BY THEVA

POLYCYTHEMIA IN THE NEWBORN

Polycythemia /erythrocythemia an abnormal of the circulating red blood cell mass

Neonatal polycythemia normal fetal adaptation to hypoxemia rather than hematopoietic defecct

Abnormal the risk of hyperviscosity, microcirculation hypoperfusion and multisystem organ dysfunction

INTRODUCTION

DefinitionPathophysiologyClinical presentationManagement

Venous hematocrit >65% or Hb>22g / dL

incidence - postterm neonates - SGA

- IDM - TTT - Indentical

twins

DEFINITION

Cause

Active( fetal

erythropoiesis)

Placental insufficieny

Endocrine Abnormaliti

es

Genetic disorders

Passive(erytrocyte transfusion)

Placental-fetal

transfusion with

delayed cord

clamping

Twin-to-twin

transfusion syndrome

PATHOPHYSIOLOGY..

Viscoscity thickness of a fluid / measure of the fluid’s internal resistence to flow

Viscosity linearly with Hct until it reaches 60% but exponentially when Hct ≥ 70%

POLYCYTHEMIA AND HYPERVISCOSITY

Polycythemia & hyperviscosity blood flow to the brain( cerebral blood flow) heart, lung, intestines carcass, renal plasma flow and glomerular filtration rate

Changes in blood flow alters the delivery of substrates.

CLINICAL FINDINGS “Hyperviscosity syndrome” symptom complex associated with polycythemia Most patients asymptomatic Clinical features 1 to 2 hours after birth as the Hct peaks with normal postnatal fluid shifts. Borderline Hct symptoms may be delayed untill the 2nd or 3rd postnatal day when excessive depletion of the extracellular fluid leads to hemoconcetration & hyperviscosity Infants who hv no symptoms by 48 – 72 hrs are

likely to remain asymptomatic

•Ruddy complexion•Irritability•Jitteriness•Tremors•Feeding difficulties•Lethargy•Apnea•Cynosis•Respiratory distress•seizures

NON SPESIFICSYMPTOM

S

•60% of affected patients

•Due to reduced cerebral blood flow , altered tissue metabolisme and metabolic derangement (hypocalcemia and hypoglycemia )

•Hypocalcemia 1- 11 % related to CGRP concentrations which is accentuated in infants

Neurologic manifestatio

ns

•Pathogenic factors in term or near term neonates

•Indentified in half of all term neonates

•Recent data attempts to reduce Hct with partial ET contributes to NEC

• GFR•Oliguria•Hematuria•Proteinuria•Renal vein

thrombosis

•Seen in 1/3 of cases

•Due to platlet consumption in the microvasculature

•Also a due to “ progenitor steal” diversion of hematopoietic progenitors toward erythropoiesis at the expense of other lineage

NEC

RENAL MANIFESTATIO

N

THROMBOCYTOPENIA

Detection of venous Hct ≥ 65% Hct remains widely used markers

of hyperviscosity due to limited availability of tools for direct measurement of blood viscosity

DIAGNOSIS

Detection of Hct (≤55%) in cord blood helps to predict risk of polycythemia at 2 hrs of postnatal age.

Detection of Hct in the first few hrs of life trigger follow up measurement in a few hours to identify any futher rise with normal post natal shifts

Capillary blood Hct 5- 15% higher than venous sample

Technique of sample analyses should be taken into account in serial evaluation of Hct

TECHNIQUE OF SAMPLE COLLECTION AND ANALYSIS

Neonates with polycythemia should be evaluated for underlying causes and systemic complications of polycythemia

Controversial because lack of evidence aggressive treatment improves long term outcomes

Asymptomatic infant with Hct 60-70% monitored closely & aggressively hydrated

Hct should be reassesed in 12-24 hrs & plasma glucose, bilirubin & cardiorespiratory status should be monitored

If Hct or stable & patient is asymptomaticmonitoring should be continued for further 24-48hrs

TREATMENT

In asymptomatic infant with Hct ≥70% the treatment is controversial

Studies show lack of diffrence in outcomes with continued hydration and expctant management vs aggressive managemant with PET

The decision to perform PET case by case basis with a careful analysis of risks and potential benefits

None of the studies documented a beneficial effect of PET on neurodevelopmental outcome

Dempsey and Barrington reviewed 5 of this studies documented no improvement in long term neurologic outcome( mental developmental index, incidence of neurodevelopmental delay and incidence of neurologic diagnosis) and no evidence of of improvement in early neurobehavioural assesment scores

Ozek and coworkers reviewed 6 randomized to determine the effect of PET on primary outcomes at 2 years and school age.

Only 1 study reported data on mortality and no significant increase noted with PET

4 studies reported neurodevelopmental outcome at 18 mo or older and no signficant delay reported in PET group

However this results were based on data limited by poor follow up and did not account for patients who were lost in follow up

The authors performed a worst case/ best case scenario post hoc analysis significant skewing toward or away from association of PET with poor neurodevelopmental outcomes & concluded that no significant benefit of PET in asymptomatic patient/with mild symptoms

Patients who hv polycythemia and manifest S/S of hyperviscosity treated with PET even though not supported by high quality evidence

The arguments are in favour of PET because pathophysiology hyperviscosity syndrome related to altered microcirulatory perfusion and tissue hypoxia

By replacing RBC mass with crystalloid solution in PET helps to reduce blood viscosity and improve end organ perfusion

No randomized clinical studies demonstrates clear benefit of PET in treating symptomatic polycythemia

In non randomized clincal reports PET has been shown to lower pulmonary vascular resistance, improved cerebral blood flow velocity, and possibly normalize cerebral hemodynamics and improve the clinical status of infants who have polycythemia

However long term benefits of PET remains unclear

PET risk in NEC in the systemic reviews performed by both Dempsey and Ozek and typical risk diffrence

Malan and de V Heese reported 1 of their 24 patients develop NEC within 24 hours after PET with none compared to control patients

Black and associates NEC in 8 out their 43 infants in PET group compared to none in control group

PET did not alter the frequency of hypoglycemia and thromocytopenia

ADVERSE EFFFECTS

General reluctant to use PET in asymptomatic infant in view of risks of PET and lack of evidence indicating the clear benefit

PET is offered to treat infants with hyperviscosity symptoms but this decision has to be taken cautionly with careful review of all the risk factors

Routine use of PET not supported by current evidence and further study needed to identify patients who will benefit from aggressive correction of polycythemia

THANK YOU FOR YOUR KIND ATTENTION…