Haematology Flashcards
How much Iron is there in the body?
4g
Where is dietary iron absorbed and briefly describe how.
Duodenum and jejunum
Stomach acid causes Ferrous (Fe2+) iron to be made, which is more soluble and so more readily absorbed than ferric (Fe3+)
What are some complications of iron overload?
Cirrhosis, HF, arrhythmia, diabetes, bronzing of skin
(e.g. Hereditary haemachromatosis)
Due to deficiency of hepcidin due to mutation in HFE gene
What are the side effects of oral ferrous sulphate or ferrous fumarate?
Constipation, black coloured stool
What is haemolytic anaemia?
Anaemia related to a reduced RBC lifespan, increased destruction of red cells. < 20 days
Reduced Hb
Increased Reticulocytes, unconjugated bilirubin
splenomegaly
What is the complication of hyposplenism?
Increased risk of infection from encapsulated organism
SNKHSCP
Strep. pne, Nesseria meningitis, klebiella pne, H. infulenz
Long-term penicillin V
Target cells and Howel jolly bodies
Give an example of abnormal red cell enzymes and how it causes intravascular haemolytic anaemia?
Glucose 6 phosphate deficiency. X-linked recessive
No protection against oxidative stress
Stress causes lysis in the blood - free Hb - bind to haptoglobin in the blood - haemaglobinuria.
Give an example of abnormal red cell enzymes and how it causes extravascular haemolytic anaemia?
Pyruvate kinase AR
ATP deficiency
RES recognises it as abnormal and so engulfs it - IC haemoglobin - biliverdin - bilirubin in haptocytes
Splenomegaly and hepatomegaly due to increased RBC destruction
What are the AI causes of haemolytic anaemia?
Cold type - IgM - Agglutinate in cold parts of the body- acrocyanosis. Intravascular. Myocplasma infection, EBV or idiopathic
Warm type - IgG - IgG bind to RBC and damages membrane. Agglutinates EV. CLL/NHL, Hapten (drug)
Give some examples of intravascular haemolysis?
Breakdown by defective mechanical heart valve, malaria, ABO incompatibility, transfusion, cold IgM
What are findings in IV haemolysis?
Haemoglobinuria, haemoglobinaemia, haemosiderinuria, acrocyanosis, anaemia (reticulocytes and unconj Bili)
Where is B12 absorbed?
Terminal ileum
2-3mg in the body sufficient for 3 years
What type of anaemia is from B12 deficiency?
Megaloblastic microcytic anaemia. With Hypersegmented neutrophils.
B12 is required for DNA synthesis and neurological functioning
What is pernicious anaemia?
A form of B12 deficiency
AI disease to parietal cell - loss of intrinsic factor needed for B12 absorption in the terminal ileum
Atrophic gastritis
What blood results are in B12 deficiency anaemia?
LDH increased
Homocysteine increased
Fe stores increased
Leucopenia and thrombocytopenia
How do you treat B12 deficiency?
1mg Hydroxocobalamin IM every 2-3months
folic acid PO 5mg daily for4 months
Where is folate absorbed?
Proximal jejunum
What is anaemia of chronic disease?
Failure of iron utilisation, Iron trapped in RES
Inflammatory mediated reduction in RBC production
normocytic normochromic or microcytic hypochromic
What is Talassaemia?
Inadequate production/ decreased synthesis of normal globulin genes. Relative lack of globulin genes.
What are the different types of alpha thalassaemia? (1 gene missing, 2 genes missing etc)
AR
1 missing - asymptomatic carrier
2 missing - mild anaemia
3 missing - HbH disease, severe anaemia, hepatosplenomegaly, jaundice, infection - need transfusion in times of stress. Hb 65-75g/L
4 missing - Hb Barts hydrops fetalis- incompatible with life
What chromosomes are the alpha and beta globulin genes on?
Alpha - 16
Beta - 11
What would thalassaemia look like on a blood smear?
Microcytosis, hypochromic, target cells, nucleated red cells, increased reticulocytes
What treatment is available for alpha thalassaemia?
Folic acid. May need transfusion
What type of beta thalassaemia is there?
MICROCYTIC ANAEMIA
AR mutation to Chr 11
Beta thalassaemia minor - asymptomatic - MCV too low for Hb*. no tx required
Beta thalassaemia major (Cooley’s anaemia) -
Sx present at ~3-6month -
Anaemia (SoB, fatigue, Pallor), Hepatosplenomegaly (jaundice, distended abdo), Growth retardation, chipmunk face, hair-on-end skull Xray, failure to thrive
Transfusion dependent
What treatment ins available for beta thalassaemia major?
Lifelong blood transfusions - 2-4 wks
Iron chelation therapy
What is aplastic anaemia?
A gross reduction or absence in the haemopoietic precursors of all 3 lineages in the bone marrow causing pancytopenia in the peripheral blood.
What are some causes of aplastic anaemia?
Chemotherapy, BM failure, hepatitis A, B, C, CMV, EBV, Falconi anaemia (10-20% cases), drugs (NSAIDs, gold, carbamazepine)
What clinical signs indicate aplastic anaemia?
Pancytopenia, purpura, ecchymosis, bleeding from mucosal surface, infections, anaemia
What is Fanconi anaemia?
A rare genetic syndrome, AR, impaired response to DNA damage. Bone marrow failure. FANCA-G gene
What are some symptoms if falconi anaemia?
Microphthalmia, hydrocephalus, short stature, GU and GI malformations, Increased risk of malignancy, Hypopigmentation of freckles, hearing loss, mental retardation
What is gold standard treatment in fanconi anaemia?
Allogenic stem cell transplant
What patients are likely to get neutropenic fever?
85-95% acute leukaemia patients receiving induction chemotherapy
What is neutropenic sepsis?
Neutrophil count <0.5 or < 1 x 10^9/L
PLUS
Fever/hypothermia, or SIRS or sepsis/septic shock
What is the most common cause of neutropenia?
Chemo
What is neutropenic fever?
A single oral temperature of >. 38.3 or a temperature of >38 sustained for over an hour in a neutropenic patient.
What treatment would you use for standard, high and critical risk neutropenic sepsis?
Standard: IV piperacillin/ Tazobactam 4.5g/6hr ± IV vancomycin
High: IV Pip/tazo 4.5g/6hr + IV vancomycin + IV gentamicin
Critical: IV meropenam 1g/8hr + amikacin + Vancomycin
What is sickle cell anaemia?
Abnormal Hb and shape of red blood cells, sickling causes them to be destroyed more easily (10-20days)
AR
Single aa substitution in the beta chain at position 6
Glutamine to lysine Hb C
glutamine to valine Hb S
What are the complications of sickle cell anaemia?
Veno-occulsion - tissue hypoxia/ infarction
Haemolysis
Sickling causes acidosis, hypoxia and dehydration
What does a low haptoglobin indicate?
Intravascular haemolysis
each haptoglobin takes 3Hb
e.g. sickle cell anaemia, cold IgM, G6PD
What organ systems are affected in sickle cell anaemia?
Rep - acute chest syndrome / pulmonary HTN Brain - stroke/ moya moya Kidney - loss of concentration / infarction GU - priapism Eye - vascular retinopathy Placental - IUGR, foetal loss Bones - osteonecrosis Spleen - hyposplenic