pituitrin and Spinal-Cord-Injuries

A male quadriplegic (C6--complete) with persistent chronic hyponatremia (serum sodium values ranging consistently from 117-132 mmol/L) developed acute hyponatremia with a serum sodium concentration of 98 mmol/L. This extreme hyponatremia related, in part, to a reversible defect in the excretion of a water load, while on a low (46 mmol/day) sodium diet. Subsequent ingestion of a normal sodium diet (150 mmol/day), with or without 0.1 mg of fludrocortisone (Florinef), reestablished his ability to excrete a water load normally. The etiology of this patient's hyponatremia is discussed as well as the unique concordance of factors which make hyponatremia a common occurrence among spinal-cord injured patients.

Topics: Acute Disease; Diet, Sodium-Restricted; Fludrocortisone; Humans; Hyponatremia; Male; Middle Aged; Osmolar Concentration; Sodium, Dietary; Spinal Cord Injuries; Vasopressins; Water Intoxication; Water-Electrolyte Balance

Urinary dysfunction is a common complaint following spinal cord injury (SCI) and is a leading issue for individuals with SCI that impacts their quality of life. One urinary complication that has received little attention is SCI-induced polyuria, even though individuals with SCI will significantly restrict their fluid intake to decrease urine production, leading to sequelae of medical complications. Understanding the mechanisms instigating the development of polyuria will allow us to target interventions that may alleviate polyuria symptoms, leading to significant improvements in the quality of life and urinary health of individuals with SCI. In a rat SCI contusion model, an increase in the amount of urine excreted over a 24-h period ( P ≤ 0.001) was found at 2 wk postinjury. The urine excreted was more dilute with decreased urinary creatinine and specific gravity ( P ≤ 0.001). Several factors important in fluid balance regulation, vasopressin (AVP), natriuretic peptides, and corticosterone (CORT), also changed significantly postinjury. AVP levels decreased ( P = 0.042), whereas atrial natriuretic peptide (ANP) and CORT increased ( P = 0.005 and P = 0.031, respectively) at 2 wk postinjury. There was also a positive correlation between the increase in ANP and urine volume postinjury ( P = 0.033). The changes in AVP, ANP, and CORT are conducive to producing polyuria, and the timing of these changes coincides with the development of SCI-induced polyuria. This study identifies several therapeutic targets that could be used to ameliorate polyuria symptoms and improve quality of life in individuals with SCI.

Topics: Animals; Disease Models, Animal; Male; Motor Activity; Natriuretic Peptides; Polyuria; Rats, Wistar; Recovery of Function; Spinal Cord Injuries; Vasopressins

This study investigated the renal and endocrine responses to arm exercise in persons with spinal cord injury (SCI) under euhydration conditions (ad libitum drinking of water) and determined the physiological effects of exercise on renal function in these subjects. Eleven SCI (spinal lesions between T6 and L1, American Spinal Injury Association impairment scale A) and 14 able-bodied (AB) persons first rested for 1 h in a sitting position, before undergoing 2-h arm-crank ergometer exercise at 60% of maximum oxygen consumption followed by a 2-h recovery period. On another day, all subjects participated in a time control study (5 h of rest condition in sitting position). Urine and blood samples were collected hourly. There were no differences in mean blood pressure between the two groups. SCI patients showed attenuated increase in plasma adrenaline and increase in plasma aldosterone compared with AB controls, but similar changes in human atrial natriuretic polypeptide, plasma renin activity and plasma antidiuretic hormone following the exercise. Creatinine clearance, osmolal clearance, free water clearance and fractional excretion of Na(+) did not change during exercise in any of the subjects. These findings suggested that activated aldosterone and attenuated adrenaline responses during exercise in SCI could be due to adaptation to disordered sympathetic nervous system triggered to maintain renal function. The results showed no exercise-related adverse effects on renal function in hydrated subjects with SCI.

Topics: Adult; Aldosterone; Analysis of Variance; Arm; Atrial Natriuretic Factor; Blood Pressure; Case-Control Studies; Creatinine; Dopamine; Drinking; Epinephrine; Exercise Therapy; Glomerular Filtration Rate; Hormones; Humans; Japan; Kidney; Male; Natriuresis; Oxygen Consumption; Renin; Spinal Cord Injuries; Sympathetic Nervous System; Time Factors; Treatment Outcome; Urodynamics; Vasopressins

Topics: Anti-Bacterial Agents; Cervical Vertebrae; Demeclocycline; Fluid Therapy; Humans; Oliguria; Respiratory Distress Syndrome; Spinal Cord Injuries; Vasopressins

Healthy individuals have a nocturnal decrease in urine output due to increased plasma antidiuretic hormone levels at night. This does not occur in spinal cord injury and most patients experience nocturnal polyuria, which triggers dysreflexic crises secondary to urinary bladder overdistension, and interferes with patients' sleep due to the need for extra catheterization.. To evaluate the diurnal variation in ADH level, urinary output, and plasma and urine osmolality in SCI patients with regard to their level of injury and in comparison with age- and sex-matched healthy individuals.. Sixteen ASIA-A spinal cord-injured patients, eight with paraplegia, eight with tetraplegia, and eight healthy individuals, were evaluated for urinary output, urine and serum osmolality, and antidiuretic hormone levels during day and night hours.. Absence of diurnal variation in urinary output and antidiuretic hormone secretion was detected in both paraplegic and tetraplegic patients, while antidiuretic hormone levels rose significantly at night in the control group.. Antidiuretic hormone levels should be monitored both day and night in spinal cord injury patients, with severe nocturnal polyuria. Treatment with desaminocystein-D-arginine vasopressin can be attempted when conservative measures fail to control nocturnal polyuria, especially in patients who are on an intermittent catheterization program.

Topics: Adult; Analysis of Variance; Blood Proteins; Case-Control Studies; Circadian Rhythm; Female; Humans; Male; Osmolar Concentration; Polyuria; Radioimmunoassay; Spinal Cord Injuries; Statistics, Nonparametric; Vasopressins

Intracerebroventricular (i.c.v.) choline (50-150 microg) increased blood pressure and decreased heart rate in spinal cord transected, hypotensive rats. Choline administered intraperitoneally (60 mg/kg), also, increased blood pressure, but to a lesser extent. The pressor response to i.c.v. choline was associated with an increase in plasma vasopressin. Mecamylamine pretreatment (50 microg; i.c.v.) blocked the pressor, bradycardic and vasopressin responses to choline (150 microg). Atropine pretreatment (10 microg; i.c.v.) abolished the bradycardia but failed to alter pressor and vasopressin responses. Hemicholinium-3 [HC-3 (20 microg; i.c.v.)] pretreatment attenuated both bradycardia and pressor responses to choline. The vasopressin V1 receptor antagonist, (beta-mercapto-beta,beta-cyclopenta-methylenepropionyl1, O-Me-Tyr2, Arg8)-vasopressin (10 microg/kg) administered intravenously 5 min after choline abolished the pressor response and attenuated the bradycardia-induced by choline. These data show that choline restores hypotension effectively by activating central nicotinic receptors via presynaptic mechanisms, in spinal shock. Choline-induced bradycardia is mediated by central nicotinic and muscarinic receptors. Increase in plasma vasopressin is involved in cardiovascular effects of choline.

Topics: Animals; Antidiuretic Hormone Receptor Antagonists; Arginine Vasopressin; Atropine; Blood Pressure; Cerebral Ventricles; Choline; Dose-Response Relationship, Drug; Heart Rate; Hemicholinium 3; Hormone Antagonists; Hypotension; Injections, Intraventricular; Male; Rats; Rats, Wistar; Spinal Cord; Spinal Cord Injuries; Time Factors; Vasopressins

To establish baseline ADH levels in spinal cord injury patients and to evaluate whether spinal cord patients have attenuation of diurnal variation of ADH similar to children with enuresis and elderly with nocturnal polyuria.. Twenty-seven healthy quadriplegic patients, ASIA impairment scale A, were evaluated for serum ADH levels at night and during the day.. Evaluation of whether bladder overdistention caused by attenuation of diurnal variation of ADH is responsible for the episodes of autonomic dysreflexia and recurrent urinary tract infections in spinal cord injury patients who are on intermittent catheterization for bladder management.. A lack of diurnal variation of ADH in the subject population.. A trial of desaminocystein-D-arginine vasopressin (DDAVP) should be considered for patients with established attenuation of the diurnal variation ADH.

Topics: Adult; Aged; Circadian Rhythm; Humans; Male; Middle Aged; Osmolar Concentration; Polyuria; Spinal Cord Injuries; Urinary Catheterization; Vasopressins

Chronic cervical spinal cord injury is characterized by defects in sodium and water homeostasis and defects of adaptive hormonal responses. The plasma osmolality is maintained in a relatively narrow range, the lower limit of which is determined by osmotic threshold for vasopressin release and the upper limit by the third threshold. Antidiuretic hormone as an important mediator of fluid and electrolyte balance was well investigated in able bodied children comparing children with normal voiding pattern and children with enuresis. The normal subjects were found to have higher plasma ADH at night, not detected in the group with enuresis. The findings were similar in elderly patients with increased diuresis at night, suggesting an important role of ADH in nocturnal decrease of urine output. Investigators studied the effect of rapid tilt on plasma ADH in tetraplegic compared with normal subjects, but there are no data available in the literature regarding ADH and its effects on water and electrolyte balance in healthy tetraplegic subjects with a normal lifestyle. We decided to undertake a pilot study to attempt to establish baseline ADH levels in this subject group, to better understand and manage tetraplegic patients with water and electrolyte dysregulation. Our preliminary data suggest that these individuals lack the normal diurnal variation of ADH, a phenomenon similar to that demonstrated in enuretic children and elderly, and furthermore appear to have generally depressed ADH levels.

Topics: Adult; Aged; Circadian Rhythm; Humans; Male; Middle Aged; Osmolar Concentration; Polyuria; Spinal Cord Injuries; Vasopressins

Studies on two quadriplegic patients who developed severe hyponatremia during episodes of acute respiratory distress were performed to determine whether differences in osmoregulation of vasopressin release could be identified in these patients compared to other quadriplegic subjects previously studied in a similar manner. Both patients were clinically stable and normonatremic, with no signs or symptoms of respiratory distress, when the studies were performed. However, both exhibited evidence of hemodynamic instability in the sitting posture. Linear regression analysis of the plasma vasopressin/plasma osmolality (Pavp:Posm) relationship during infusions of 0.85 M sodium chloride showed no significant differences in either the slope (sensitivity) or abscissal intercept (osmotic threshold) of this relationship compared to that of other quadriplegic subjects when the patients were supine. In contrast, when the patients were studied in the sitting posture there was a marked shift in the relationship of Pavp:Posm indicative of increased sensitivity and reduced osmotic threshold for vasopressin release. The slopes of the Pavp:Posm relationships were 0.249 and 0.178 for the two patients, respectively, compared to 0.092 +/- 0.03 ( +/- SD) for previously studied quadriplegic subjects. Oral water-loading studies performed on one patient revealed marked impairment of urine-diluting ability and free water clearance in the sitting posture compared with observations in similar studies performed when the patient was supine. Impairment of renal water excretion could not be attributed to an effect of vasopressin, which was reduced to unquantifiable levels by water loading. These studies have shown that hemodynamic stress related to autonomic dysfunction in quadriplegic patients may result in marked alteration of osmoregulation of vasopressin release in more severely affected individuals. Such altered osmoregulation, which may also be associated with vasopressin-independent impairment of renal water excretion in the sitting posture, may be a predisposing factor in the development of hyponatremia, especially in the presence of other potent nonosmotic stimuli.

Topics: Aged; Blood; Blood Pressure; Hemodynamics; Humans; Male; Middle Aged; Osmolar Concentration; Posture; Renin; Saline Solution, Hypertonic; Sodium; Spinal Cord Injuries; Vasopressins; Water; Water-Electrolyte Balance

The authors discuss about five cases of diabetes insipidus observed in patients affected by traumatic cervical spine fractures and/or dislocations, without either evident lesions of the cerebral structures at CT scan examination, or important craniocerebral trauma. In all patients polyuria and hyperthermia arose some days after the traumatic accident and regressed spontaneously or after exogeneous vasopressin administration. Vasopressin urinary levels confirmed the presence of a true diabetes insipidus, the origin of which is in largely obscure. A central medullary vasopressin mediated pathway, demonstrated only in experimental animals, may be responsible for such a finding.

Topics: Adolescent; Adult; Cervical Vertebrae; Diabetes Insipidus; Female; Fever; Fractures, Bone; Humans; Hypothalamo-Hypophyseal System; Joint Dislocations; Male; Polyuria; Radiography; Spinal Cord Injuries; Syndrome; Vasopressins