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Endocrine Blueprint
PANCE Blueprint
Diseases of Thyroid
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Hyperparathyroidism-
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Should be suspected when high
serum calcium levels are detected
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Primary hyperthyroidism occurs due
to PTH activation of osteoclasts
leading to more bone reabsorption
causing elevated calcium levels
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This also causes increased
intestinal absorption of calcium
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Most common cause of primary
hyperthyroidism is due to
parathyroid adenoma
Hyperparathyroidism
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Diagnosis of primary
hyperparathyroidism is made with a
high PTH or one that is in the normal
range but elevated inappropriately
given the elevated given the patients
hypercalcemia
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Patients with primary
hyperparathyroidism are usually
asymptomatic
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Elevated isolated serum calcium level
should be repeated.
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Malignancy is another cause for
hypercalcemia. Malignancy and
Primary Hyperparathyroidism account
90 percent of cases of hypercalcemia
Hyperparathyroidism
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If malignancy is present, the PTH level is usually normal or low, where
as in primary hyperparathyroidism the levels are usually high
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Familial hypocalciuric hypercalcium (FHH) is due to an inactivating
mutation of the calcium sensing receptor in the kidneys. See a
hypercalcemia with a mildly elevated PTH concentration
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Family history of hypercalcemia that is symptomatic is helpful for coming
up with the diagnosis
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Thiazide diuretics reduce calcium urine excretion and can cause mild
hypercalcemia
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Lithium decreases parathyroid gland sensitivity to calcium, and
decreases urinary excretion.
Hyperparathyroidism
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Secondary Hyperparathyroidism is
when the parathyroid appropriately
responds to a reduced level of
calcium. This causes elevated
PTH, the calcium absorption from
the intestines to increase and
increase bone reabsorption.
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Secondary Hyperparathyroidism
has an elevated PTH and a low or
normal calcium
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Secondary hyperparathyroid may
come from renal failure and
impaired calcitrol production and
inadequate calcium uptake. Vitamin
D Deficiency can cause.
Hyperparathyroidism
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Normocalcemic Primary
Hyperparathyroidism-secondary
hyperparathyroid causes need to be
ruled out. Normal calcium and
elevated PTH. Vitamin D deficiency
can cause
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Clinically most the time
hyperparathyroidism can be
asymptomatic
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Classic symptoms if present
"bones, stones, abdominal moans,
and psychic groans." Anorexia,
nausea, constipation, polydipsia,
bone pain, kidney stone, muscle
weakness, polyuria, and psychiatric
psychosis.
Hypoparathyroidism
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Most common cause is neck surgery on the
thyroid or parathyroid
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After surgery hypoparathyroidism may be
transient or may be permanent
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Clinically will see a low PTH and low serum
calcium
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Calcium and vitamin D supplementation are the
mainstays of hypoparathyroidism treatment
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Symptoms of hypoparathyroidism
include: tingling in hands and feet, involuntary
muscle movements, muscle cramps, fatigue,
irritability, anxiety, and depression
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Long term hypoparathyroidism can cause
cataracts, dry skin, coarse hair, and brittle
fingernails
Hyperthyroidism
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Many disorders can cause
hyperthyroidism: Graves Disease,
Hashiomotos Thyrotoxicosis, Toxic
Adenoma, Toxic Multiple Nodular Goiter,
Iodine Induced Hyperthyroidism,
Trophoblastic Disease from Germ Cell
Tumors, TSH mediated hyperthyroidism,
Thyroiditis, and exogenous and ectopic
hyperthyroidism
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Graves Disease is the most common
cause of hyperthyroidism.
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Graves Disease is an autoimmune
disorder that causes thyrotropin (TSH)
receptor antibodies, which stimulate
thyroid gland growth and thyroid hormone
synthesis and release.
Hyperthyroidism
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Hashimoto's Thyroiditis is an autoimmune disease that causes patients initially to
present with hyperparathyroidism and high radio iodine uptake similar to Graves
disease but eventually go hypothyroid
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Hypothyroid develops because of the infiltration of the thyroid gland with
lymphocytes
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Toxic adenoma and multinodular goiter result from focal or diffuse hyperplasia of the
thyroid follicular cells whose functional capacity is independent regulation of TSH.
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Toxic multinodular goiter tends to be more common in areas where iodine uptake is
low
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Thyroid adenomas are not related to iodine uptake
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Iodine Induced Hyperthyroidism can occur after an iodine load such as IV contrast
for CT scan, or amiodarone administration.
Hyperthyroidism
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Iodine Induced Hyperthyroidism is rare
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Trophoblastic or germ cell tumors can be rare causes of
hyperthyroidism
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Can occur as a hydatidiform mole in women
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Can occur in Choriocarcinoma in men with testicular germ cell
tumors via direct stimulation of the TSH receptors
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TSH mediated hyperthyroidism is when there is a pituitary
adenoma producing TSH. Therapy is directed at removing the
tumor
Hyperthyroidism
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Thyroiditis is a group of heterogenous
disorders that result from inflammation
of thyroid tissue with transient
hyperthyroidism
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Thyroiditis has hyperthyroid phase,
then hypothyroid phase and then a
recovery of thyroid function
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Exogenous and ectopic
hyperthyroidism occurs from taking too
much thyroid hormone or it being
produced by other parts of the body.
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Exogenous thyroid hormone can be
produced by struma ovarii, which is
from a functioning ovarian neoplasm.
Hyperthyroidism
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Thyroid hormone effects almost every
organ system in the body.
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Skin-hyperthyroidism causes increased
sweating due to increased caloric burning
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Hyperthyroidism causing softening of nails,
thinning of hair, and can cause
hyperpigmentation
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Stare and lid lag occur in patients with
hyperthyroidism because of sympathetic
overactivity
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Patients with graves disease can get
exophthalmus because of inflammation of
the extraocular muscles and orbital fat and
connective tissue.
Hyperthyroidism
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Hyperthyroid patients have lower serum total and HDL cholesterol
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Hyperthyroid patient can have impaired glucose tolerance if
untreated
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Hyperthyroidism can result in lower serum cortisol concentrations
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Dyspnea can occur with hyperthyroidism because oxygen
consumption and CO2 production increase
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Can be tracheal obstruction due to large goiter
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Respiratory muscle weakness can cause dyspnea with
hyperthyroidism
Hyperthyroidism
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Weight loss with hyperthyroidism is due to
increased metabolic rate and increased gut
motility.
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Dysphagia may occur because of goiter
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RBC mass index is increase with
hyperthyroidism
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May have a normochromic normocytic anemia
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Hyperthyroidism can be associated with ITP
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Urinary frequency and nocturia are common
with hyperthyroidism
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Woman with hyperthyroid may see high serum
estradiol, high LH, and may get oligomenorrhea
and anovulatory infertility
Hyperthyroidism
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Thyroid hormone stimulaters bone reabsorption, bone loss
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May see increased urinary calcium excretion
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Hyperthyroidism can cause psychosis, agitation and depression
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Treatment of hyperthyroidism includes beta blockers, PTU or methimazole, or
radioactive iodine
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Beta Blockers are for symptomatic treatment of hyperthyroidism
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PTU or methimazole are thyroid hormone antagonists
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Radioactive iodine is indicated for graves disease
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Surgical removal of thyroid gland is an option if necessary
Hypothyroidism
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Several different causes of
hypothyroidism
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Primary hypothyroidism is when there
is decreased secretion of T3 and T4
which results in a increase int TSH
secretion
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Chronic autoimmune (Hashimoto's)
Thyroiditis- most common cause of
hypothyroidism. When there is cell and
antibody mediated destruction of
thyroid tissue
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Iatrogenic Hypothyroidism-caused by
thyroidectomy radio iodine treatment,
or external radiation and there is less
secretion of T3 and T4 as a result of it
Hypothyroidism
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Iodine related hypothyroidism-excess or iodine deficiency can cause
hypothyroidism. Iodine excess causes the inhibition of iodide
organification from T4 to T3 synthesis. Iodine deficiency causes the
inability to synthesize thyroid hormone.
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Drugs such as PTU and methimazole can cause hypothyroidism.
Lithium, Amiodarone and Ethionamide have been known to cause
hypothyroidism.
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Infiltrative disease such as fibrous thyroiditis, hemochromatosis,
scleroderma, leukemia, and cystinosis are rare causes of
hypothyroidism
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Hypothyroidism in infants and children are caused by agenesis and
dysgenesis of the thyroid
Hypothyroidism
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Transient hypothyroidism can be
caused by post partum thyroiditis,
subtotal thyroidectomy, or patients
post radioactive iodine therapy with
Graves disease
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Secondary Hypothyroidism is
caused by lack of TSH secretion
from the anterior pituitary gland
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Tertiary (Central) is caused by lack
of TRH secretion form the
hypothalamus
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Hypothyroidism affects essentially
every organ system
Hypothyroidism
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Hypothyroidism causes decreased sweating, skin
discoloration, hair to be coarse, non pitting edema
(myxedema), vitiligo, and alopecia
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Hypothyroidism cans cause periorbital edema
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Hypothyroidism can cause normochromic normocytic anemia
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Hypothyroidism causes decreased cardiac output and
reduction of heart rate and cardiac contractility. Hypertension
can be caused from an increased in peripheral vascular
resistance. Increased cholesterol can be seen from decreased
cholesterol metabolism
Hypothyroidism
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Fatigue, shortness of breath on exertion
and rhinitis can be caused by respiratory
muscle weakness with hypothyroidism
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Hypothyroidism causes decreased gut
motility, constipation, and decreased taste
sensation, and gastric atrophy
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Hypothyroidism can cause
oligomenorrhea, amenorrhea, or
hypermenorrhea. This can lead to
infertility. Decreased libido, erectile
dysfunction, and delayed ejaculation are
possible in hypothyroidism
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Hypothyroidism left untreated can cause
hashimotos encephalopathy, myxedema
coma, and carpal tunnel syndrome
Hypothyroidism
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Hypothyroidism can also cause
joint pain, aches, and
stiffness. There is an increased
incidence of gout with
hypothyroid patients.
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Hypothyroidism can cause
hyponatremia
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Standard treatment of
hypothyroidism is replacement
therapy. Synthetic thyroxine (T4)
or combination T3 and T4
therapy. There is also T3 alone
therapy