Hydrops Flashcards
Definition
Hydrops fetalis is a condition in the fetus characterized by an abnormal collection of fluid with at least two of the following:
• Skin oedema (fluid beneath the skin, more than 5 mm). • Ascites • Pleural effusion • Pericardial effusion
In addition, hydrops fetalis is frequently associated with polyhydramnios and a thickened placenta (>6 cm).
How is hydrops identified?
Hydrops fetalis is typically diagnosed during ultrasound evaluation for other complaints such as : • Polyhydramnios • Size greater than dates • Fetal tachycardia • Decreased fetal movement • Abnormal serum screening • Antenatal hemorrhage - Also when monitoring MC twins for TTTS
Cause?
Immune (10-20%) or non-immune (80-90%)
Immune causes?
• Maternal antibodies against red-cells of the fetus cross the placenta and coat fetal red cells which cause hemolysis.
• The severe anemia leads to
o High-output congestive heart failure.
o Increased red blood cell production by the spleen and liver leads to portal hypertension
• Anti-D, anti-E, and antibodies directed against other Rh antigens comprise the majority of antibodies responsible for hemolytic disease of the newborn.
Less commonly encountered, antibodies:
- anti-K (Kell), anti-Fya (Duffy) , and anti-Jka (Kidd) may also cause hemolytic disease of the newborn.
Non-immune causes (general principle)
• In general nonimmune hydrops (NIH) is caused by a failure of the interstitial fluid (the liquid between the cells of the body) to return into the venous system .
This may due to: • Cardiac failure (High output failure from anemia, sacrococcygeal teratoma, fetal adrenal neuroblastoma, etc.) • Impaired venous return (Metabolic disorders) • Obstruction to normal lymphatic flow (Thoracic malformations) • Increased capillary permeability • Decreased colloidal osmotic pressure (Congential nephrosis)
Some conditions may involve more than one mechanism . For example, parvovirus may cause cardiomyopathy and anemia from marrow suppression.
Non immune hydrops- conditions causing it
o Cardiac
Cardiomyopathy, Ebstein’s anomaly, pulmonary atresia, coarctation of the aorta, hypoplastic left heart, complete AV canal, left sided obstructive lesions, premature closure of the foramen ovale
Intracardiac tumors (tuberous sclerosis)
Cardiac arrhythmia
SVT, flutter, heart block, WPW syndrome
o Chromosomal /Genetic Syndromes
T13, T18, T21, XO (Turners syndrome) , Noonan syndrome , multiple pterygium syndrome, Pena-Shokeir, arthrogryposis
o Fetal Anemia
Alpha (α) thalassemia, parvovirus, fetal hemorrhage, G-6-PD deficiency
o Infection
Parvovirus, CMV, syphilis, coxsackie virus, rubella, toxoplasmosis, herpes,varicella, adenovirus, enterovirus, influenza, listeria
o Thoracic Abnormalities
Congenital cystic adenomatoid malformation (CCAM) , chylothorax, diaphragmatic hernia, mediastinal tumor, skeletal dysplasias
o Twinnning
Twin to twin transfusion Severe anemia in the donor twin or high-output failure in the recipient
o Tumors
Fetal sacrococcygeal teratoma, hemangiomas (Hepatic, Klippel-Trenaunay syndrome), fetal adrenal neuroblastoma, placental tumors (chorioangioma)
o Miscellaneous
Cystic hygromas, inheritable disorders of metabolism (lysosomal storage diseases) ,maternal thyroid disease, congenital nephrotic syndrome.
Hydrops detected- what investigations do you perform?
• Obtain maternal history (including pedigree)
• Evaluate for immune hydrops
o Obtain maternal indirect Coombs test to screen for antibodies associated with blood group incompatibility.
• Evaluate for nonimmune hydrops
o MCA-PSV to assess for fetal anemia. If there is evidence for anemia or equivocal result obtain:
FBC and Hb electrophoresis (with hemoglobin DNA analysis), Kleihauer, G6PD screen.
TORCH screen, RPR, listeria, parvovirus B19, coxsackie, adenovirus, and varicella IgG and IgM, as indicated.
o Fetal echo
o Amniocentesis for fetal karyotype and PCR for infections
o In the presence of a family history of an inheritable metabolic disorder or recurrent nonimmune hydrops test for :
Storage disorders such as Gaucher’s, gangliosidosis, sialidosis, beta-glucuronidase deficiency, and mucopolysaccharidosis
Enzyme analysis and carrier testing in parents and/or analysis of fetal or neonatal blood or urine.
Histological examination of fetal tissues.
Maternal thyroid antibodies
What is Mirror syndrome?
The mother develops oedema , hypertension, and proteinuria
Prognosis
NIHF is associated with an overall perinatal mortality rate of 50 to 98 percent.
Prognosis depends upon the aetiology, the gestational age at onset, and whether pleural effusions are present.
• If the cause of NIH cannot be determined, the perinatal mortality is approximately 50%
• Prognosis is much poorer if diagnosed at less than 24 weeks , pleural effusion is present, or structural abnormalities are present .
o Fetal hydrops associated with a structural heart defect is associated with an almost 100% mortality rate.
RANZCOG Q:
Multiparous woman unexpectantly found to have fetal hydrops. Her blood group is O pos.
a) Outline the possible causes of fetal hydrops (8 points)
Immune versus non immune
Immune:
- Antibody present in maternal blood which attacks fetal red cells and causes haemolysis
- Antibodies causing hydrops: Anti-c, C, D, E, G, Anti-kell, Duffy,
Non-Immune:
Genetic:
• Aneuploidy (monosomy X, T21, T18, T13, triploidy, tetraploidy)
• Metabolic storage diseases (Gaucher’s disease, Hurler syndrome)
Cardiovascular:
• Structural (AVSD, hypoplastic left heart, isolated VSD/ASD)
• Arrhythmias (tachyarrhythmias, bradyarrhythmias)
• Arteriovenous and venous malformations (placental chorioangiomas)
Thoracic:
• CPAM
• Diaphragmatic hernia
Gastrointestinal:
• Volvulus or malrotation
• Cholestasis, biliary atresia, hepatitis
Urinary:
• Posterior urethral valve
Haematology:
• Haemoglobinopathy (a-thalassaemia)
• Haemorrhage (FMH, in-utero fetal haemorrhage)
Infections:
• Parvovirus B19
• TORCH
• Syphilis
Twins:
• TTTS, TRAP
Idiopathic
RANZCOG Q:
b) What are the pathophysiological mechanisms of the increased interstitial fluid? (2 points)
The pathogenesis of NIHF remains unclear, and likely depends, in part, on the underlying disorder.
NIHF is the end result of one or more abnormalities:
• obstructed lymphatic drainage in the thoracic and abdominal cavities (congenital anomaly, neoplasm)
• increased capillary permeability (infection)
• increased venous pressure due to myocardial failure or obstructed venous return to the heart
• reduction in osmotic pressure (liver disease, nephropathy)
• anaemia causing high output cardiac failure and increased capillary permeability
RANZCOG Q:
Multiparous woman unexpectantly found to have fetal hydrops. Her blood group is O pos.
c) How would you manage this situation? (5 points)
History:
• Fetal movements
• Maternal symptoms; weight gain, peripheral oedema, dyspnoea (mirror syndrome)
• Recent exposure to infectious agents (parvovirus)
• Current pregnancy (Rh status, serology, aneuploidy screening, imaging)
• Previous pregnancies (adverse outcomes)
• Personal and family history (cardiac anomalies, alpha thalassaemia, genetic syndromes, metabolic disorders)
• Ethnic background
Examination:
• Basic obsverations and FHR
• Abdominal palpation (polyhydramnios)
Maternal investigations:
• FBC +/- haemoglobin electrophoresis (DNA genotyping) if MCV is low
• Blood group and antibody
• Indirect coombs
• Serologies (TORCH screen, parvovirus, non-treponemal test for syphilis)
• Kleihauer to exclude FMH
• G6PD deficiency screen
Fetal investigations:
• CTG
Referral to tertiary centre for multidisciplinary team approach (MFMU, genetic counsellors, neonatology)
Tertiary USS: • Assess AFI and hydrops • Exclude major structural anomalies • MCA Doppler assessment o Anaemia = infective, FMH, haematological o Non-anaemic = cardiac, genetic, others
Consider fetal echo if concerns regrading cardiac abnormality or arrhythmia
Invasive fetal testing:
• Karyotype (CVS, amniocentesis, cordocentesis)
• PCR for TORCH pathogens, especially CMV, parvovirus and toxoplasmosis
• Obtain fetal haemoglobin if cordocentesis performed
Management options include:
• termination of the pregnancy
• therapeutic intervention when possible (medical Rx for fetal arrhythmia)
• supportive care/monitoring of the mother and fetus in continuing pregnancies
Antenatal surveillance:
• Antenatal consultations with relevant subspecialty services (neonatology) should be obtained.
• Frequent USS surveillance with BPP testing at least weekly
• Serial Doppler velocimetry of the MCA is not useful in the absence of suspected fetal anemia.
• Delivery if there is evidence of fetal or maternal decompensation (mirror syndrome)
• Give corticosteroids if required
• Delivery should occur at a tertiary care center, with coordination of the MFMU and neonatology
RANZCOG Q:
Multiparous woman unexpectantly found to have fetal hydrops. Her blood group is O pos.
d) What is mirror syndrome?
Mirror syndrome (also called Ballantynes syndrome):
• Condition of generalized maternal edema, often with pulmonary involvement
• ‘mirrors’ the edema of the hydropic fetus and placenta
• Usually associated with NIHF
• Pathogenesis unknown
• One hypothesis is that the hydropic placenta causes a systemic inflammatory response as a result of increased shedding of trophoblastic debris into maternal blood
• Mirror syndrome can occur at any time during the antepartum period and may persist postpartum.
• It may present with rapid weight gain, increasing peripheral edema, and progressive shortness of breath, or with a clinical presentation and course similar to that of severe PET
• Delivery is usually required to induce remission of maternal symptoms, which can be life-threatening
In contrast to PET:
• Maternal hematocrit is often low (haemodilution) rather than high (haemoconcentration)
• Amniotic fluid volume is often high (polyhydramnios) rather than low (oligohydramnios)
• Fetus always shows signs of hydrops.
Potential causes of isoimmunisation
- ECV
- Amnio/CVS/cordocentesis
- Abruption
- Trauma
- Choriocarcinoma
- Multiple pregnancy
- Delivery/ectopic/TOP/miscarriage
Delivery options for baby with hydrops
- LSCS should be reserved for routine obstetrical indications
- High frequency of non-reassuring CTG & dystocia increases the likelihood of LSCS
- Aspiration of pleural fluid or ascites prior to delivery may ↓ risk of dystocia & facilitate neonatal resuscitation
At delivery, there is an increased risk of:
• birth trauma due to soft tissue dystocia
• postpartum hemorrhage
• retained placenta
Neonatal management:
• Immediate intubation almost certainly needed
• High flow ventilation and high airway pressures
• Consider thoracentesis and paracentesis
• UAC, UVC
• Blood product, albumin, diuretics
• ECHO and CXR
Post partum: • Debrief • Autopsy always indicated • Recurrence depends on aetiology • Pap smear
