blood, pure and eloquent a gp’s guide to haematology douglas wardrop
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Blood, Pure and Eloquent
A GP’s guide to Haematology
Douglas Wardrop
Background
• Oxford Experience – in the lab, getting GP calls
• Email service – 24h reply – What is the GP’s hunch?
• Three cell lines – logical; too many? Too few?
• Don’t treat cell lines in isolation
• Blood film – part of the examination but requestor needs to supply clinical details
Subspecialties
• General
• Red cell
• Leukaemia
• Lymphoma
• Stem Cell Transplant
• Haemophilia and Thrombosis
• Transfusion
Blood films
Normal FilmX
Y
Z
Acute Leukaemia
The Most Common Questions
1. Neutropenia – 13%
2. Anaemia - 10%
3. Thrombocytosis (9%)
4. Serum Electrophoresis (9%)
5. Anticoagulation/clotting test interpretation (8%)
6. Thrombophilia (7%)
NEUTROPENIA
• 48 yo lady TATT
• PMHx – Epilepsy (well controlled on Epilim)
• Hb – 142 g/L
• WBC – 3.2 x 109/L
• Plts 274 x 109/L
• Neutrophils – 1.2 x 109/L
neutropenia
• 1 (one) is the magic number
• Rarely a problem in isolation (i.e. look at the other cell lines)
• Blood film?
• Leading causes – post viral, drugs (esp. anti-epileptics, anti-psychotics), black race.
• Younger cf. older patients
• If persists, think of B12/folate def., HIV, Hep infections, autoimmune (e.g. SLE)
Reasons for heightened concern
• Severe Neutropenia (<0.5 x 109/L) or rapidly dropping
• Other cell lines affected, especially if a downward trend.
• Abnormal blood film - ?check monocyte count
• Sick/feverish patient – treat first and ask questions later
ANaemia
• 45 yo lady TATT
• Hb – 81g/L
• WBC – 5.2 x 109L (normal differential)
• Plts 322 x 109/L
• MCV 71fl
Microcytic Anaemia
YX
Think about….
• Each cell lines in turn
• Check film – any clues?
• Stepwise approach:• Ferritin• Transferrin sats• HPLC
• Always search for a cause – very rarely dietary
• Iron – poorly tolerated – try at least x2 (before IV)
• Take with orange juice (empty stomach), avoid coffee, tea, milk
Consider haemoglobinopathies
• If Iron replete and still microcytic?
• Thalassaemia?
• β-trait -HPLC
• α-thalassaemia – genetic tests expensive. Presumptive diagnosis if HPLC and ferritin normal
HPLC
Normal (Hb A) Hb βThal. Trait
Thrombocytosis
• 48 y.o. man noted to be hypertensive (confirmed with ABPM)
• Bloods:
• Hb – 140g/L (N MCV)
• WBC 8.2 x 109/L (N diff)
• Plts – 620 x 109/L
Thrombocytosis
• 1. Reactive (Much more likely)• Infection• Cancer• Bleed• Fe2+ deficiency• Trauma
• 2. Consider clonal causes• Check other cell lines (?PRV, ET)• Check after 6-8 weeks• Blood film/ferritin/ESR• JAK2 V617F/MPL mutations
Thrombocytosis
Serum Electrophoresis
• 70 y.o. lady (N - F+W) presents with acute left visual loss
• Hb – 115g/L (N MCV)
• WBC 7.2 x 109/L (N diff)
• Plts –322x 109/L
• SEP – IgG PP 5.1g/L (no immunoparesis)
• Seen by ophthalmologist – CRVO
Questions to ask
• 1. All all Igs present and correct in correct numbers
• 2. Is there a paraprotein? Which type?
• 3. Is there immunoparesis?
• Look for end-organ failure
MGUS
• Very common (and increasingly detected)
• Vast majority will never need treatment
• Be aware of infections
MGUS
• MGUS vs Smouldering Myeloma vs Multiple Myeloma
• 4 x diagnostic criteria (all must be met)
• PP <30g/L
• BM plasma cells <10%
• No evidence of other B cell lymphoproliferatve disorder
• No end-organ damage
Thrombophilia
• 28 y.o. asymptomatic man - Factor V Leiden heterozygosity detected
• Father had unprovoked DVT aged 50 and found to be a carrier
• What do you do differently?
• Avoid the thrombophilia screen!
Hereditary Thrombophilias
• Affect venous system• Factor V Leiden• P20210A mutation• Protein C deficiency• Protein S deficiency• Antithromin III deficiency
• Acquired thrombophilia • Anti-phospholipid syndrome (both arterial and
venous)
Use of Thrombophilia Screens
• Less frequently requested
• Occasional use in obstetrics/very strong FHx
• Presence of positive result does increase lifetime risk of PE/DVT but not enough to treat
• If strong FHx, a negative screen does not rule out increased clotting risk
• Personal/family history much more important
Clotting Assays
• 25 yo lady – easy bruising
• Hb – 142 g/L
• WBC – 5.2 x 109/L
• Plts 274 x 109/L
• PT – 12.2s (11-16s)
• APTT – 45s (26-36s)
Bleeding risk
• Bleeding is most important risk (cf. clotting)
• History and pattern of bleeding? FHx? Drugs?
• Haemostatic challenges• Tooth extraction• Trauma• Surgery• Menses
• Much more valuable to the physician that clotting screen
History of bleeding disorder?
• Prothrombin time (PT)
• Activated partial thromboplastin time (aPTT)
• Platelet count
• Fibrinogen
Only meaningful when combined with a clotting history.
Pronlonged aPTT
• In this case, is this significant?
• Raised aPTT• Benign causes – e.g. Factor XII deficiency• Lupus anticoagulant• Bleeding diatheses (congenital or acquired)
• Correlate with history and consider repeating
• Haematology will do a 50:50 mix and go from there.
Thank you for listening
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