37 HYPERNATREMIA General Discussion Hypernatremia is defined as a serum sodium concentration exceeding 145 mEq/L. In contrast to hyponatremia, which usually results from a defect in renal water handling, the primary defect in hypernatremia is impaired water intake. Hypernatremia represents a deficit of water in relation to the body’s sodium stores, which may result from a net water loss or a hypertonic sodium gain. Unlike hyponatremia, hypernatremia always represents a hyperosmolar state. The majority of cases of hypernatremia result from a net water loss. Hypernatremia is rarely found in an alert patient who has access to water and a normal thirst mechanism. Sustained hypernatremia occurs when thirst is impaired or access to water is limited, so the groups at highest risk are patients with altered mental status, intubated patients, elderly persons, and infants. In elderly persons, hypernatremia is usually associated with infirmity or febrile illness. Hypernatremia is also more common after age 60 because increased age is associated with decreased osmotic stimulation of thirst and decreased maximal urinary concentration. Signs and symptoms of hypernatremia reflect central nervous system dysfunction and are most prominent when the increase in the serum sodium concentration is large and occurs rapidly. Elderly patients generally have few symptoms until the serum sodium concentration exceeds 160 mmol per liter. Brain shrinkage induced by hypernatremia can cause vascular rupture, with cerebral bleeding and permanent neurologic damage or death. Central diabetes insipidus results from deficient vasopressin secretion while nephrogenic diabetes insipidus results from end organ hyporesponsiveness to vasopressin. Diabetes insipidus is associated with variable degrees of polyuria and an inability to concentrate urine maximally. Medications Associated with Hypernatremia Amphotericin B Demeclocycline Foscarnet Lactulose Lithium Loop diuretics Methoxyflurane Vasopressin receptor antagonists Causes of Hypernatremia Net water loss • Burns • Excessive sweating Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: ARTHRITIS AND ARTHRALGIA HAIR LOSS INFERTILITY, MALE SYNCOPE Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on HYPERNATREMIA Full access? Get Clinical Tree
37 HYPERNATREMIA General Discussion Hypernatremia is defined as a serum sodium concentration exceeding 145 mEq/L. In contrast to hyponatremia, which usually results from a defect in renal water handling, the primary defect in hypernatremia is impaired water intake. Hypernatremia represents a deficit of water in relation to the body’s sodium stores, which may result from a net water loss or a hypertonic sodium gain. Unlike hyponatremia, hypernatremia always represents a hyperosmolar state. The majority of cases of hypernatremia result from a net water loss. Hypernatremia is rarely found in an alert patient who has access to water and a normal thirst mechanism. Sustained hypernatremia occurs when thirst is impaired or access to water is limited, so the groups at highest risk are patients with altered mental status, intubated patients, elderly persons, and infants. In elderly persons, hypernatremia is usually associated with infirmity or febrile illness. Hypernatremia is also more common after age 60 because increased age is associated with decreased osmotic stimulation of thirst and decreased maximal urinary concentration. Signs and symptoms of hypernatremia reflect central nervous system dysfunction and are most prominent when the increase in the serum sodium concentration is large and occurs rapidly. Elderly patients generally have few symptoms until the serum sodium concentration exceeds 160 mmol per liter. Brain shrinkage induced by hypernatremia can cause vascular rupture, with cerebral bleeding and permanent neurologic damage or death. Central diabetes insipidus results from deficient vasopressin secretion while nephrogenic diabetes insipidus results from end organ hyporesponsiveness to vasopressin. Diabetes insipidus is associated with variable degrees of polyuria and an inability to concentrate urine maximally. Medications Associated with Hypernatremia Amphotericin B Demeclocycline Foscarnet Lactulose Lithium Loop diuretics Methoxyflurane Vasopressin receptor antagonists Causes of Hypernatremia Net water loss • Burns • Excessive sweating Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: ARTHRITIS AND ARTHRALGIA HAIR LOSS INFERTILITY, MALE SYNCOPE Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on HYPERNATREMIA Full access? Get Clinical Tree
