Pituitary Dysfunction Flashcards
Which physiologic functions do hormones regulate?
Energy production
Temperature regulation
Fluid and electrolyte balance
Stress response
Sexual development
Which organs rely on the hormones secreted by the pituitary gland?
Parathyroids
Thyroid
Adrenals
Pancreas
Testes
Ovaries
Hormones produced in the anterior pituitary
*TSH (thyroid stimulating hormone)
*ACTH (adrenal corticotropic)
LH
FSH
PRL
*GH (growth hormone)
MSH
Hormones produced by the posterior pituitary
*Vasopressin (ADH)
Oxytocin
How is hormone secretion in the pituitary gland regulated?
Endo and neuro systems work together to regulate hormone balance through negative feedback mechanism:
Decreased hormone levels stimulate production
Increased hormone levels inhibit production
Etiology of hypopituitarism
Hypophysectomy (removal of pituitary gland)
Pituitary tumors
Severe malnutrition (anorexia nervosa)
Shock or severe hypotension (Sheehan’s syndrome)
S/S of hypopituitarism
Secondary adrenocortical insufficiency
Hypothyroidism
Deficient growth hormone
Sexual and reproductive disorders:
Men: decreased facial/body hair, libido, impotence
Women: decreased pubic/axillary hair, libido, breast atrophy
Diagnostics for hypopituitarism
CT scan / MRI to look for tumor
Draw hormone levels (one will be very low while other likely not as low)
Interventions for hypopituitarism
Medical: remove cause, replace hormones
Nursing: assessment of organs involved
Patient problems: body image disturbance, sexual dysfunction, ineffective individual coping
*Removal of pituitary gland = lifelong hormone replacement
Two types of hyperpituitarism
Gigantism
Acromegaly
What is gigantism?
Excess GH in children, resulting in overgrowth of long bones
What is acromegaly?
Excess GH in adults, resulting in increased bone thickness and hypertrophy of soft tissue
Causes of hyperpituitarism
Benign pituitary adenoma (GH secreting tumor)
Prolactinomas (form of pituitary tumor)
ACTH secreting tumor
Tumors secreting gonadotropin or TSH
Effects of hyperpituitarism
Rapid growth of all body tissue
Full blown DM (from over-secretion of ACTH)
Destruction of pituitary causing hypopituitarism (tumor encroaches on gland and ruins it)
Pressure on optic nerve causing blindness
S/S of hyperpituitarism
Headaches
Diplopia/blindness
Goiter
Enlargement of organs
*Broad hands and feet
*Increased ring and shoe size
Thickening of skull
*Protruding of supraorbital ridges
*Coarse facial features
*Prognathism
Arthritic changes
DM
Enlarged, but weak skeletal muscles
Lethargy/fatigue
*Deepening voice
Thickened heel pads
Diagnostics for hyperpituitarism
Plasma hormone levels
CT scan
MRI
Angiography
Patient problems for hyperpituitarism
*Body image disturbance r/t altered physical appearance
Sexual dysfunction r/t loss of libido, infertility, impotence
Interventions for hyperpituitarism
*Surgery = #1 tx
Medication therapy
Radiation therapy
What is the surgery for hyperpituitarism?
Transsphenoidal hypophysectomy
Incision in upper lip with long scissors to cut out pituitary gland. Pt will be on hormone replacement for life
Where is ADH produced?
Hypothalamus and stored in/released from posterior pituitary gland
Function of ADH
AKA vasopressin
Acts of renal collecting tubules and results in water reabsorption
Disorders associated with ADH
Diabetes insipidus
SIADH
What is diabetes insipidus?
Deficiency in synthesis or release of ADH
Excess water losses
Two types of DI and what causes each?
Neurogenic: ADH deficiency
Nephrogenic: kidneys insensitive to ADH (can’t respond to it)
What causes neurogenic DI?
Trauma to pituitary or hypothalamus (to head/brain)
Ex: craniotomy sometimes causes acute DI, will go away after swelling goes down
What causes nephrogenic DI?
Chronic renal disease
Drugs (alcohol, phenytoin, lithium)
*S/S of DI
Major concern?
Clinical picture of DEHYDRATION:
Polyuria: 5-40L per 24 hr
Urine pale and dilute
*Hypovolemia/shock = major concern
Dehydration:
- thirst
- constipation
- thick secretions
Diagnostics of DI
Serum osmolality >295 mOm/kg of water
*Serum Na >145 mEq/L
Dilute urine with decreased specific gravity and osmolality <100
Main issues with DI that need to be treated
Dehydration
Hormone deficiency
Treatment for DI
- First: replace fluid that is lost (primarily water) so need to replace with D5W (added sugar is scooped up by cells if enough insulin and water is left)
BUT: if pt is shocky, will use NS instead - Next: ADH (aka vasopressin) replacement (if neurogenic)
Can be given SQ, IV, nasal spray, but usually IV in c.c.
Note: watch for fluid overload (*JVD)
Side effects of vasopressin administration
HA
Nausea
Mild abdominal cramps
Patho of SIADH
Excess ADH unrelated to plasma osmolality
Due to failure in negative feedback mechanism
Leads to plasma hypoosmolality which leads to fluid retention and ascites
What can cause SIADH?
Malignancy (ex: NSCLC b/c these cells release ADH)
Pulmonary disorders (TB, COPD, pneumonia)
CNS trauma, tumors
Drugs (if you suspect SIADH and can’t find another cause, need to look at pt’s drugs)
S/S of SIADH
*Will have clinical picture of water intoxication aka fluid volume overload:
CV: *weight gain, HTN, RAP>10, PCWP>12
*Edema
Neuro: decreased LOC, HA, seizures, coma
Renal: *dark urine, *decreased UOP
GI: N/V/A, decreased bowel sounds, muscle cramps
Respiratory: tachypnea, dyspnea, *frothy pink sputum
Lab values for SIADH
Decreased serum osmolality
Increased urine osmolality
*Serum NA: <135
*Serum osmolality: <275 mOsm/Kg H2O
Serum ADH: elevated
Urine Na: >20 mEq/L
*SIADH interventions and nursing care
*Fluid restriction (800-1000 mL/day)
*Diet liberal in sodium
*then, if serum Na <110 mEq/L, hypertonic saline and diuretics (Lasix) (need to react fast b/c water is pulled from tissues and cells)
Intake and output
Specific gravity
Weights
Mouth care
How should a nurse develop a schedule for fluid administration for a pt being treated for SIADH?
Develop schedule for 800 mL/day restriction (this is less than 2 quarts)
Know how many mL are allowed for AM shift and PM shift, document and post this so everyone can see
What changes might need to be made regarding med administration for a pt being treated for SIADH?
May need to switch from IV to tube administration of meds due to fluid restriction
How can you ensure that at pt being treated for SIADH doesn’t ingest additional fluids?
Good education for patient and family about how important fluid restriction is
Post fluid restriction guidelines for that pt where everyone can see
