Endocrine Flashcards
What is a common presentation of Neuroblastoma in children?
palpable asymptomatic abdominal mass that Crosses Midline
What are histological features of a Neuroblastoma?
- ganglion cells
- primitive, small, round blue cells organised in Rosettes
- embedded in a fibrillary pink matrix
What gene disorders are a/w Neuroblastoma?
amplification of MYCN oncogene
Flushing
Diarrhea
Bronchospasm (cough, wheezing)
Carcinoid Syndrome
What gene and tumor marker is associated with Adrenal Neuroblastoma?
N-myc oncogene
Bombesin Tumor marker
How do PTH and serum calcium levels compare in primary Osteoporosis to normal levels?
PTH and Ca2+ levels are typically normal in primary osteoporosis
identify:
female infant
subsequent recurrent vomiting, volume depletion, hypotension, failure to thrive
Increased Skin pigmentation
Congenital adrenal hyperplasia (21-hydroxylase deficiency)
During sex determination what factor causes testes development? what is the role of sertoli cells and leydig cells?
TDF (from SRY gene on Y chromosome) act on undifferentiated gonad to form testes
Sertoli cells - Antimullerian hormone (AMH) - involution of paramesonephric ducts
Leydig cell - Testosterone - male internal genitalia
–DHT - male external genitalia
What are Symptoms of Von-Hippel-Lindau disease?
CNS tumors (ie decreasing vision in an eye)
dermatologic hemangiomas
renal cell carcinoma
pheochromocytoma
What can hypothyroidism develop into if left untreated?
myxedema coma (social withdrawal, lethargy, drowsiness, confusion
Which DM drug can cause acute pancreatitis?
Exanatide (GLP-1 analog)
Which DM drug can cause weight gain and edema and progress to congestive heart failure in the most severe cases?
Pioglitazone (TZD’s)
-fluid retention from increased sodium reabsorption
Which DM drug has a dangerous adverse effect of lactic acidosis? (Presents with nausea, vomiting, fatigue, altered levels of consciousness, low serum bicarb)
Metformin
Triad of Pituitary, Pancreas, Parathyroid dysfunction
MEN 1
Triad of Parathyroid, pheochromocytoma, medullary thyroid carcinoma?
MEN 2a
Pheochromocytoma, medullary thryoid carcinoma, oral/intesetinal ganglioneuromatosis (wide spread benign neuromas most often in the mucosal surface of the eyes and mouth)
Marfan-type appearance
MEN 2b
mucosal neuromas - could possibly be tumor of the tongue
what neurotransmitter stimulates the adrenal medulla?
ACh from sympathetice PREganglionic neurons
Where are the following located and what is their fxn:
- GLUT-1
- GLUT-2
- GLUT-3
- GLUT-4
- GLUT-5
- RBC, brain, cornea, placenta (insulin independent)
- bidirectional: B islet cells, liver, kidney, small intestine (insulin independent)
- brain, placenta (independent)
- Adipose, striated muscle (INSULIN DEPENDENT)
- fructose: spermatocyte, GI tract
What hypothalamic secretion increases prolactin production?
TRH
increase in prolactin production in primary or secondary hypothyroidism
what 2 hormones inhibit GH secretion?
glucose
somatostatin
via negative feedback by somatomedin
How do magnesium levels influence PTH secretion?
slightly decreased Mg = increased PTH secretion
greatly decreased Mg = decreased PTH secretion
what are the 4 functions of T3 hormone?
4B’s
- Brain maturation
- Bone growth
- B-adrenergic fx (increase B1 in heart)
- increased Basal metabolic rate
What is the mechanism of action of Propylthiouracil (PTU)
inhibits both:
1. thyroid peroxidase = responsible for oxidation and organification of iodide, couples MIT, DIT to T4 and T3
- 5’-deiodinase: changes T4 to T3
What is the mechanism of action of Methimazole?
inhibits thyroid peroxidase (responsible for oxidation and organification of iodide, couples MIT, DIT to T4 and T3)
What is the mechanism/classification of Glipizide, Glyburide, Glimepiride what is a side effect to be careful of?
Sulfonylureas - close the K+ channel in pancreatic B-cells = insulin release
Hypoglycemia
How is congenital adrenal hyperplasia managed?
exogenous corticosteroids to suppress excessive ACTH secretion
What structures are derived from the Neural Crest Cells?
MOTEL PASS
Melanocytes Odontoblasts Tracheal cartilage Entercromaffin Cells Laryngeal Cartilage
Parafollicular Cells of thyroid
Adrenal Medulla + all ganglia
Schwann Cells
Spiral Membrane (Aorticopulmonary septum)
What is the mechanism of action of Leuprolide? what malignancy can it be used in?
GnRH analog - initial use can cause increase in LH (increase testosterone) but prolonged use decreases LH (decreases testosterone)
Prostate Cancer (test reduction can slow progression)
How do you distinguish Central Diabetes Insipidus caused by damage to Hypothalamic Nuclei (Supraoptic) or the Pituitary Gland?
Damage to pituitary = transient DI because axonal regeneration can occur
damage to hypothalamic nuclei = Permanent DI
moodswings, difficulty concentrating, hand tremor
pain in front of neck radiates to ears, worse with swallowing
history of flu-like illness few weeks ago
thyroid is tender
diffuse DECREASE in radioactive iodine uptake
elevated ESR
identify dz and histological appearance of biopsy
subacute granulomatous thyroiditis (de Quervains)
- follows viral illness
- mixed cellular infiltrate with multinucleated giant cells
How does a Prolactinoma affect GnRH, LH, Testosterone levels?
decrease in all
increased serum levels of prolactin suppress GnRH secretion
47 year old man present with weightloss + swollen lips for past 2 months
3 weeks of painful migrating rash (begins as blisters and crusts over)
–erythematous papules and plaques with scaling/crusting at borders involving face, extremities
–Some papules coalesced, other have central clearing with bronze pigmentation replacing the erythema
Fingerstick glucose = 274mg/dL
Identify dz and decrease serum element?
Glucagonoma
- -weightloss, Necrolytic migratory erythema
- Normacytic Anemia
Which HLA type is a/w Hashimotos Thyroiditis?
HLA-DR5
Pts with Hashitmotos Thyroiditis are at an increased risk for what malignancy?
non-Hodgkin lymphoma
5 month boy presents w poor feeding
difficulty holding up head, low body weight, head size, length
hepatomegaly, hypotonia
cardiac gallop rhythm, cardiomegaly
Muscle biopsy = enlarged lysosomes containing periodic acid-Schiff (PAS)-positive material
identify dz and deficient enzyme
Pompe disease (glycogen storage dz type II) --deficiency of acid a-glucosidase
What is the mechanism of action of Nateglinide, Repaglinide?
Stimulate postprandial insulin release by binding to K+ channels on B-cell membranes (site differs from sulfonylureas)
What is the mechanism of action of Exenatide, Liraglutide?
GLP-1 analogs (increased glucose dependent insulin release, decrease glucagon release, decrease gastric emptying, increase satiety)
What is the mechanism of action of Linagliptin, Saxagliptin, Sitagliptin?
DPP-4 inhibitors
–DPP-4 deactives GLP-1
What is the mechanism of action of Pramlintide? What is its use?
Type 1 DM Amylin analog (decreased gastric emptying, decreased glucagon)
3 year old present with neck swelling, painful, started 1 week ago
brief hx of URI
no PHM, met all milestones
Tender, midline mass just below the hyoid bone
identify
Thyroglossal duct cyst
What electrolyte activity does insulin cause?
activates the Na,K ATPase pump
increased cellular uptake of potassium, release of sodium
12 hour old infant with respiratory distress and difficulty feeding. Tachypneic
generalized hypotonia and hoarse cry. Significant macroglossia
mother from south america
identify cause
Congenital hypothyroidism - most common cause worldwide is Iodine deficiency
What antibody is associated with Hashimoto thyroiditis?
anti-peroxidase antibodies
elderly pt with T2DM present with progressively decreasing eyesight over the past two years. has a glare when looking directly at lights. what is happening and what is mechanism of damage?
Cataracts - converion of glucose to sorbitol in the lens (toxic)
pt w worsening dysphagia “feels like food gets stuck her throat”
Prominent, nontender thyroid gland
normal TSH, normal T4
Histopathology of thyroid: mix of fibrous tissue and infiltrative lymphocytes, neutrophils, plasma cells, eosinophils.
What is the dz? what can be a complication?
Riedel (Infiltrative) thyroiditis -
painless thyroid enlargement, normal thyroid hormone production
complication: Obstructive pneumonia
What is the initial step in management of a pheochromocytoma
alpha blockers (a1 and a2) FIRST
then beta blockers
then surgery
12 year old has notably short stature and rounded face. fourth metacarpals are shortened. Labs show hypocalcemia, hyperphosphatemia, increased PTH
what is dz?
Psuedohypoparathyroidism (end-organ resistance to PTH)
-hypocalcemia, hyperphosphatemia, increased PTH.
pt has short stature, rounded face, shortened fourth/fifth metacarpals.
40 yr old pt finds a slowly enlarging nodule in the thyroid gland. TSH is low. Radioiodine studies show increase radioiodine uptake in the solitary nodule. what is the most likely dx?
Follicular adenoma - suspected when a nodule discovered is hyperfunctioning
–does not require therapy unless they produced signs of hyperthyroidism
What should diabetic pts be aware of when prescribed B-blockers?
B-blockers can mask the symptoms of hypoglycemia:
–palpitations, paresthesias, behavioral changes when plasma blood sugar is low
What vitamin deficiency can be seen with carcinoid syndrome? what are symptoms?
what is an additional finding of carcinoid syndrome (20% initial presentation)
Niacin deficiency
—tryptophan is the precursor for both serotonin and niacin, all the tryptophan is used up to make serotonin
Sx: Dermatitis, Diarrhea, Dementia, Death
–Tricuspid regurgitation
A 5 year old pt is treated for T1DM. four hours later, pt presents with muscle weakeness, fatigue, chest palpitations
what is the cause of the new sx?
Excess insulin causes HYPOKALEMIA
–enhances the Na/K ATPase pump in skeletal muscle
–weakness, cramps, fatigue, palpitations, arrhythmias
What serum level should be measured when a pt presents with Sx of acromegaly
IGF-1
GH fluctuates too much to be accurate
What is the most appropriate med to relieve gastroparesis from poor glycemic control?
Metoclopramide - prokinetic agent that sensitive GI tract to acetylcholine
–also used as an antiemetic agent
What other lab should be checked if oral potassium fails to correct hypokalemia?
Check magnesium levels
- -Mg is a cofactor in potassium channel function in the kidney
- -Mg closes channels in absence of aldosterone (low Mg = channels stay open and K is lost)
63 yr old pt w weight loss, diarrhea, chest pain. Hx of recent flu-like illness. Initial exam shows sinus tach, painful and enlarged thyroid. what is the dx?
Subacute granulomatous thyroiditis
- -leakage of thyroid hormone from inflamed thyroid gland
- -commonly follows viral URI
- -the only form of thyroiditis that results in a PAINFUL thyroid gland.
pt w tachycardia, frequent sweating, tremor, and reports “feeling hot”. labs show decreased TSH. what is the drug of choice to initially control her cardiac symptoms? why?
Propranolol
- -nonselective beta blocker that decreases sympathetic Sx
- -also INHIBITS 5’deiodinase
38 yr old African American female presents complaining of chronic fatigue and lower back pain for 11 months. she is taking phenytoin for epilepsy. Exam shows wide-based “waddling” gait, accentuated lumbar lordosis, proximal muscle weakness in the lower extremities. Palpation of hip = symmetrical nonradiating pain.
- What is dz.
- What serum lab findings?
- Osteomalacia from vit D deficiency
- Increased PTH
- blacks - higher prevalence of vit D deficiency
- phenytoin activates p450 to degrade Vit D faster
