Approach to Pancytopenia Flashcards
Types of reductions in cells:
Red cells – Anaemia
– Male: <13.5 (14.0) g/dL
– Female: <11.5 (12.0) g/dL
White cells – Leukopenia
– WCC: <4.0 x 109 /L
Platelets – Thrombocytopenia
– Platelet count: < 150 x 109/L
Causes of the Cell reductions
Decreased Production
Increased destruction-can be a combination
Decreased Production
- Aplasia
- Nutritional deficiency
- Bone marrow infiltration
- Haematological malignancies
- Connective tissue disorders
- Paroxysmal nocturnal
haemoglobinuria (PNH)
Aplasia
Aplastic anaemia/bone marrow
failure
Nutritional deficiency
Megaloblastic anaemia –
Vitamin B12 or folate
Bone marrow infiltration
Metastases • Infections • Tuberculosis • Overwhelming bacterial infection • Viruses
Haematological malignancies
- Myelodysplasia
- Myelofibrosis
- Lymphoma
- Myeloma
- Acute leukaemia
Connective tissue disorders
Systemic lupus erythromatoses
• Rheumatoid arthritis
• Others
Increased Destruction
Splenomegaly
– Including hypersplenism
Connective tissue disorders*
Paroxysmal nocturnal haemoglobinuria*
*Can be associated with cytopenias
and can be a combination of reduced
production and increased destruction
Investigations
FBC &Diff
Peripheral smear
Reticulocyte count
Bone marrow
Other tests:
Vit B12 & folate
Liver function
Viral studies
Autoimmune studies
PNH screen
Radiological studies
Genetic studies
Peripheral Smear
Round macrocytes:
-Liver dysfunction, aplasia, haematologicalmalignancies etc.
Megaloblastic changes:
- Oval macrocytes, anisocytosis, poikilocytosis, hypersegmented neutrophils
- Platelets rarely <60-70 x 109 /L
Leukoerythroblastic reaction:
-Possible bone marrow infiltration
Dysplasia
Immature cells
Infective change:
-Toxic granulation, left shift, vacuolization
Reticulocyte Count
Normal value
Adults: 50 – 100 (150) x 109/L / 0.5-2%
Distinguish between marrow failure and peripheral
destruction
Bone Marrow Aspirate and Trephine
Hypocellular/Aplastic
Hypercellular
Infiltrations – Granuloma – Aggregates – Malignant cells – Metastases
Differential Diagnosis for Bone Marrow Aspirate
Hypercellular Bone Marrow
Hypocellular Bone Marrow
Connective tissue disorders may fit either side
Hypercellular Bone Marrow Differential Dx
Megaloblastic anaemia
Peripheral destruction
Splenomegaly
Myelodysplasia
- Older patients
- Leukoerythroblastic reaction
- Blasts
Hypocellular Bone Marrow Differential Dx
Aplasia
-Primary or secondary
PNH
Myelofibrosis
-Primary or secondary
Hypocellular Marrow and Cytopenia
Aplastic Anaemia
Aplastic Anaemia:
Definition
Aplastic (Hypoplastic) anaemia
- Pancytopenia
- Bone marrow aplasia-Hypocellular bone marrow
Primary or secondary: Acquired or inherited
Aplastic Anaemia:
Pathogenesis
Reduction in the number of haematopoietic stem cells
– Remaining stem cells may be normal or abnormal
Aplastic Anaemia:
Types
Primary Aplastic Anaemia
- Idiopathic acquired
- Congenital/Inherited Bone Marrow Failure
Secondary Aplastic Anaemia
Primary Aplastic Anaemia:
Causes
Acquired
– Idiopathic
Congenital
– Fanconi anaemia
– Dyskeratosis congenita
– Others
Secondary Aplastic Anaemia:
Causes
Radiation
Chemicals/Toxins
-Benzene, organophosphates, DDT, organic solvents etc.
Drugs
- Chemotherapy- Antimetabolites, Alkylating agents, etc.
- Antibiotics – Chloramphenicol, sulphonamides etc.
- Anticonvulsants/antidepressants
- Anti-inflammatory drugs – gold, etc.
Viruses
– Non-A, -B, -C, -D, -E, -G hepatitis, EBV, HIV
Primary Aplastic Anaemia-Idiopathic
Etiology
Onset at any age:
-Peak incidence 30 years
Slight male predominance
Primary Aplastic Anaemia-Idiopathic
Clinical Features
Insidious onset
Symptoms related to cytopenias
- Anaemia
- Thrombocytopenia-Bruising, gum bleeding, menorrhagia, epistaxis
- Infections
Lymphadenopathy and hepatosplenomegaly is NOT a
feature of aplastic anaemia
-If present, consider an alternative diagnosis
Primary Aplastic Anaemia-Idiopathic
Laboratory Diagnosis
Anaemia:
- Normochromic, normocytic or macrocytic (round)
- MCV 95-110fL
- Reticulocyte count extremely low
Leukopenia:
- Usually granulocytes only
- Usually <1.5 x 109/L
- Severe cases may also show a lymphopenia
Thrombocytopenia-Always present
Peripheral smear:
-No abnormal cells seen
Bone marrow:
-Hypoplasia
-Haematopoietic tissue replaced by fat-May show patchy haematopoiesis
-Prominent lymphocytes and plasma cells, relative to
reduction of other cells
Primary Aplastic Anaemia-Idiopathic
Treatment
Supportive – Transfusion – Red cell or platelets • Should be leucoreduced and irradiated – Especially if transplant is required or patient is on immunosuppressive treatment – Antibiotics if infections is suspected • Specific – Immunosuppressive treatment • Antilymphocyte globulin (ALG)/Antithymocyte globulin (ATG) – Horse/Rabbit – Stem cell transplant • HLA-matched sibling preferred – Other
Fanconi Anaemia
Etiology
Autosomal recessive inheritance
Usually between 5 and 10 years-but can present up to 4th decade
10% risk of developing acute myeloid leukaemia (AML)
Increased risk of myelodysplasia (MDS)
Increased risk of solid tumours-often squamous cell lung carcinoma
Genetics: Heterogeneous – 13 different genes: A, B, C, D1, D2, E, F, G, I, J, L, M, N – FANCG: Common in African population – FANCA: Common in Afrikaner population – FANCC: Common in Jewish population
• Encoded proteins are part of a common pathway
– Protection against genetic damage
– Fanconi cells show high frequency of chromosomal
breakage
Fanconi Anaemia
Clinical Presentation
Growth retardation
Skeletal abnormalities (Microcephaly, absent radii or thumbs) also other general abnormalities
Renal tract (horse shoe or pelvic kidney)
Skin (Hyper- or hypopigmentation)
May show mental retardation
About 40% no abnormalities-Only progressive bone marrow aplasia
Fanconi Anaemia
Laboratory Diagnosis
Pancytopenia
-Anaemia and macrocytosis may precede neutropenia
and thrombocytopenia
Bone marrow may be normo- or hypocellular
Screening test-Chromosomal breakage studies
Definitive
-Gene studies – Specific gene
Conventional karyotyping
-Patient may have chromosomal abnormalities
TREATMENT
OTHER CONGENITAL
Fanconi Anaemia
Treatment
Symptomatic-As for idiopathic aplastic anaemia
Androgens-Side-effects severe including virilisation and liver dysfunction
Stem cell transplant-Only cure
Other Congenital Abnormalities
Dyskeratosis Congenita
Diamond-Blackfan syndrome
Shwachman-Diamond syndrome
Amegakaryocytic thrombocytopenia
Thrombocytopenia with absent radii
Secondary Aplastic Anaemia
Causes
Direct damage to bone marrow
- Radiation
- Cytotoxic therapy-Mostly temporary/Alkylating agents may cause chronic aplasia
Idiosyncratic drug reactions
- Rare
- Drugs not known to be cytotoxic
Secondary Aplastic Anaemia
Drugs Causes
Antibiotics
Anti-inflammatory
Anti-convulsants
Anti-thyroids
Anti-depressants
Anti-diabetics
Anti-malarial
Others-Mebendazole
Secondary AA
Viral Infections
Viral hepatitis
- Usually during/within a few months
- Usually Non-A, -B, -C, -D, -E, -G hepatitis:Hepatitis A and C associated AA is rare
HIV
Other:
CMV, EBV
Secondary AA
Haematological Malignancies
Myelofibrosis
Some lymphomas
• E.g. Hairy cell lymphoma, Hodgkin lymphoma, other non Hodgkin lymphomas.
Hypoplastic acute myeloid leukaemia or myelodysplasia-Rare
Presenting features of acute lymphoblastic leukaemia in children-Rare
Hypercellular Marrow and Cytopenias
Macrocytosis
Macrocytosis:
Classification
Megaloblastic anemia
-Oval macrocytes, anisocytosis, tear drops
Vit B12 or Folic acid deficiency
Macrocytic anaemia with
normoblastic erythropoiesis
Stress erythropoiesis
Megaloblastic anemia
• Oval macrocytes,
anisocytosis, tear drops
Vit B12 or Folic acid deficiency
Drugs, e.g. folate antagonists
N2O
Macrocytic anaemia with
normoblastic erythropoiesis
Liver disease Ethanol toxicity Hypothyroidism Haematological malignancies Aplastic anaemias Chronic hypoxic lung disease
Stress erythropoiesis
Haemolytic anaemia
Recovery from anaemia or blood
loss
Haematinic treatment
Macrocytosis
Drugs which cause Macrocytosis
HIV treatment:
-Reverse transcriptase inhibitors (e.g., stavudine [Zerit],
lamivudine [Epivir], zidovudine [Retrovir])
Anticonvulsants (e.g., valproic acid [Depakote], phenytoin [Dilantin])
Folate antagonists (e.g., methotrexate)
Chemotherapeutics (e.g., alkylating agents, pyrimidine, purine inhibitors)
Trimethoprim/sulfamethoxazole (Bactrim, Septra)
Biguanides (e.g., metformin [Glucophage]), cholestyramine(Questran)
Megaloblastic Anaemia
Macrocytic anaemia with oval macrocytes
Bone marrow: -Hypercellular -Megaloblastic morphology -Delayed maturation of nucleus relative to that of the cytoplasm-Due to defective DNA synthesis
Most commonly caused by:
-Deficiency of VIT B12 (COBALAMIN) OR FOLIC ACID
Vitamin B12/Cobalamin
Minimum daily requirement: 6 - 9 mcg/day
Total body stores: 2-5 mg (2000 – 5000 mcg)
– ~50% in the liver
– Takes years to develop deficiency
Synthesized in nature by micro-organisms
Found in foods of animal origin: – Liver, – Meat, – Fish, – Dairy products
Vitamin B12 Absorption:
Location
Stomach
Duodenum
Terminal ileum
Vitamin B12 Absorption:
Stomach
Acidic environment
Cbl released from food
Bind to R protein
IF secreted by parietal cells
Cbl: Cobalamin (Vitamin B12)
IF: Intrinsic factor
R: R-protein (R binder/R factor)
Vitamin B12 Absorption:
Duodenum
Pancreatic enzymes create alkaline environment
Cbl released from R-protein
Cbl binds to IF to form the
IF-Cbl complex
Vitamin B12 Absorption:
Terminal Ileum
Vit B12-IF bind to cubulin/amnionless receptor on
enterocyte
Absorbed by endocytosis
IF destroyed
Cbl transported to portal circulation
Vitamin B12 Transport
From enterocyte Cbl enters the portal circulation
Enters plasma bound to transcobalamin:
- Also called transcobalamin II
- Delivers vitamin B12 to bone marrow & other tissues
Vitamin B12 Metabolism
Enters cells through endocytosis-Cobalamin then metabolized to:
*Methyl-cobalamin
– Homocysteine → Methionine
– Folate metabolism and DNA synthesis
*Adenosyl-cobalamin
– Methylmalonyl CoA → Succinyl CoA
Factors required for Vitamin B12 Absorption
Dietary intake
Acid-pepsin in the stomach to liberate Cbl from binding to proteins
Pancreatic proteases to free Cbl from binding to R factors
Secretion of intrinsic factor (IF) by the gastric parietal cells to bind to Cbl
An intact ileum with functional Cbl-IF receptors
Causes of Vitamin B12 Deficiency
Gastric Abnormalities
Small bowel disease
Pancreatitis
Diet
Agents that block or inhibit
Inherited transcobalamin II deficiency
Causes of Vitamin B12 Deficiency:
Gastric Abnormalities
PERNICIOUS ANEMIA
Gastrectomy/bariatric surgery
Gastritis
Autoimmune atrophic gastritis
Causes of Vitamin B12 Deficiency:
Small bowel disease
Malabsorption syndrome Ileal resection or bypass Crohn's disease Blind loops Diphyllobothrium latum (fish tapeworm) TB of the distal ileum
Causes of Vitamin B12 Deficiency:
Pancreatitis
Pancreatic insufficiency
Agents that block or inhibit absorption
Causes of Vitamin B12 Deficiency:
Diet
Strict vegans
Vegetarian diet in pregnancy
Causes of Vitamin B12 Deficiency:
Agents that block/inhibited absorption
Neomycin
Biguanides (eg, metformin) Proton pump inhibitors (eg,
omeprazole)
Histamine 2 receptor antagonists (eg,
cimetidine)
N2O anaesthesia inhibiting methionine
synthase
Folate Description
Found in most foods – Highest concentration: • Liver, Green leafy vegetables, Yeast – Easily destroyed by heat • Normal daily requirement: – Unstressed individuals = 200 - 400 mcg/day – Pregnancy/lactation/haemolysis = 500 - 800 mcg/day • Deficiency rare in general population – Flour fortified with folate
Folate Absorption and Transport
Folate is ingested as folate polyglutamates and the it
is converted to methyltetrahydrofolate (M-THF).
M-THF is then absorbed through duodenum and
jejunum
Transported bound to albumin.
Folate Deficiency:
Causes
Nutritional Deficiency
Malabsorption
Drugs
Increased Requirements
Folate Deficiency:
Causes-Nutritional Deficiency
Substance abuse
Alcoholism
Poor dietary intake
Overcooked foods
Depressed patients
Nursing homes
Folate Deficiency:
Causes-Malabsorption
Celiac disease (sprue)
Inflammatory bowel disease
Infiltrative bowel disease
Short bowel syndrome
Folate Deficiency:
Causes-Drugs via various Mechanism
Methotrexate
Trimethoprim
Ethanol
Phenytoin
Folate Deficiency:
Causes-Increased Requirements
Pregnancy, lactation
Chronic haemolysis
Exfoliative dermatitis
Megaloblastic Anaemia:
Clinical Features
Insidious onset
Gradually progressive anaemia
Mild jaundice
Glossitis
– Beefy, painful, smooth red tongue
Angular stomatitis
Mild malabsorption symptoms
– May have loss of weight
Melanin pigmentation
ortant
Megaloblastic Anaemia:
Neurological Manifestations
Vitamin B12
Neuropathy
Progressive neuropathy
- Posterior and lateral columns
- Symmetrical
- Pain/ parasthesia in feet
- Difficulty walking
- Loss of proprioception
Optic atrophy
Psychiatric symptoms
Vitamin B12/Folate
Neural tube defects
- Encephalocoele
- Spina bifida
- Anencephaly
Supplementation in pregnancy with folic acid
very important
Megaloblastic Anaemia:
Diagnosis
FBC and Peripheral Smear
Biochemistry-Blood(Urine)
Investigation
Megaloblastic Anaemia:
Diagnosis-FBC and PS
Macrocytic anemia
Pancytopenia
Oval macrocytes
Megaloblasts
Hypersegmented neutrophils
Very seldom – blasts
Megaloblastic Anaemia:
Diagnosis-Biochemistry
Vitamin B12
Serum vitamin B12
Metabolites
– ↑ Serum homocysteine
– ↑ Serum (and urinary) methylmalonic acid (MMA)
Folate
Serum folate
Metabolites
– ↑ Serum homocysteine
– MMA normal
Megaloblastic Anaemia:
Diagnosis-Investigation of Cause
Vitamin B12:
Diet
Serum gastrin
Intrinsic factor and/or parietal cell antibodies
Endoscopy
Folate:
Diet
Intestinal malabsorption
Anti-transglutaminase and endomysial antibodies
Duodenal biopsy
Pernicious Anaemia:
Etioology
Common cause of Vitamin B12 deficiency
Auto-immune disease caused by:
– Anti-IF antibodies
– Anti-parietal cell antibodies
Under-diagnosed
– Especially older patients
Pernicious Anaemia:
Clinical Presentation
F >M
Peak age 60 years
Early greying of hair
Associated with autoimmune disorders
Blue eyes
Blood group A
Pernicious Anaemia Associations:
Female
Blue Eyes
Early Greying
Northern European
Familial
Blood Group A
Vitiligo
Myxoedema
Hashimoto’s Disease
Thyrotoxicosis
Addison’s Disease
Hypoparathyroidism/ Hypogammaglobulinemia/Carcinoma of the Stomach
Schilling Test
Radiolabeled vitamin B12 measure % excreted in urine
Method:
Part I:
- Oral radiolabelled B12
- Non-radiolabelled IM dose
- Collect 24 hour urine sample
Interpretation:
-Normal excretion:Inadequate dietary intake
-Reduced excretion:
Malabsorption
Pernicious anaemia
Part II:
Second test dose with intrinsic factor
-Pernicious anaemia:
Correction of absorption
-Malabsorption: No correction
Not often used/available at present-More historic value
Pernicious Anaemia:
Treatment
Vitamin B12 supplementation:Lifelong
– 1000ug IM daily for one week
– 1000ug IM weekly for one month
– 1000ug IM 1-3 monthly, lifelong
Prophylactic
– Total gastrectomy
– Ileal resection
Folate supplementation
– 5mg daily PO for 4 months
Prophylaxis – Pregnancy – Severe haemolysis – Dialysis – Prematurity
Vitamin B12 deficiency should be excluded before treatment with folate is commenced to prevent aggravation of neurological symptoms.
Hypersplenism
Description
Normal spleen:
Store ~5% of red cells and ~30% of platelets, 50% of marginated neutrophils
Enlarge spleen
– Increased sequestration
– Can sequestrate up to 90% of platelets
Definiton:
Presence of peripheral cytopenias with a enlarged spleen, bone marrow can be normal/hypercellular and the cytopenia is usually corrected when the spleen is removed
Hypersplenism:
Causes
The underlying cause for the splenomegaly should be
investigated.
Consider bone marrow examination if cause is not
apparent.
Congestive
Malignancy
Infection
Infiltrative, Non-malignant
Haematologic(Hypersplenic) states
Hypersplenism:
Causes-Congestive
Cirrhosis
Heart failure
Thrombosis of portal, hepatic, or splenic veins
Hypersplenism:
Causes-Malignancy
Lymphoma, usually indolent variants
Acute and chronic leukaemia
Myeloproliferative disorders
Multiple myeloma and its variants
Primary splenic tumours
Metastatic solid tumours
Hypersplenism:
Causes-Infection
Viral - hepatitis, infectious mononucleosis,
cytomegalovirus
Bacterial - salmonella, brucella, tuberculosis
Parasitic - malaria, schistosomiasis,
toxoplasmosis, leishmaniasis
Infective endocarditis
Fungal
Hematologic (hypersplenic) states
Hypersplenism
Cause-Inflammation
Sarcoid
Serum sickness
Systemic lupus erythematosus
Rheumatoid arthritis (Felty syndrome)
Hypersplenism
Cause-Infiltrative-Non-Malignant
Storage disorders
Infiltrative, nonmalignant
Amyloid
Langerhans cell histiocytosis
Hemophagocytic lymphohistiocytosis
Hypersplenism:
Cause-Hypersplenic States
Acute and chronic haemolytic anaemias
Sickle cell disease (children)
Following use of recombinant human
granulocyte colony-stimulating factor
