Transcript ITP in Pregnancy

Thrombocytopaenia in
Pregnancy
Dr Guan Yong Khee
Hospital Melaka
Platelets
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Diameter of 1 – 4 μm
Cell volume of 2 to 20 fL
Young platelets being larger than the older ones
No cell nucleus but has residual mRNA from the
megakaryocytes
Normal
Platelet
Giant
Platelet
 Approximately 70 to 80 % of platelets circulate in the
blood
 20 to 30 % are stored in the spleen
 Decomposition of platelets takes place in the spleen
and partly in the liver
 Average life span is 5 to 12 days : mean 7 days
Normal Platelet Count
 What is the normal platelet count?
 ? 150-450 x 109/L ?150-300 x 109/L
 Are there racial differences?
 Western Vs Asian?
 Malays Vs Chinese?
Possible inaccuracies in platelet
count
 Methods of platelet counting
 Separation by cell volume – the impedance
measurement principle  problematic if platelet sizes
are large or there are RBC fragmentations
 RNA staining and flow cytometry(Optical method)
Might only be available in some higher end analysers
 Separation by detection of the membrane receptors
CD61 and CD41 complicated and very expensive
What is thrombocytopaenia?
 Conventionally <150 x 109/L
 Might be more reasonable to consider it < 100x 109/L
 Should be confirmed with a peripheral blood film
Thrombocytopaenia
 What is the minimum platelet number required for
normal haemostasis?
 Some studies say 5/mcl
 Threshold for transfusion
 If febrile, transfuse if platelets < 20/mcl
 If afebrile, transfuse if platelets < 10/mcl
 If bleeding, transfuse if < 50 or < 100(if CNS bleed)
Thrombocytopaenia
 Bleeding might not be due to low platelet itself only
 Usually must rule out other causes of bleeding
 Concomitant peptic ulcer disease? Bladder pathology?
Cervix or endometrial pathology?
Thrombocytopaenia
 Problems with platelet transfusions
 1 random unit usually rises the platelet count by about
10/mcl
 1 apheresis unit usually rises the platelet count by 4060/mcl
 Platelet lifespan is short (7-10 days)
 Transfused platelet’s lifespan is even shorter (1-2 days)
 Transfusion might lead to platelet refractoriness
Thrombocytopaenia
 Is there a threshold of platelet count to do a BMA?
 No
 However, I might want to transfuse platelets if it is < 20
to avoid a big haematoma if adequate pressure is not
applied long enough post BMA at the BMA site
Thrombocytopaenia
Other considerations
 Low platelet is usually the earliest sign of DIC
 Platelets numbers might be underestimated in TTP/
MAHA picture/ increase RBC fragmentation in certains
Acute Leukaemias
 Possible to be ITP? Unlikely if there is pancytopaenia
Diagnosis
 FBP
 BMA and Trephine biopsy and other investigations
 Immunophenotyping
 Cytogenetics/ FISH
 Molecular/ PCR
Diagnosis
 Extremely important to guide further treatment
 Transfusing without investigating is like filling up a
bucket which is leaking
Diagnosis
 Possible diagnosis not to be missed
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Aplastic Anaemia – Transplant emergency
Acute Leukaemias - ?APML, ?ALL, ?AML M7
Myelodysplastic Syndrome
B12/Folic Deficiencies
Hypothyroidism
What about the platelet count in
Pregnancy?
 Normal physiology – platelet counts are lower in
pregnancy!!
 Cause for this drop in pregnancy is unknown –
proposed theories include
 dilution
 decreased platelet production
 increased platelet turnover during pregnancy
Thrombocytopaenia in Pregnancy
 How common?
 6-10% of pregnant ladies
 Pregnancy – specific causes of thrombocytopaenia
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Gestational Thrombocytopaenia
Preeclampsia/ Eclampsia
HELLP Syndrome
Acute Fatty Liver
Thrombocytopaenia in Pregnancy
 Other Non- Pregnancy specific causes
Gestational Thrombocytopaenia
 MOST COMMON CAUSE OF LOW PLATELETS IN
PREGNANCY
 70% of cases of low platelets
 late 2nd or 3rd trimester
 Usually mild
 Unusual for platelets to be < 70 x109/L
Gestational Thrombocytopaenia
 Diagnosis of exclusion
 Might not be possible to differentiate with ITP
 Might make epidural anaesthesia troublesome –
might need platelet transfusion
 Does not respond to ITP treatment(ie steroids/ IVIG)
 Resolved post delivery 1-2 months
ITP in Pregnancy
 Rare – about 5% to 10% of causes of low platelets in
pregnancy
 compared to Gestational Thrombocytopaenia(70+%) and
hypertensive disorders in pregnancies(20+%)
 1 in 1,000 to 1 in 10,000 pregnancies
ITP in Pregnancy
 Goal of treatment – Prevent Bleeding
 Treatment is generally not required if Platelets are >
20-30x109/L
 Might need to keep it higher if planned LCSC or for
epidural anaesthesia
www.moh.gov.my/attachments/3911
ITP in Pregnancy
 Diagnosis –
 Diagnosis of exclusion
 BMA usually unnecessary unless suspecting
MDS/Leukaemia/ Lymphoma
ITP in Pregnancy
 Management before term (36weeks)
 Asymptomatic with Plt > 20 x 109/L
 No treatment
 To expect platelets to drop after 36 weeks
 Symptomatic or Plt < 20 x 109/L
 Corticosteroids
 IVIG
ITP in Pregnancy
 Management after 36 weeks
 Plt > 30 x 109/L (Malaysian CPG) – safe for vaginal
delivery
 Mode of delivery is always based on Obstetrics
indications (Malaysian CPG) and not platelet counts!!!
ITP in Pregnancy
 Management after 36 weeks
 If Caesarian section is required for obstetric indications
a) iv corticosteroids if platelet count 30-50 x 109/L
b) IVIG and iv corticosteroids if platelet count <30 x 109/L
c) IVIG and iv corticosteroids plus platelet transfusion if
platelet count <10 x 109/L
ITP in Pregnancy
 Management during labour
 Platelet count above 50 x 109/L is safe for caesarian
section under general anaesthesia
 Epidural anaesthesia is best avoided
 If platelet counts < 50 x 109/L and emergency LSCS is
required:
 Give – IVIG, IV Methylprednisolone immediately
 Give platelet transfusion just prior to surgery
ITP in Pregnancy
 ‘Safe’ Platelet Thresholds for delivery
• vaginal delivery: > 30 x 109/L
• caesarean section: > 50 x 109/L
• epidural anaesthesia: > 80 x 109/L
ITP in Pregnancy – What I would
do…or what I have learned from my
sifus
 Determining if there are any unusual bleeding
tendencies ( - deciding if the patient is a so called
bleeder or non-bleeder) – careful history taking
 If non- bleeder and no obstetric risks factors, I tend to
monitor rather than give treatment
ITP in Pregnancy – What I would
do…or what I have learned from my
sifus
 Determining if the patient is a responder to treatment
or not (?full recovery, partial recovery of platelet
counts)
 Careful history and notes review
 steroid responsiveness
 IVIG responsiveness – bear in mind repeated IVIG might
cause refractoriness to IVIG
ITP in Pregnancy – What I would
do…or what I have learned from my
sifus
 If unsure of treat, I would give a trial of treatment
especially for moderate to severe
thrombocytopaenia, this is only if there is time to play
with…
 Early in pregnancy – trial of steroids
 Still time but Limited – trial of IVIG
ITP in Pregnancy – What I would
do…or what I have learned from my
sifus
 If treatment responsive and indeed platelet drops
nearing term
 I would start steroids and anticipate an increase from
about 1-2 weeks
 I would start IVIG and anticipate an increase in from 3-5
days but likely only lasts about 1-2 weeks
ITP in Pregnancy
 Neonatal care
 Neonatal thrombocytopaenia in pregnant ladies with ITP
is unpredictable
 NOT correlated to platelet count, maternal antibodies,
or other factors
 Only Consistently known risks factor is history of a
sibling with neonatal thrombocytopaenia
ITP in Pregnancy
 Neonatal care
 Paediatrician/ Neonatologist should be alerted
 Platelet count nadir might be 2-5 days post natal
ITP in Pregnancy
 A note about other forms of treatment
 No evidence about safety, efficacy and thus not
recommended
References
 Platelet Analysis Overview, Sysmex Xtra Online, Volume
No 2, December 2007
 ASH Education Book 2010 - Immune Thrombocytopenia
by Adam Cuker and Douglas B. Cines
 ASH Education Book 2010 - Thrombocytopenia in
Pregnancy by Keith R. McCrae
 CLINICAL PRACTICE GUIDELINES – MANAGEMENT OF
IMMUNE THROMBOCYTOPENIC PURPURA, August 2006,
MOH/P/PAK/115.06 (GU)
Thank you