Clinical - White Blood Cells

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White Blood Cellll Countt (WCC)

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White Blood Cellll Countt (WCC)
Full Blood Counts will provide information on total White
Cells
This is total of all components of White Cells
Differential usually included which breaks total WCC into
these different elements
Elevation - most commonly infection of some type, although
may rise as acute phase reaction eg inflammation, tissue
damage

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WCC relative Differential

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WCC relative Differential
Total WCC (leucocytes) 5-14 x 103 cells/mm3
Segmented Neutrophils (PMNs) 60%
Band Neutrophils 2%
Lymphocytes 25%
Monocytes 8%
Eosinophils 3%
Basophils 2%

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overally picture of wcc formation

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Leukocytes - categories and characteristics

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Leukocytes

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Phagocytes - types

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Phagocytes
• Phagocytes include granulocytes
(neutrophils, eosinophils, basophils) and
monocyte macrophages. Neutrophils are
further divided into polymorphonuclear
leukocytes and band leukocytes.
Granulocytes

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Phagocytes- characteristics

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Phagocytes
Phagocytes possess no memory i.e. has no mechanism for increasing
response on future exposure
Phagocytes have receptors for carbohydrates that are not normally
expressed in vertebrates, they also receptors for antibodies and
complements. Therefore, they can distinguish between self and
non-self.

Phagocytes also remove the bodies dead and dying cells.
Dying cells in necrotic tissue release necrotic substances that
trigger an inflammatory response
Dying cells from programmed cell death (apoptosis) express
molecules on their cell surface that identify them as candidates
for phagocytosis

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Neutrophils

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Neutrophils
They are the most populous circulating white cells (60%). They
are produced in response to stress:
Infection, trauma,
emotional distress, or
other noxious stimuli.
(*A each pack of cigarettes per day can raise the count by
1000/μL.)
Neutrophils phagocytose “invaders” but kill themselves in the
process.

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Shift to the Left

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Shift to the Left
Total WCC 5-14 x 103 cells/mm3
Segmented Neutrophils (PMNs) 60%
Band Neutrophils 2%
Lymphocytes 25%
Monocytes 8%
Eosinophils 3%
Basophils 2%
Segs \ Lympo \ Mono \ Eosino \ Baso \ Bands

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Monocytes - what do they turn into, what are they good and bad at

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Monocytes
Monocytes are precursors to Macrophages
Monocytes circulate in the blood - activated to macrophages in the
tissue
Macrophages in the tissue present antigens to lymphocytes.
Macrophages are good at phagocytosis and poor at killing.
Some micorganisms can survive in macrophages for years.

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Eosinophils

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Eosinophils
? No one really is sure what they do.
They often seen at the site of invasive parasitic infections
i.e. counts are raised.
Individuals with chronic allergic conditions (atopic rhinitis or
extrinsic asthma) typically have elevated eosonophil counts

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Basophils

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Basophils
? No one really is sure what they do.
⇑ in chronic inflammation
⇑ in leukaemia
Same as mast cell??
In allergic conditions blood basophils decrease in number
while tissue mast cells increase
Basophils contain heparin, histamine, and leukotrienes

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Lymphocyte

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Lymphocytes
• Lymphocytes: are the other components of
WBC (25%).
Lymphocytes are brainy- These cells give specificity and
memory to the body’s defense against invaders. They
have two categories:
B-Lymphocytes
T-Lymphocytes
Phagocytes are dumb

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B-Lymphocytes

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B-Lymphocytes
• B-lymphocytes are derived from the bone
marrow i.e. B-lymphocyte.
B-lymphocytes development is regulated by T lymphocytes
B-lymphocytes are involved in humeral immunity. (humeral
immunity; antibody immunity).
B-lymphocytes develop into plasmocytes that produce
antibodies.

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over view of all wcc

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T-Lymphocytes

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T-Lymphocytes
• T-lymphocytes are derived from the bone
marrow but they mature in the thymus i.e.
T-lymphocyte.
T lymphocytes regulate B-lymphocytes development
T-lymphocytes are involved in cellular immunity and T killer
cells.
Responsible for delayed hypersensitivity, rejection of
organs and defense against viral infections

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Neutrophilia - level and cause

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Neutrophilia > 12,000 cell/mm3
– Acute bacterial infection
– Trauma
– Myocardial infarction
– Chronic bacterial infection
– Adrenaline, corticosteroids, lithium
– Leukaemia

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Neutropenia - level cause

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Neutropenia < 1,500 cell/mm3
– Radiation Exposure
– Medications: cytotoxics, captopril, ticlopidine etc
– Overwhelming acute bacterial infection
– Vitamin B12 or folate deficiency
– Salmonellosis
– Pertussis

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Eosinophilia and Eosinopenia

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Eosinophilia > 350 cell/mm3
• Causes include
– Allergic disorders (asthma)
– Parasitic infections
– Leukaemia
– Medications: ACE inhibitors, allergic reactions to drugs
Eosinopenia < 50 cell/mm3
•Causes include
•Acute infection

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Basophilia

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Basophilia > 300 cell/mm3
• Causes include
– Chronic inflammation
– Leukaemia
Monocytosis > 800 cell/mm3
• Causes include
•Recovery stage of acute bacterial infection
•TB disseminated
•Endocarditis
•Protozoal infection
•Leukaemia

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Lymphocytosis causes

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Lymphocytosis > 4,000 cell/mm3
• Causes include
– Infections
•Lymphopenia < 1,000 cell/mm3
Causes include
•HIV
•Radiation exposure
•Corticosteroids
•Lymphoma (Hodgkin’s disease)
•Aplastic anaemia

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Pllattelletts- characteristics

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Pllattelletts (160-420,,000//mm3)
• Function
– maintain integrity of blood vessels
– interact to facilitate blood coagulation
• provide specific receptor site for clotting factors
• provide necessary phospholipid surface for conversion
of prothrombin to thrombin
• protection of thrombin from enzyme antithrombin

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Pllattelletts
• Production & metabolism

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Pllattelletts
• Production & metabolism
– produced in bone marrow as megakaryocytes
– megakaryocyte maturation & proliferation controlled
by megakaryocyte colony stimulating factor (Mk-CSF)
& thrombopoietin
– 2/3 platelets in circulation, 1/3 in spleen
– life of platelet 8 - 11 days
– Spleen site of destruction

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Pllattelletts
• Decrease (Thrombocytopenia)

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Pllattelletts
• Decrease (Thrombocytopenia)
– Decreased production
– abnormal distribution
– dilution
– Causes include
• neoplastic diseases
• immune processes
• infections
• metabolic disorders
• drugs & chemicals
• Spleenomegaly
• bone marrow failure eg Aplastic anaemia

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Pllattelletts
• Increases (thrombocytosis)

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Pllattelletts
• Increases (thrombocytosis)
– part of reactive process
– myeloproliferative disorder
• Significant thrombocytosis may be associated with
increased risk of vascular events

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Drug Induced Haemattollogiicall Diisorders - disgnosis, rechallenge, groups

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Drug Induced Haemattollogiicall Diisorders..
• Uncommon event apart from cytotoxic drugs where it is
the norm.
• Diagnosis difficult as usually number of co-existing
diseases, multiple drugs
• Diagnosis often by exclusion
• Rechallenge may not be possible/ethical
• Broadly divided into 4 categories
– Abnormal sensitivity to drug or metabolite
– Genetic predisposition eg G6PD Deficiency
– Abnormal metabolism with toxic metabolite
– Immune mediated

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Aplastic Anaemia - requiremetns for classfication, what is it

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Aplastic Anaemia
• Pancytopenia ie all cell lines affected
• hypocellular marrow with no evidence of
increased peripheral destruction
• Requires at least 2 of WCC<3.5,
Platelets<55, Hb < 10 with retics<30
• For drug induced, must be no infiltrates in
bone marrow, no history of cytotoxic drugs
or radiation exposure.

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Aplastic Anaemia - onset, incidence, cause

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Aplastic Anaemia
Onset
– usually slow
– symptoms approx 6 weeks post exposure
– Sx include fatigue, weakness, stomatitis, bruising,
petechiae, purpura
Incidence
– approx 2.2 per 1,000,000
– higher with some drugs
Aetiology
– damage to haematopoietic stem cell
– earlier stem cell is affected, the more severe and
prolonged the aplasia

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Aplastic Anaemia
• Mechanisms

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Aplastic Anaemia
• Mechanisms
– Dose related eg cytotoxics (predictable effect)
– Idiosyncratic - most common
– abnormal metabolism and excretion
• eg Chloramphenicol - nitroso group from nitrobenzene ring
reacts with stem cell DNA causing chromosome damage and
cell death.
• Phenytoin, Carbamazepine metabolites bind covalently to
macromolecules causing stem cell or lymphocyte death
• Phenylbutazone - ? Abnormal clearance

Genetic Predisposition
• ? Involved in Chloramphenicol aplasia
– Immune reaction
• eg Quinine affects on suppressor T cells could inhibit stem cell
production suggested by responsiveness to antithymocyte
globulin

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Aplastic Anaemia
Drugs more commonly involved include

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Aplastic Anaemia
Drugs more commonly involved include
Acetazolamide OHA’s
Antihistamines Phenylbutazone
Carbamazepine Penicillamine
Chloramphenicol Oxpentifylline
Chloroquine Phenothiazines
Thiazides Phenytoin
Felbamate Propylthiouracil
Frusemide Quinine/Quinidine
Gold Salts Sulphonamides
Indomethacin Ticlopidine
Interferon alpha

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Aplastic Anaemia
Treatment

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Aplastic Anaemia
Treatment
• Identify and remove cause, earlier the better
• Symptomatic treatment eg antibiotics, blood products
• Antithymocyte globulin (20mg/kg/d for 8 days)
• Corticosteroids ? Efficiacy
• Immunosuppressants - ? cyclosporin
• Colony Stimulators - eg GM-CSF, G-CSF - some case
reports of success with interleukin 1
• Bone Marrow transplantation

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Agranulocytosis- onset incidence

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Agranulocytosis
Onset
– usually rapidly
– symptoms approx 7-14 days post initiation of therapy
– Sx include sore throat, fever, fatigue, weakness,chills
(resemble flu) stomatitis,
Incidence
– Varies;
– More frequent in females
– Mortality 16% overall; increased with organ failure and
sepsis.

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Agranulocytosis
Mechanisms

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Agranulocytosis
Mechanisms
– May be directly on mature granulocytes causing arrest of
maturation or
– toxic effect on myeloid colony forming units in bone
marrow (? More likely)
• 1. Immune mediated involving drug or metabolite,
antibodies and neutrophils
– Drug membrane complex acts as hapten to stimulate antibody
formation eg high dose penicillin
– Innocent bystander - drug/antibody complex absorbed onto
neutrophil membrane causing complement activation and cell
destruction eg Quinine
– Complex of drug and protein carrier causing antibody activation;
complex attaches to neutrophil surface causing cell destruction
– Drug produces change in neutrophil surface which activates
autoantibody formation

2. Accumulated drug toxicity in hypersensitive
individual
– Penicillins - high concs inhibit myeloid colony forming units
– Antithyroid agents (PTU, Carbimazole) 0.3-0.6% patients, > in
patients more than 40years
– Phenothiazines - onset 2-15 weeks, total dose > 10-20g; most
common females > 50years
– Clozapine - 10 times more common than with Chlorpromazine;
increases with age most common first 6 months; marker is steady
decline in WCC; ? Free radicle metabolite
• Type 111 reaction - combination immune & toxic
mechanisms

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Agranulocytosis
Treatment

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Agranulocytosis
Treatment
• Identify and remove offending agent
• Symptomatic treatment and support while recovery
• Severe cases may benefit from Immune Globulin
400mg/kg/d
• Colony Stimulators (G-CSF, GM-CSF) may reduce time of
neutropenia

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Agranulocytosis
Drugs involved include

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Agranulocytosis
Drugs involved include
Acetazolamide Benzodiazepines Aspirin
Allopurinol beta lactams ACEI’s
Antithyroid agents Carbamazepine Chloramphenicol
Cimetidine Clindamycin Clozapine
Dapsone Doxycycline Hydralazine
OHA’s Thiazides Frusemide
Phenylbutazone Phenothiazines Penicillamine
Quinine/Quinidine Indomethacin Sulphonamides
Ganciclovir TCA’s Methyldopa
Phenytoin Isoniazid Metronidazole
Pyrimethamine Rifampicin Vancomycin
HIV drugs etc etc

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process of agranulocytosis

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Drug iinduce Haemollytiic Anaemiia

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Drug iinduce Haemollytiic Anaemiia
• Disorder where RBC’s damaged or destroyed
• Destruction can occur
– within blood vessel (intravascular haemolysis)
• mainly Immune mediated
– outside vascular space (extravascular haemolysis)
• mainly metabolic mediated.
• Anaemia occurs when destruction exceeds bone marrow
production

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Drug iinduce Haemollytiic Anaemiia
Drugs implicated include

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Drug iinduce Haemollytiic Anaemiia
Drugs implicated include
Cephalosporins & Penicillins Phenothiazines
NSAID’s Thiazides
Hydralazine Levodopa
Melphalan Methyldopa
Methysergide Omeprazole
Probenecid Procainamide
Quinine/Quinidine Rifampicin
Sulphonamides Sulphonylureas
Tetracyclines Triamterene
etc

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Drug iinduce Haemollytiic Anaemiia
Immune Haemolytic Anaemia
Mechanisms - similar to agranulocytosis

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1. Hapten Formation
2. Innocent bystander
3. Low Affinity Hapten
4. Protein binding

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Drug iinduce Haemollytiic Anaemiia
Immune Haemolytic Anaemia
Mechanisms - similar to agranulocytosis
hapten formation
innnocent bystander

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Drug iinduce Haemollytiic Anaemiia
Immune Haemolytic Anaemia
Mechanisms - similar to agranulocytosis
1. Hapten Formation
– Drug absorbed onto RBC membrane to form hapten with antibody
formation
– RBC’s destroyed by phagocytosis or cell mediated cytotoxicity
– seen with penicillins & cephalosporins, tetracyclines, cytotoxics
(Cisplatin, Cyclophosphamide, Melphalan)
2. Innocent bystander
– Drug forms complexes with drug specific antibodies in serum;
– loosely adhere to RBC membranes;
– activate complement system which lyses RBC membrane with release of
drug/antibody complex back into serum where it may attach to other
RBC’s
– seen with Quinine, Quinidine

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Drug iinduce Haemollytiic Anaemiia
Immune Haemolytic Anaemia
Mechanisms - similar to agranulocytosis
3. Low Affinity Hapten
4. protein binding

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Drug iinduce Haemollytiic Anaemiia
Immune Haemolytic Anaemia
Mechanisms - similar to agranulocytosis
3. Low Affinity Hapten
– drug or metabolite binds to antigenic sites on RBC membrane forming
complete antigen or change to shape to unmask antigen site
– activation of complement system leads to cell destruction and release of
drug/metabolite for further damage.
4. Protein binding
– drug combines with nonspecific protein eg Albumin, IgA, Fibrinogen
– combination adheres to RBC
– While this binding is not immunologic and usually does not cause
haemolysis, the complex interferes with blood cross matching due to
nonspecific binding of antibodies to RBC membranes eg Cephalosporins

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Drug iinduce Haemollytiic Anaemiia
Test for Haemolytic Anaemia

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1. Coombes Test
2. Haptoglobin
3. Haemopexin
3.Metabolic Haemolytic Anaemia G6PD deficiency- drug or genetically induced

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Drug iinduce Haemollytiic Anaemiia
Test for Haemolytic Anaemia
1. Coombes Test

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Drug iinduce Haemollytiic Anaemiia
Test for Haemolytic Anaemia
1. Coombes Test
– Screening test to detect antibodies against RBC
– Indirect Coombes - determining presence of antibodies in serum
rather than attached to RBC
– Direct Coombes - presence of Ab bound to RBC
– eg Methyldopa - 25% patients have positive Coombes test, only
0.8% develop HA (? Methyldopa inhibits proliferation of
nonspecific T cells thus allowing unregulated production of
autoantibodies positive Coombes test. Methyldopa also may
inhibit RE systems thus preventing HA ; patients without
impairment of RE system may develop HA

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Drug iinduce Haemollytiic Anaemiia
2. Haptoglobin
3. Haemopexin

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Drug iinduce Haemollytiic Anaemiia
2. Haptoglobin
• Circulating alpha globulin
• Acts as carrier for haemoglobin to reduce toxicity of Hb
• As large complex, not filtered by glomerulus
• Delivers Hb to RE system for metabolism
• Measure of haemolysis
– No haemolysis - Normal
– Moderate haemolysis - decreased
– Severe haemolysis - markedly decreased or absent
3. Haemopexin
• Beta globulin that binds free heme molecules
• Measure of haemolysis
– No haemolysis - Normal
– Moderate haemolysis - normal or slightly decreased
– Severe haemolysis - decreased or absent

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Drug iinduce Haemollytiic Anaemiia
3.2 Metabolic Haemolytic Anaemia

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Drug iinduce Haemollytiic Anaemiia
3.2 Metabolic Haemolytic Anaemia
– Due to hereditary RBC defect with intravascular
destruction
– Oxidative haemolysis most commonly associated with
Glucose-6-phosphate dehydrogenase (G6PD)
deficiency
– G6PD deficiency most common in Mediterranean
population, less common in American blacks
– Exposes patients to high risk of haemolysis

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Drug iinduce Haemollytiic Anaemiia
3.2 Metabolic Haemolytic Anaemia
– drugs with high risk in G6PD deficiency include

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Drug iinduce Haemollytiic Anaemiia
3.2 Metabolic Haemolytic Anaemia
– drugs with high risk in G6PD deficiency include
Ascorbic Acid Aspirin
Benzocaine Chloramphenicol
Dapsone Diazoxide
Methylene Blue Nitrofurantoin
Phenopyridine Primoquine
Sulphonamides
– Careful evaluation of therapy essential in patients with
G6PD Deficiency

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Drug induce Thrombocytopeniia

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Drug induce Thrombocytopeniia
• Most common of drug induced haematological disorders.
• Associated with a large number of drugs including
Acetazolamide Aspirin Allopurinol
Benzodiazepines Cephalosporins
Cimetidine & H2 antagonists Digoxin Frusemide
Heparins Hydroxychloroquine Interferon
Isoniazid NSAID’s Morphine
Phenothiazines Penicillins Thiazides
Sulphonamides Phenytoin Procainamide
Quinine/Quinidine Rifampicin Trimethoprim
Sulphonylureas etc.etc

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Drug induce Thrombocytopeniia - when classifed
Mechanisms

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Drug induce Thrombocytopeniia
• Thrombocytopenia defined as platelet count < 100,000/mm3
• Complications unlikely until < 30,000
• Symptoms vary with severity - early signs bruising,
petechiae, epistaxis, with frank bleeding as worsens
Mechanisms
• Similar to those seen with other haematological disorders
– immune mediated
• increased peripheral destruction of platelets; increased
megakaryocytes in bone marrow
– direct toxicity
• effects in the bone marrow; decreased megakaryocyte production

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Drug induce Thrombocytopeniia
Specific examples
1. Heparin

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Drug induce Thrombocytopeniia
Specific examples
1. Heparin
– Occurs in up to 25% patients; any dose or route
– 2 distinct types
• Mild form occurs early, with platelet count < 100,000; no
symptoms; resolves rapidly on cessation (? Due sequestration
of platelets)
• Severe form; likely immune mediated with antibody formation
to platelet/heparin complex leading to Platelet destruction
– usually occurs late (6-12 days) with
– platelets fall to < 30,000,
– associated with bleeding, & worsening of thrombosis. Platelet
antibodies attach to endothelial cells on the walls of blood
vessels leading to thrombosis
– Rate reported at 1-1.3% with porcine Heparin.
– Less common with LMWH’s but still possible; Danaparoid
probably not implicated.

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Drug induce Thrombocytopeniia
Specific examples
2. Gold Salts
3. Quinine/Quinidine

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Drug induce Thrombocytopeniia
Specific examples
2. Gold Salts
– antibody formation to platelets
– Incidence 1-3%
– Often abrupt and severe, but may be delayed and even occur months
after cessation of Gold
3. Quinine/Quinidine
– Various mechanisms including Innocent bystander, hapten reaction,
antibodies against platelet membrane glycoproteins
– May occur 7-10days after first exposure, but subsequent treatment
more likely to precipitate full blown event
– Minute doses may precipitate thrombocytopenia (eg bitters)
– Rapid fall in platelets with early bleeding
– Signs include petechiae, purpura, oral haemorrhagic bullae, overt
bleeding

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Drug induce Thrombocytopeniia
Specific examples
4. Thiazides
5. alcohol

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Drug induce Thrombocytopeniia
Specific examples
4. Thiazides
– direct bone marrow suppression usually, although
antibodies have been identified.
5. Alcohol
– acts as general bone marrow suppressant
– chronic alcohol intake decreases production, decreases
platelet survival, and platelet dysfunction
– Rates - hospitalised alcoholics 26%, well patients 3%