Case 3 - Neonatal Hypotonia & Cyanosis

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SCVMC NICU
Teaching Module
Newborn with Hypotonia and Cyanosis in the Delivery Room
A 3500g term AGA hispanic female infant is born by fairly quick spontaneous vaginal vertex
delivery to a 20 year old primigravidum with “good/complete prenatal care” by parental and labor
& delivery report (detailed obstetric chart still awaited). She is noted to be fairly dusky “all over”
with feeble cry and remarkable hypotonia at birth. Apgars are 4, 6 and 7 and 1, 5 and 10 minutes
respectively, after birth. She is in no respiratory distress and room air saturations at 10 minutes of
life are noted to be 86%. On closer exam she is noted to have multiple dysmorphic features
including hypertelorism, upslanted palpebral features, flat facial profile, low-set small (length =
2.8 cm) ears, bilateral 5th finger cleido-clinodactyly, wide space between 1st and 2nd toes, severe
generalized hypotonia (shoulders slip through the examiner’s hands) and an abnormal Moro with
an extensor phase but no flexion phase.
1. The most likely diagnosis is:
A. An inborn Error of Metabolism (IEM)
B. Severe neuromuscular disease (eg. Pena-Shokier phenotype)
C. Down syndrome
D. Cri-du-chat (5p-)
E. Trisomy 9p mosaic
Balaji Govindaswami, M.D.
Answer C. Down syndrome is the most likely diagnosis.
Down syndrome (DS) is the commonest chromosomal birth defect worldwide.1 It occurs in 1 in
~600-800 livebirths2 in the absence of prenatal intervention.
The prevalence is relatively high but depends on maternal age range of the population. 8-30% of
affected pregnancies are associated with spontaneous loss between amniocentesis and birth. In
addition, many pregnancies are electively terminated.
Clinical recognition is possible in 90 and 100% of Trisomy and Translocation DS respectively but
only in 37.5% of mosaic DS patients.3
While the features are highly variable they are not very specific and thus care must be taken not
to provoke undue anxiety in parents whose children do not actually have DS. On the other hand,
it is important for caregivers to point out salient abnormalities on physical exam, fairly early to
parents, if such an important diagnosis is seriously contemplated. Achieving this balance takes
some clinical experience.
Several other chromosomal abnormalities may present with hypotonia and dysmorphic features
and these would include 5p- (Cri-du-chat syndrome) and Trisomy 9p mosaic.
Most babies with IEM tend to be unrecognized this early in the newborn period and seldom have
such obvious phenotypic features.
Severe neuromuscular disease seldom present with these dysmorphic features. The Pena-Shokier
phenotype results from Fetal akinesia and maybe confused with Trisomy 18 or Potter sequence. It
is often accompanied by contractures and rigidity rather than hypotonia.
While the range of “normal” ear length varies widely and the majority of infants with DS overlap
in the normal range. Small ears4 (<2 standard deviations below the mean) are likely a highly
specific finding in the context of this baby’s other clinical features.
2. In addition, which of the following statement(s) is/are most applicable to this baby:
A. She is visibly dusky and thus highly likely to have cyanotic congenital heart disease.
B. She is as likely as not to have a structural defect of the heart.
C. She probably has normal saturations for age, given her physiology.
D. Her hypotonia and age may be associated with desaturation.
E. B, C and D are all true.
Balaji Govindaswami, M.D.
Answer E. is the most applicable answer.
Cyanotic heart disease is suspected when one fails the 100% Oxygen challenge test. While
possible, this need not be strongly entertained at the present time as the baby is early in the fetalneonatal transition and still on Room air.
Her saturations are “normal” for a newborn in the first minutes of life5-7 and visible cyanosis in
newborns occurs with 3g/dl of desaturated hemoglobin. As newborns have hemoglobin levels of
14-22g /100 ml of blood, she may appear more readily centrally cyanosed in the presence of a
higher hemoglobin concentration.
Hypotonia is often associated with slower improvement in oxygenation due to suboptimal
alveolar recruitment.
In addition, this early in life all babies have elevated pulmonary artery pressures and are prone to
right to left shunts at the foramen ovale and ductus arteriosus.
It is generally known that DS babies have more sustained elevation of these pressures and in the
context of her hypotonia this child would be expected to be slower to make the transition into
higher saturations in the first few minutes after birth.
Supplemental Oxygen, while not indicated, may be provided by some caregivers to help make her
transition easier.
Approximately one half of babies with Down syndrome have structural heart disease, thus she is
as likely as not to have a structurally normal heart.
3. True statements for this mom would include all of the following except:
A. With “good prenatal care” this should have been diagnosed prenatally.
B. Sociocultural/religious factors are important in prenatal diagnosis.
C. Her age alone would have predicted low risk for having a baby with DS.
D. Her risk of a subsequent baby with DS is easy to predict at this time.
E. She is likely to require extensive support with breastfeeding this baby.
Balaji Govindaswami, M.D.
Answer: A. is the correct answer as it is NOT true.
Increased prenatal detection of DS has resulted in increased elective termination of pregnancies.8
Quad Marker Screening (alpha fetoprotein, unconjugated estriol, human chorionic gonadotrophin
and Inhibin-A) performed on maternal blood between the 15-20th week of pregnancy can predict
75% of DS in women <35 and ~80% of DS in women =/>35. However of 1000 women tested
only 40 will have a Quad screen + for DS. Of these 40 only 1-2 will actually have DS. Thus the
majority of Quad screen + women do not have babies with DS. Adding measures of nuchal fold
and long bones to Quad screening improve positive predictive value for DS from 1:42 to 1:18.9
Families vary widely in their religious, social and cultural beliefs. Some families do not believe in
therapeutic termination and as such may decline amniocentesis in the context of increased risk
detected on Quad/expanded screening. As such prenatal confirmation is not infrequently
impossible; this is especially true in the Hispanic population.10
The risk of Trisomy 21 at birth increases fairly exponentially with maternal age from 1:1667 at 20
to 1:952 at 30, 1:106 at 40 and 1:11 at 49. Recurrence risk for this mom is 1% for Trisomy DS.
Recurrence for translocation is 3-5 % if mother is a carrier, 2 to 4 percent if father is a carrier.
Hence it is impossible to predict until chromosomal testing is completed.
Infants with DS often have difficulties with feeding. Primigravida require extra special support to
achieve success with breast feeding. Hence both mother and baby are likely to require a lot of
attention to achieve breast feeding success.
4. Important aspects of the baby’s immediate care might include:
A. Provide supplemental Oxygen if saturations do not show further improvement in the next
several minutes to ease transitional physiology, while recognizing that Oxygen is not absolutely
medically indicated. It may be relatively indicated to ease anxiety on the part of family members
and care providers with the goal being to facilitate early transfer of the baby to mom to promote
bonding.
B. Notify a Dysmorphologist/Geneticist and a medical social worker ASAP.
C. Counsel parents about concerns visualized while making it clear that further expert
opinion is essential and confirmatory testing necessary.
D. Stay with the baby and family for as long as possible to continue to evaluate the baby
medically.
E. All of the above.
Balaji Govindaswami, M.D.
E. All of the above is the correct answer.
Bibliography
1. Modell B, Howson C. March of Dimes Global Report on Birth Defects: The Hidden
Toll of Dying and Disabled Children 2006. March of Dimes Birth Defects Foundation.
2. Jones, KL. Smith’s Recognizable Patterns of Human Malformations, 6th ed, Elsevier Inc,
Philadelphia 2006. p7-9, Down Syndrome, p861 Ear Length.
3. Devlin L and Morrison PJ. Accuracy of the clinical diagnosis of Down syndrome. Ulster
Med J. 2004 May; 73(1):4-12
4. Aase JM, Wilson AC and Smith DW: Small ears in Down syndrome – A helpful
diagnostic aid. J Pediatr, 82:845, 1973
5. Saugstad OD. Oxygen saturations immediately after birth.
J Pediatr 2006; 148:569-570
6. Kamlin CO, O’Donnell CPF, Davis PG, Morley CJ. Oxygen saturations in healthy infants
immediately after birth. J Pediatr 2006; 148:585-589.
7. Rabi Y, Yee W, Chen YC, Singhal N. Oxygen saturation trends immediately after birth. J
Pediatr 2006; 148:590-594.
8. Collins VR, Muggli EE, Riley M et al. Is Down syndrome a disappearing birth defect? J
Pediatr 2008; 152:20.
9. Benn PA, Kaminsky LM, Ying J et al. Combined second-trimester biochemical and
ultrasound screening for Down syndrome. Obstet Gynecol. 2002 Dec; 100(6):1168-76
10. Saucier JB, Johnston D, Wicklund CA et al. Racial-Ethnic differences in Genetic
Amniocentesis Uptake. J Gen Counseling 2005; 14:189-195
Submitted by Balaji Govindaswami, MBBS, MPH
Balaji Govindaswami, M.D.
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