Haematology: Non-Malignant

Mr En Lin Goh, BSc (Hons), MBBS (Dist.), MRCS

25th February 2021 Introduction

• ICSM Class of 2018

• Distinction in Clinical Sciences • Pathology = 94% • Wallace Prize for Pathology • Jasmine Anadarajah Prize for Immunology • Abrahams Prize for Histopathology Content

1. Anaemia

2. Haemoglobinopathies

3. Haemostasis and thrombosis

4. Obstetric haematology

5. Transfusion medicine Anaemia Background

• Hb <135 g/L in males and <115 g/L in females

• Causes: decreased production, increased destruction, dilution

• Classified based on MCV: microcytic (<80 fL), normocytic (80-100 fL), macrocytic (>100 fL)

• Arise from disease processes affecting synthesis of haem, globin or porphyrin Microcytic anaemia work-up

• Key differentials • Iron deficiency anaemia • Thalassaemia • Sideroblastic anaemia

• Key investigations • Peripheral blood smear • Iron studies Iron deficiency anaemia

• Commonest cause is blood loss

• Key features • Peripheral blood smear – pencil cells • Iron studies – ↓iron, ↓ferritin, ↑transferrin, ↑TIBC • FBC – reactive thrombocytosis

• Management – investigate underlying cause, iron supplementation Thalassaemia

• α-thalassaemia, β-thalassaemia, thalassaemia trait

• Key features • Peripheral blood smear – basophilic stippling, target cells • Iron studies – all normal

• Management – iron supplementation, regular transfusions, iron chelation Sideroblastic anaemia

• Congenital or acquired

• Key features • Peripheral blood smear – basophilic stippling • Iron studies – ↑iron, ↑ferritin, ↓transferrin, ↓TIBC • Bone marrow – ringed sideroblasts

• Management – treat underlying cause, regular transfusions Macrocytic anaemia work-up

• Key differentials • Megaloblastic anaemia: vitamin B12 deficiency, folate deficiency • Alcohol • Hypothyroidism

• Key investigations • Peripheral blood smear • LFTs • TFTs Megaloblastic anaemia

• Vitamin B12 or folate deficiency

• How to differentiate? • Duration – months for folate deficiency, years for vitamin B12 deficiency • Clinical findings – vitamin B12 deficiency associated with neurological changes • Serum methylmalonic acid – elevated in vitamin B12 deficiency • Schilling test – positive in vitamin B12 deficiency 2º to pernicious anaemia • Drug history – phenytoin inhibits folate absorption

• Management – vitamin supplementation Non-megaloblastic anaemia

• Alcohol, hypothyroidism, pregnancy

• How to differentiate? • History – features of hypothyroidism • Clinical findings – hepatomegaly, gynaecomastia, abdominal veins, ascites, jaundice • LFTs – ↑AST, ↑ALT, ↑GGT, AST:ALT >2:1 • TFTs – ↑TSH, ↓T3/T4, anti-thyroid peroxidase antibodies

• Management – treat underlying cause Normocytic anaemia work-up

• Key differentials • Haemolytic: inherited or acquired (immune-mediated, non-immune-mediated) • Non-haemolytic: anaemia of chronic disease, failure of erythropoiesis

• Key investigations • Peripheral blood smear • DAT • CRP, ESR Anaemia of chronic disease

• Infection, inflammation, malignancy

• Key features • Inflammatory markers – raised CRP, ESR • Iron studies – ↑iron, ↑ferritin, ↓transferrin, ↓TIBC

• Management – treat underlying cause SBA 1

A 65-year-old lady presents with recent onset of fatigue and dyspnoea on exertion. She reports a decrease in appetite, constipation and weight gain. Her full blood count results show: Hb = 100 g/L, MCV = 102 fL. Which of the following is the likely diagnosis?

a. Underlying malignancy b. Vitamin B12 deficiency c. Hypothyroidism d. Inflammatory bowel disease e. Liver disease SBA 1

a. Underlying malignancy b. Vitamin B12 deficiency c. Hypothyroidism d. Inflammatory bowel disease e. Liver disease VSA 1

A 25-year-old lady presents with a 3-month history of worsening paraesthesia in her feet. She is a life-long vegetarian. Hb = 100 g/L, MCV = 110 fL. Which vitamin is she likely deficient in? VSA 1

A 25-year-old lady presents with a 3-month history of worsening paraesthesia in her feet. She is a life-long vegetarian. Hb = 100 g/L, MCV = 110 fL. Which vitamin is she likely deficient in?

Vitamin B12 Haemolytic anaemia

• Inherited or acquired (immune-mediated vs non-immune-mediated)

• Inherited • Hereditary spherocytosis • Glucose-6-phosphate dehydrogenase deficiency

• Immune • Autoimmune: warm vs cold haemolytic anaemia • Alloimmune: ABO or Rhesus incompatibility

• Non-immune • Microangiopathic vs macroangiopathic • Infection Hereditary spherocytosis

• Autosomal dominant

• Defect in the vertical interaction of the red cell membrane

• Key features • Peripheral blood smear: spherocytes, polychromasia • Positive osmotic fragility test • Positive eosin-5-maleimide (most sensitive test)

• Management – folate supplementation, splenectomy G6PD

• X-linked recessive

• G6PD generates NADPH via pentose phosphate pathway

• Key features • Episodes of acute haemolysis following exposure to oxidative stress (e.g. fava beans, mothballs, drugs) • Peripheral blood smear: Heinz bodies, bite cells • Intravascular haemolysis: ↑unconjugated bilirubin, ↓haptoglobin, haemoglobinuria

• Management – avoidance of triggers, supportive care AIHA

• Immune-mediated destruction of red blood cells, DAT positive

• Warm • Mediated by IgG • Associated with CLL, SLE, methyldopa • Extravascular haemolysis

• Cold • Mediated by IgM • Associated with Mycoplasma, EBV, hepatitis C • Intravascular haemolysis

• Management – treat underlying cause, steroids, rituximab MAHA

• Non-immune-mediated, small vessel disease

• Damage to endothelial cells within the vasculature à fibrin deposition and platelet aggregation à fragmentation of red blood cells

• Key features • Peripheral blood smear: schistocytes, thrombocytopenia • Disorders – HUS, TTP, DIC • Distinguish from DIC with normal APTT, PT, fibrinogen

• Management – treat underlying cause, supportive HUS

• Commonly caused by Escherichia coli O157:H7 – Shiga-like toxin

• More frequent but less severe in children

• Key features • Symptoms occur after a diarrhoeal illness – do not give antibiotics to treat • Triad of MAHA, thrombocytopenia, acute renal failure – self-limiting in children • Features of MAHA on peripheral blood smear

• Management – supportive care TTP

• Deficiency of ADAMTS13 à decreased break down of multimers of vWF

• Can be inherited or acquired

• Key features • Pentad of MAHA, thrombocytopenia, acute renal failure, neurological symptoms, fever • High mortality rate

• Management – supportive care, plasma exchange SBA 2

A 6-month-old African boy presents with abdominal pain, jaundice and dark urine. He was diagnosed with a urinary tract infection three days ago and was started on nitrofurantoin. He has not experienced any similar episodes in the past. Which of the following is a likely diagnosis?

a. Sickle cell anaemia b. Glucose-6-phosphate dehydrogenase deficiency c. Sepsis d. β-thalassaemia major e. Autoimmune haemolytic anaemia SBA 2

a. Sickle cell anaemia b. Glucose-6-phosphate dehydrogenase deficiency c. Sepsis d. β-thalassaemia major e. Autoimmune haemolytic anaemia VSA 2

An 83-year-old man with a diagnosis of chronic lymphocytic leukaemia presents with worsening tiredness, dyspnoea and reduced exercise tolerance. Hb = 66 g/L, DAT positive. What is the causative antibody underlying his condition? VSA 2

IgG Haemoglobinopathies Background

• Genetic disorders of globin chain synthesis

• Haemoglobin

• HbA (α2β2) – late foetus, infant, child and adult • HbA2 (α2δ2) – infant, child and adult

• HbF (α2ɣ2) – foetus, infant

• Diagnosis made with Hb electrophoresis

• Disorders – thalassaemia, sickle cell disease β-thalassaemia Chr 11 β-globin

• Reduced synthesis of β globin chain (Chromosome 11) β-globin

• Major (homozygous), intermedia and minor (heterozygous)

• Key features • Major – severe anaemia requiring regular blood transfusions • Intermedia – genetically complex, moderate reduction in β globin chain production • Minor – benign but important genetically

• Management – regular blood transfusions, iron chelation, folate supplementation α-thalassaemia

• Reduced synthesis of α globin chain (Chromosome 16)

• Hb Barts (x4), HbH (x3), trait (x2), silent (x1) Chr 16 α-globin α-globin • Key features α-globin α-globin • Hb Barts – fatal in utero, hydrops foetalis • HbH – severe anaemia in childhood, hepatosplenomegaly • Trait – mild anaemia • Silent – asymptomatic

• Management – regular blood transfusions, iron chelation, folate supplementation Sickle cell disease

• Autosomal recessive • Glu à Val mutation at codon 6 on the β globin chain à HbS

• HbSS, HbAS, HbSC, HbSβ

• Key features • Haemolytic crisis, sequestration crisis, aplastic crisis, infection (Streptococcus pneumoniae – sepsis, Salmonella sp– osteomyelitis) • Peripheral blood smear: sickle cells • Sickle solubility test positive in HbSS and HbAS

• Management – vaccination, folate supplementation, hydroxyurea, supportive for acute crisis SBA 3

A 23-year-old lady presents to her GP for a routine appointment after moving into the area. Her full blood count shows: Hb = 105 g/L, MCV = 65 fL. Hb electrophoresis demonstrates reduced HbA, elevated HbA2 and normal HbF. Which of the following chromosomes is implicated in this disorder?

a. Chromosome 5 b. Chromosome 7 c. Chromosome 11 d. Chromosome 13 e. Chromosome 17 SBA 3

a. Chromosome 5 b. Chromosome 7 c. Chromosome 11 d. Chromosome 13 e. Chromosome 17 VSA 3

A 15-year-old boy with sickle cell anaemia presents with a 5-day history of pain and swelling of his left knee. Initial radiographs are equivocal but MRI reveals findings suggestive of osteomyelitis. What is the likely causative organism? VSA 3

Non-typhoidal Salmonella Haemostasis and thrombosis Background

• Disorders of primary or secondary haemostasis • Primary – platelet adhesion and aggregation (quantitative and qualitative defects) • Secondary – coagulation cascade (inherited and acquired)

• Disorders of thrombosis occur as a result of Virchow’s triad • Inherited – factor V Leiden, anti-thrombin deficiency, protein C/S deficiency • Acquired – HIT, malignancy, immobilisation Haemostasis

• Dysfunction in primary haemostasis à bleeding disorders (superficial bleeding) • Qualitative defect in platelets – von Willebrand disease • Quantitative defect in platelets – ITP, HIT

• Dysfunction in secondary haemostasis à coagulation disorders (deep bleeding) • Inherited disorders – haemophilia A, haemophilia B • Acquired disorders – liver disease, vitamin K deficiency von Willebrand disease

• Subtypes • Type I – autosomal dominant, quantitative defect • Type II – autosomal dominant, qualitative defect • Type III – autosomal recessive, quantitative and qualitative defects

• Key features • Mucocutaneous bleeding • ↓platelet adhesion, ↓factor VIII, abnormal ristocetin • ↓platelet count, ↑bleeding time, ↑APTT, normal PT • Differentials include Bernard-Soulier disease (large platelets) and Glanzmann’s thrombasthaenia (normal ristocetin)

• Management – desmopressin, vWF and factor VIII concentrates ITP

• Acute and chronic forms

• Acute • Predominantly children, M:F 1:1 • Preceding infection • Self-limiting, treatment with steroids and IVIG if platelet count ↓↓↓, major bleeding

• Chronic • Commonly adults, M:F 1:3 • No trigger • Long-term relapsing-remitting, treatment with steroids, IVIG or splenectomy Haemophilia A

• X-linked recessive

• Factor VIII deficiency

• Key features • Spontaneous, deep bleeding, haemarthrosis • Normal platelet count, normal bleeding time, ↑APTT, normal PT • More common than Haemophilia B

• Management – factor VIII concentrate Haemophilia B

• X-linked recessive

• Factor IX deficiency

• Key features • Spontaneous, deep bleeding, haemarthrosis • Normal platelet count, normal bleeding time, ↑APTT, normal PT

• Management – factor IX concentrate Vitamin K deficiency

• Vitamin K necessary for synthesis of factors II, VII, IX and X, protein C/S

• Secondary to malabsorption, warfarin, antibiotic therapy

• Key features • Factor VII first factor to be depleted • Normal platelet count, normal bleeding time, ↑APTT, ↑PT • Differentials include liver disease (↓platelet count), scurvy (corkscrew hair)

• Management – vitamin K replacement, PCC, FFP Factor V Leiden

• Autosomal dominant – most common inherited prothrombotic disorder

• Key features • Resistance to protein C à failure to degrade factor V à hypercoagulable state • Predisposition to venous thromboembolism (arterial thromboembolism rare)

• Management – long-term anti-coagulation Anti-thrombin deficiency

• Autosomal dominant

• Key features • Carries highest risk of thrombosis • Develop thromboembolism in unusual locations (e.g. splenic or mesenteric veins) • Anti-thrombin assay used to make diagnosis • Key differentials include protein C/S deficiency

• Management – long-term anti-coagulation with warfarin and argatroban Protein C/S deficiency

• Autosomal dominant

• Key features • Predisposition to venous thromboembolism (arterial thromboembolism rare) • Associated with warfarin-induced skin necrosis – initial pro-coagulant state à ischaemia of skin vessels • Protein C/S assay

• Management – long-term anti-coagulation with argatroban SBA 4

A 15-year-old girl presents to her GP for heavy menstrual bleeding. Her cycles occur every 28 days and her periods last for around 7 days. This began when she went through menarche at the age of 13. She is doing well in school but does not play sports as she bruises easily. On examination, she is pale but otherwise well. Which of the following is a likely diagnosis?

a. von Willebrand disease b. Haemophilia A c. Immune thrombocytopenic purpura d. Vitamin K deficiency e. Factor V Leiden SBA 4

a. von Willebrand disease b. Haemophilia A c. Immune thrombocytopenic purpura d. Vitamin K deficiency e. Factor V Leiden VSA 4

What is the commonest mode of inheritance of von Willebrand disease? VSA 4

What is the commonest mode of inheritance of von Willebrand disease?

Autosomal dominant Obstetric haematology Background

• Volume expansion à ↑cardiac output, dilutional anaemia

• Thrombocytopenia – returns to normal post-partum

• Hypercoagulable and hypofibrinolytic state à ↑risk of venous thromboembolism Haematological changes

Plasma volume ↑↑ Red cell mass ↑ Haemoglobin ↓ MCV ↑ Haematocrit ↓ Platelets ↓ WCC ↑ Factors VII, VIII, IX, X, XII ↑ Factor XI ↓ Protein S ↓ HDFN

• Prior sensitisation of Rh-negative women from previous pregnancy

• Key features • IgG-mediated • Foetal anaemia, hydrops foetalis, neonatal jaundice, kernicterus • Monitor foetus for anaemia with MCA doppler ultrasound

• Management – prevent sensitisation with anti-D Ig routinely at 28 weeks and within 72 hours of sensitising event, intra-uterine transfusion HELLP syndrome

• Haemolysis, elevated liver enzymes, low platelets

• Life-threatening complication associated with pregnancy

• Key features • MAHA, ↑↑AST, ↑↑ALT, ↓platelets, normal APTT, PT • Differentials include DIC (↑APTT, ↑PT, ↓fibrinogen), AFLP (marked transaminitis)

• Management – supportive, delivery of foetus SBA 5

Which of the following physiological changes occur in pregnancy?

a. Decreased red cell mass b. Increased factor XI c. Decreased MCV d. Thrombocytopenia e. Decreased factor VII SBA 5

Which of the following physiological changes occur in pregnancy?

a. Decreased red cell mass b. Increased factor XI c. Decreased MCV d. Thrombocytopenia e. Decreased factor VII VSA 5

Which stage of pregnancy is associated with the highest risk of venous thromboembolism? VSA 5

Which stage of pregnancy is associated with the highest risk of venous thromboembolism?

Post-partum Transfusion medicine Background

Febrile non-haemolytic transfusion reaction Transfusion-related acute lung injury GvHD Bacterial contamination Transfusion-associated Delayed haemolytic Anaphylaxis ABO incompatibility circulatory overload transfusion reaction

Minutes Hours Days Acute (≤24 hours)

• Anaphylaxis • Symptoms occur within minutes • Risk increases in patients with IgA deficiency

• ABO incompatibility • Symptoms occur within minutes to hours • Intravascular haemolysis – IgM-mediated

• Bacterial contamination • Symptoms occur within minutes to hours • More commonly occurs with platelet transfusion Acute (≤24 hours)

• Febrile non-haemolytic transfusion reaction • Rise in temperature of ≤1ºC without circulatory collapse • Caused by release of cytokines by leukocytes and prevented by leukodepletion

• Transfusion-associated circulatory overload • Symptoms of pulmonary oedema/fluid overload occur within hours • Look for signs of heart failure: ↑JVP, ↑PCWP

• Transfusion-related acute lung injury • Symptoms similar to TACO • Caused by interaction with anti-HLA antibodies in donor blood with recipient • Absence of heart failure Delayed (>24 hours)

• Delayed haemolytic transfusion reaction • Occurs within 1 week • Extravascular haemolysis – IgG-mediated

• Graft vs host disease • Symptoms include diarrhoea, liver failure, skin desquamation and bone marrow failure • Donor lymphocytes recognise recipient’s HLA as foreign and attack gut, liver, skin and bone marrow • Prevent by irradiating blood components for immunosuppressed recipients Warfarin reversal

• INR ≤5 – lower or omit next dose

• INR 5-9 – either omit next dose or oral vitamin K

• INR >9 – omit next dose + oral vitamin K

• Any bleeding – omit next dose + IV vitamin K + PCC or FFP SBA 6

A 22-year-old man is brought into A&E following a motorcycle accident. He undergoes emergency laparotomy for intra-abdominal haemorrhage and requires 5 units of packed red cells intra-operatively. In recovery, he develops fever, abdominal pain, chills and rigors. His vitals are: HR = 150, BP = 85/55, RR = 22, T = 37.8º. JVP is not visible. Which of the following is the most likely diagnosis?

a. Febrile non-haemolytic transfusion reaction b. ABO incompatibility c. Sepsis d. Transfusion-associated circulatory overload e. Transfusion-related acute lung injury SBA 6

a. Febrile non-haemolytic transfusion reaction b. ABO incompatibility c. Sepsis d. Transfusion-associated circulatory overload e. Transfusion-related acute lung injury VSA 6

Which blood product is most susceptible to bacterial contamination? VSA 6

Which blood product is most susceptible to bacterial contamination?

Platelets Resources

• Revision • MedEd Path Guide • MedEd Lecture Series • Pathology Course Lectures Slides

• Question banks • Pathbase (https://candidate.speedexam.net/signin.aspx?site=pathbase) Feedback https://forms.gle/zKw6Zbb2XxrJtBG87 Thank you [email protected]