Case Volum

  Case -1-     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.

View CXR.

     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

low.

     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

is appreciated.

     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. 

References

     Nypaver MM, et al.  Emergency Department

This Case From PEDIATRIC CLINICAL TEST By Dr Aml Ashour