Seizure and VSD in 2-month old Infant
Radiology Cases in Pediatric Emergency Medicine
Volume 2, Case 2
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
This is a 2 month old male with a history of a VSD
arriving in the ED for a possible seizure. He has had
some cold symptoms since yesterday. This evening,
his parents noted an episode of body stiffness, jerking
of all extremities, and upward rolling of his eyes lasting
one minute. An ambulance was called. His face was
described as being blue toward the end of the episode.
Paramedics noted him to be breathing spontaneously
with no cyanosis. He was transported to the ED. An IV
was attempted en route, but this was not successful.
No fever was noted in the ambulance. There was no
history of fever prior to this episode.
Exam: VS T36.6 (rectal), P132, R60, weight 4.36
kg. He was alert and active. Fontanelle soft and flat.
Neck supple. Heart regular, harsh grade III/VI systolic
murmur. Lungs clear. Good color, perfusion, and tone.
Shortly after arrival in the ED, another seizure was
witnessed. His upper extremities were flexed and
jerking. His lower extremities were extended and
jerking. No one could recall what his eyes were doing.
An IV was attempted during the seizure but this was not
successful. The seizure stopped on its own after five
minutes. His oxygen saturation was 100% throughout
the seizure with an oxygen mask in place. After the
seizure, he was crying. He was not drowsy. He was
moving around a lot during other IV attempts. He was
noted to be very strong. An IV was started. He was
given 0.1 mg/kg of lorazepam and 10 mg/kg of
phenobarbital. He was more sedated at this point. His
respiratory effort and perfusion remained good.
A CBC, blood culture, electrolytes, glucose, and
calcium were drawn. A quick glucose check was 175
mg/dl. He was given 50 mg/kg of cefotaxime IV. A
portable chest radiograph was obtained and a CT of the
head was ordered.
There is cardiomegaly with slightly prominent
pulmonary vascularity suggesting a left to right shunt.
Compare this CXR to his CXR taken at birth.
View CXR at birth.
Birth history: He was born to a 22 year old G3P2,
O+, rubella immune, syphilis negative, hepatitis B
negative mother at 40 weeks gestation via spontaneous
vaginal delivery weighing 3.9 kg with apgar scores of 8
and 9. Membranes were ruptured at delivery. Amniotic
fluid was clear. His newborn exam noted small ears. A
heart murmur was not noted initially, but two hours after
birth a grade II/VI systolic murmur was noted. A CXR
taken at birth [Click on Birth] showed cardiomegaly
without pulmonary edema. An echocardiogram
performed the next day showed a large VSD with an
overriding aorta and a relatively narrow main
pulmonary artery (consistent with a mild Tetralogy of
Fallot; however, minimal pulmonic stenosis and no right
to left shunting). Despite the cardiomegaly noted on
the CXR, the echocardiogram showed normal chamber
sizes and contractility. He was discharged on day 2 of
life. Several weeks later, he developed worsening
congestive heart failure. He was treated with digoxin.
Returning to the E.D. and his current condition, his
head CT study was normal. Other lab results: CBC,
WBC 5,300, 59% segs, 20% lymphs, 17% monos, 4%
eos, Hgb 10, Hct 30, platelets 310,000. Na 133, K 4.4,
Cl 91, Bicarb 26, glucose 144, Ca 6.0, digoxin level 2.0,
creatinine 0.4. The calcium value is very low (normal
8.0-10.0 mg/dl). Mg and Phos levels were run when
the low calcium was noted. Mg 1.9 (normal), Phos 8.9
(high, normal range 4.0-6.0).
DiGeorge syndrome was suspected. Review of his
CXR's revealed the absence of a thymic shadow
consistent with thymic aplasia (a feature of DiGeorge
syndrome). Review his CXR's again. They are very
similar. Click on [Birth]. His newborn CXR shows a
narrow superior mediastinum. In normal newborns, the
superior mediastinum is enlarged due to the presence
of a normal large thymus.
View normal newborn CXR.
These two normal newborn CXR's show a normal
thymus configuration. The upper mediastinum is wider
than our DiGeorge patient's CXR. The normal thymus
can be very large. It may sometimes protrude to the
side exhibiting a "sail sign". The thymus may
sometimes be elevated in a pneumomediastinum.
The lateral view of the newborn CXR is most
important in distinguishing these features. The normal
newborn CXR will have the space anterior to the heart
filled by the thymus.
View normal lateral CXR.
The arrows indicate a space anterior and superior to
the heart. In adults, this space should be filled with
lung tissue (lucent). Obliteration of this space in an
adult indicates the presence of right ventricular
enlargement or a mediastinal mass. In newborns, this
space should be filled with a tissue density (the
thymus). If this space is filled with air, it is indicative of
a pneumomediastinum. If this space is filled with lung
tissue, it is indicative of thymic aplasia or hypolasia.
View DiGeorge patient's lateral CXR.
In this lateral CXR, our patient with DiGeorge
syndrome has no thymus. Thus, the space anterior and
superior to the heart is empty. The radiologist who
initially read his newborn CXR commented on the
absence of a thymic shadow. The thymus can also be
hypoplastic in the presence of physiologic stress such
as sepsis and shock.
Further studies and clinical features confirmed the
diagnosis of DiGeorge Syndrome. His parathyroid
hormone level in the presence of hypocalcemia was
DiGeorge syndrome is predominantly a syndrome of
hypoparathyroidism and T-lymphocyte deficiency due to
thymic aplasia or hypoplasia. The thymus and the
parathyroid glands both arise from the same pharyngeal
pouches (3rd and 4th) during embryogenesis. Failure
of these pouches to develop results in deficiencies of
the thymus and parathyroids. DiGeorge syndrome is
classified as an immunodeficiency syndrome. Patients
with DiGeorge syndrome are susceptible to
opportunistic infections. However, patients with
DiGeorge syndrome typically present initially with tetany
and hypocalcemia (resembling seizures) due to
hypoparathyroidism long before any immunodeficiency
Other clinical features of DiGeorge syndrome
include congenital heart and aortic defects, hypoplastic
mandible, defective ears, and other subtle facial
features. The expression of all the clinical features of
DiGeorge syndrome is variable.
Although a serum calcium measurement is often
included in the laboratory evaluation of a child with a
first time seizure, it is rarely abnormal. Febrile seizures
are most common and are not associated with any
electrolyte or calcium abnormalities. DiGeorge
syndrome is a rare occurrence when hypocalcemia is
the cause of the "seizure" (tetany). Children under five
months of age are unlikely to have benign febrile
convulsions. Thus, a calcium measurement should be
performed in all young infants (under 6 months) with an
apparent seizure. The yield of a serum calcium
measurement in older children is much lower. A
seizure is difficult to distinguish from tetany in an infant.
In this instance it appeared to be a true seizure as it
was witnessed by an emergency pediatrician and many
pediatric ED nurses.
Nypaver MM, et al. Emergency Department
Laboratory Evaluation of Children with Seizures:
Dogma or Dilemma? Pediatric Emergency Care
Turnbull TL, et al. Utility of Laboratory Studies in the
Emergency Department Patient with a New-Onset
Seizure. Annals of Emergency Medicine
DiGeorge Syndrome. In: Behrman RE, Vaughan
VC. Nelson Testbook of Pediatrics, 13th edition. W.B.
Saunders, Philadelphia, 1987, p464.
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