o Central Nervous System Disorders Tumors Craniopharyngioma –Originates in Rathke pouch but may develop into a suprasellar tumor. o Symptoms: headache, visual deficiency, growth failure, polyuria and polydipsia. o Imaging: Calcification in suprasellar region is hallmark of craniopharyngioma. Usually can be seen on computed tomography, not on MRIs. Usually cystic appearance o Treatment: Resection and/or radiation therapy. Extrasellar tumors –these tumors involve the hypothalamus and produce sexual infantilism. Tumors are usually germinomas, gliomas, and astrocytomas. Other acquired cental nervous system disorders Lead to hypothalamic-pituitary dysfunction Developmental defects
Defects of the central nervous system may cause hypogonadotropic hypogonadism or other types of hypothalamic dysfunction Cleft palate as well as other midline anomalies may be associated Optic dysplasia often associated. Radiation therapy Central nervous system radiation therapy involving the hypothalamic- pituitary area can lead to hypogonadotropic hypogonadism with onset at 6-18 months after treatment. Usually causes GH deficiency hypogonadotropic hypogonadism o Isolated gonadotropin deficiency Kallmann syndrome 1 Deficiency is associated with hypoplasia or aplasia of the olfactory lobes and olfactory bulb causing hyposmia or asnomia. Failure of GnRH-containing neurons’ migration from olfactory placode to the medial basal hypothalamus. Patients may have undescended testes, gynecomastia, obesity, as well as abnormal development of corticospinal tract. X-linked Kallman Syndrome Due to gene deletions causing absence of KAL1 gene coding for anosmin. (Anosmin codes for an adhesion molecule that plays a key role in migration of GnRH neurons and olfactory nerves to hypothalamus) Kallmann syndrome 2 and 3 Both are due to mutations of specific genes. 2 is inherited in an autosomal dominant pattern, while 3 is autosomal recessive pattern. o Idiopathic hypopituitary dwarfism Congential GH deficiency with early onset of growth failure. This distinguishes them from patients with GH deficiency due to hypothalamic tumors. Delayed onset of puberty associated with delayed bone ages. With human growth hormone (hGH) therapy, onset of puberty occurs at a normal age. Patients with combined GH and gonadotropin deficiency do not undergo puberty even when bone age reaches pubertal stage. After birth, syndrome of microphallus as well as neonatal hypoglycemic seizures Must be diagnosed and treated early to avoid central nervous system damage due to hypoglycemia Treatment: testosterone in low doses can increase size of penis in infants diagnosed with congenital hypopituitarism without advancing the bone age.
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- Spring '14
- Precocious puberty, central precocious puberty