Endocrine Flashcards
Functions of endocrine system
- growth and development
- sex differentiation
- metabolism
- adaption
4 hormones of hypothalamus
- TRH
- CRH
- growth hormone
- GnRh
Hormones of anterior pituitary
- TSH
- LH
- FSH
- ACTH
- GH
- Prolactin
Hormones of posterior pituitary
- Oxytocin
- ADH
Primary disorder
Malfunction of the actual target organ
Secondary disorder
Target gland is normal, however altered function of the stimulating hormones - it is a pituitary problem
Tertiary
Both pituitary and target problem
Low TSH
High T3 and T4
Primary hyperthyroidism
High TSH
Hight T3 and T4
Secondary hyperthyroidism
High TSH
Low T3 and T4
Primary hypothyroidism
Low TSH
Low T3 and T4
Secondary hypothyroidism
What are the basics of the hypothalamus-pituitary axis-thyroid gland axis?
Hypothalamus (TRH) –> Pituitary (TSH) –> Thyroid (T3 and T4)
What mineral deficiency can lead to hypothyroidism?
Iodine deficiency
How does hypothyroidism affect metabolism?
Metabolism decreases
What happens in long-standing hypothyroidism?
Myxedema
What are the clinical manifestations of hypothyroidism
- Bradypnea
- Constipation
- Cold intolerance
- Fatigue
- Weakness
- Dry skin
- Coarse hair
- Impaired memory and reproduction
What are the clinical manifestations of Myxedema
- Swollen face
- Puffiness around the eyes
- Swelling of tongue
Another term for Myxedema
Cardiomegaly
What kind of patients would you see Myxedema in?
- Patients who haven’t been compliant with the hormone treatment
- Get sick
What differs in Myxedema Coma from Myxedema
More diffuse edema, precipitated by an acute event, weakness, confusion
What do you look for in lab diagnostics of hypothyroidism?
TSH levels
T3 and T4 levels
Thryoid autoantibodies - to see if an autoimmune disease attacked the thyroid
Antithyroglobulin
How do you treat primary hypothyroidism?
Thyroid hormone replacement therapy
i. e. levothyroxine and syntheroid
- slowly raise the levels
How do you treat secondary hypothyroidism?
Removal of the pituitary tumor
What happens to the metabolism in hyperthyroidism?
Metabolism increases
What condition is a form of secondary hyperthyroidism?
Grave’s disease (autoimmune disease)
-IgG binds to TSH receptors on the thyroid
What clinical manifestation is present in both hypo and hyperthyroidism?
Goiter
What are clinical manifestations of hyperthyroidism?
- Diarrhea
- Weight loss
- Oily skin
- Fine hair
- Exopthalmus
- Heat intolerance
- Tachycardia, agitation
What is Thyroid Storm ?
Worsening of hyperthyroidism symptoms due to stress, infection, pulmonary or cardiovascular disorders
-extreme vitals
What can occur after thyroidectomy?
Thyroid crisis = exaggeration of the effects of hyperthyroidism
Describe the effect of immobility on serum Ca and PTH
Immobile –> bone release Ca –> hypercalcemia –> inhibit PTH
Describe the effect of renal disease on serum Ca and PTH
Renal disease –> inability reabsorb Ca –> hypocalcemia –> stimulation of parathyroid –> releases PTH –> bone release Ca –> bone loss
What are the calcium levels in hypoparathyroidism?
Low serum calcium (hypocalcemia)
What state of serum magnesium causes hypothyroidism?
Hypomagnesemia
How does magnesium affect PTH
Magnesium is needed for adequate production of PTH
What is the relationship between calcium and phosphate?
They are inverse
Hypocalcemia = hyperphophatemia
Describe the relationship between hyperphosphatemia and hypocalcemia?
High phosphate levels interfere with vitamin D activation –> cannot absorb calcium –> hypocalcemia
How does vitamin D affect calcium absorption
Vitamin D activation is needed for calcium absorption in the GI
What is the relationship between calcium and neuromuscular excitability?
They are inverse
-Calcium is necessary for resting membrane potential, thus lack of calcium = increased neuromuscular excitability
Clinical Manifestations of Hypothyroidism?
- Tetany
- Muscle spasm
- dry skin
- loss of body hair
- diarrhea
- increased peristalsis
What are unique diagnostic findings in hypothyroidism?
Chvostek and Trousseau signs
- low Ca
- low PTH
What causes primary hyperparathyroidism?
Error in the negative feedback loop
-High Ca levels normally inhibit PTH release –> but neg feedback loop is malfunctioning –> so PTH continues to be released
What causes secondary hyperparathyroidism
Increase PTH due to issues not related to the feedback loop (hypocalcemia)
How does chronic renal failure affect PTH levels?
Chronic renal failure –> lack of Ca reabsorption –> hypocalcemia –> high PTH
How does lack of vitamin D activation affect PTH levels?
Vitamin D is necessary to absorb Ca through GI –> lack of vitamin D = lack of Ca absorption –> hypocalcemia –> high PTH
Clinical manifestations of Hyperparathyroidism
- Decreased neuromuscular excitability
- Bone disease
- Calcium stones
- Polyuria (b/c kidneys are trying to flush calcium out)
- Constipation
- Abdominal pain
- Anorexia
In chronic kidney disease, are the phosphate levels increased or decreased?
In CKD, hyperphosphatemia due to decreased phosphorus secretion.
How does the kidney response to the hyperphoshatemia lead to hypocalcemia?
Kidneys excrete calcium as a precept with the phosphorus –> excretion of Ca –> hypocalcemia
Why are patients with CKD stay in hypocalcemia states despite hyperparathyroidism?
PTH causes release of calcium from the bone but their inability to activate vitamin D decreases calcium absorption
What is another term for ADH?
Vasopressin
What is the most common cause of SIADH?
Ectopic secretion
What kind of sodium imbalance occurs with SIADH?
Hypotonic hyponatremia
Clinical Manifestations of SIADH
- decreased urine output
- concentrated urine
- hyponatermia –> irritability, weakness, nausea and vomiting, coma
- edema / third spacing
How does water intoxication mimic DI?
Water intoxication –> body has sufficient water –> body thinks we no longer need ADH –> less ADH production –> mimics DI
Clinical Manifestations of DI?
- polyuria
- dilute urine
- hypernatremia –> CNS manifestations (seizures and coma)
- hypovolemic shock
What is the serum osmolality in DI?
High serum osmolality due to the hypernatremia
Will the specific urine gravity be high or low in DI?
Low (because of low electrolyte content)
When is the adrenal gland axis triggered?
When the body is under stress
What is the pathway of the adrenal gland axis?
Hypothalamus –> secretes CRH –> anterior pituitary releases ACTH –> triggers adrenal gland –> production and release of steroids, glucoroticoids, and corticoids
What are the two different causes of Cushing’s?
- Long term administration of glucocorticoids (i.e. prednisone) –> cushing’s syndrome
- Ectopic secretion –> cushing’s disease
Clinical manifestations of Cushing’s
- Moon face
- Buffalo hump
- Fat pad
- Obesity of trunk
- Weakness
- Osteoporosis
- Kidney Stones
- Hyperglycemia (due to cortisol inhibiting insulin production)
- Suppression of immunity
- Hypokalemia
In Cushing’s is cortisol high or low?
High cortisol
Is ACTH high or low in Cushing’s
High ACTH
Is ACTH high or low in Addison’s
Low ACTH
What does PTH respond to?
Low levels of calcium
Describe primary Addisons’s
Problem with the adrenal gland –> low glucocorticoid, mineralcorticoid, and androgen production
- Low levels trigger ACTH b/c of negative feedback
- Increased level of ACTH
Is glucocorticoid/mineralcorticoid/androgen level high or low in Cushing’s?
High
Is glucocorticoid/mineralcorticoid/androgen level high or low in Addison’s?
Low
What is secondary Addison’s?
Low ACTH (and low production by adrenal gland)
Clinical manifestations of Addison’s
If primary (high ACTH) –> hyper pigmentation
- Hypoglycemia
- Lack of aldosterone –> salt cravings
- Dehydration
- Hyperkalemia –> arrhythmia
What is the adrenal stimulation test?
ACTH is given, and serum cortisol levels are monitored over time to see if adrenals are responding to the ACTH.
What type of Addison’s does the adrenal stimulation test test for? (Primary or secondary)
Primary Addison’s
In treating a patient with Addison’s what should you educate them on?
Signs and symptoms of addison/adrenal crisis
