Analysis of pituitary lesions in fatal closed head injury.

We analyzed forensic autopsy findings of 66 consecutive patients with fatal closed head injury who survived up to 48 days after trauma to ascertain the causal factors and the time course of development of posttraumatic pituitary lesions. Pituitary lesions were identified in 27 patients. In patients with pituitary lesions, posterior lobe hemorrhage was observed in 21 patients, followed by anterior lobe hemorrhage in 10 patients and anterior lobe infarct in 7 patients. Comparisons between patients with and without pituitary lesions showed that falls and subdural hematoma were significantly frequent in patients with pituitary lesions. Immunohistochemistry of neurophysin showed increased immunoreactivity in the hypothalamus of patients with pituitary lesions and brain edema, providing morphologic evidence of pituitary dysfunction. Hemorrhage in the anterior or posterior lobe was identifiable in patients with short survival periods, whereas infarct in the anterior lobe appeared in patients surviving at least 14 hours. These data further our understanding of the mechanisms of pituitary dysfunctions and help in the estimation of the survival period after head trauma.

Factors affecting the development of hypothalamus and pituitary lesions in fatal closed head injury: a prospective study.

OBJECTIVES: To determine the factors affecting the development of pituitary and hypothalamic lesions after fatal closed head injury. MATERIALS: Thirty-four patients with severe closed head injury succumbing to the effects of brain trauma before or during admission, whether managed conservatively or surgically, formed the study group. Clinical parameters, injury to death interval, radiologic data, and management details were taken into consideration. Autopsy was performed within 48 hours of death; hypothalamus and pituitary were carefully removed and evaluated for the presence of lesions on hematoxylin and eosin and immunohistochemical staining. RESULTS: Patients were categorized into early death group (n = 11, those succumbing before/on admission) and late death group (n = 23, those succumbing after admission). Histopathologic evaluation of pituitary revealed capsular hemorrhages in 50%, posterior pituitary hemorrhage in 25%, anterior pituitary infarct in 21.8%, and anterior pituitary hemorrhage in 6.2% patients. Hypothalamic hemorrhage was observed in 65.2% patients and infarcts in 17.3%. Lesions in hypothalamus and pituitary were significantly related to the presence of ventricular compression on computed tomography scan and survival of >24 hours after injury (p < 0.05). Capsular hemorrhage, anterior pituitary hemorrhage, and posterior pituitary hemorrhage were present in 40%, 10%, and 30% of the patients in the early death group when compared with 54.5%, 4.5%, and 22.7% of the patients in the late death group. Anterior pituitary infarcts were present in 10% of the patients with early deaths and 27.3% patients in the late death group. Hypothalamic hemorrhages were present in 44.4% of patients in early death and 78.6% in late death groups. Hypothalamic infarcts (40%) were present in the late death group only. Two patients (25%) in the early death group and 11 (84.6%) in the late death group had lesions in pituitary as well as hypothalamus (p < 0.05). CONCLUSIONS: Presence of ventricular compression on computed tomography scan and survival >24 hours after severe head injury has a significant correlation with the development of hypothalamic and pituitary lesions. Secondary insults account for a proportion of pituitary and hypothalamic lesions after trauma, which may be amenable to prevention by early intervention to treat raised intracranial pressure (ICP)/herniation.

Evidence for a role of dopaminergic mechanisms in the immunostimulating effect of mu-opioid receptor agonist DAGO.

The present study demonstrates that: (1) activation of micro -opioid receptors by systemic administration of a highly selective agonist DAGO (100 microg/kg) results in a significant increase in the number of plaque- and rosette-forming cells in the spleen of CBA mice as well as Wistar rats on the 5th day following sheep red blood cells (5 x 10(8)) immunization, (2) the immunostimulatory effect of DAGO is mediated by central mechanisms including the hypothalamus-hypophysis complex; (3) the postsynaptic dopamine (DA) receptors of D2 type are involved in the DAGO-induced immunostimulation since the combined treatment of animals with haloperidol (2 mg/kg), a blocker of DA D2 receptors, and DAGO abolished this effect; (4) the nuclei caudatus and accumbens of the nigrostriatal and mesolimbic DAergic systems, respectively, are implicated in the immune response stimulation caused by DAGO.

Expression of nitric oxide synthase in hypothalamic nuclei following axonal injury or colchicine treatment.

Nitric oxide (NO) has recently gained much attention due to its apparently double-edged role in neuronal injury. This study was aimed at elucidating neuronal nitric oxide synthase (nNOS) expression in the brain after two types of injury, namely axonal transection and colchicine treatment. The neurosecretory hypothalamo-pituitary pathway served as a model for the reaction of central neurons to these two types of injury. Axonal transection, i.e., pituitary stalk section, resulted in a qualitative increase in NOS content in the supraoptic and paraventricular nuclei. In these nuclei, there was also an increase in the number of NOS-expressing neurons after the operation. Surprisingly, in the periventricular nucleus, a strong decrease in the number of NOS-positive magnocellular neurons was observed in the anterior part of the nucleus. Intracerebroventricular injection of colchicine resulted in an increase in the cell count in the paraventricular nucleus, while the other nuclei remained unchanged. Our results suggest that axonal injury results in an increase in nNOS expression in the major neurosecretory nuclei, while the periventricular nucleus shows the opposite reaction. Colchicine treatment has an effect similar to that of axotomy in the major neurosecretory nuclei, suggesting that an increase in NOS expression may be induced by interrupted axonal transport. In the periventricular nucleus, the decrease in the number of NOS-containing neurons suggests differences among hypothalamic NOS-containing neuron groups in response to neuronal injury.

[Temporal hemianopia and diabetes insipidus following head injury].

Bitemporal hemianopia and diabetes insipidus following head injury are caused by a lesion in the center of the optic chiasm, together with injury to the adjacent pituitary stalk or the hypothalamus. This combination was thought to be a rare complication of severe head injury. The case of a 16-year-old male is presented, which together with recent reports suggests that this relatively under-recognized syndrome is not infrequent, that it may follow even minor head injury, and that magnetic resonance imaging can demonstrate the chiasmal lesion.

Traumatic lesions of the suprasellar region: MR imaging.

The authors studied nine patients with injuries to the suprasellar region with 1.5-T magnetic resonance (MR) imaging. Five patients had chiasmal injuries diagnosed by means of clinical examination. MR imaging demonstrated complete transection in two of these five patients, contusion of the chiasm by inferior herniation of the gyrus rectus in one, and a normal chiasm in two. Two patients had large tears of the floor of the third ventricle resulting in wide communication between the third ventricle and the prepontine cistern. One of these patients also had an avulsed third nerve. Transection of the pituitary stalk was seen in two patients. MR imaging can demonstrate injuries to the suprasellar structures. The MR imaging appearance of optic chiasm correlates with different types of injury to the chiasm described in the clinical literature and may alleviate the need for additional diagnostic studies to help explain the patient's symptoms.

Neuroendocrine abnormalities in patients with traumatic brain injury.

This article provides an overview of hypothalamic and pituitary alterations in brain trauma, including the incidence of hypothalamic-pituitary damage, injury mechanisms, features of the hypothalamic-pituitary defects, and major hypothalamic-pituitary disturbances in brain trauma. While hypothalamic-pituitary lesions have been commonly described at postmortem examination, only a limited number of clinical cases of traumatic hypothalamic-pituitary dysfunction have been reported, probably because head injury of sufficient severity to cause hypothalamic and pituitary damage usually leads to early death. With the improvement in rescue measures, an increasing number of severely head-injured patients with hypothalamic-pituitary dysfunction will survive to be seen by clinicians. Patterns of endocrine abnormalities following brain trauma vary depending on whether the injury site is in the hypothalamus, the anterior or posterior pituitary, or the upper or lower portion of the pituitary stalk. Injury predominantly to the hypothalamus can produce dissociated ACTH-cortisol levels with no response to insulin-induced hypoglycemia and a limited or failed metopirone test, hypothyroxinemia with a preserved thyroid-stimulating hormone response to thyrotropin-releasing hormone, low gonadotropin levels with a normal response to gonadotropin-releasing hormone, a variable growth hormone (GH) level with a paradoxical rise in GH after glucose loading, hyperprolactinemia, the syndrome of inappropriate ADH secretion (SIADH), temporary or permanent diabetes insipidus (DI), disturbed glucose metabolism, and loss of body temperature control. Severe damage to the lower pituitary stalk or anterior lobe can cause low basal levels of all anterior pituitary hormones and eliminate responses to their releasing factors. Only a few cases showed typical features of hypothalamic or pituitary dysfunction. Most severe injuries are sufficient to damage both structures and produce a mixed endocrine picture. Increased intracranial pressure, which releases vasopressin by altering normal hypothalamic anatomy, may represent a unique type of stress to neuroendocrine systems and may contribute to adrenal secretion by a mechanism that requires intact brainstem function. Endocrine function should be monitored in brain-injured patients with basilar skull fractures and protracted posttraumatic amnesia, and patients with SIADH or DI should be closely monitored for other endocrine abnormalities.

Fracture of the sella turcica.

A patient with a fracture of the sella turcica, visible on lateral X-ray films of the skull, is described. This fracture, although not diagnosed during life, was present in approximately 20 per cent of a series of consecutive autopsies on patients who died of head injury. The significance of this injury to the hypothalamopituitary axis is discussed and methods of investigation suggested.