Pituitary Gland Disorders: Hyperpituitarism

Pituitary Gland Disorders

• Hyperpituitarism: Hypersecretion of GH or ACTH
• Causes Gigantism in children (excessive growth of all bones) and Acromegaly in adults (enlargement of peripheral body parts and soft tissue)

Acromegaly

• Caused by excess GH in adults
• Characterized by:
  • Enlargement of peripheral body parts (feet, hands, jaw)
  • Bone and tissue deformity
  • Diaphoresis (cold sweats)
  • Oily and rough skin
  • Organomegaly (enlargement of organs)

Hypopituitarism

• Hyposecretion of growth hormone by the anterior pituitary gland
• Causes:
  • Trauma
  • Tumor
  • Vascular lesion
  • Surgery/radiation of pituitary gland
• Panhypopituitarism (Simmond's disease): Total absence of all pituitary secretion
• Sheehan's syndrome: Common in maternal problems due to postpartum pituitary necrosis

Symptoms of Hypopituitarism

• Retarded physical growth
• Premature aging (hair loss, wrinkles) if it occurs after puberty
• Low intellectual development
• Poor development of secondary sex change characteristics
• Hemianopsia (loss of vision in half the vertical visual field in one or both eyes)
• Headache due to tumor
• Weight loss
• Emaciation

Posterior Pituitary Gland

ADH Dysfunction

• Excess of ADH: Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
• Etiology:
  • Head injury
  • Brain surgery or tumor
  • Infection
  • Medications (vincristine, phenothiazines, tricyclic antidepressants, thiazide diuretics, and nicotine)
• Clinical manifestations:
  • Inability to excrete dilute urine
  • Fluid retention
  • Sodium deficiency (dilutional hyponatremia)
  • Fluid volume overload
  • Changes in mental status due to brain edema
  • Weight gain
  • Edema
  • Tachycardia
  • Hypertension

Medical Management of SIADH

• Restricting fluid intake
• Diuretic agents (furosemide) may be used along with fluid restriction
• In severe hyponatremia, hypertonic NaCl (3%) may be prescribed and administered IV

Nursing Management of SIADH

• Close monitoring of I&O, daily weight, urine and blood chemistries, and neurologic status

Diabetes Insipidus (DI)

• Hyposecretion of ADH
• Characterized by:
  • Abnormally large volumes of dilute urine
  • Polyuria (greater than 250 mL per hour; 4L-24L urine per day)
  • Diluted urine (white colored urine)
• Etiology:
  • Central DI: head trauma, surgery, infection, brain tumors, or cerebral vascular disease
  • Nephrogenic DI: kidney injury, medications (lithium), hypokalemia, and hypercalcemia
  • Dipsogenic DI: defect in the hypothalamus