FUNCTIONS OF THE NEPHRON - Responds to ADH by reabsorbing water from the
collecting ducts
DISEASES OF THE POSTERIOR PITUITARY- Significant hormone alternation in the posterior pituitary usually related to
Significant hormone alternation in the posterior pituitary usually related to abnormal ADH
These pathological states have significant clinical effects on:
The modulation of body fluids and electrolytes
Cognitive function
SYNDROME OF INAPPROPRIATE ADH: SIADH ETIOLOGY (sia has ADH)
SIADH is characterized by ↑ ADH in spite of having normal or low plasma osmolarity
SIADH: PATHOPHYSIOLOGY - osmolality? (think…too much water)
Cardinal features of SIADH are the result of excess water retention
ADH acts on the renal collecting ducts increasing H2O reabsorption
Leads to:
Increased intravascular fluid volume → dilutional hyponatremia
Overall serum hypo-osmolality
SIADH: CLINICAL MANIFESTATION- main issue is low what?
Sx of SIADH are primarily related to hyponatremia
The severity and rapidity of low Na+ determines the extent of Sx:
SIADH: Criteria for dx - sodium
Criteria for dx:
hyponatremia: < 135 mEq/L (normal 135-145)
SIADH: TREATMENT - what % of sodium solution?
Correct underlying cause
Gradual correction of hyponatremia with hypertonic solutions e.g. 3% sodium
Vigilant monitoring of Na levels and mental status
SIADH: PHARMACOLOGIC TREATMENT - LASIX - when can you give it? - what number exactly
LASIX to promote UOP (only if Na >125 since Lasix can cause further Na loss)
SIADH: NURSING CONSIDERATIONS
Seizure precaution
Fluid restriction (minimize thirst with ice cold drinks, sugar free chewing gum, cold water sprays)
Monitor I/O
Daily weight
Monitor electrolytes
ADH DEFICIENCY: DIABETES INSIPIDUS - the 3 types
DI : Deficiency in ADH or decrease renal response to ADH
3 TYPES:
Central DI, Nephrogenic, Primary DI :
ADH DEFICIENCY: DIABETES INSIPIDUS - Nephrogenic (die don’t collect)
Nephrogenic: Inadequate response of renal collecting tubules to ADH even when levels are normal
DI: Pathophysiology - bladder?
Fluid and electrolyte imbalance d/t ↑urine output and ↑ serum osmo
Large bladder capacity and hydronephrosis in long standing DI
DI: CLINICAL MANIFESTATION - BP?
POLYURIA
POLYDIPSIA
NOCTURIA
HYPOTENSION
DI: EVALUATION - how many liters of urine a day?
Eliminate other differential diagnosis which may cause polyuria state
Dx criteria
Polyuria (2-20 L/day)
Polydipsia
DI: what medication?
IV fluid and hormone replacement DDAVP (desmopressin) (analog of ADH) SC, IV, IM, intranasal
DI: NURSING CONSIDERATIONS - what intranasal spray? (die is depressing)
Strict I&O
Monitor urine specific gravity
Daily weights
Goal is maintaining fluid and electrolyte balance
Discharge teaching with intranasal Desmopressin (synthetic vasopressin- increases water) BID
DISORDERS OF THE ANTERIOR PITUITARY
Disorders of the Anterior Pituitary may involve either hypopituitarism or hyperpituitarism
Hypopituitarism etiology:
Inadequate supply of the hypothalamic-releasing/inhibiting hormones
Damage to the pituitary stalk
Inability of the pituitary to produce hormones
HYPOPITUITARISM - Pituitary infarction (hemorrage) is seen in the setting of (little pitt and sheeran are pregnant)
Sheehan Syndrome: Ischemic pituitary necrosis caused by severe postpartum hemorrhage ( may lead to failure to lactate and amenorrhea)
HYPOPITUITARISM: s/sx
S/S vary depending on the degree of dysfunction and response of the target glands
HYPOPITUITARISM: EVALUATION (measure little brad’s hormones and MRI)
Simultaneous measurement of all trophic hormones from the pituitary and the target glands
Imaging: MRI, CT
HYPERPITUITARISM: GH HYPERSCRETION
Benign autonomic GH secreting pituitary adenoma
Acromegaly:
Gigantism:
ACROMEGALY: CLINICAL manifestation - and edema where?
Enlarged tongue, interstitial edema, coarse skin and body hair
ACROMEGALY: diagnosis (agro glucose)
Diagnosis:
MRI, CT, visual exam
Fails GH suppression during oral glucose tolerance test (GH levels fail to fall below 1/ng/ml)
Elevated IGF- 1 levels
meds - ACROMEGALY (aggro octavia and peg need meds)
Octreotide/lanreotide ( Somatostatin analogues)
Reduces elevated GH levels and causes tumor shrinkage
SQ or IM
Pegvisomant (Growth hormone receptor agonist)
Most effective treatment to date
Costly, given SQ
Cabergoline (Dopamine agonist):
Used off label to lower IGH1 levels
Given PO