management of risk factors
Acute presentation = thrombolysis, antiplatelet/anticoagulant drugs
Secondary prevention = aspirin + antiplatelets (e.g. rivaroxaban)
A type of clot usually due to stasis and hypercoagulability
composition, consequences, risk factors, presentation, diagnosis, management
Venous thrombosis
composition: fibrin + some red cells “red thrombus”
Consequences: clot –> backpressure + valvular insufficiency –> post thrombotic syndrome
Risk factors:
obesity, age, high oestrogen (pregnancy, OCP, HRT), tissue trauma, surgery, immobility, systemic disease (cancer, autoimmune disease), FH
Presentation: Limb DVT, PE,
post thrombotic syndrome (hyperpigmentation, redness, swelling, pain - risk for up to 2 yrs)
Diagnosis:
Pre-test probability scoring: Wells/Geneva
If probability low: D-dimer
Then/if probability high: imaging
- Doppler USS*
- V/Q scan
- CT pulmonary angiogram (gold standard in PE)
Management: (aim to prevent clot extension, embolisation, recurrence)
- anticoagulants (LMWH, warfarin, DOACs)
- thrombolysis (in massive PE)
*Thrombosed vein = large + non compressible +/- echogenic material
An inherited predisposition to venous thrombosis
examples
Heritable Thrombophilia
e.g. Factor V Leiden Prothrombin G20210A Antithrombin deficiency Protein C/S deficiency
((Screening of family members is possible but not recommended as there is no intervention taken on diagnosis and it may negatively affect their insurance etc.
Majority of diagnoses are nor predictive of recurrent events ))
Mixed thrombi formed of platelets and/or fibrin, principally occurring in DIC
presentation
Microvascular Thrombus
Presentation: diffuse ischaemia
DIC stands for…
pathophysiology, occurs in…, management
Disseminated Intravascular Coagulation
path:
Systemic activation of coagulation cascade AND fibrinolysis pathway –> microvascular thrombi –> tissue ischaemia –> organ failure + gangrene
Eventually clotting factors become exhausted –> bleeding
Occurs in: septicaemia, malignancy, eclampsia
Management: Cautious use of very low dose anticoagulants (leads to correction in the long term)
