II. Case Presentation
The index patient was a 5-month-old male infant, born to
non-consanguineous healthy parents. He was the second child of the
family and his female sibling was healthy. No history of abortion, early
death, or prenatal abnormality was reported. )Figure.1 )
The baby was born post-term (at 40 weeks of gestation) through vaginal
delivery with a birth weight of 3500 grams. At birth, the cleft lip and
palate were diagnosed, and he was admitted to the neonatal ward for 24
hours to practice sucking under health care team observation. The
physical examination was otherwise normal. He was PO tolerant and was
discharged on the second day of birth with personal permission.
He was screened for the presence of accompanying anomalies by the
ultrasound of the brain, heart, abdomen, and pelvis, which revealed
normal results except for patent foramen ovale (PFO) and a small patent
ductus arteriosus (PDA). (Figure.2 (A-C) )
The mother states that the number of diapers that became completely
heavy from birth was about 7-8 diapers per day. The infant had no
problem thereafter and had a normal weight gain. At the fourth month of
age, the mother noticed episodes of myoclonic (UWG) movements lasting
for a few seconds about 2 to 3 times during daytime and when falling
asleep. The frequency of these attacks gradually increased, and limbs
spasm was added on. During an outpatient visit to a pediatric
neurologist, the primidone (Liskantin®) is started,
and he was recommended to return if there was no response to treatment.
The levetiracetam was added after a week due to the continued seizure
attacks, with no significant response, and the infant was admitted to
the Qom Shohada Hospital. In the spiral brain computed tomography (CT)
the septal agenesia was suspected and in the magnetic resonance imaging
(MRI), the septum pellucidum was absent and holoprosencephaly was
reported. The electroencephalogram (EEG) was abnormal. In addition, the
serum sodium level was above the normal range (Na: 169 meq/L). During
his two-week admission, the number of seizure episodes declined but the
hypernatremia did not resolve.
Due to his refractory hypernatremia, he was referred to the Mofid
Children’s Hospital and the nephrology and neurology services were
consulted. Upon admission to this center, he had fever and hypernatremia
(Na: 170 meq/L). The maintenance serum (1.2 L) was placed for the
patient and the paraclinical workup was performed to rule out infectious
etiologies (including COVID-19 PCR), all of which were negative. On the
second day of hospitalization, according to the low urine specific
gravity (SG: 1003) and high serum sodium level (Na: 169 meq/L), he was
diagnosed with diabetes insipidus (DI). With the serum sodium of 145
meq/L, he received a puff of DDAVP spray equivalent to 10 micrograms of
desmopressin, while on cardiac monitoring and vital signs check. The
serum sodium reached 131 meq/L two hours after receiving desmopressin
and 118 meq/L four hours later, and the urine SG reached 1011. The
patient developed seizures, controlled by hypertonic sodium and
diazepam. Three days later, the patient’s condition stabilized and he
was re-initiated on desmopressin spray, diluted in a proportion of 1:4.
There was no change in plasma sodium and urine SG levels. The next day,
with a serum sodium level of 144 meq/L, a two-fold dose of desmopressin
(1:2 concentration) was administered which resulted in a sodium drop to
134 meq/L, 2 hours later, and 119 meq/L, 4 hours later, with urine SG of
1015. and received hypertonic sodium again. In the re-administration of
a quarter dose with serum sodium of 154 meq/L, this time, he experienced
a decrease in sodium by 102, 2 hours after receiving desmopressin, the
urine SG reached 1015, and urine volume decreased subsequently. The
desmopressin was discontinued and no hypernatremia was detected during
the follow-up.