1/9. Hypodipsic hypernatremia with intact AVP response to non-osmotic stimuli induced by hypothalamic tumor: a case report.Anatomical lesions of hypothalamic area associated with hypodipsic hypernatremia have been reported only rarely. We report here a case of hypodipsic hypernatremia induced by a hypothalamic lesion. A 25-yr-old man, who had been treated with radiation for hypothalamic tumor 5-yr before, was admitted for evaluation of hypernatremia and hypokalemia. He never felt thirst despite the elevated plasma osmolality and usually refused to drink intentionally. plasma arginine vasopressin (AVP) level was normal despite the severe hypernatremic hyperosmolar state and urine was not properly concentrated, while AVP secretion was rapidly induced by water deprivation and urine osmolality also progressively increased to the near maximum concentration range. All of these findings were consistent with an isolated defect in osmoregulation of thirst, which was considered as the cause of chronic hypernatremia in the patient without an absolute deficiency in AVP secretion. hypokalemia could be induced by activation of the renin-angiotensin-aldosterone system as a result of volume depletion. However, inappropriately low values of plasma aldosterone levels despite high plasma renin activity could not induce symptomatic hypokalemia and metabolic alkalosis. The relatively low serum aldosterone levels compared with high plasma renin activity might result from hypernatremia. hypernatremia and hypokalemia were gradually corrected by intentional water intake only.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |
2/9. Tanycytomas: a newly characterized hypothalamic-suprasellar and ventricular tumor.We report five cases of tumors occurring in three children and in two adults. The tumors had unusual histomorphology and a mixture of ependymal and piloid-like astrocytic features and a myxoid stroma similar to myxopapillary ependymomas. MR imaging in three of the cases showed aggressive, intensely enhancing partially cystic hypothalamic-suprasellar masses near midline and near the floor of the third ventricle. In the three pediatric cases, the tumor encased the circle of willis. This newly characterized tumor, the tanycytoma, has neoplastic cells with histomorphologic and ultrastructural characteristics similar to those of the tanycyte.- - - - - - - - - - ranking = 2keywords = near (Clic here for more details about this article) |
3/9. Isolated vertical diplopia as the initial manifestation of presumed pretectal and anterior hypothalamic germinomas.A 21-year-old man with a 5-month history of diplopia caused by isolated vertical ocular misalignment had normal laboratory studies, including brain magnetic resonance imaging (MRI). Eight months after the onset of diplopia, he reported dry mouth, polydipsia, polyuria, and absent sweating. Examination now disclosed light-near dissociation of the pupillary responses, convergence-retraction nystagmus, and upgaze palsy. MRI revealed enhancing suprasellar and pretectal masses presumed to be germinomas. Two years after brain irradiation and systemic chemotherapy, no lesions are apparent on MRI and hypothalamic dysfunction has partially resolved. In a young patient with isolated vertical diplopia and normal brain imaging, one should consider an early pretectal syndrome and inquire after manifestations of hypothalamic dysfunction.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |
4/9. Linear accelerator stereotactic radiosurgery for the treatment of gelastic seizures due to hypothalamic hamartoma.PURPOSE: There are reports of successful gamma-knife stereotactic radiosurgery (SRS) for the treatment of gelastic seizures associated with a hypothalamic hamartoma. The authors reviewed the results of linear accelerator (LINAC) radiosurgery for patients with medically refractory gelastic seizures due to a sessile hypothalamic hamartoma. methods: Three patients with gelastic seizures received SRS between 2003 and 2004. All patients had associated partial complex and/or generalized seizures. One patient demonstrated aggressive behavior. Sessile hamartomas varying in diameter from 6 to 14 mm were identified by MRI. SRS was delivered to a single isocenter by a dedicated LINAC equipped with either a circular beam collimator or a micromultileaf collimator. patients received 1500 to 1800 cGy prescribed at the 90 to 95 % isodose line. Seizure outcome was scored according to Engel's classification. RESULTS: Two patients became free of gelastic and partial complex/generalized seizures seven and nine months after radiosurgery. These patients remain free of seizures at 17 and 15 months, respectively, after treatment (Engle Class IA). One patient experienced a decline in gelastic seizure frequency nine months after treatment (Engle Class II) without significant reduction in aggressive behavior. Follow-up MRI demonstrated no change in the size or signal characteristics of any tumor. No patient developed post-treatment cranial neuropathy or hypothalamic-pituitary suppression. CONCLUSIONS: LINAC SRS represents a safe and effective therapeutic alternative for patients with medically refractory gelastic seizures due to unresectable hypothalamic hamartomas. radiosurgery is associated with a latency of several months from treatment to reduction in seizure frequency. Further follow-up is required to establish the duration of seizure control following radiosurgery.- - - - - - - - - - ranking = 5keywords = near (Clic here for more details about this article) |
5/9. intraoperative neuronavigation using diffusion tensor MR tractography for the resection of a deep tumor adjacent to the corticospinal tract.OBJECTIVE AND IMPORTANCE: Delineation of cerebral white matter tracts using MR tractography adds essential information for planning intracranial surgery. Integrating tractography with intraoperative neuronavigation may reduce the likelihood of new neurological deficits after surgery done to remove tumors adjacent to the projection fibers of eloquent cortex. We report the utility of such integration for the resection of deep (paraventricular) tumors. CLINICAL PRESENTATION: A 67-year-old male with malignant melanoma underwent stereotactic radiosurgery for a single metastasis within the paraventricular white matter of the right frontal lobe near the corticospinal tract. The lesion doubled in size within 12 months of radiotherapy. Surgical extirpation was performed aided by intraoperative neuronavigation. TECHNIQUE: MR images of the brain including MR tractography and post-contrast T1-weighted sequences were acquired and imported into a neuronavigational workstation. Asymmetric fusion of contrast-enhanced images and tractography was employed to assist in preservation of the integrity of critical white matter tracts during the surgical procedure. CONCLUSION: Inclusion of tractography in standard imaging protocols for neuronavigational systems may increase the safety of neurosurgical intervention near white matter tracts, including deep areas adjacent to the ventricles.- - - - - - - - - - ranking = 2keywords = near (Clic here for more details about this article) |
6/9. Hypothalamic hamartomas and sexual precocity. Evaluation of treatment options.We describe four male patients with hypothalamic hamartomas associated with sexual precocity. Our assessment of their management suggests that resection using current microsurgical techniques is a valid treatment option if the patient has a normal pubertal endocrine makeup, if the hamartoma is pedunculated, and if the patient is young enough to require years of parenteral medical treatment. Such surgical treatment can be curative, and subsequent growth and development can be normal (patients 1 and 2). However, if the patient is near to pubertal age (patient 3) or if neurosurgical or gonadotropin releasing hormone analogue treatment is not available, the natural history (patient 4) suggests that the only undesirable effects are accelerated growth, tall stature for age, and premature sexual development during childhood, as well as the psychosocial problems that may accompany them. adult height may be compromised, although the two patients who did not undergo a surgical procedure and did not receive gonadotropin releasing hormone analogue therapy are above the lower limits of the normal range of adult male height. Therefore, if the hamartoma is pedunculated and cessation of pubertal development is desired, resection of the hamartoma is a reasonable therapeutic option.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |
7/9. Profound pulmonary shunting without edema following stereotaxic biopsy of hypothalamic germinoma. Case report.Hypoxemia is a nearly constant accompaniment of head injury. Diverse theories have been proposed to explain this relationship. The authors report the case of a patient who suffered an episode of severe, transient, arterial oxygen desaturation during "controlled" brain trauma: an otherwise uneventful stereotaxic biopsy of a small germinoma of the hypothalamus. Evidence is provided that pure ventilation-perfusion mismatching, without pulmonary edema, underlay the hypoxemia. The hypothalamus is intimately involved in matching pulmonary ventilation to perfusion; the hypoxemia of various brain injuries may be mediated by perturbation of this structure.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |
8/9. hamartoma of CNS associated with precocious puberty.A male infant had precocious puberty and hamartoma of the CNS. Signs of puberty appeared and progressed from 6 months of age. A computed tomographic scan disclosed an interpedunculary tumor. A craniotomy was successfully performed at 11/2 years of age, and 90% of the tumor was removed. Histologically, the tissue was identified as a hypothalamic hamartoma. Pubertal development stopped. The patient is now 4 years 9 months old and well. review of medical literature covering a span of 47 years showed 50 cases of hamartomas in or near the hypothalamus confirmed by surgical exploration or autopsy. The male-female ratio of hamartomas with precocious puberty derived from these data is 2:1. Convulsions, mental retardation, or behavioral disorders were present in 48% of the cases; 36% had precocious puberty.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |
9/9. Hypernatremic myopathy.We describe a 21-year-old man presenting with proximal muscle weakness associated with hypernatremia. His manifestations other than muscle weakness included dry skin, loss of axillary and pubic hair, decreased libido and loss of thirst sensation. His serum sodium level was elevated to 169-171 mEq./l but all other electrolytes were normal. In addition, serum CK was elevated and an EMG study showed myogenic changes. Endocrinological studies revealed hypothalamic hypopituitarism, while MRI revealed a suprasellar mass. A partial correction of hypernatremia led to an immediate recovery of the muscle weakness as well as a normalization of both the serum CK level and EMG findings, suggesting a direct association between the muscle weakness and hypernatremia. The phosphocreatine/inorganic phosphorus (PCr/Pi) ratios in the resting calf muscle, obtained using 31P magnetic resonance spectroscopy (MRS), were very low during the state of muscle weakness, while they returned to nearly normal values after clinical improvement, suggesting that the muscle weakness in hypernatremic state was caused by a depletion of the intramuscular energy stores, probably due to an overworking Na-K pump to correct the intracellular electrolyte imbalance.- - - - - - - - - - ranking = 1keywords = near (Clic here for more details about this article) |