187- What is gelastic seizure?
Gelastic seizures are characterized by irresistible episodes of laughter accom-
panied with dysautonomia (sweating, flushing, and tachycardia) without
impairment in sensorium. The most common cause of gelastic seizure is hypo-
thalamic hamartoma. Patients with hypothalamic hamartomas of size >10 mm
or located near mammillary bodies are predisposed for gelastic seizures.
Although rare, lesions extending up to the floor of third ventricle (e.g., gliomas,
meningioma, basilar artery aneurysms) may also result in gelastic seizure.
These seizures are usually refractory to conventional antiepileptic therapy and
may require surgical excision/stereotactic radiotherapy.- A 6-year-old boy presented with increased penile length and appearance of
pubic hair. On evaluation, his testicular volume was 2 ml bilaterally. Is it GDPP
or GIPP?
The index patient had increase in penile length and premature pubarche without
testicular enlargement, thereby suggesting a diagnosis of GIPP. Gonadotropin-
dependent precocious puberty (GDPP) is due to the reactivation of HPG-axis
with a sequential and progressive evolution of secondary sexual characteristics
like testicular enlargement followed by phallic enlargement in boys and thelar-
che followed by menarche in girls, as seen in normal puberty. During normal
pubertal development, testicular growth (6–8 ml) precedes phallic enlargement
in boys, and menarche appears at breast Tanner stage 4 in girls. However, in
GIPP, there is discordance in the appearance of secondary sexual characteristics;
penile enlargement can occur without testicular growth in boys and menarche
may occur even at breast Tanner stage 2 in girls. This discordance is due to inap-
propriate exposure to sex steroids, both in tempo and quantity, as pubertal devel-
opment in GIPP is independent of HPG-axis reactivation.
Fig. 6.6 Sagittal CEMR
depicting small isointense
well-defined lesion close to
mammillary body
suggestive of hypothalamic
hamartoma (red arrow)
6 Precocious Puberty