Anaemia Flashcards
A 50 year old man presents with lethargy and fatigue
DDx?
- Psychological
- Environmental
- Endocrine
- Haematological
- Rheumatologcal
- Cardiovascular
- Respiratory
- Pharmacological
- Dietary
What are the (5) broad causes of blood loss?
- Gastrointestinal tract
- Urinary
- Menstrual loss
- Chronic recurrent epistaxis
- Hereditary AVM
What are the (5) broad causes of decreased production of blood in anaemia?
Anaemia of Chronic Disease
- Chronic renal failure
- Rheumatological disorders (RA)
- Malignancy
Bone marrow infiltration (leukaemia, lymphoma, myeloma, myeloproliferative disease, myelodysplastic syndromes, secondary malignancies)
Endocrine – thyroid disorders (hypothyroidism), EPO deficiency (renal failure)
Nutritional Deficiency – B12, folate, iron
Infectious – acute or chronic. (e.g. TB, chronic suppurative disease, HIV, HCV, CMV, EBV, parvovirus)
What should you ask on Hx of possibly anaemic pt?
- blood loss: haematemesis, melaena, change bowel habit, tenesmus, PR bleed, LOW, menstruation Hx
- chronic disease/inflammation: RA, chronic infection, renal failure, thyroid disease
- diet: vegan, vego, coeliac, parasite infection
- bone marrow failure: bleeding, infection, fevers, sweats, LOW, hx of RADIATION!!!, prior malignancy
- increased destruction: dark urine, jaundice, gall stones, FMHx of splenectomy, cholycystectomy
- malabsorption
Discuss classifications of anaemia based on MCV & the flowchart for diagnosis
- microcytic
- normocytic
- macrocytic
Microcytic (less than 80 MCV): check Fe.
- if low Fe: establish cause
- if normal Fe: anaemia of chronic disease or haemoglobinopathy
Normocytic: check reticulocytes
- if high: haemolysis or blood loss
- if low: anaemia of chronic disease, renal failure, marrow failure
Macrocytic: measure B12 & folate
- if normal: consider bone marrow if cause is not obvious
- if low: establish cause
Describe the iron studies results in:
- iron deficiency anaemia
- anaemia of chronic disease
- thalassaemia trait
Iron deficiency anaemia:
- low serum iron
- high transferrin/TIBC
- low serum ferritin!!
- high soluble transferrin receptor
Anaemia of chronic disease
- low serum iron
- low transferrin/TIBC
- HIGH serum ferritin!!!
- low or normal soluble transferrin receptor
Thalassaemia trait:
- normal serum iron
- normal transferrin/TIBC
- normal serum ferritin
- HIGH soluble transferrin receptor
Px of iron deficiency
- anaemia: fatigue, pallor, exertional dyspnoea
- Koilonychia (spoon-shaped nails)
- Angular cheilosis
- Glossitis
Ix of iron deficiency
- Faecal occult blood: screening
- Gastroscopy
- Colonoscopy: if symptomatic
- Tumour markers
Causes of:
- hypochromic microcytic anaemia
- normochromic normocytic anaemia
- macrocytic anaemia
- Hypochromic microcytic: Iron deficiency (pencil cells), thalassemia (target cells), sickle cell, lead poisoning and sideroblastic anaemia. -> iron studies. Ferritin down, sat up in iron deficiency.
- Normochromic normocytic: Anaemia chronic disease, haemolysis, renal failure, pregnancy dilution
- Macrocytic: B12 or folate deficiency, alcohol, liver disease, drugs, hypothyroidism, myeloma
(5) Expected key Ix results of haemolytic anaemia
- elevated LDH
- elevated unconjugated bilirubin
- low haptoglobin (carries free Hb)
- blood film: spherocytes (AIHA or hereditary), bite cells (oxidative injury), fragments (microangiopathy)
- direct Coombs test: to r/o AIHA
Compare features of intravascular vs. extravascular haemolytic anaemia
Intravascular:
- Blood film fragmentation
- Haemoglobinuria
- Haemoglobinaemia
- Haemosidinuria
Extravascular:
- Spherocytes
- Bite cells
- Sickle cells
Causes of intravascular haemolysis
- DIC
- Sepsis
- Cardiac valvular disease
- PNH (Paroxsymal haemoglobinuria)
- Extracorporeal circulation
- TTP/HUS
- Disseminated malignancy
- Arteriovenous malformations
Causes of extravascular haemolysis
Non-immune causes:
- Hypersplenism
- Immune mediated
- Red cell membrane disorders
- Red cell enzyme disorders
Immune causes: AIHA
- Cold Agglutinin- IgM Ab (EBV, mycoplasma pneumoniae, lymphoma)
- Warm Agglutinin- IgG Ab (drug induced, lymphoproliferative disorder, SLE, RA, idiopathic AIHA, transfusion reaction)
Describe autoimmune haemolytic anaemia
2 types: warm & cold
Warm:
- IgG, agglutinate at 37’C
- Positive Direct Coombs’ test for IgG +/- C’
- idiopathic, 2’ to lymphoproliferative disorder/autoimmune disease. Drug induced
- Blood film: spherocytes
- Mx: treat underlying cause, corticosteroids, immunosuppression, splenectomy, folic acid
Cold:
- IgM, agglutinate at 4-21’C
- positive for complement on Direct Coomb’s test
- idiopathic, 2’ to infection (mycoplasma pneumoniae)/lymphoproliferative disorder
- Blood film: agglutination
- Mx: treat underlying cause, warm pt, immunosuppression, plasmapharesis, folic acid.
Where are iron, folate & B12 absorbed in the GIT?
Iron - duodenum
Folate - jejunum
B12 - ileum
