Neonatal Alloimmune Thrombocytopenia
(NAIT)

 

Reviewed and approved by Clinical Practice Committee
August 2015
Clinical Guidelines Back Newborn Services Home Page
Background Presentation Differential Diagnosis Investigation
Management References Index of Related Documents

  • Low platelet count in an otherwise healthy term newborn is due to NAIT until proven otherwise.
  • Urgent matched platelet transfusion should be discussed with specialist on call at all times.

Background

Presentation

The commonest mode of presentation is the well neonate with bruises or petechiae, but the spectrum of disease ranges from sub-clinical moderate thrombocytopenia to catastrophic intracranial haemorrhage and death. A high index of suspicion is essential in all cases of active bleeding, but also in asymptomatic laboratory diagnosed thrombocytopenia. A history of thrombocytopenia in a previous sibling makes the diagnosis almost certain.
 

Modes of presentation
  • Bruising/bleeding neonate
  • Excessive haematoma at injection site
  • Previously affected sibling
  • Recurrent fetal loss and stillbirth
  • Antenatal ICH/hydrocephalus
  • Disseminated intravascular coagulopathy
  • Postnatal ICH (e.g.: silent, full fontanel, seizures)

Differential Diagnosis

Also see Neonatal Thrombocytopenia protocol

Timing Most Common Aetiology
Fetal
  • Allo-immune (e.g. NAIT)
  • Congenital infection
  • Aneuploidy
  • Autoimmune (e.g. ITP, SLE)
  • Inherited (e.g. Wiskott-Aldrich syndrome)
Early-Onset
 
  • Placental insufficiency
  • Perinatal asphyxia
  • Early onset sepsis
  • Congenital infection
  • DIC
  • Allo-immune
  • Autoimmune
  • Kasabach-Merritt syndrome
  • Metabolic disease
  • Inherited
Late-Onset
  • Sepsis
  • NEC
  • Infection
  • Autoimmune
  • Kasabach-Merritt syndrome
  • Metabolic disease
  • Inherited
  • Thrombus

Investigation

FURTHER TESTING SHOULD NOT DELAY PLATELET TRANSFUSION IF REQUIRED URGENTLY(2)

Infant
  • FBC to confirm platelet count
  • If no paternal blood available or paternity is uncertain, send 1 x infant EDTA (purple, 1 mL) tube for genotyping.
Mother
  • FBC: normal platelet count during pregnancy
  • 4 x CPDA (yellow) tubes for genotyping and 1x plain (red) tubes for anti-platelet antibodies.
Father
  • 4 x CPDA (yellow) tubes for genotyping.

Management(2)

Platelet Count (x109) Action
<30 Transfuse
30-49 Transfuse if any bleeding or high risk
50-99 Transfuse if major bleeding
>99 Do not transfuse


Transfusion (3,4,5)

IvIg (1,2)

Other considerations


References

1 Bakchoul T, Bassler D, Heckmann M, Thiele T, Kiefel V, Gross I, et al. Management of infants born with severe neonatal alloimmune thrombocytopenia: the role of platelet transfusions and intravenous immunoglobulin. Transfusion. 2014;54:6405.
2 Kaplan C. Foetal and neonatal alloimmune thrombocytopaenia. Orphanet J Rare Dis. 2006 Jan;1:39.
3 Roberts I, Murray N a. Neonatal thrombocytopenia. Semin Fetal Neonatal Med. 2008;13:25664.
4 Edinur H a, Dunn PPJ, Lea R a, Chambers GK. Human platelet antigens frequencies in Maori and Polynesian populations. Transfus Med. 2013;23:330-7
5 Transfusion Medicine Handbook. 2008;New Zealand Blood Service, www.nzblood.co.nz