Endocrine: Thyroid and Adrenal Disorders Flashcards
What do T3/T4 hormones control?
Metabolism
Energy
Fluid balance
Tissue use of macronutrients
What hormones does the thyroid produce?
Thyroxine (T4)
Thriiodothyronine (T3)
Thryocalcitonin (Calcitonin)
What does calcitonin do?
Inhibits release of calcium from bone
Induces kidneys to excrete calcium
What is hyperthyroidism?
A hypermetabolic state that affects all body systems and exaggerates normal body function (everything is up!)
What is the most common cause of hyperthyroidism and explain it?
Grave’s disease
It is an autoimmune disease that produces antibodies that trigger the thyroid to release T3/T4 even when the pituitary has stopped releasing TSH.
What are some other causes of hyperthyroidism?
Family hx
Enlarged goiter or thyroid gland
Thyroid tumors
Excessive iodine consumption
What do we keep in mind re: s/s w/ hyperthyroidism?
They are all elevated with additional weight loss (due to hyperbolic state) and irregular menses
A thyrotoxic crisis is also called a…
thyroid storm
What is a thyrotoxic crisis?
emergent and most severe form of hyperthyroidism
What are some things that can trigger a thyrotoxic crisis?
Infection
Trauma
Emotional stress
Subtotal thyroidectomy / thyroid is manipulated
What are the s/s of thyrotoxic crisis?
acute exacerbation of all hyperthyroidism s/s w/ marked tachycardia, hyperpyrexia, cns irritability, heart failure and coma
What are the four diagnostic tests used for hyperthyroidism?
Serum TSH
Serum free T3
Radioiodine uptake
Radioiodine scintiscan
What do the results of a Serum TSH indicate?
HIGH TSH:
Thyroid is underactive and TSH is working to stimulate the thyroid to produce more hormones
LOW TSH:
Thyroid is overactive and pituitary is suppressing TSH to reduce thyroid hormone production
What do the results of Serum Free T3 indicate?
High = hyperthyroidism
Low = Hypothryroidism
Both will require further testing
What does the Radioiodine uptake show?
Hot and cold nodules
Hot = producing hormones
Cold = not
This scan cannot tell if nodules aren’t functioning due to non/malignancy
What does the Radioiodine scintiscan show?
That the gland is working properly and can determine malignancy of nodules/tumors
What is hypothyroidism?
Under production of thyroid hormone resulting in decrease in metabolic rate
What are PRIMARY causes of hypothyroidism?
Iodine deficiency Thyroiditis/atrophy Neck radiation Manipulation of gland PTU induced decrease in synthesis of TH
What are SECONDARY causes of hypothyroidism?
Pituitary dysfunction or removal
What are TERTIARY causes of hypothyroidism?
Hypothalmic reduction in release of TRH
What is myxedema coma?
a severe form of HYPOthyroidism that most commonly occurs in individuals with undiagnosed or untreated hypothyroidism who are subjected to an external stress
exaggerated hypothyroidism
What are the s/s of myxedema coma?
Altered mental status Hypothermia Bradycardia Hypercarbia Hyponatremia Cardiomegaly (overworked heart), pericardial effusion, cardiogenic shock, and ascites (the accumulation of fluid in the peritoneal cavity, causing abdominal swelling) may be present
What are the key characteristics of myxedema coma to keep in mind?
Develops slowly
>50% mortality rate
It needs prompt and aggressive treatment
Re: myxedema coma
How do we treat hypoventilation, hypoglycemia, hypothermia and hypotension?
Hypoventilation = O2, intubate if unconscious Hypoglycemia = IV glucose Hypothermia = give blanky NOT electric Hypotension = fluids, as always
S/S in hypothyroidism are generally
supressed
The adrenal medulla produces
ephedrine, norepinephrine and dopamine
The adrenal cortex produces
Glucocorticoids (cortisol)
Mineralocorticoids (aldosterone)
both of the above are steroids
Androgen
What does cortisol do?
regulates BP, metabolism, anti-inflammatory response, emotional behavior
What does aldosterone do?
Regulates sodium levels and in tern, fluid levels, BP, etc
Cortisol deficiency results in…
altered (slowed) metabolism, decreased stress tolerance, emotional lability
Aldosterone deficiency results in…
urinary loss of sodium, chloride and water resulting in dehydration and electrolyte imbalances
The release of cortisol, aldosterone and androgen are stimulated by the release of what from where?
adrenocorticotropic hormone (ACTH) anterior pituitary
Is adrenal insufficiency primary or secondary?
can be either
Secondary insufficiencies typically occur from disorders of…
the pituitary gland
What is Addison’s disease?
deficiency of adrenocortical hormones following destruction of adrenal cortex
What is the primary cause for Addison’s?
pathologic condition of adrenals
What is the secondary cause of Addison’s?
caused by prior tx w/ glucocorticoids
pituitary issues that inhibit ACTH
Glucocorticoid deficiency results in…
o Retards mobilization of tissue protein & Inhibits the liver’s ability to store glycogen
Decreased aldosterone:
Na, Cl & water loss & increased K
Characteristics of Acute Adrenal Insufficiency/Addisonian Crisis:
Life-threatening Cortisol & aldosterone (lose function) Acute adrenal insufficiency (Addison’s) Crisis follows: Stress Most common • steroid withdrawal Adrenalectomy Removal of adrenal tumor Destruction of pituitary Injury to adrenals
