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Altered hormonal and metabolic functions (Addison Disease (Causes…
Altered hormonal and metabolic functions
Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
Diagnostic criteria
Hypotonicity (plasma osmolality < 280 mOsm/kg)
Absence of renal, adrenal, thyroid abnormalities
Hyponatremia (serum sodium < 135 mEq/L)
Treatment modalities
Water restriction if mild
Isotonic or hypertonic IV solutions if more serious
Correct the cause
Medications to block ADH effects or increase urine output
Clinical manifestations
Hypotonic hyponatremia
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Decreased/concentrated urine output
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Water retention/ edema
Nausea/vomiting
Anorexia
Headache
Disorientation
Muscle cramps
Cause
Excessive production/release of ADH
Hypothyroidism
Clinical manifestations
Cold intolerance
Weight gain
Fatigue/lethargy
Constipation
Dry skin/coarse hair
Impaired memory
Impaired reproduction
Goiter
Myxedema (image source
https://www.mythyroidproblems.com/myxedema-coma/
)
Diagnostic criteria
TSH levels elevated
Lower levels of free T4, total T4, T3 uptake
Confirmed clinical manifestations
Thyroid autoantibodies
Causes
Congenital
Lack of thyroid development in fetus
TSH secretions affected
Lack of synthesis of thyroid hormone
Acquired
Insufficient thyroid hormone synthesis
Destruction of thyroid gland
Impaired TSH or TRH secretion
Autoimmune disorder (Hashimoto thyroiditis)
Iodine deficiency
Removal or radiation of thyroid gland
Treatment modalities
Hormone replacement
Ultimate goal: normal levels of TSH, T3, T4; reduced signs/symptoms
Addison Disease
Clinical manifestations
Glucocorticoids deficiency
Low blood sugar, weakness, fatigue, anorexia, nausea/vomiting, weight loss
Mineralocorticoids deficiency
Dehydration, hyponatremia, hyperkalemia, hypotension, weakness, fatigue, shock
Androgens deficiency
Lack of body hair in women
Diagnostic criteria
Confirmed clinical manifestations
Confirmed hyponatremia, hyperkalemia
Low levels of corticosteroids; resistant to administered ACTH
Causes
Autoimmune damage to adrenal cortex
Adrenal gland not able to produce glucocorticoids, mineralcorticoids, or androgens
Adrenal cortex not secreting hormones
Damage to pituitary gland
Treatment modalities
Lifelong oral glucocorticoids and mineralocorticoids
Possible increased salt consumption
Isotonic IV for acute dehydration; may be administered with hydrocortisone solution
Acute ACTH deficiency is medical emergency
Cushing Syndrome
Diagnostic criteria
Imaging to confirm tumors
24-hr urine collection; cortisol levels
Dexamethasone administration to replicate cortisol levels
High level of cortisol: Cushing
Low level of cortisol: normal
Clinical manifestations
Glucose intolerance/excessive blood glucose levels --> diabetes mellitus
Suppressed inflammatory/immune responses (more infections/illness, poor wound healing)
Buildup of fat stores in trunk, face, upper back ("buffalo hump")
Muscle weakness/wasting; thin extremities
Osteoporosis
Treatment modalities
Surgery/radiation for tumors
Therapeutic corticosteroid administration to prevent withdrawal complications
Ultimate goal: remove cause of excess hormone production
Causes
Continued high levels of endogenous or exogenous glucocorticoids
Long-term use of corticosteroids (e.g. prednisone)
Pituitary tumors --> excess ACTH production
Production of ACTH or CRH from distant tumor
Adrenal gland tumors --> excess cortisol production
Hyperthyroidism
Clinical manifestations
Increased metabolic rate/weight loss
Agitation/restlessness
Enlarged thyroid
Sweating/heat intolerance
Diarrhea
Tachycardia/palpitations
Irregular menstrual cycle
Diagnostic criteria
Confirmed clinical manifestations
Family history of thyroid or autoimmune disease
Enlarged/firm thyroid
Protrusion of eyes
Serum-free thyroxine levels
Elevated T3 and T4 levels
Causes
Excessive stimulation of thyroid gland
Thyroid diseases
Excess production of TSH by pituitary tumor
Autoimmune disorder (Graves disease)
Treatment modalities
Ultimate goal is reducing thyroid hormone levels
Destruction of thyroid gland
Radioactive iodone
Thyroid hormone blocking medications
Surgical removal of thyroid
Diabetes Insipidus
Diagnostic criteria
Recent surgery (esp cranial) or head trauma?
Dehydration?
Overfilling of bladder due to fluid loss?
Blood work
ADH levels
Urine osmolality (<200 msm/kg)
Specific gravity of urine (<1.005)
Treatment modalities
IV with hypotonic solution
Adequate hydration
Desmopressin (potent antidiuretic)
Clinical manifestations
Polyuria
Excessive thirst
Depends on severity
Very diluted urine, low specific gravity
Serum hyperosmolality due to fluid loss
Severe dehydration
Shock/death if untreated
Causes
Insufficient ADH production by hypothalamus or secretion by posterior pituitary
Nephrogenic DI (poor kidney response to ADH)
Consumption of large amounts of liquids, water intoxication
Produced in hypothalamus
ADH
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Adrenal glands; adrenocorticotropic hormone
Normal or increased ACTH levels
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Excessive production of ACTH
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