Path Flashcards
HLA Class II Molecules
HLA-DR
HLA-DP
HLA-DQ
HLA Class I Molecules
HLA-A
HLA-B
HLA-C
HLA Matching in Organ Donation
Clinically most important
HLA-A
HLA-B
HLA-DR
Score in series e.g. 0:0:0
Would no mismatches across HLA-A, HLA-b and HLA-DR between recipient and donor
As two alleles from each, opportunity to match 6 alleles
Maximum of 6 mismatches (MM)
6 MM= bad
0 MM = good
Sibling to sibling:
25% - 6MM
50% - 3MM
25% - 0MM
HLA matching is an important part of organ allocation procedure
Bone marrow
Kidney
HLA matching not as important (Size is more important)
Heart
Lung
T Cell Mediated Transplant Rejection
T cell mediated
Phase 1 - Recognition
Acute Rejection
Direct: donor APC presents to recipient CD8 or CD4 T cell which recognises APC as foreign and leads to destruction
Chronic Rejection
Indirect: Indirect is recipient APC finding a foreign protein (HLA molecule) and presenting to immune system
Phase 2 - T cell activation by foreign antigen
First signal is the inetreaction of APC with the T cell receptor
Second signal is co-stimulatory signals that enhance T cells activation
Third signal is when activated T cell produces cytokines, IL-2 autocrine effect
Phase 3 - Effector cells Recruited all the immune cells They recognise the HLA molecule as foreign Infiltrate organ Cause damage to the organ Produce lytic enzymes Direct cytotoxicity Antigen-dependent cell mediated cytotoxicity
Graft infiltration by alloreactive CD4+ cells Cytotoxic” T cells Release of toxins to kill target Granzyme B Punch holes in target cells Perforin Apoptotic cell death Fas -Ligand
Macrophages Phagocytosis Release of proteolytic enzymes Production of cytokines Production of oxygen radicals and nitrogen radicals
Symptoms of acute T-cell mediated rejection
Deteriorating graft function
Kidney transplant: Rise in creatinine, fluid retention, hypertension
Liver transplant: Rise in LFTs, coagulopathy
Lung transplant: breathlessness, pulmonary infiltrate
Pain and tenderness over graft
Fever
Antibody Mediated Rejection
Phase 1 – exposure to foreign antigen
Phase 2 - proliferation and maturation of B cells with antibody production
Phase 3 – effector phase; antibodies bind to graft endothelium (capillaries of glomerulus and around tubules, arterial)
Antibodies
Anti-A or anti-B antibodies are naturally occurring
Anti-HLA antibodies are not naturally occurring
Pre-formed – previous exposure to epitopes (previous transplantation, pregnancy, transfusion)
Post-formed - arise after transplantation
Path
Endothelium with foreign HLA antigens
Antibody against epitope on ENDOTHELIUM
Recruit complement
Complement is activated
(can detect complement for diagnosis on biopsy)
Cause formation of membrane attack complex –> cell lysis
Also liberate C3a and C5a –> potent chemotactic
Recruit inflammatory cells directly to the endothelium through the Fc receptors on macrophages and NK cells and polymorphs
Histology of T and B cell rejection
In T cell
Heavy monocytic infiltrates
In B cells
Discrete accumulation of inflammatory cells including polymorphs
Stain for complement
Prevention and Treatment of Transplant Rejection
Preventing rejection:
A. AB/HLA matching
B. Screening for anti-HLA antibodies
Before transplantation
At time of transplantation: when a specific deceased donor kidney has been assigned to the patient
After transplantation, repeat measurements to check for new antibody production
3 main types of assay
Cytotoxicity assays
Flow cytometry
Solid phase assays
C. Immunosuppression: dampen the immune system of the recipient
Induction agent ex. OKT3/ATG, anti-CD52, anti-CD25
Base-line immunosuppression: CNI inhibitor + MMF or Aza, with or without steroids = calcineurin inhibitor (cyclosporine) and anti-proliferative drug (micophenolate)
Treatment of episodes of acute rejection:
Cellular: steroids, ATG/OKT3
Antibody-mediated: IVIG, plasma exchange, anti-C5, anti-CD20
Always balance the need for immunosuppression with the risk of infection/malignancy/drug toxicity
Graft vs Host Disease
Eliminate hosts immune system (total body irradiation; cyclophophamide; other drugs)
Replace with own (autologous) or HLA-matched donor (allogeneic) bone marrow
Allogeneic HSCT leads to reaction of donor lymphocytes against host tissues
Related to degree of HLA-incompatibility
Also graft-versus-tumour effect
GVHD prophylaxis: Methotrexate/Cyclosporine
Preparative regimen for haematopoietic transplant has a role to play in developing graft vs host disease
Injury in recipients GI tract
Helps to prone donor T cells
Form immune reaction against recipients tissue
Skin: rash
Gut: nausea, vomiting, abdominal pain, diarrheoa, bloody stool
Liver: jaundice
Treat with corticosteroids
Post transplantation infections
Bacterial, viral, fungal
Opportunistic
Cytomegalovirus
BK virus
Pneumocytis carinii
Post-transplantation Malignancy
Viral associated (x 100) Kaposi’s sarcoma (HHV8) Lymphoproliferative disease (EBV)
Skin Cancer (x20)
Risk of other cancers eg lung, colon also increased (x 2-3)
Causes of microcytic Anaemia
FAST Fe Iron deficiency anaemia Anaemia of chronic disease Sideroblastic anaemia Thalassaemia
Faecal calprotectin
Marker of GI inflammation
Produced by neutrophils
Coeliac Disease HLA associations
HLA-DQ2
HLA-DR8
Histopathological Changes in Coeliac Disease
Villous height is reduced and crypts become hyperplastic, resulting in reduced or reversed villous: crypt ratio
Although height of villi are reduced, mucosal thickness remains the same due to crypt hyperplasia
Villous atrophy results in decreased surface area –> malabsorption
Increased to >20 IELs/100 epithelial cells
These lymphocytes are 𝛄ƍ T cells
Causes of Increased Intra-epithelial lymphocytes
Coeliac Disease Dermatitis herpetiformis Cows milk protein sensitivity IgA deficiency Tropical sprue Post infective malabsorption Drugs (NSAIDs) (Lymphoma)
Causes of Villous Atrophy
Coeliac Giardiasis Tropical sprue Crohn’s disease Radiation/chemotherapy Bacterial overgrowth Nutritional deficiencies Graft versus host disease Microvillous inclusion disease Common variable immunodeficiency
Complications of Coeliac Disease
Malabsorption
Osteomalacia and osteoporosis (bone scan every 3 years)
Neurological disease
Epilepsy
Cerebral calcification
Lymphoma
Hyposplenism
Positive Anti-TTG on gluten free diet
The TTG antibody should be negative
It can only be positive in two cases:
Not sticking to gluten free diet
Developed lymphoma
Coeliac Associated Conditions
Dermatitis herpetiformis (prevalence = 100%)
Type 1 diabetes mellitus (prevalence = 7%)
Autoimmune thyroid disease
Down’s syndrome
Recombinant Cytokines
IFN-alpha
Hepatitis C
Hepatitis B
Kaposi’s Sarcoma (HHV-8)
IFN-gamma
Chronic granulomatous disease
T Cell Inhibiting APC
T cell expresses CTLA4, binds to CD80/CD86 on APC
Transmits inhibitory signal
Iplimumab
Block CTLA4 (inhibitory signal from T cell --> APC) Leading to great T cell response
Indications
- Advanced melanoma
APC inhibiting T cell
PD-1 is expressed on T cells
PD-1 Ligand expressed on APC
APC causes inhibition of T cell
PD-1 also expressed on some malignant cells
Pembrolizumab and Nivulomab
Antibody binds to PD-1
Blocks immune checkpoint
Allows T cell activation
Indications
Advanced melanoma
Corticosteroids
Reduces prostaglandin synthesis
Corticosteroids inhibit phospholipase A2
- Blocks arachidonic acid and prostaglandin formation
Inhibits phagocyte migration and function
Decreased traffic of phagocytes to inflamed tissue
Decreased phagocytosis
Decreased release of proteolytic enzymes
Inhibits lymphocyte proliferation
Sequestration of lymphocytes in lymphoid tissue
Affects CD4+ T cells > CD8+ T cells > B cells
Blocks cytokine gene expression
Decreased antibody production
Promotes apoptosis
Cytotoxic Anti-Proliferative Drugs
Cyclophosphamide
Mycophenolate
Azathioprine
Methotrexate
Inhibit DNA synthesis –> affect rapidly dividing cells
Toxicity Bone marrow suppression Infection Malignancy Teratogenic
Cyclophosphamide
Alkylates guanine base of DNA
Damages DNA –> prevents cell replication
Affects B cells > T cells
Indications: Multi-system connective tissue disease/vasculitis with severe end-organ involvement
SLE, Granulomatosis with polyangiitis,
Side Effects
Toxicity to proliferating cells (bone marrow, sterility)
Haemorrhagic cystitis
Malignancy (Bladder, haematological, Non-melnoma skin)
Infection: PCP
Azathioprine
Metabolsied by liver
Azathioprine –> 6-mercaptopurine
6-mercaptopurine blocks de novo purine synthesis –> inhibits DNA replication
Preferentially inhibits T cell
Indications
Transplant
Autoimmune
Autoinflammatory disease (IBD)
Side Effects
Bone Marrow Supression (1 in 300 have polymorphism of Thiopurine methyltransferase –> inability to metabolise azathiopurine –> accumulation)
Check TPMT levels before prescribing
Hepatotoxicity
Infection
Mycophenolate Mofetil
Blocks de novo nuceltodie synthesis –> prevents DNA replication
T cell > B cells
Indications
As alternative to azathioprine in transplants
As alternative to cyclophosphamide in autoimmune and vasculitis
Side Effects
Bone marrow suppression
Infection:
Herpves virus reactivation
Progressive multi-focal leukoencephalopathy (PML) (JC virus)
Plasmapheresis
Patient’s blood passed through cell separator
Removal of pathogenic antibody
Own cellular constituents reinfused
Plasma treated to remove immunoglobulins and then reinfused (or replaced with albumin in ‘plasma exchange’)
Problems
Rebound antibody production limits efficacy, therefore usually given with anti-proliferative agent
Indications
Severe antibody-mediated disease
Goodpastures syndrome
Anti-glomerular basement membrane antibodies
Severe acute myasthenia gravis
Anti-acetyl choline receptor antibodies
Severe vascular rejection
Antibodies directed at donor HLA molecules
Cyclosporin and Tacrolimus
Block Calcineurin (normally activates NFATc which is transcription factor for cytokines)
Prevents cytokine transcription factor –> prevents lymphocyte proliferation
Indications
Transplant –> Improves graft survival
Side effects Nephrotoxic Neurotoxic Hypertension Diabetogenic (particularly tacrolimus) Dysmorphism (Cyclosporin only)
Tofacitinib
JAK signalling inhibitor
Indications: Rheumatoid Arthitis
Apremilast
PDE4 inhibitor
Indications: Psoriasis and Psoriatic arthritis
Anti-Thymocyte Globulin
Antibody against human thymocyte
Lymphocyte depletion
Modulation of T cell activation and migration
Indications;
Allograft rejection (renal or heart)
Give daily infusion
Toxicity Infusion reactions Leukopenia Infection Malignancy
Basiliximab
Anti-CD25 (IL-2 R alpha-chain)
Prevents T cell proliferation
Indications: pre and post-transplant
Prophylaxis against transplant rejection
Toxicity
Infusion reactions
Infection
Concern over long-term malignancy
Abatacept
Fusion: Antibody-CTLA4
CTLA4 normally on CD4 cell –> binds to APC
CTLA4 binds to APC but has antibody on the other end, blocks T cell from binding –> prevents T cell activation
Indications
Rheumatoid arthritis
Weekly subcut
Monthly IV
Toxicity
Infusion reactions
Infection (TB, HBV, HCV)
Rituximab
Anti-CD20 (Mature B cell)
–> depletion of mature B cell
Indications
Lymphoma
Rheumatoid arthritis (2 doses every 6-12 months IV)
SLE
Toxicity
Transfusion reaction
Infection (progressive multifocal leukoencephalopathy, JC virus)
Exacerbated CV disease
Natalizumab
Anti-a4 integrin
a4 expressed with b1 or b7 integrin
a4b1 bind to VCAM1 and MadCAM1 on endoethelium to mediate cell rolling
Inhibits T cell migration
Indications
Multiple sclerosis
(Crohn Disease)
IV every 4 weeks
Toxicity
Infusion reaction Infection (Progressive Multifocal Luekoencephalopathy)
Hepatotoxicity
Concern over long-term malignancy
Tocilizumab
Anti-IL-6R
Reduces Activation of:
Macrophages
T cells
B cells
Indications
Castleman’s disease
Rheumatoid arthritis
IV or SC
Toxicity Transfusion reactions Infection Hepatotoxicity Elevated lipids Concern over long-term malignancy
Agents directed at cytokines
Infliximab – anti-TNFa Adalimumab – anti-TNFa Certolizumab – anti-TNFa Golimumab – anti-TNFa Etanercept – TNF receptor p75-IgG fusion protein
Ustekinumab – anti-IL-12 and IL-23
Secukinumab – anti-IL-17
Denosumab – anti-RANK ligand
Agents directed at cell surface antigens
Rabbit anti-thymocyte globulin Basiliximab – anti-CD25 Abatacept – CTLA4-Ig Rituximab – anti-CD20 Natalizumab – anti-a4 integrin Tocilizumab – anti-IL-6 receptor
Anti-TNFa Antibodies
Infliximab
Adalimumab
Certolizumab
Golimumab
Indications Rheumatoid arthritis Ankylosing spondylitis Psoriasis and psoriatic arthritis IBD SC or IV
Toxicity Infusion or injection reaction Infection (TB, HBV, HCV) Lupus-like syndrome Demyelination Malignancy
Etanercept
TNF Antgaonists
- Inhibits TNFa and TNFb
Indications and dosing Rheumatoid arthritis Ankylosing spondylitis Psoriasis and psoriatic arthritis Subcutaneous weekly
Toxicity Injection site reactions Infection (TB, HBV, HCV) Lupus-like conditions Demyelination Malignancy
Ustekinumab
Anti-p40 (IL-12 and IL-23)
IL-12: p40+p35
IL-23:p40+p19
Inhibits IL-12 and IL-23
IL-12 and IL-23 on NK cell and T cell
Indications
Psoriasis and psoriatic arthritis
Subcut every 12 weeks
Complications
Injection reaction
Infection (TB)
Concern regards long-term malignancy
Secukinumab
Anti-IL-17A
Dimer of IL-17A or IL-17A/F
Binds to IL-17RA/RC receptor
IL-17AR on keratinocyte
Indications
Psoriasis and psoriatic arthritis
Ankylosing spondylitis
SC load and then monthly
Action
Inhibits IL-17A
Toxicity
Infection (TB)
Denosumab
Anti-RANKL
Inhibits RANK mediated osteoclast
differentiation and function
Indications
Osteoporosis
Subcutaneous every 6 months
Toxicity
Infection
Avascular necrosis of jaw
HIV-1
HIV-1 Retrovirus positive sense ssRNA virus 9 genes Reverse transcriptase: RNA --> DNA DNA then integrated into host DNA Infects CD4+ T cell and CD4+ monocyte Receptor = CD4 Co-receptor = CCR5 or CXCR4
Immunity against HIV-1
Non-specific activation of NK cells and complement associated with slower disease course
Acquired immunity – B cells
Anti-gp120 and anti-gp41 (Nt) antibodies are thought to be important in protective immunity.
Non-neutralising anti-p24 gag IgG also produced.
HIV remains infectious even when coated with antibodies.
CD8+ T cells
Secrete soluble molecules (cytokines and chemokines such as MIP-1a, MIP-1b, and RANTES) which are able to prevent infection by blocking entry of virus into CD4+ T cells.
Recognise processed antigen - (peptides) - in the context of class I HLA molecules
HAART
HAART = 2NRTIs + PI (or NNRTI)
Management of Anaphylaxis
IM adrenaline 0.5mg (may repeat)
Oxygen by mask
IV Intravenous anti-histamines (10mg Chlorpheniramine)
Nebulised bronchodilators (driven by oxygen)
Intravenous corticosteroids (Hydrocortisone 200mgs)
Intravenous fluids (if hypotensive)
Causes of recurrent meningococcal meningitis
Immunological Complement deficiency (susceptible to encapsulated bacteria) Antibody deficiency (susceptibility to upper and lower respiratory tract infections)
Neurological: any disruption to BBB
Occult skull fracture
Hydrocephalus
Features of immune deficiency (SPUR)
Serious
Persistent
Unusual
Recurrent
Management of Complement Deficiency
Meningovax
Pneumovax
HIB vaccines
Daily prophylactic penicillin
Anti-CCP
Anti-citrullinated peptide antibodies
70% Sensitivity for RA
95% Specificty for RA
Antibodies against citrullinated proteins
Rheumatoid Arthritis HLA Associations
HLA-DR1
HLA-DR4
Rheumatoid Factor
IgM Antibody against Fc portion of human IgG
60-70% Sensitivity for RA
60-70% Specificity for RA
Genetic Predisposition to Rheumatoid Arthritis
5%DZ and 30%MZ twins
Peptidylarginine deaminase polymorphisms
PAD Type 2 & 4
Increase citrullination of proetins
PTPN 22: Protein tyrosine phosphatase non-receptor 22
Lymphocyte-specific tyrosine phosphatase –> supresses T cell activation activation
1858T allele increases susceptibility to rheumatoid arthritis, SLE, type 1 diabetes
HLA
HLA-DR1
HLA-DR4
Treatments for Rheumatoid Arthritis
Standard Mx Methotrexate Sulphasalazine Hydroxychloroquine Leflunomide
Further Mx
TNFalpha antagonist
Inhibits downstream events in inflammation.
Rituximab
Antibody specific for CD20
Depletes B cells (not plasma cells)
Abatacept
CTLA-4 – Ig fusion protein
Binds to ligands of CD28 (CD80 and CD86) and thereby inhibits T cell activation
Tocilizumab
Antibody specific for IL-6 receptor – widespread effects
Before Starting Biologics:
Screen for exposure to TB using CXR and TB ELISPOT
Screen for exposure to Hepatitis B
Screen for exposure to Hepatitis C
Consider possibility of HIV infection
Prior history of septic arthritis/infected joint prosthesis
Educate patient to stop drug and seek advice if acute infection
Consider need for vaccinations
Consider risk of malignancy
Prior history of malignancy
Advise re sun exposure/skin protection
Serum Sickness
Penicillin can bind to cell surface proteins
Acts as “neo-antigen”: stimulates very strong IgG antibody response
Individual is “sensitised” to penicillin
Subsequent exposure to penicillin stimulates
Formation of immune complexes with circulating penicillin
Production of more IgG antibodies
Fever
Arthralgia of large joints
Vasculitic skin rash
Renal function deteriorates
Sjögren’s syndrome
Chronic auto-immune disease of salivary glands
Primary: by itself
Secondary: as a result of connective tissue disorder
F>M Dry mouth Dry eyes Dry skin Chronic cough Muscle and joint pains Thyroid problems
Increase risk of lymphoma
ANA +ve
SA/Ro
SB/La (far more specific)
Antithrombin
Inhibits factor IIa and factor Xa
Tissue factor pathway inhibitor
Inhibits VII –> VIIa
Protein C and S
Inhibits factor Va and VIIIa
Antithrombotic Mediators on Endothelium
Endothelial expression TFPI Endothelial Protein C TFPI Heparans
Secretes Anti-platelet mediators
Prostacyclin
NO
ENDOTHELIUM DOES NOT EXPRESS TISSUE FACTOR
Pregnancy and Susceptibility to Thrombosis
Decrease Protein S
Increase Factor VIII, Increase Fibrinogen
Stasis
Compression
Malignancy and Susceptibility to Thrombosis
Tissue Factor on tumour
Increased Inflammation
Decreased Flow
Anticoagulant Drugs
Heparin
LMWH
Unfractionated
Potentiate Antithrombin, Factor IIa and Xa
Immediate acting (potentiate anti-coagulant activity)
Warfarin Vitamin K antagonist Inhibits vitamin K dependent factors: II VII IX and X Delayed action Reduce procoagulant activity
New oral anticoag (rivoraxaban) are immediate
Heparin
Three forms
LMWH (subcut)
Unfractionated (IV only)
Pentasaccharide (subcut)
Provide immediate effect (eg for treatment of thrombosis)
Disadvanatges
Long term disadvantage – have to be given by injections, risk of osteoporosis
Difficult to dose: Variable renal dependence
Low molecular weight heparin (LMWH)
Reliable pharmacokinetics so monitoring not usually required
Can use anti-Xa assay in at-risk eg:
Renal failure (CrCl<50)
Extremes of weight or risk
In anti-Xa assay you measure ability to potentiate antithrombin in its inhibition of thrombin and Xa
Unfractionated heparin
Much more complex, Variable kinetics
Variable dose-response
Always monitor therapeutic levels with APTT or anti-Xa
Direct acting anticoagulants
Anti-Xa
Rivaroxaban, apixaban, edoxaban
Anti-IIa
Dabigatran
Properties Oral administration Immediate acting –peak in approx. 3-4 hours (cf LMWH) Short half-life No monitoring
New agents
Oral admin
Reliable dose response,
No monitoring
Warfarin
Oral
Only anti-coagulant that can be used for metallic heart valves
Indirect effect by preventing recycling of Vit K
Action is delayed
II, VII, IX & X
Takes some time to fall
Levels of anticoagulant protein C and protein S also fall (also vit K factors, transient increase thrombotic risk at onset)
Reversal of Heparin
Protamine
Low molecular weight heparin (LMWH) dosing
Thromboprophylaxis
Tinzaparin 4500U
Clexane 40mg
Risk Factors for VTE
Patient Factors Age > 60yrs Previous VTE Active cancer Acute or chronic lung disease Chronic heart failure Lower limb paralysis (excluding acute CVA) Acute infection BMI>30
Procedure (circumstance) Hip or knee replacement Hip fracture Other major orthopaedic surgery Surgery > 30mins Plaster cast immobilisation of lower limb
Bleeding risk assessment
Patient Factors Bleeding diathesis (eg haemophilia, VWD) Platelets < 100 Acute CVA in previous month (H’gge or thromb) BP > 200 syst or 120 dias Severe liver disease Severe renal disease Active bleeding Anticoag or anti-platelet therapy
Procedure
Neuro, spinal or eye surgery (v high risk if bleeding occurs)
Other with high bleeding risk
Lumbar puncture/spinal/epidural in previous 4 hours
Treatment of DVT/PE
Start LMWH eg Tinzaparin 175u/kg \+ warfarin Start Warfarin at the same time, measure INR Stop Hep when OK Stop LMWH when INR >2 for 2 days
Continue for 3-6 months, takes this for patients to settle
Patients with cancer: continue LMWH not warfarin.
OR Start Rivaroxaban (NEW WAY)
DOES NOT DISSOLVE CLOT, STOPS PROPAGATION OF CLOT
Thrombolysis
About to die or critical limb
Only for life threatening PE or limb threatening DVT
Risk of haemorrhage(Intracranial Haemorrhage) 4%
Reduces subsequent post-phlebitic syndrome
Indications broadening slowly
Same treatment for stroke, potentiate fibrinolysis (TPA) tissue plasminogen activator
Risk of VTE recurrent
Higher risk (put on on long-term anticoag)
Idiopathic thrombosis (no external stimulus)
Male
Have higher d-dimer after coming off anticoagulant –> high risk of recurrence
Presentation of Anaemia in Cancer
Fe Deficiency (Occult blood loss)
GI cancer: Gastric, colonic
Urinary tract cancer: Renal cell carcinoma, bladder cancer
Anaemia of Inflammation
Leucoerythroblastic anaemia –> bone marrow infiltration
Cancer
Myrelofibrosis
Severe Infection
Haemolytic anaemias
Immune mediated
Non Immune; fragmentation (micro-angiopathic haemolytic anaemia)
Leucoerythroblastic anaemia
Bone Marrow Infiltration
Cancer
Haematopoietic: Leukaemia, Lymphoma, Myeloma
Non-Haematopoietic: Breast, Bronchus, Prostate
Severe Infection:
Miliary TB
Severe Fungal Infection
Myelofibrosis
Dry tap apriate of BM
MASSIVE Splenomegaly
Myelofibrosis
Bone marrow failure due to progressive scarring
Leukoerythroblast changes
Dry tap on BM aspirate
Massive splenomegaly
May eventually develop a serious form of acute leukaemia
Haemolytic Anaemia
Inherited: Defects of the red cell.
OR
Acquired: Defects of the environment in which the Red cell finds itself, the red cell itself is fine
Anaemia (though may be compensated) Reticulocytosis Raised Bilirubin (unconjugated) Raised LDH Reduced haptoglobins
In bone marrow failure, you can’t increase red cell output so you don’t see reticulocytosis and the anaemia is not compensated
Inherited Haemolytic Anaemias
Membrane
Spherocytosis
Elliptocytosis
Haemoglobin
Mutation of beta chain, structurally abnormal beta chain –>
Structural (sickle cell disease)
Quantitative (thallasaemias) imbalance between alpha and beta chains
Enzymes
G6PD
Continual Red Cell breakdown –> pigment stones
Acquired Haemolytic Anaemia
Immune
OR
Non-Immune
DAT test +ve –> IMMUNE
Diseases that produce autoimmune haemaolytic immune
- Cancer of immune system: lymphoma or lymphocytic leukaemias
- Disease of the immune system: SLE or Sjorgen’s
- Infection (disturbing the immune system) e.g. Mycoplasma
Mycoplasma = Cold agglutinin disease is an autoimmune disease characterized by the presence of high concentrations of circulating antibodies, usually IgM, directed against red blood cells
In autoimmune haemolytic anemia you also get acquire spherocytes
DAT NEG –> NON-immune
These diseases damage the red cells but are not immune mediated
Infection (malaria) gets into red cell
Micro-angiopathic Haemolytic anaemia (MAHA)
Red cell fragments
low platelets (activation of clotting system)
DIC/bleeding
Underlying adenocarcinoma (prostate or stomach)
Coombs Test
Direct coombs = DAT Test
Used to test for autoimmune hemolytic anemia
Tests for presence of IgG on Red cells
Blood sample is taken and the RBCs are washed (removing the patient’s own plasma) and then incubated with anti-human globulin (also known as “Coombs reagent”). If this produces agglutination of RBCs, the direct Coombs test is positive#
AND
Indirect coombs
Used in prenatal testing of pregnant women and in testing blood prior to a blood transfusion
Detects antibodies against RBCs that are present unbound in the patient’s serum
Serum is extracted from the blood sample taken from the patient. Then, the serum is incubated with RBCs of known antigenicity; that is, RBCs with known reference values from other patient blood samples. Finally, anti-human globulin is added. If agglutination occurs, the indirect Coombs test is positive.
micro-angiopathy haemolytic anaemia from an adenocarcinoma
Low grade DIC
Occult cancer secreting pro-thrombotic factors into blood
Activated coagulation pathway
Coagulation systemic throughout blood – not confined to local site
In microvasculature Blood flow slow Pro-coagulation factors At sites of slow flow, fibrin able to be formed Fibrin goes across blood vessel Causes red cell trauma Fragmented cells Platelets consumed s part of process
Polycythaemia
Appropriate e.g. high altitude
True: polycythaemia vera
Secondary: Ectopic Erythropoietin
Hepatocellular carcinoma
Renal cancer
Bronchial cancer
Causes of Neutrophilia
TIMUC
Corticosteroids (demargination of neutrophils –> apparent increase)
Underlying neoplasia
Tissue inflammation (e.g.colitis, pancreatitis)
Myeloproliferative/ leukaemic disorders
Infection -itis
Reactive:
Neutrophil count up to 15 –> infection or malignant
Presence bands, toxic granulation, and signs of infection/inflammation
Malignant:
Neutrophil count 250 –> leukaemia
Find neutrophils along with immature cells: Neutrophilia basophilia plus immature cells myelocytes, and splenomegaly. Suggest a myeloproliferative (CML)
Neutropenia plus precursors cells (Myeloblasts) (AML)
Eosinophilia
Reactive eosinophilia
Parasitic infestation
allergic diseases e.g. asthma, rheumatoid, polyarteritis,pulmonary eosinophilia.
Underlying Neoplasms, esp. Hodgkin’s, T-cell NHL (reactive eosinophilia)- lymphoma secretes eosinophil secreting factor
Drugs (reaction erythema mutiforme)
Chronic Eosinophilic leukaemia
Eosinophils part of the “clone”
FIP1L1-PDGFRa Fusion gene
Monocytosis
Rare but seen in certain chronic infections and primary haematological disorders TB, brucella, typhoid Viral; CMV, varicella zoster sarcoidosis chronic myelomonocytic leukaemia (MDS)
Lymphoid Vs Myeloid Clinical Distinguishing Factor
If you have splenomegaly and hepatomegaly and no lymph nodes –> Myeloid disorder
Haemopoiesis can go back to where it occurred in fetal, in liver
If you have splenomegaly and hepatomegaly and lymphadenopathy –> lymphoid disorder
Lymphoma Associated with Antigenic Stimulation
H.Pylori : Gastric MALT (mucosa associated lymphoid tissue) lymphoma
Sjogren’s syndrome : Parotid lymphoma
Autoimmune thyroid disease –> thyroid marginal lymphomas
Coeliac disease: small bowel T cell lymphoma EATL (enteropathy associated T-Cell lymphoma)
Lymphoma Associated with Translocation
Lymphoma associated translocations
e.g. t(8,14)
Involve the Ig Locus Ig promoter highly active in B cells Bring intact oncogenes close to the Ig promoter Oncogenes may be anti apoptotic, proliferative. bcl2 bcl6 Myc cyclinD1
Risk Factors for Lymphoma
Constant antigenic stimulation
Infection( direct viral infection of lymphocytes)
Loss of T cell function
(HIV and Immunosuppression)
Lymphoma and Infectious Agents
1) Direct Viral Integration
HTLV1 infects T cells by vertical transmission
Carribean and Japan
May develop Adult T cell leukaemia lymphoma (2.5% at 70 years)
2) Immunosuppression + EBV infection
EBV infects B lymphocytes
Carrier state and regulated by healthy T cells
Iatrogenic supression of T cells (to prevent transplant rejection increase in B cell lymphomas)
3) HIV
60 fold increase in lymphoma in HIV (high grade B-NHL)
Loss of T cell regulation of EBV infected B cells
Immuno Markers
B Cell
CD20
Immature blast B cell = TDT
Cyclin D1 not normally expressed by B cells, Expression of cyclin D1 indicative of mantle cell lymphoma
CD5 expression in B cells indicative of mantle B cell lymphoma OR small lymphocytic lymphoma
(CD5 is normally a T cell marker)
T Cell
CD3
CD5
Mantle Cell Lymphoma
Middle aged male
Lymph node, GI tract
Present in mantle zone
Median survival 3-5 yrs
B cell expressing
cyclin D1
CD5
Translocation
t(11,14) = diagnostic
Follicular Lymphoma
Lymphadenopathy in the elderly
CD10
bcl-6 +ve
t(14,18) involving bcl-2 gene
Small Lymphocytic Leukaemia
Middle aged/ Elderly
Nodes or blood
Small lymphocytes, naive or post-germinal centre B cell
CD5
CD23
Indolent
Undergo Ritcher transformation into high grad elymphoma
Marginal Zone / MALT lymphoma
Arise at extranodal sites e.g. Gut, lung, Spleen
In response to chronic stimulation form antigen e.g. H.Pylori
Post germinal centre memory B cell
Indolent, but can transform into high grade lymphoma
Can treat if remove antigen stimulation early
Burkitt’s Lymphoma
Jaw or abdominal mass in Children
EBV associated
Immunodeficiency
Sporadic
Stary-sky appearance
C-myc
t(8,14)
Aggressive
Diffuse Large B Cell
Middle aged/Elderly
Lymphadenopathy
Germinal centre or post-germinal centre B cell
Sheets of large lymphoid cells
p54 positive
Peripheral T Cell Lymphoma
Middle aged/ Elderly
Lymphadenopathy and extra nodal sites
Large T lymphocytes
Associated with reactive cells e.g. eosinophils
Aggressive
Special Forms of T Cell Lymphoma
Adult T Cell Leukaemia / Lymphoma
HTLV-1 Japan and Caribbean endemic
Enteropathy associated T cel lymphoma
Longstanding Coeliac
Cutaneous T cell lymphomas
Mycosis fungiodes
Anaplastic large cell lymphoma
Anaplastic Large Cell Lymphoma
Children/ Young adults
Lymphadenopathy
Large epitheloid lymphocytes
T cell or null phenotype
t(2,5)
Alk-1
Agressive BUT alk-1 expression = better prognosis
Non-Hodgkin’s Lymphoma
Multiple nodal sites
Spreads discontinuously
B Cell
T Cell
Hodgkin’s Lymphoma
Single nodal site
Spreads continuously
Split into Classical and Lymphocyte predominant
Classical Three subtypes Nodular sclerosing Mixed cellularity Lymphocyte rich and Lymphocyte depleted
Lymphocyte predominant = some relation to non-hodgkin’s lymphoma
Classical Hodgkin’s Lymphoma
Young/Middle aged
Single site of nodes
germinal centre or post-germinal centre B cell
EBV associated
Sclerosis
Mixed cellularity
Reed-Sternberg and Hodgkin cells
with eosinophils
Rarely Alcohol-induce pain
Nodular Lymphocyte Predominant Hodgkin’s Lymphoma
Isolated lymphadenopathy
Germinal centre B cell
B cell rich nodules with scattered L&H cells
NO ASSOCIATION WITH EBV
Can transform into high grade B cell lymphoma
B Cell Non-Hodgkin Lymphomas
Low Grade Follicular lymphoma Small lymphocytic lymphoma/ Chronic lymphocytic leukaemia Marginal zone lymphoma Mantle zone lymphoma
High Grade
Diffuse large B cell lymphoma
Intermediate
Burkitt’s Lymphoma
Staging of Hodgkin Lymphoma
Stage I; one group of nodes II; >1 group of nodes same side of the diaphragm III; nodes above and below the diaphragm IV; extra nodal spread
Suffix A if none of below, B if any of below
Fever
Unexplained Weight loss >10% in 6 months
Night sweats
Treatment of Hodgkin Lymphoma
Chemotherapy for all cases (ABVD)
ABVD 2-6 cycles +/- Radiotherapy
PET CT
Interim: post x2 cycles, response assessment
End of Treatment: Guides need for radiotherapy
Relapse then Autologous Stem cell transplant as salvage
Chemotherapy ABVD Adriamycin Bleomycin Vinblastine DTIC ABVD, is given at 4-weekly intervals.
Effective treatment Preserves fertility (unlike MOPP the original chemo) Can cause (long term) Pulmonary fibrosis cardiomyopathy
Treatment of Diffuse Large B Cell Lymphoma
International Prognostic Index (IPI) Age > 60y serum LDH > normal performance status 2-4 stage III or IV more than one extranodal site
Treated by x 6-8 cycles of R-CHOP (Rituximab-CHOP)
Combination drug regimens e.g. CHOP Cyclophosphamide Adriamycin Vincristine Prednisolone
Doxorubicin
Relapse: Autologous Stem Cell transplant salvage 25% of patients
Chronic Lymphocytic Leukaemia
Proliferation of mature B-lymphocytes
Age at presentation median 72 Commonest leukaemia in the western world Lymphocytosis between 5 and 300 x 109/l Smear cells Normocytic normochromic anaemia Thrombocytopenia Bone marrow Lymphocytic replacement of normal marrow elements
Mature B cells (CD19) co-expressing CD5
Further immuno studies CLL score 4-5
CLL Score (Need 4/5) CD5 CD23 FMC7 CD79b SmIg
Binet and Rai staging
CD38 expression = bad prognosis
Deletion of 17p (TP53) = bad prognosis
unmutated IgH gene = bad prognosis
CD5 also expressed in Mantle Cell Lymphoma
Normally a T cell marker
Treatment of CLL
Prophylaxis and treatment of infections
Aciclovir
PCP prophylaxis for those receiving fludarabine or alemtuzumab (Campath)
IVIG is recommended for those with hypogammaglobulinemia and recurrent bacterial infections
Immunisation against pneumococcus, and seasonal flu
Auto-immune phenomena
1st Line Steroids
2nd Line Rituximab
Irradiated Blood products if risk of TA GVHD
Variants of CLL
Transformation to high grade lymphoma = Richter’s syndrome
~1% per year
Treat as high grade lymphoma with CHOP-R
BCR Kinase inhibitors
New drugs in CLL
Ibrutinib
Idelalisib
Myelodysplastic Syndromes
Typically a disorder of the elderly. (over 60) Common in 70s
Symptoms/signs are those of general marrow failure
Develops over weeks & months
Development of clone marrow stem cells with abnormal cell development
- -> functionally defective blood cells
- -> numerical reduction
Cytopenia
Anaemia –> tiredness, lethargy, severely anaemic –> heart failure
Neutropenia –> infection
Thrombocytopenia –> bleeding
AND Increased risk of transformation to leukaemia
Myelodysplastic Features in Bone Marrow and Blood
Pelger Huet = bilobed neutrophils
Ring sideroblast = iron arranged in ring
Dysgranulopoiesis of neutrophils = abnormal granules
Myelokathexis of neutrophils = abnormal appearance of neutrophils and pre-cursors in bone marrow
Dyserythropoiesis of red cells = Abnormal red cells in the bone marrow (bridge sand blebbing)
Dysplastic megakaryocytes = Abnormally small megakaryocytes
INCREASED PROPORTION OF BLAST CELLS (normally <5%) –> prognostic significant
More than 20% = defined as having an Acute Leukaemia
Auer rods stain deep red
They are indicative of acute myeloid leukaemia
WHO classification of MDS
Refractory anaemia (RA)
- without ringed sideroblasts
- with ringed sideroblasts (RARS)
Refractory cytopenia with multilineage dysplasia (RCMD)
Refractory anaemia with excess of blasts (RAEB)
- RAEB-I (BM blasts 5-9%)
- RAEB-II (BM blasts 10-19%)
5q- syndrome
Unclassified MDS: MDS with fibrosis, childhood MDS, others
The Revised International Prognostic Scoring System IPSS-R
BM blasts % Karyotype Hb Neutrophils Platelets
0 = Good
4=Bad
Used to predict risk of development of AML
Treatment choices
Prognosis of MDS
Deterioration of blood counts
Worsening consequences of marrow failure
Development of acute myeloid leukaemia
– Develops in 50%< 1 year
– Some cases of MDS are much slower to evolve
– AML from MDS has an extremely poor prognosis and is usually not curable
As a rule of thumb
• 1/3 die from infection
• 1/3 die from bleeding
• 1/3 die from acute leukaemia
Treatment of MDS
Prolong survival:
- allogeneic stem cell transplantation (SCT)
- intensive chemotherapy
Supportive care Blood product support Antimicrobial therapy Growth factors (Epo, G-CSF) EPO = red cells G-CSF = neutrophils
Biological Modifiers Immunosuppressive therapy Hypomethylating agents Azacytidine Lenalidomide (5q- syndrome)
Oral chemotherapy
Hydroxyurea
Low dose chemotherapy
Subcutaneous low dose cytarabine
Intensive Chemotherapy/SCT
AML type regimens
Allo/VUD standard/ reduced intensity
Bone Marrow Failure
Failure of stem cell
Depending on whereabouts in lineage the stem cell fails –> different outcome
Could fail to make lymphocytes and myeloid
Or either depending on location of failure
Results from damage or suppression of stem or progenitor cells
PLURIPOTENT HAEMATOPOIETIC CELL
- Impairs production of ALL peripheral blood cells
- rare
COMMITTED PROGENITOR CELLS
- Result in bi- or unicytopenias
Causes of Bone Marrow Failure
Primary
Congenital
Fanconi’s Anaemia –> MULTIPOTENT
Diamond-Blackfan Anaemia –> Red cell progenitor
Kostmann Syndrome –> neutrophil progenitor
Acquired Primary: Idiopathic aplastic anaemia –> MULTIPOTENT
Secondary Bone Marrow Infiltration (haematological = leukaemia, lymphoma, myelofibrosis, non-haematological = solid tumour) Radiation Drugs Chemicals (Benzene) Autoimmune Infection (Parvovirus, Hepatitis)
Drugs causing Bone Marrow Failure
Cytotoxic
Antibiotics
Chloramphenicol
Sulphonamide
Diuretic
Thiazide
Anti-Thyroid
Carbomazole
Aplastic Anaemia
Aplastic Anaemia = Pancytopenia
Subtype of Bone Marrow Failure in which all three cell lines are NOT produced
CLASSIFICATION:
- Severe aplastic anaemia (SAA)
- Non-severe aplastic anaemia (NSAA)
Camitta criteria:
2 out of 3 peripheral blood features
- Reticulocytes < 1% (<20 x 109/l)
- Neutrophils < 0.5 x 109/l
- Platelets < 20 x 109/l
AND Bone marrow <20% cellularity
MULTIPOTENT defect - “Stem cell” problem (CD34, LTC-IC
Causes Primary Idiopathic - 70% (Telomeric shortening is a feature of both idiopathic aplastic anaemia and dyskeratosis congenita) Fanconi's Anaemia Dyskeratosis congenita Schwman-Diamond Syndrome
Secondary Radiation Drugs: chloramphenicol Infection: hepatitis SLE
Immune attack:
Humoral or cellular (T cell) attack against multipotent haematopoietic stem cell.
Dyskeratosis Congenita
3 patterns of inheritance
Abnormal telomeric structure and function is implicated.
Telomere length is reduced
X-linked recessive trait = mutated DKC1 gene - defective telomerase function
Autosomal dominant trait = mutated TERC gene
RNA component of telomerase
Autosomal recessive trait, gene not yet been identified
Progressive bone marrow failure –> aplastic anaemia
Cancer predisposition
Somatic abnormalities
Triad of:
Reticulated skin hyperpigmentation,
Nail dystrophy
Oral leukoplakia
Tx:
Supportive
Blood/platelet transfusions
Antibiotics
Drugs to promote marrow recovery
Oxymetholone
Growth factors
Haemopoietic stem transplantation
Telomeric shortening is a feature of both idiopathic aplastic anaemia and dyskeratosis congenita
Schwman-Diamond Syndrome
Congenital disorder characterized by:
Exocrine pancreatic insufficiency
Bone marrow dysfunction –> Aplastic anaemia
Skeletal abnormalities
Short stature
Differential Diagnoses of Pancytopenia & Hypocellular Marrow
Hypoplastic MDS / Acute Myeloid Leukaemia
Hypocellular Acute Lymphoblastic Leukaemia
Hairy Cell Leukaemia
Mycobacterial (usually atypical) infection
Anorexia Nervosa
Idiopathic Thrombocytopenic Purpura
Management of Bone Marrow Failure
Seek a cause (detailed drug & occupational exposure history)
Supportive
Blood/platelet transfusions (leucodepleted, CMV neg, irradiated)
Antibiotics
Iron Chelation Therapy (avoid iron overload)
Drugs to promote marrow recovery
Oxymetholone (=anabolic steroid)
Growth factors
Immunosuppressive therapy (due to t cell attack of bone marrow)
Stem cell transplantation
Treatment for Idiopathic Aplastic Anaemia
Immunosuppressive therapy – older patient
Anti-Lymphocyte Globulin (ALG)
Ciclosporin
Androgens – oxymethalone
Stem cell transplantation
Younger patient with donor (80% cure)
VUD/MUD for > 40 yrs (50% survival)
Fanconi’s Anaemia
Autosomal recessive/ X-linked
- -> abnormalities in DNA repair
- -> chromosoma fragility *in vitro addition of diepoxybutane or Mitomycin –> chromosomal breakages
Normal blood count at birth
Marrow failure and pancytopenia slowly progress onset at 5-10 years
10% result in acute leukaemia
Tx:
Supportive
Androgens
full blood count in pregnancy
Mild anaemia (due to net dilution)
Red cell mass rises (120 -130%)
Plasma volume rises (150%)
Macrocytosis
Normal
Check Folate or B12 deficiency
Neutrophilia
Thrombocytopenia
increased platelet size
Incidental thrombocytopenia in third trimester
Not due to volume expansion
As plasma volume expansion finished by end of second trimester
Causes of Thrombocytopenia in Pregnancy
1) Physiological (normal to have lower platelets in pregnancy)
2) Pre-Eclampsia (HELLP)
3) Immune thrombocytopenia
4) MAHA = Schisyocytes
HELLP (remits after delivery)
TTP and HUS (do not remit after delivery)
5) All others:
Bone marrow failure
Leukaemia
Hypersplenism
Lower the platelets –> more likely pathological
*NEED >70 for epidural
Iron Deficiency in pregnancy
May Cause: Anaemia IUGR Prematurity Postpartum haemorrhage
Coagulation changes in pregnancy
Increase in:
von Willebrand
Factor VIII
PAI-2 (placenta produced)
Decrease in:
Protein S
Antiphospholipid Syndrome
Recurrent miscarriages
Lupus anticoagulant positive
Anti-cardiolipin antibody
Obstetric outcome improved with herparin and aspirin
Myeloproliferative Disorders
Ph Neg Polycythaemia vera (PV) Essential Thrombocythaemia (ET) Primary Myelofibrosis (PMF)
Ph Pos
Chronic myeloid leukaemia (CML)
Myeloproliferative Disorders Gene Mutation
JAK2 = PV
Calreticulin
MPL
Polycthaemia vera treatment
Venesection
Hydroxycarbamide
Aspirin
Essential thrombocythaemia treatment
Aspirin
Anagrelide
Hydroxycarbamide
Treatment of Primary Myelofibrosis
Anaemia –> transfusion
Splenectomy –> symtpomatic relief
Thrombocytosis –> hydroxycarbamide
Ruxolotinib = JAK2 inhibitor
Bone marrow transplant
Treatment of CML
Imatinib
2nd generation: Dasatanib, and Nilotinib
Treatment of Multiple Myeloma
Melphalan (mustard-type alkylating agent)
Steroids
Proteasome inhibitors
IMIDs“ - Thalidomide, Lenalidomide, Pomalidomide
Treatment of Graft vs Host Disease
Corticosteroids Cyclosporin A FK506 Mycophenylate mofetil Monoclonal antibodies (against T cells) Photopheresis Total lymphoid irradiation
Prevention of GvHD
Methotrexate Corticosteroids Cyclosporin A CsA plus MTX FK506
T-cell depletion
T(15,17)
T(15,17)
Translocation of retinoic acid receptor
Acute promyelocytic leukaemia
Responsive to trans retinoic acid (ATRA) aka tretinoin
AML Disease Hotspots, Mutations and Translocations
Duplication
+8
+21 gives predisposition
Loss
deletions and loss of 5/5q & 7/7q
Common mutations
NPM1
CEBPA
FLT3: internal tandem duplication = bad prognosis
Translocations = Core binding Factor Changes –> cause arrest of cell development
t(8;21) fuses RUNX1 (encoding CBFα) with RUNX1T1
15% of adult AML
inv(16) fuses CBFB with MYH11
12% of adult AML
inv(16) , t(16;16) –> eosinophilic subtype
Acute Promyelinocytic Leukaemia
t(15,17) = PML:RARA
Causes thrombocytopenia
Can present with haemorrhage of easy bruising
Because of coagulation defects and low platelets
Hyperactive fibrinolysis
Can cause DIC
Treated with ARTA – all trans retinoic acid (not chemotherapy)
Nearly all curable
Block in differentiation is further down pathway – excess of promyelocytes
AML vs CML Cytochemistry
Cytochemical stain AML ALL
Myeloperoxidase + (Gr) -
Sudan black + (Gr) -
Non-specific esterase + (Mo) -
All negative = ALL
AML vs ALL immunohistochemistry
ALL:
Precursor-B-cell: CD19, CD20, TdT, CD10 +/-
B-cell: CD19, CD20, surface Ig
T-cell: CD2, CD3, CD4, CD8,TdT
AML:
MPO, CD13, CD33, CD14, CD15 glycophorin (E), platelet antigens
Both: CD34, CD45, HLA-DR
Clinical features of AML
Bone marrow failure
Anaemia
Neutropenia
Thrombocytopenia
Local infiltration into tissues Splenomegaly Hepatomegaly Gum infiltration (if monocytic) Lymphadenopathy (only occasionally) Skin, CNS or other sites (Cranial nerve palsy)
Complications
septic shock
Complicated by renal failure
DIC
Clinical features of ALL
Bone marrow failure — effects of
Anaemia
Neutropenia
Thrombocytopenia
Local infiltration Lymphadenopathy (± thymic enlargement) Splenomegaly Hepatomegaly Testes, CNS, kidneys or other sites Bone (causing pain)
Lymphoid cells are more likely to enter lymph nodes
T cells –> thymus enlargement
Bone pain in long bones of children
Hereditary Haemolytic Anaemias
Red cell membrane defects
Hereditary spherocytosis
Hereditary elliptocytosis
Haemoglobin defects
Sickle cell anaemia
Glycolytic pathway defects
Pyruvate kinase deficiency
Pentose shunt defects
G6PD deficiency
Paroxysmal Nocturnal Haemoglobinuria
Destruction of red blood cells by the complement system
Only hemolytic anemia caused by an acquired (rather than inherited) intrinsic defect in the cell membrane (deficiency of glycophosphatidylinositol leading to the absence of protective proteins on the membrane)
GPI anchor missing
GPI binds complement regulatory proteins
Red urine in the morning
cholelithiasis in chronic haemolytic anaemia
Coinheritance of Gilbert syndrome further increases risk of cholelithiasis in chronic haemolytic anaemia
Reduced/absent haptoglobins
Intravascular haemolysis
Hereditary spherocytosis
Vertical interaction
Band 3
Protein 4.2
Ankyrin
Beta Spectrin
Autosomal dominant
Osmotic fragilty test
Reduced binding of dye eosin-5-maleimide
Blood film
Looks spherical
Looks dense
Mean cell haemoglobin conc is increased
Hereditary elliptocytosis
Horizontal interaction
Alpha Spectrin
Beta Spectrin
Protein 4.1
Hereditary pyropoikilocytosis = homozygous form
Glucose-6-phosphate dehydrogenase deficiency
X-linked
Enzyme catalyses first step in pentose phosphate(hexose monophosphate) pathway - generates NADPH required to maintain intracellular glutathione(GSH)
Clinical effects
Neonatal jaundice
Acute haemolysis(triggered by oxidants/infection)
Chronic haemolytic anaemia(rare)
Drugs, infections or fava beans –> Acute haemolysis
Blood Film Nucleated red blood cells Bite cells Hemighosts Poikilocytes Contracted cells **Heinz bodies formed of denatured haemoglobin = Characteristic of oxidative haemolysis
Agents triggering haemolysis in G6PD
Anti-malarials
Primaquine
Antibiotics
Sulphonamides
Ciprofloxacin
Nitrofurantoin
Other drugs Dapsone Vitamin k Fava beans Mothballs
Pyruvate kinase deficiency
Echinocytes (sea urchin)
Pyrimidine 5’-nucleotidase deficiency
Pyrimidine nucleotides are toxic to red cells but red cells need to retain and salvage purine nucleotides
eliminating pyrimidine nucleotides = pyrimidine 5’ nucleotidase
Prominent basophilic stickling
Lead also inhibits this enzyme
Ham’s Test
=Flow cytometry of GPI-linked proteins
Paroxysmal nocturnal haemoglobinuria
Heinz Bodies
Marker of oxidative stress
=G6PD (and bite cells present)
JAK2 V617F
Polycthaemia vera
Idoiopathic erythrocytosis
Isolated erythrocytosis
von Willebrand’s
Type 1 Partial quantitative deficiency
Type 2 Qualitative deficiency
Type 3 Total quantitative deficiency (similar to haemophilia A as apparent factor VIII def)
Inhibitors of Cell wall Synthesis
Beta-Lactams
Penicillins
Cephalosporins
Carbapenems
Glycopeptides
Vancomycin
Teiciplanin
Penicillins
Penicillin
Gram positive organisms = streptococci, clostridia
Broken down by beta-lactamase
Amoxicillin
Gram positives and extended to cover enterococci and gram negatives
Broken down by beta-lactamse (staph aureus and many gram negs produced)
Co-amoxiclav (augmentin) = amoxicillin + clavulanic acid
Flucloxacillin
Resistant to beta-lactamase
Used for staph aureus
Piperacillin Similar to amoxicillin Extends coverage to pseudomonas and other non-enteric gram negatives Broken down by beta-lactamase Tazocin = piperacillin + tazobactam
Cephalosporins
3 Generations (increasing activity against gram negative bacilli with each gen)
Need to add in metronidazaole to cover anaerobes
First generation = Cephalexin
Second generation = Cefuroxime
Third generation = Cefotaxime, Ceftriaxone, Ceftazidime
Ceftriaxone = 1st line meningitis
Ceftazidime = psudomonas coverage, give in cystic fibrosis
Carbapenems
Meropenem, Imipenem, Ertapenem
Stable to extended spectrum beta-lactamase (ESBL)
Broad spectrum
Broken down by carbapenemase enzyme –> breaks down all three types of beta-lactams (penicillins, cephalosporins, and carbapenems)
Multi-drug resistant acinetobacter and klebsiella species
Glycopeptides
Vancomycin and Teicoplanin
Unable to penetrate gram negative outer cell wall
Active against gram positives
Inhibit cell wall synthesis
Bind to D-Ala D-Ala and prevent cross-linking
Slowly bactericidal
Nephrotoxic: must monitor levels and check for accumulation
MRSA
oral for serious C.Diff
Antibiotics inhibiting Protein Synthesis
Aminoglycosides
Gentamicin
Amikacin
Tobramycin
Tetracyclines
Doxycycline
Macrolides
Erythromycin
Clarithromycin
Azithromycin
Linocosamides
Clindamycin
Streptogramins
Synercid
Chloramphenicol
Oxazolidinones
Linezolid
Aminoglycosides
Gentamicin
Akimacin
Tobramycin
30S ribosomal subunit Streptococci are intrinsically resistant (requires specific transporter) no activity against anaerobes Ototoxic and nephrotoxic used synergistically with beta-lactams
Bactericidal
Gentamicin and tobramycin active against pseudomonas
Tetracyclines
Doxycycline
Activity against intracellular pathogens
Chlamydia
Mycoplasma
Rickettsiae
Bacteriostatic
Reversibly bind to 30S subunit
Light-sensitive rash
Do not give to children or pregnancy women
Macrolides
Erythromycin
Clarithromycin
Azithromycin
Bind to 50S subunit
Bacteriostatic
Minimal activity against gram negatives
USed for streptococcal infections and mild staphylococcus in penicillin-allergic patients
Also active against atypical pneumonias
Campylobacter
Legionella
Chloramphenicol
Broad spec
Used in eye preparations
Risk of aplastic anaemia
Grey baby syndrome
Bacteriostatic
50S subunit
Oxazolidinones
Linezolid
Highly active against gram positive (including MRSA and VRE)
Not active against gram negatives
Bind to 23S of 50S subunit
May cause thrombocytopenia and neurological problems
Inhibitors of DNA synthesis
Flouroquinolones
Ciprofloxacin
Levofloxacin
Moxifloxacin
Nitroimidazoles
Metronidazole
Tinidazole
Fluoroquiniolones
Ciprofloxacin
Levofloxacin
Moxifloxacin
Act on alpha subunit of DNA gyrase
Bactericidal
Gram negatives including pseudomonas
Levofloxacin and moxifloxacin also against gram positive and intracellular bacteria e.g. chlamydia
Use for UTIs Pneumonia Atypical pneumonia Bacterial gastroenteritis e.g. salmonella
Nitroimidazoles
Metronidazole
Tinidazole
Active against anaerobes and protozoa (Giardia)
Bactericidal
Inhibitors of RNA synthesis
Rifampicin
Rifabutin
Rifampicin
Mycobacterium e.g. TB
Binds to DNA-dependent RNA polymerase
Bactericidal
Monitor LFTS
induces CYP450
Turns secretions orange
Daptomycin
Cell membrane toxin
MRSA and VRE
Antibiotics inhibiting Folate Metabolism
Sulfonamides: Sulphamethoxazole
Diaminopyrimidines: Trimethoprim
Co-trimoxazole
trimethoprim + sulphamethoxazole
Used in PCP
Eagle Effect
Penicillins don’t work unless dividing
If large bacterial burden –> no active replication as nutrient deficiency
–> penicillins won’t work
Cytomegalovirus
Usually minimally symptomatic and self-limiting
Can cause mild mononucleosis-like illness and hepatitis
Groundglass appearance on CT
Owl’s eye inclusion
Retinal haemorrhages
Remains latent in bone marrow and monocytic cells
Epstein-Barr Virus
Exudative pharyngitis
Atypical lymphocytosis
Infectious mononucleosis
Associated with lymphoproliferative disease in immunosupressed
Burkitt’s
Post-transplant lymphoproliferative disease (PTLD)
Antivirals for CMV
Ganciclovir (given to all transplant recipients)
Valganciclovir (pro-drug of ganciclovir)
Foscarnet
Cidofovir
All very toxic
Classification of Human herpesvirus
Alpha = rapid growth and latency in sensory ganglia
HSV-1 - oral
HSV-2 - genital
VZV
Beta = slow-growth restricted range
CMV
HHV-6
HHV-7
Gamma = oncogenic
EBV
HHV-8
HHV-8
Kaposi’s sarcoma
Multicentric Castleman’s disease
Timing of Vaccine Ractions
Inactivated: within 48 hours
Live attenuated, need time to replicate
Measles: rash, fever, malaise 6-11 days
Rubella: pain, stiffness, swelling of joints 2nd week
Mumps: parotid swelling 3rd week
Acellular vaccines
Pertussis
Diptheria toxoid
Hib polysaccharide
Diptheria
Bacteria = corynebacterium diptheria or corynebacterium ulcerans
Airborne
Bull neck
Early: mild fever, swollen neck glands, anorexia, malaise, cough
2-3 days: grey membrane of dead cells form in throat, tonsils, larynx or nose “pseudomembrane”
Untreated: Infectious for up to 4 weeks
5-10% extensive organ damage: neurological and heart damage
Tetanus
Clostridium tetani: forms spores that can survive in environment
Non-communicable: infection by contamination of cut with soil or manure
Incubation 4-21 days
No natural immunity, ever if you have had tetanus, need to be immunised
Muscle stiffness, lock-jaw
Followed by neck stiffness, difficulty swallowing, stiffness of stomach muscles, muscle spasm, sweating and fever
Complications: fractures, laryngospasm, PE, aspiration, Death
neonatal tetanus due to infection of umbilical cord stump
Pertussis
Whooping cough
Bordatella pertussis
3 x 2 week phases:
Catarrhal phase: URI
Paroxysmal phase: paroxysms of coughing, inspiratory whoop, vomiting, apnoeic episodes
Convalescent phase: resolution but dry cough may persist for months
Acellular pertussis vaccine
Poliomyelitis
Transmission through contact with faeces or pharyngeal secretions
Can be asymptomatic
Mild-influenza-like illness
<1% result in flaccid paralysis (develops 1-10 days after prodromal illness)
Meningococcal vaccines
Meningococcal C: conjugate vaccine (polysaccharides chemically joined to tetanus or diptheria carrier proteins)
Men B: recombinant vaccine
Men ACWY: quadrivalent
Pneumococcal vaccines
PPV:purified polysaccharide vaccine = pneumovax II
23 serotypes
PCV: conjugated pneumococcal vaccine = Prevanar 13
13 valent
Measles
Morbillivirus
negative sense SSRNA
Airborne
Incubation: 7-18 days
Prodromal period: High fever and 3Cs
Cough
Coryza
Conjunctivitis
Enanthem phase
Koplik spots
Exanthem phase
Rash develops from face and upper neck –> hands and feet over 3 days
Lasts 5-6 days
Recovery: persistent cough
Complications Severe diarrhoea Pneumonia Otitis media (supresses immune system for 6 weeks, infections occur) Convulsions Encephalitis subacute sclerosing panencephalitis (SSPE) Death 1 in 5,000
Mumps
Paramyxovirus
SSRNA
Cause epithelial cells to fuse, multi-nucleated giant cell
Airborne
Incubation: 14-25 days
Headache, fever, parotid swelling (unilateral or bilateral)
Meningism: photophobia, neck stiffness
Complications: Pancreatitis Orchitis Oophoritis Neurlogical complications: meningitis, bilateral/unilateral deafness
Rubella
Togavirus
Direct droplet contact
Incubation:14-21 days
Infectivity until 5-7 days after the rash onset
Usually mild illness
Swollen lymph glands, low grade fever, malaise
Conjunctivitis
Maculo-papular rash on face, neck, and body
Swollen joints
Congenital rubella syndrome
Cardiac defects
Auditory
Ophthalmic
Neurological
Risk
90% <10 weeks
10-20% 10-16 weeks
Rare >20 weeks
Causes of Meningitis
Acute
Neisseria meningitides = gram negative diplococci
Streptococcus pneumoniae = gram positive diplococci
Haemophilus influenzae B
Listeria monocytogenes = gram positive rod
Group B streptococcus = gram positive cocci
E.Coli = gram negative rod
Chronic
TB
Spirochetes (leptospirosis)
Cryptococcus (Cryptococcus neoformans)
Aseptic
Cocksackie B viruses
Echviruses
Septicaemia (4 processes)
1) Capillary leak
Lack of albumin and other plasma proteins –> hypovolaemia
2) Coagulopathy
Bleeding and thrombosis
Exposure to tissue factor
Activation of protein C
3) Metabolic derangement
Acidosis
4) Myocardial failure
- -> Multi-organ failure
Chronic Meningitis
4+ days
usually TB
Can result in tuberculous granulomas, tuberculous abscesses, cerebritis
CT changes = leptomeningeal enhancement
Encephalitis
HSV most common viral cause
Arboviruses (neonates, younger adults)
Western equine encephalitis (infants, children)
St Louis encephalitis (>40 yrs)
California encephalitis (school-aged)
Eastern equine encephalitis (infants/children)
Rabies
All more common in summer/autumn
Bacterial = listeria
Amoebic
Toxoplasmosis
