Haematological system Flashcards
What are the red cell indices
Haemoglobin, MCV, WBC
How is the dietary intake and absorption of iron done?
- Dietary iron exists mostly in the insoluble oxidized state (Fe3+ Ferric ion)
- Absorbed in its reduced state (Fe2+ Ferrous ion)
- Ferric reductase = Duodenal cytochrome b (Dcytb)
o Converts Fe3+ to Fe2+ in the intestinal brush border at the apical cell membrane
o Requires acidity in stomach and hence decreased iron absorption in prolonged PPI
usage and atrophic gastritis
Mechanism
method 1: divalent metal transporter (DMT1) transports Fe2+ across cell membrane into the enterocyte
Method 2: heme transport occurs by the heme carrier protein 1 (HCP1): more Fe2+ is further extracted from heme by heme oxygenase 2(HO2)
A proportion of Fe3+ are bound to ferritin and trapped within the cytoplasm of enterocytes without going into the circlation. Ferritin that is iron free is termed apoferritin. Iron bound to ferritin is lost when the epithelial cells are shed from the mucosa during desquamation.
Remaining Fe2+ transported across the basolateral membrane by ferroportin 1 (FPN) and a protien called hephaestin (HP) into circulation. Ferroportin 1 present in macrophages.
What are the types of iron deficiency?
Absolute iron deficiency
* Blood loss
* Decreased iron intake: malabsoprtion, anorexia nervosa
* Decreased iron absorption: gastrectomy, atrophic gastritis
Functional iron deficiency
* EPO stimulation in chronic renal failure: relative iron deficiency for haematopoiesis
Iron sequestration
* Anemia of chronic disease
Causes of anemia (production defect, destruction, sequestration, diluation)
Sequestration (pooling of blood cells): hypersplenism (splenomegaly), portal HT, chronic infections, haematological diseases
Dilution (increase in plasma volume relative to red cell mass): pregnancy, blood loss with fluid resuscitation
What is the history taking for anemia?
What is the PE for anemia?
What is the biochemical tests for anemia?
What are the ddx for anemia and expected results in CBC with DC + reticulocyte count?
How to differentiate iron deficiency anemia and anemia of crhonic disease based on red cell indices, iron profile?
Negative acute phase reactant: serum iron, transferrin
Positive acute phase reactant: ferritin, hepcidin
- Raised ferritin =/= not Fe deficiency anaemia (e.g. in CKD, both deficiency and chronic disease)
- Use of ferritin: Monitoring in (1) repeated transfusion, (2) inflammatory conditions, e.g. rheum/HLH
What information does an iron profile give you in anemia?
How to diagnose thalassemia in anemia?
How to differentiate the types?
What are the tests for hemolytic anemia and the results?
What is the direct and indirect Coombs test used for?
What is the physiology of anemia of chronic disease?
How to classify haemolytic anemia?
What is the etiology of autoimmune hemolytic anemia associated with warm/cold antibodies?
What CBC result for vit B12 and folate deficiency?
megaloblastic anemia
macrocytic anemia = morphological term describing large RBC in peripheral blood and include all anemias with high MCV
How is vit B12 absorption done?
Ingested vit B12 is bound to haptocorrin (transcobalamin I) in the mouth: dissociated in the stomach because of presence of gastric enzymes such as pepsi nand acid
haptocorrin is replaced by intrinsic factor (secreted by gastric parietal cells) of the stomach
Vit B12- intrinsic factor complex attaches to teh receptro cublin on the surface of the epithelial cells of the terminal ileum (ileal mucosa)
Intrinsic factor is absorbed into the bloodstream and bound to transcobalamin II: vit B12 bound to TC-II is taken up by other cells in the body by receptor medaited endocytosis
How is absorption of folate done?
- Folate polyglutamates cleaved by monoglutamates and absorbed in jejunum
- Absorption is both carrier mediated and passive diffusion
- Folate must be reduced to be effective in its biologicacl role in 1C transfer: folate is reduced to dihydrofolate (DHF) –> tetrahydrofolate (THF) –> 5,10 methylene THF –> L-5 methyl THF via series of enzymatic stpes
- Folatae enters cells by binding to a folate receptor known as megalin
What is the storage of vit b12 and folate, if deficient how long will it take to manifest?
Storage of vit B12. Large total body stores = 2-5mg with 1/2 of it stored in liver –> deficiency of vit B12 does not develop for at least 1-2 years or even longer (5-10 years if vit B12 intake ceases)
Storage of folate: small body stores 5-10mg. Deficiency of folate develops rapidly within weeks to months or even more rapidly if demands for folate is increased (e.g. chronic hemolytic anemia)
What are the functions of vit b12 and folate
DNA synthesis/RNA synthesis/DNA methylation
* Deficiency can casue a cell to arrest in DNA synthesis (S phase) of cell cycle, makes errors in DNA replication and undergo apoptotic death
* Principle action of vit B12: cofactor in recycling 5-methyl THF back to THF which can then be converted to frms that can act as 1-C donros
* Princple action of folate: supply methyl groups that are added to other molecules (i.e. act as a 1C donor)
* 1C metabolism is used in synthesis of purines and pyrimidines used for DNA synthesis. Purine = 10 formyl THF donates 2-methyl groups for purinre synthesis. Pyrimidine = 5,10-methylene THF donates 1 methyl group to convert dUMP into dTMP
Haematopoiesis
Megaloblastic changes: caused by slowing of nuclear division cycle relative to cytoplasmic maturation cycle. Macrocytic RBC and hypersegmented neutrophils are classical findings on peripheral blood smear
Ineffective erythropoiesis: premature death of developing erythropoietic precursor cells in the bone marrow (phagocytosis), evidence of hemolysis including elevated indirect bilirubin, LDH and low haptoglobin
Neuronal function
Vit B12 deficiency = subacute combined degeneration of cord
Degeneration of dorsal and lateral columns of spinal cord due to demyelination
Reduced methylation of neuronal lipids and proteins such as myelin basic protein can lead to demeyelination
Folate deficiency = neural tube defect. Periconceptual or 1st trimester folic acid supplementation decreases occurence of neural tube defects by >70%.
What are the causes of vit B12 deficiency?
- Pernicious anemia
- Inadequate dietary intake: strict vegetarians (that dont consume fortified food but rare (as all carbs are fortified)
- H.pylori infection/gatritis: bacteria elicitc antibodies that cross react with gastric parietla H+K+ ATPase due to molecular mimicry
- Intestinal malabsorption: IBD, pancreatic insufficeincy, fish tapeworm infection
- Gastrectomy/bariatric surgery: absence of gastric acid and pepsin results in impaired liberation of vit b12 from food proteins. Reduced production of intrinsic factor impairs vit B12 absorption
- Extensive ileocecectomy (distal ileum no absorption of vit b12)
- Drug induced
PPI/H2 antagonists/antacids: medications that reduce gastric acid may decrease vit b12 absorption since gastric acid plays a role in dissociation of vit B12 from food proteins which allows it to bind intrinsic factors
Metformin: decreased vit B12 absorption in the ileum due to effects of metformin on Ca2+ dependent membrane action (absorption of vit B12-IF complex is calcium dependent)
What are the casues of folate deficiency?
- Inadequate dietary intake: nearly impossible (unless chronic alcohlism, anorexia nervosa and reduced oral intake)
- Intestinal malabsorption: surgery (gastric bypass), IBD
- Increased folate requirements: pregnancy, chronic hemolytic anemia, exfoliative skin diseases, haemodialysis
- Drug induced: methotrexate (folate antagonist), antibioics (trimethoprim inhibits DHFR), anticonvulsants (valproate/carbamazepine/phenytoin)
What are the clinical manifestations of vit b12 or folate deficiency?
- Anemia and jaundice: combined anemia and jaundice (due to hemolysis)
- Glossitis/angular cheilitis/mouth ulcers. Glossitis presents with pain, swelling and loss of papillae of the tongue occurs in vit B12 deficiency. Mouth ulcers occurs in folate deficiency
- Neuropsychiatric symptoms: presents in both vit B12 and folate deficiency but most of the findings are commonly ascribed in vit b12 deficeincy
Subacute combined degeneration of cord - Presents as slowly progressive weakness, sensory ataxia and paresthesias and ultimately spasticity, paraplegia and incontinence. Not all patients with neurologic abnormalities will have anemia or macrocytosis and thus absence of haematological changes cannot be used to exclude dx
What are the biochemical tests for suspected folate or vit b12 deficiency?
- CBC with DC: macrocytic anemiae with MCV>100fL, low reticulocyte count, mild leukopenia or thrombocytopenia
- Peripheral blood smear: macroovalocytes, hypersegmented neutrophils
- Serum vit b12 level
- Serum holotranscobalamin level (better)
- Serum and RBC folate level: normal level of serum folate is >4ng/mL
- Not routine is methylmalonic acid and homocysteine. Reserved when results for vit B12 and folate levels are borderlines or inconclusive. MMA elevated in vit b12 deficiency but not folate since vit B12 is a cofactor in conversion of methylmalonyl CoA in succinyl CoA
- Serum autoantibodies: anti gatric parietal cell antibody, anti intrinsic factor antibody (both have high specificity but low sensitivity)
Evidence of hemolysis (premature destruction of developing RBCs in bone marrow (intamedullary hemolysis) and peripheral circulation (hemolysis)
* Increased AST
* Increased unconjugated bilirubin
* Increased LDH level
* Increased methemoglobin: oxidized form of Hb inserum which occurs in intravascular hemolysis giving serum a brownish color
* Decreased haptoglobini: free hb binds to haptoglobin in which the haemoglobin-haptoglobin complex is rapidly removed by the liver leading to a reduction in plasma haptoglobin
What is treatment for vit b12 and folate deficiency?
Vit b12 deficiency
* Parenteral admin (dont have capacity to absorb oral replacement i.e. pernicious anemia. symptomatic anemia/neurological findings in which absorption is ensured
Cyanobalamin 1000mcg 1x/week until deficiency corrected and then 1x/month
* Oral admin: cyanobalamin 1000mcg1x/day
Treatment of folate deficiency
* Oral admin: folic acid 5mg 1x/day for folate deficiency. Usually sufficient even if malabsorption is present it is considerable in excess of the 200mcg recommended dietary allowance.
* Folid acid 0.4mg (400mcg) 1x/day for pregnancy
Define neutropenic fever?
- ANC ≤ 500/ μL (AND)
o Single oral temperature ≥ 38.3oC (OR)
o Persistent temperature ≥ 38.0oC sustained over ≥ 1 hour
What are the pathogens causing neutropenic fever?
Bacterial pathogens: S. epidermidis is most common. P. aeruginosa also common
Viral pathogens: human herpes virus common in high risk patients with chemotherapy induced mucositis
* Reactivation of HSV1 and HSV2 (herpes simplex)
* Reactivation of VZV (herpes zoster)
* Reactivation of CMV/EBV and HHV can also occur in patients as a result of immunosuppression or reciept of blood products or stem cells
Fungal pathogens: candida and aspergillus
Candida: acquired through GIT colonization and translocation across damaged intestinal epithelail surface
Candida albicans: C. glabrata, C. tropicalis account for the remainder
Aspergillus species: acquired through inhalation of airborne spores into upper and lower respiratory tract followed by germination and invasive hyphal growth. Aserpgillus common fungal cause in immunocompromised hosts
Primarily affects the upper resiratory tract (sinusitis) and pneumonia but also invovles CNS, bones and skin
What is the pathogenesis of neutropenic fever?
- Chemotherapy/RT induced mucositis of GIT: mucositis through GIT leading to seeding of endogenous flora in the GIT throughout the bloodstream occurs in majority of cases. Neutropenia usually occurs 10-14 days post CT
- Immune defect associated with malignancy
- Presence of indwelling catheters
- Obstruction: obstruction to lymphatic, biliary tract, bronchial, GI or urinary ssytem. Secondary to tumor or result of surgical procedures
What history taking and PE for neutropenic fever?
Detailed examination with emphasis on sites most likely infected including skin, oral cavity, lungs, abd, perianal areas, catheter and biopsy sites
Vital signs and evidence of sepsis: BP/pulse/ temp/RR/GCS. Ill looking, mental obtundation or decreased oral intake suggests sepsis
Specific examination on different organs
* IV catheter sites: erythema and tenderness suggesting infection (must exclude line sepsis)
* Lungs: signs of pneumonia
* Abd: abd tenderness or peritoneal signs may represent neutropenic enterocolitis or C.difficile colitis
* Perianal area: erythema, pain and tender hemorrhoids suggesting infection (avoid DRE which can introduce infection by traumatizing the fragile mucosa)
* Skin and mucous membranes: evidence of rash or mucositis (ask for diarrhea for potential GI mucositis introducing infection)
What Ix for neutropenic fever?
- CBC
- Electrolyte profile (sepsis)
- LFT
- RFT
- Samples for culture and sensitivity test
Blood culture (2 sets from peripheral and central venous catheter if present)
Stool for C.difficile antigen detection or PCR
Urine/sputum/skin lesions/CSF/ peritoneal fluid
Radiological tests
* CXR
* CT thorax/sinus/abdomen/pelvis
Patients with symptoms suggestive of neutropenic enterocolitis or C.difficile colitis should undergo abd CT scan with IV and oral contrast
What is the treatment for neutropenic fever
Environmental precautions: reverse barrier isolation. HSCT recipients should be placed in rooms with positive pressure and high efficiency particular air (HEPA) filtration
Neutropenic diet: low bacterial or low microbial diet consisting of well cooked food, often instituted but may not reduce occurence of infection/fever
Risk stratification
Low risk: expected to be neutropenic <7days and who have no active comorbidities or evidence of hepatic or renal dysfunction
High risk: expected to be neutropenic for >7days and have comorbidities or evidence of hepatic or renal dysfunction
Duration of therapy
Known source = complete standard course of 14 days
Unknown source: continue antibiotics until afebrile and ANC >500cells/uL
medical treatment
Empirical
PO for low risk patients: amoxicillin clavualnate + ciprofloxacin/levofloxacin
IV for high risk patients (must cover for P. aeruginosa (gram-ve, facultative anaerobe): meropenem/ imipnem/ piperacillin/tazobactam
Addition of antifungal agents: should be initated for neutropenic fever after 4-7 days. Liposomal amphotericin B/caspofungin/voriconazole/posaconazole
What is the pathogenesis of DIC?
Widespread activation of coagulation
* Intravascular formation of fibrin
* Thrombotic occlusions of small vessels
* Leads to multiple organ failure
Depletion of platelets and clotting factors
* Widespread intravascualr coagulation and secondary fibrinolysis
* Consumption of clotting factors, inhibitors of coagulation and platelets
* Leads to severe bleeding
What Ix and results for acute DIC/chronic DIC?
What are the causes of DIC?
What is treatment of DIC?
Principle: precipitating trigger must be eliminated before treatment of DIC is effective. Control of bleeding with frequent monitoring of coagulation screen is essential
Platelet and fresh frozen plasma (FFP): supportive therapy
Anticoagulants not favaroable
Antithrombin concentrate not favorable
What is the classification of ITP?
Primary ATP: acquired thrombocytoepnia due to autoimmune platelet destruction in the absence of causes or disorders
3 phases
* newly diagnosed ITP = within 3 months from dx
* Persistent ITP = ongoing ITP between 3-12 months
* Chronic ITP = ITP lasting> 12 months
Secondary ITP
* ITP associated with an underlying condtion most commonly: HIV, HCV, SLE + CLL
* Infections: HIV/HCV/ CMV/VZV/H.pylori
* Autoimmune: SLE/antiphospholipid syndrome/ evans sydnrome (AIHA +ITP)
* Lymphoproliferative disorders = CLL
* Vaccination side effects
* Common variable immune deficiency (CVID)
Drug induced immune thrombocytopenia
* Result of drug dependent platelet antibodies that cause platelet destruction
* Should be distinguished from drug induced bone marrow suppression which is a non-immune related phenemenon
What is the ddx for immune thrombocytopenia?
Congenital platelet disorders
Thrombocytipenia (quantitative)
* Bernard soulier syndrome
* Wiskott aldrich syndrome: considered in young males with thrombocytopenia and small platelets particularly if there is a history of eczema and recurrent infection
* Inherited bone marrow failure syndrome. Congenital anasplastic anemia: fanconi anemia, Schwachman-Diamond syndrome, dyskeratosis congenita
Platelet function disorder (qualitative)
* Defects of adhesion: Bernard Soulier syndrome
* Defects of degranulation: grey platelet syndrome/storage pool disease
* Defects of aggregation: Glanzmanns thromasthenia
Acquired platelet disorders
Thrombocytopenia (quantitative)
Decreased production from bone marrow
* Acquired aplastic anemia
* MDS
* Bone marrow infiltration: leukemia/lymphoma
* Chemotherapy/RT
Increased destruction
Immune related
* ITP
* SLE
* Drug induced thrombocytopenia
Non immune related
* TTP (thrombotic thrombocytopenic purpura)
* Haemolytic uremic syndrome (HUS)
* DIC
* Hypersplenism
Platelet function disorder (qualitative)
* Liver disease
* Uremia
* Drug induced platelet dysfunctino
COX inhibitor: aspirin
GP2b/3a inhibitor: abciximab/tirofiban/eptifibatide
ADP receptor antagonist: clopidogrel/prasugrel/ticlopidine
What is the different presentation of platelet and coagulation disorders?
What is the pathogenesis of immune thrombocytopenia?
Reduced platelet lifespan by antibody mediated destruction
Impaired platelet production
Inciting events
Infection: some cases of ITP associated with a preveding viral infection such as HIV and HCV
Immune alteration
Alteration in immune haemostasis might induce loss of peripheral tolerance and promote development of self reactive antibodies e.g. SLE and CLL
Antibody production: specific IgG autoantibodies produced by patients B cells directed against platelet membrane glycoprotien such as GP2b/3a
What are the SS of immune thrombocytopenia?
Major are asymptomatic
Bleeding
* Result of thrombocytopenia and typically occurs in skin or mucous membrane
* Petechiae: flat, red, discrete lesions that do not blanch under pressure. Occurs in depedent areas of body such as lower legs in ambulatory patients and sacral area in recumbent patients
* Purpura: purpura on skin as dry purpura –> not serious. Purpura on mucous membrane are wet purpura and is a predictor of more serious bleeding
* Epistaxis: minimal epistaxis occuring during nose blowing is common. Continuous epistaxis that requires intervention is a predictor of more serious bleeding
* Hemorrhage: intracranial hemorrhage, overt GI bleeding and haematura is uncommon
How to make dx of ITP (immune thrombocytopenia)?
Diagnosis of ITP is one of exclusion
* Isolated thrombocytopenia (without anemia or leukopenia) without another apparent cause
* Presumptive dx of primary ITP when history, PE and lab testing include peripheral blood smear do not reveal with other potential etiology for thrombocytopenia
* Presumptive dx of secondary ITP when patient with ITP has underlying associated condition such as HIV, HCV, SLE and CLL
What biochemical tests done for immune thrombocytopenia?
- CBC with DC: thrombocytopenia which varies from mild (100-150x10^9/L) to severe (<10 x10^9/L)
Absence of other haematological findings. Evans syndrome = AIHA + ITP - Clotting profile: evaluate for other treatable causes of thrombocytopenia
- Peripheral blood smear: required to confirm that thrombocytopenia is not artifactual due to platelet clumping. ITP not characterized by abnormal platelet morphology
- Anti platelet antibodies: generally not useful but done in QMH
- Serum complements C3/4 levels
- Serum autoimmune markres: ANA/RF/antiphospholipid antibodies
- Viral serology (HBV/HCV/HIV/EBV) and parvovirus B19/CMV PCR +H.pylori antibody. All patients are tested for HIV and HCV because thrombocytopenia is a common presenting finding for these conditions
Bone marrow exam: not routine. Indicated in patients with other unexplained cytopenia, dysplasia on peripheral blood smear
Demonstrate normal cellularity, and normal erythropoiesis and myelopoiesis
What is the history taking of immune thrombocytopenia?
HPI
Bleeding symptoms
* Subcutaneous bleeding such as petechiae, purpura, ecchymosis
* Mucosal bleeding such as epistaxis, gum bleeding and menorrhagia
* Intraaritcular or intramuscular bleeding such as haemarthrosis or muscle haematoma
Medical history
* HIV + HCV +SLE and CLL
* Hypersplenism
* Liver diseases
* History of platelet or coagulation disorers
FH: platelet/coagulation disorders
DH: medication that can cause drug induced thrombocytopenia. Heparin induced thrombocytopenia (HIT)
What is the treatment of immune thrombocytopenia?
General approach
Dx of ITP does not imply therapy is needed
Indications to start treatment
* Platelet count <10x10^9/L
* Clinical evidence of bleeding including mucosal bleed with platelet count 10-30x10^9/L: nose bleeding that cannot be stopped for >15mins, oral mucosal bleeding including gum bleeding or blood retention cyst, GI bleeding
* Severe bleeding regardless of platelet count: intracranial hemorrhage (ICH), retinal hemorrhage
ITP and surgery: platelet count >50x10^9/L is considered safe for minor procefdures
Medical treatment
* Platelet transfusion ineffective in ITP (only emergency situation)
* IVIG is 1st lin therapy: induces a rapid rise of platelet count within 24-48 hours but effect is transient lasting only for 1-2 weeks. Increases platelet count by interfering with macrophage uptake of autoantibody coated platelets
Infuse the drug gradually (5ml/15min; than 10ml/min…) and give it over 1-2 days rather than 4 days
* Corticoisteroids is 2nd line therapy for ITP: must perform bone marrow aspirate to rule out leukemia before starting
* Anti RH(D): alternative to conventional IVIG for patients whose RBC is Rh (D) +ve
* Other treatment options: rituximab, (anti CD20), azathioprine/ cyclosporine/cyclophosphamide/mycophenolate mofetil
Surgical treatment
* Splenectomy (requires immunization for encapsulated organisms)
* Indications: when disease is refractory to steroid, relapse after responding to steroid. High dose of steroids is required for maintenance of safe platelet count.
What is normal platelet lifespan?
in ITP?
Lifespan of platelet is normally about 10 days
* Reduced to 1 – 2 days in immune thrombocytopenic purpura (ITP)
What can be the ddx for ITP?
All causes of bone marrow failure
* Acute leukemia
* Aplastic anemia
* Myelodysplastic syndrome (MDS)
* Bone marrow infiltration by neoplastic disease
All causes of increased platelet consumption
* Hypersplenism
* DIC
* TTP
What is expected bone marow biopsy findings in ITP?
Increased megakaryocytes
* Suggests a consumptive cause of thrombocytopenia
What are the useful investigations for exclusion of DIC?
Peripheral blood film
* Fragmented red cell
Clotting profile
* ↑ PT and APTT
* ↑ D-dimer
* ↓ Fibrinogen level
What are the indications for splenectomy in ITP?
Splenectomy is indicated if
* Disease is refractory to steroid
* Relapse after responding to steroid
* High dose of steroids is required for maintenance of safe platelet count
What are the features of thrombotic thrombocytopenic purpura?
- Thrombotic microangiopathy caused by severely reduced activity of vWF cleaving protease ADAMTS13
- Characterized by small vessel platelet rich thrombi that causes thrombocytopenia, microangiopathic hemolytic anemia and widespread multiorgan thrombosis and injury
What are the different types of TTP?
hereditary TTP (<5%): also known as Upshaw schulman syndrome. Inherited mutations isn ADAMTS13
Acquired TTP (>95%): autoimmune or immune mediated TTP. Result of development of autoantibodies inhibitors to ADAMTS13. Categorized further into primary (idiopathic) or secondary cause
What are the secondary causes of TTP?
- Pregnancy (female predominant with median age of 41 years (rare in children)): accounts for 5-25% of all cases of TTP
- Connective tissue diseases: SLE, RA, sjogren syndrome
- Infections: CMV infection, HIV infection
- Drug induced: clopidogrel, ticlopidine, cyclosporine, quinine
What is the pathogenesis of TTP?
- Von willebrand factor (vWF) has multiple ADAMTS13 specific cleavage sites that are susceptible to cleavage by protease when exposed. ADAMTS13 is a metalloprotease that regulates the platelet aggregating activity of vWF by cleaving it at specific sites
- Deficiency of von willebrand factor (vWF) cleaving protease ADAMTS13 in TTP
Deficiency is due to inherited mutations in the enzymes or autoantibodies against it
Results in increased levels of unusually large vWF multimers - Consequences of vWF induced platelet aggregation
Thrombocytopenia due to platelet consumption. Microangiopathic haemolytic anemia from mechanical fragmentation or RBCs.
What is ss of TTP?
Clinical pentad in 5% of patients: fever, fluctuating neurological symptoms, renal impairment, microangiopathic hemolytic anemia (MAHA), thrombocytoepnia
FAT RN = Fever, anaemia (MAHA), thrombocytopenia, renal dysfunction, neurological abnormalities
SS of hemolytic anemia: jaundice, pallor, dyspnea, palpitation, fatigue and wewakness
SS of thrombocytopenia: subcutaneous bleeding (petechiae, purpura, ecchymosis), mucosal bleeding: epistaxis, gum bleeding, menorrhagia), retinal hemorrhage, intracranial hemorrhage
SS of CNS involvement: headache, confusion, focal neurological deficits: weakness, paresthesia, seizure, visual disturbance
SS of CVS involvement (MI, arrhythmia, HF): chest pain, orthopnea, paroxysmal nocturnal dyspnea)
SS of GI involvement (bowel ischemia): nausea and vomiting, abd pain, diarrhea
SS of UG involvement: microscopic or macroscopic haematuria, proteinuria, oliguria/anuria
Ix for TTP?
- CBC: anemia (microangiopathic hemolytic anemia, MAHA), thrombocytopenia (deposition of platelets in microthrombi)
- Peripheral blood smear: schizocytes (fragmentation of RBC as RBC passes through platelet rich microthrombi in the microvasculature. Nucleated RBC: normoblasts. Polychromasia
- Clotting profile: should be normal
- Serum haptoglobin level: decreased haptoglobin (free hb from hemolysis binds to haptoglobin and the complex is rapidly removed by liver)
- Serum LDH: increased LDH (reflects both hemolysis and tissue damage due to systemic ischemia)
- LFT: hyperbilirubinemia (elevated level of unconjugated bilirubin due to haemolysis)
- Urinalysis: dark urine
- Direct and indirect antiglobulin (Coombs) test: immune mediated hemolysis typically negative
- ADAMTS13 and inhibitor tests: severely reduced ADAMTS13 activity <10% during an acute episodes is a hallmark of acquired TTP. presence of antibodies against ADAMTS13
CT scan: typically normal. May show changes consistent with posterior reversible encephalopathy syndrome (PRES)
What is treatment for TTP?
TTP is a medical emergency. Platelet transfusion not indicated due to possible exacerbation of thrombosis
- Plasma exchange
Indicated in patiens with a presumptive dx of TTP
Should be initiated within 4-8 hours of clinical dx
Should not be delayed while awaiting results of ADAMTS13 activity level
Plasma replacement choices: solvent/detergent plasma, fresh frozen plasma.
Plasma infusion is not an adequate substitute for plasma exchange in the initial treatment of TTP but can be used as a temporizing measure if an unavoidable delay in plasma exchange is expected - Corticosteroids
High dose oral prednisolone 1mg/kg/day
IV methylprednisolone 1g/day for 3 days - Rituximab
What are the general features of acute myeloid leukemia?
Well defined hematopoietic neoplasms involving precursor cells committed to myeloid line of cellular development (erythroid, granulocytic, monocytic, megakaryocytic)
Characterized by clonal proliferation of myeloid precursor with a reduced capacity to differentiate into more mature cellular elements
* Accumulation of leukemic blasts or immature forms in the bone marrow, peripheral blood and other tissues
* Decreased production of normal RBC, mature granulocytes (neutrophils) and platelets.
* Increased production of malignant cells
What is the epidemiology of AML?
Most common acute leukemia in adults and accounts for 80% of cases
Acute leukemia is the most common childhood malignancy accounting for 30%
ALL accounts for majority of childhood leukemia accounting for 80%
AML is much less common than ALL accounting for 15% of all leukemia
Disease incidence increases with age. Median age of dx is 65 years.
What are the RF for AML?
Chemical exposure
Radiation exposure
Smoking
Chemotherapy drugs
* Alkylating agents (Cyclophosphamide/ Ifosfamide)
* Topoisomerase II inhibitors Genetic abnormalities
* Down’s syndrome (Trisomy 21) (15 – 20x increase in risk)
* Bloom’s syndrome
* Fanconi anemia
Acquired hematopoietic conditions
* Myelodysplastic syndrome (MDS)
* Myeloproliferative neoplasm (MPN) (particularly CML)
* Aplastic anemia
* Paroxysmal nocturnal hemoglobinuria
What are the SS of haematological abnormalities?
Anemia
* Pallor
* Palpitation
* Tachypnea
* Fatigue
* Decreased exercise tolerance (ET)
Neutropenia
* Fever
* Mucositis
* Recurrent infections Thrombocytopenia
* East bruising
* Petechiae/ Purpura/ Ecchymosis
* Gingival bleeding/ Epistaxis/ Menorrhagia
Constitutional symptoms
* Fever
* Irritability
* Anorexia and weight loss
* Fatigue and malaise
What are the signs of infiltration of haematological malignancy to other areas?
Gingival hypertrophy
* Especially in monocytic subtypes which has predilection to infiltrate gum and skin
Leukemia cutis
* Infiltrative lesions suggestive of extramedullary leukemic involvement
* Subcutaneous nodules and violaceous/gray blue in color
Myeloid sarcoma (chloromas)
* Extramedullary tumor of leuekemic cells (deposits of myeloid blasts outside the bone marrow that cause desrtruction or compression in normal tissues
* Commonly seen in the orbit and epidural space but can occur anywhere –> associated with t821
Hyperleukocytosis and leukostasis
* Presents in 10-20% of patients with newly diagnosed AML
* Leukostasis is symptomatic hyperleukocytosis: WBC occluding the microcirculation leading to symptoms of decreased tissue perfusion typically causing neurological and respiratory distress. Resiratory: dyspnea/hypoxia. CNS: visual blurring/headache/dizziness/ tinnitus/confusion/coma/ TOMA
* Medical emergency with mortality in 1 week reaching 20-40% left untreated. Cytoreduction with induction chemotherapy, hydroxyurea or leukapheresis. Prophylaxis for tumor lysis syndrome with aggressive hydration and hypouricemic agents including allopurinol or rasburicase.
Tumor lysis syndrome
* rapidly proliferating and drug sensitive neoplasm
* Hyperuricemia, hyperK, hyperphosphatemia, hypocalcemia and raised LDH and metabolic acidosis
Disseminated intravascular coagulopathy (DIC)
* especially APL. Platelet transfusion and appropriate coagulation factors such as cryoprecipitate for severe hypofibrinogenemia can be considered in select patients
What is the diagnostic criteria for AML?
Requires both of the following
Evidence of bone marrow infiltration
* >20% blasts of the total cells of the peripheral blood or bone marrow aspirate
* Leukemia with certain genetic abnormalities such as those with t8;21, inv16 or t15;17 and myeloid sarcom are considerd diagnostic of AML without regard to blast count
Leukemic cells must be of myeloid origin
* Presence of Auer rods
* Cytochemistry positivity for myeloperoxidase
* Presence of myeloid markers by immunophenotyping
What Ix for AML and results?
CBC with DC
* Anemia
* Leukocytosis
* Thrombocytopenia
Clotting profile: look for evidence of DIC (PT,aPTT and Ddimer all increased. Decreased fibrinogen)
LFT/RFT and CaPO4 level
* Look for evidence of tumor lysis syndrome: hyperK, hyperP, hypoCa
Serum LDH and uric acid level: signs of TLS
Peripheral blood smear
* Circulating myeloblasts (95% of cases), Auer rods: pathognomonic of myeloblasts
Bone marrow aspirate and trephine biopsy
* Hypercellular bone marrow
* >20% of blasts: pronormoblast, myeloblast, abnormal promyelocyte, promonocyte, megakaryoblast
* Presence of auer rods: pathognomonic of myeloblasts (pink or red like granular structure in cytoplasm)
What are the special investigations for white cell disorders?
- Cytochemistry: MPO reaction (are blasts of myeloid lineage)
- Immunophenotyping (peripheral blood/BM aspirate and trephine biopsy)
Flow cytometry (identification of cell surface antigens)
Myeloid lineage: CD117, CD13, CD33
Monocyte lineage: CD11b, CD64,CD14, CD15 - Cytogenetics (BM trephine biopsy)
Conventional karyotyping with FISH or RT-PCR
Presence of certain cytogenetic abnormalities are sufficient for dx of AML
AML with t(8;21)(q22;q22); RUNX1-RUNX1T1
AML with t(15;17) (q22;q12); PML RARA (APL)
AML with inv(16)(p13.1q22)(p13.1;q22); CBFB-MYH11
What is treatment for AML?
- Chemotherapy
Differences between AML and ALL
AML has shorter duration of treatment due to absence of maintenance phase chemotherapy
Steroids not used in AML, CNS prophylaxis not indicated in AML
Induction (7+3 days): rationale (use of cytotoxic agents to eradicate leukemic cells in bone marrow and in circulation)
Outcomes
Favorable outcome = complete remission (does not = cure): eradication of all detectable leukemic cells (<5% blasts) from bone marrow and blood. Restoration of normal haematopoiesis (>25% cellularity and normal peripheral blood counts)> patients will relapse within 4-8 months unless given additional cytotoxic therapy
Cytarabine + daunorubicin
Cytarabaine (antimetabolite): 7 days of continous infusion
Daunorubicin/idaraubicin (anthracycline): followed by 3 days
Consolidation: must always follow up induction with consolidation regimen. Destroys leukemic cells that survived induction chemotherapy but undetectable by conventional studies
* Cytarabine (high dose)
* Cytarabaine + daunorubicin: standard consolidation for older adults
* Allogenic HSCT: indicated in young adults with unfavorable risk AML. Graft vs tumor effect that decreases relapse rates
- Allogenic haematopoietic stem cell transplantation
always ask for family members such as siblings for potential allogenic HSCT candidates
Indicated in young adults with unfavorable risk of AML or risk of relapse cases after complete remission.
MOA: T cell in donor graft induce a graft vs leukemia effect against residual disease that has survived the conditioning
HLA typing required - Supportive care
TLS prophyalxsi: hydration and allopurinol/rasburicase. Prevention of uric acid nephropathy or renal failure
Antimicrobial prophylaxis
Prolonged bone marrow suppression associated with high incident of infections especially S. viridans sepsis and S.viridans shock syndrome as well as fungal infection such as aspergillus infection. Prophylactic antibiotics or G-CSF for bacterial infections. Prophylactic antifungals (fluconazole/itraconazole) for fungal infections
What is treatment for APL (acute promyelocytic leukemia)?
All transretinoic acid (ATRA) + arsenic trioxide (ATO)
APL characterized by a gene rearrangement involving the retinoic acid receptor: t(15;17);PML RARa in >95% of cases. Very responsive to ATRA and arsenic trioxide is an effective non cytotoxic therapy
Differentiation of APL from other forms of leukemia is important
APL associated with higher risk of DIC and life threatning bleeding especially intracranial bleeding
APL responds well to initial treatment with all transretinoic acid and chemotherapy
APL associated with a good prognosis: best prognosis amongst all AMLs with >90% cure
What is the prognosis of AML?
Complete remission (CR) achieved in
* 70 – 80% in patients < 60 years old
* 40 – 50% in patients > 60 years old
Overall survival is variable depending on prognostic factors
* Poor prognostic factors include age > 60 years old, unfavorable cytogenetics, poor performance status or antecedent MDS/MPN
Prior exposure to
* Radiation
* Chemotherapy
* Toxic chemicals
Past history of
* Chronic myeloid leukemia (CML)
* Myelodysplastic syndrome (MDS)
* Myeloproliferative neoplasm (MPN)
What are the general features of ALL (acute lymphoblastic leukemia (ALL)?
Malignant proliferation of lymphoid cells blocked at an early stage of differentiation
Malignancy of lymphoid cells that has primary involvement of blood and bone marrow
Leukemia (ALL/CLL): primary involvement of blood and bone marrow
Lymphoma: solid tumors of the immune system
ALL when >25% blasts in BM
Lymphoma preferred term when the process is confined to a mass lesion with minimal or no blood and bone marrow involvement (<25% blasts in BM)
What is the triphasic disease phase of CML?
Name of this genetic test
What phase of the mitotic cycle does this cell belong to
From results shown, what conclusion can you draw concerning the dx of this patient
Why is there discrepancy between the findings of the 2 genetic tests in this patient
FISH
Interphase: easier to perform since the leukemic cells need not be altered
CML due to fusion gene signl
In normal cells there should 2 BCR (green) and 2ABL1 (red) genes. Spatial location of the 4 signals should be random as they are located on separate chromosomes.
In cells of CML patient a fusion signal is detected as a pair of probe will go together
Conventional cytogenetic study: detect normal karyotype which indicates that the presence of BCRABL1 fusion gene in FISH is not due to balanced translocation
FISH: fusion gene is caused by insertion instead of translocation. A small fragmetn of ABL1 gene breaks from chromosome 9 and is inserted into BCR gene in chromosome 22 to create a fusion gene. Such breakage is sub-microscopic and hence is not detected by conventional cytogenetic study.
What are the adv and disadv of conventional cytogenetics vs FISH in detecting leukemia?
What is hodgkins lymphoma features and non classical HL (nodular lymphocytic predominant Hodgkin lymphoma)?
Hodgkin lymphoma: presence of Reed Sternberg cells
RS cells are clonal B cells (ALL HL are B cell lymphoma), bilobed nucleus + prominent nucleoli with surrounding clear space
Arises from gernal center or post germinal center
Bimodal distribution (15-35 years and >50 years old)< less common than non Hodgkinsl ymphoma
Mode of spread
* Affects superficial (usually cervical or supraclavicular) +/-mediastinal LN
* Nodal disease with a tendency to spread in an orderly anatomical fashion to contiguous areas of LN
WHO classification of lymphoid malignancy for B cell?
WHO classification of lymphoid malignancy for T cell/NK cell?
What are the specific features of B cell lymphoma?
What are the specific features of T cell lymphoma?
What are the specific features of NK cell lymphoma?
What are the primary and secondary lymphoid organs?
What classification used to stage lymphoma?
What to do for PE of lymphoma?
General exam: skin involvement
Lymphoid survey
Waldeyers ring: adenoid –> tubal –> palatine –> tonsils
* Standard lymph node
o Firm or rubbery lymph nodes
oCervical –> Supraclavicular–> Axillary –> Epitrochlear –> Inguinal –>Femoral
Popliteal lymph node
* Abdominal lymph node
o Mesenteric lymph node/ Retroperitoneal lymph node
* Liver and spleen
Head and neck examination
* Nodal and extranodal involvement of H&N is suggested by enlargement of preauricular
lymph nodes and tonsillar asymmetry
* Primary CNS lymphoma commonly involves the eyes
Chest examination
* Mediastinal adenopathy may be detected on clinical examination or chest radiograph
* Presents with persistent cough, chest discomfit with an abnormal CXR
Abdominal examination
Hepatosplenomegaly is common in indolent lymphoma with intact LFT
What are the Ix for lymphoma?
- CBC with DC
- Peripheral blood smear
- LFT
- RFT (nephrotoxic CT drugs)
- Serum Ca2+ and PO4-: hyperCa due to PTHrP (paraneoplastic syndrome), evaluation of tumor lysis syndrome
- Serum LDH level: rapidly growing tumors of NHL such as Burkitt lymphoma
- Serum uric acid level
- Serum b2-microglobulin level: used in follicular lymphoma and other indolent lymphoma for prognostic purpose
- Serum protein electrophoresis. Detection of monoclonal immunoglobulin (M spike). Large M spike associated with lymphoplasmacytic lymphoma. Small M spike associated with small lymphocytic lymphoma/chronic lymphocytic leukemia and extranodal marginal zone lymphoma
- HIV serology: systemic non HL and CNS lymphoma are AIDS defining malignancy
- HBV and HCV serology: must include HBsAg, anti HBs and anti HBc +-HBV DNA viral load
- EBV serology: EBV VCA IgA and EBV EA IgA, EBV DNA viral load
- Serum autoantibodies
- Evaluation of other tissues: pleural fluid analysis by thoracentesis, peritoneal fluid analysis by paracentesis. CSF fluid by lumbar puncture (indicated in primary CNS lymphoma, lymphomatous meningitis or patients with Burkitt lymphoma which has a high incidence of CNS involvement
Radiological tests
PET CT scna: staging disease.
All nodular lymphoma histology is considered FDG avid except chronic lymphocytic leukemia/small lymphocytic lymphoma, lymphoplasmacytic lymphoma with Waldenstrom macroglobulinemia and marginal zone lymphoma
Excisional LN biopsy (sufficient tissue for histologic, immunologic, molecular biologic assessment and classification)
LN >1cm diameter should be biopsied
LN>2cm has the best diagnostic yield
Site of LN: enlarged peripheral LN are generally preferred
FNA only for initial screening for peripheral lymphadenopathy to detect benign form of reactive lymphadenopathy (viral/bacterial, non inflammatory)
Bone marrow aspirate/trephine biopsy: done prior to initation of treatment as part of the staging evaluation. Typically evaluated for morphology, immunophenotyping, cytogenetics and molecular genetics.
Histological exam: pattern of LN involvement (nodular/follicular/diffuse pattern)
Immunophenotyping
* Flow cytometry: on fresh unfixed single cell suspensions. Detection of surface immunogloblin light chains which is very helpful in determining clonality of B cell proliferation. Superior to IHC as able to etect 2 or more markers simultaneosly, rapid turnaround time, greater quantitative capacity and higher sensitivity for certain markers
* Immunohistochemistry: on sections of fixed or fresh frozen tissues. Expression of cell surface lymphoid differentiation antigens are used to distinguish B cell and T cells at various developmental stages
Cytogenetics: karyotyping and FISH
Molecular genetics: IgH gene rearrangement by PCR, T cell receptor gene rearrangement by PCR
What is the treatment regimen for Hodgkin lymphoma?
What is the treamtent regimen non-Hodgkin lymphoma?
How to make prognosis of hodgkins lymphoma?
How to make prognosis of non hodgkins lymphoma?
What is the diagnostic criteria for polycythemia vera?
What Ix done for polycythemia vera (PV) and results?
What is the ddx of thrombocytosis (in essential thrombocytosis)
What is the WHO diagnostic criteria for essential thrombocytosis (ET)?
What Ix done for essential thrombocytosis (ET)?
What is treatment for essential thrombocytosis?
What is prognosis of ET
Complications associated with ET?
What are other causes of myelofibrosis?
What are SS of PMF?
What is the diagnostic criteria for pre-PMF?
What is the diagnostic criteria for overt-PMF?
What is treatment for PMF?
What is the classification of MDS?
What are the causes of MDS?
What is the ddx for pancytopenia?
What are the SS for MDS?
What are the Ix for MDS and results?
What is the treatment for MDS and prognosis?
What Ix done for aplastic anemia and results?
What main 2 treatment approaches for aplastic anemia?
Age affected by MM
What are pathological features of multiple myeloma
MM >60 yo
What is the diagnostic criteria for multiple myeloma?
What is the ddx for multiple myeloma?
What is monoclonal gammopathy of undermined significance (MGUS)?
What is smoldering multiple myeloma criteria?
What is Waldenstrom macroglobulinemia (WM) criteria?
What Ix for multiple myeloma?
CBC with DC
ESR/CRP
Electrolyte profile: hyperCa
Serum protien level: hyperproteinemia
LFT: normal ALP (meaning osteoblastic acitivity is not increased)
RFT and urinanalysis: increased serum creatinine, proteinuria (myeloma cast nephropathy), light chain amyloidosis (usually urinary protien +ve since most of the proteinuria is comprised of albumin (nephrotic syndrome)
Peripheral blood smear: rouleaux formation (RBC stack of coins), monoclonal plasma cells (rarely seen in MM), leukopenia (20%): suppressed haematopoiesis, thrombocytopeni (5%): M protein interacts with thrombocytes
Bone marrow exam (aspiration and trephine biopsy)
* Plasma cell infiltration >10%
* Normal mature plasma cells
* Myeloam cells: multiple pale bluish white, grape like accumulatin
* Immunopheotyping: normal K- λ ratio in bone marrow = 2:1, ratio >4:1 or <1:2 is considerd to be K or λ monoclonality. Significance = differentiate monoclonal gammopathies from reactive plasmacytosis due to autoimmune disease, metastatic carcinoma, chronic liver disease and AIDS
Radiological tests
Skeletal survey
PA view of chest, AP and lateral view of skull, AP view of pelvis, AP and lateral view of cervical, thoracic and lumbar spine, AP and lateral view of femur and humerus
Typical features: focal lytic lesions, diffuse osteopenia, pathological fractures, compression fractures of spine
Most frequent sites of involvement are sites with active haematopoiesis: skull, vertebral bodies, thoracic cage, pelvix, proximal humerus and femur
CT/MRI: routine before making dx of solitary plasmacytoma or smoldering myeloma. MRI can dwetect diffuse and focal bone marrow lesions in patiens with multiple myeloma without osteopenia or focal osteolytic lesions on standard metastatic bone surveys
PET/CT scan: FDG correlates with areas of active lytic bone disease
Specific test
Serum/urine protien electrophoresis and immiunofixation
What is treatment for multiple myeloma?
Q1: What complication has developed in this patient?
Q2: What should be the immediate management for this patient?
Q3: Why is renal failure common in multiple myeloma?
Spinal cord compression from vertebral collapse fracture
* Leads to acute onset of paraplegia, urinary and bowel incontinence
Urgent decompression spinal surgery or radiotherapy
Amyloidosis
Obstruction of distal renal tubules by protein casts Toxic effect of light chain on renal tubules
Deposition of light chain in renal glomeruli
Infection
Dehydration
Hypercalcemia
Hyperuricemia
What are the typical hematological findings in multiple myeloma?
Q1: What does the ALP level suggests?
Q2: What is the most likely diagnosis?
Q3: What would you do to confirm your diagnosis?
Q4: Explain why the phosphate level is interfered in the biochemical results.
Normal ALP level suggests that the underlying cause of hypercalcemia is unlikely due to osteoblastic activity
Multiple myeloma
* C: HyperCalcemia
* R: Renal insufficiency
* A: Anemia
* B: Bone lytic lesion
Serum protein electrophoresis
Calculate serum globulin = Total protein – albumin = 58 g/L (high)
B-cells in multiple myeloma produces immunoglobulin which interferes with phosphate during the assay
