Endocrine - Pathology Part 1 Flashcards
A 30-year-old male comes to clinic with central obesity and purple striae across teh abdomen. What is the likely diagnosis?
Cushing’s disease, which constitutes 70% of cases of Cushing’s syndrome
A patient with Cushings syndrome has an increased adrenocorticotropic hormone level; what are two mechanisms of increased adrenocorticotropic hormone production?
Overproduction of adrenocorticotropic hormone by the pituitary and overproduction of adrenocorticotropic hormone by an ectopic site (such as in small-cell lung cancer)
A patient with Cushings syndrome has a decreased adrenocorticotropic hormone level; what are two mechanisms of increased cortisol production with low adrenocorticotropic hormone levels?
Overproduction of cortisol by the adrenal cortex or administration of exogenous cortisol
A patient is diagnosed with small-cell carcinoma of the lung leading to Cushings syndrome. Will this patients adrenocorticotropic hormone level be high or low?
High
A patient is diagnosed with primary adrenal cortical hyperplasia. Will this patients adrenocorticotropic hormone level be high or low?
Low
What is the effect of long-term steroid administration on adrenocorticotropic hormone?
Suppression of the hypothalamic-pituitary-adrenal axis causing low adrenocorticotropic hormone levels
What is Cushings disease?
An adrenocorticotropic hormone-hypersecreting primary pituitary adenoma
What are the results of a low dose dexamethasone suppression test in a healthy person?
Decreased cortisol level; dexamethasone decreases adrenocorticotropic hormone secretion by negative feedback leading to decreased cortisol levels
What results would you expect after a dexamethasone suppression test in the setting of an adrenocorticotropic hormone-producing pituitary tumor?
With low-dose dexamethasone, we would expect high cortisol levels (no suppression); with high doses of dexamethasone, we would expect suppression and thus low adrenocorticotropic hormone and cortisol levels
Would cortisol levels be high or low after a high-dose dexamethasone suppression test in a patient with an ectopic adrenocorticotropic hormone-producing tumor?
High; the secretory activity of this tumor is independent of negative feedback
Would cortisol levels be high or low after a high-dose dexamethasone suppression test in a patient with a cortisol-producing tumor?
High; the secretory activity of this tumor is independent of negative feedback
What findings are indicative of Cushings syndrome?
Hypertension, weight gain, moon facies, truncal obesity, buffalo hump, hyperglycemia (insulin resistance), skin changes, osteoporosis, amenorrhea, and immune suppression
Why are patients who are taking chronic steroids more susceptible to infection?
Associated immune suppression
When are cortisol levels drawn for the dexamethasone suppression test and why?
In the morning; this is when cortisol levels should be at the highest
Which diuretic is used as a treatment for hyperaldosteronism?
Spironolactone, a K+-sparing diuretic that works as an aldosterone antagonist
What is the cause of Conns syndrome?
An aldosterone-secreting tumor
A patient has hypertension, hypokalemia, metabolic alkalosis, and a low plasma renin level; what is the likely diagnosis?
Conns syndrome
A patient has hypertension, hypokalemia, metabolic alkalosis, and a high plasma renin level; what is the likely diagnosis?
Secondary hyperaldosteronism
Name five causes of secondary hyperaldosteronism.
Renal artery stenosis, chronic renal failure, congestive heart failure, cirrhosis, and nephrotic syndrome
Why is secondary hyperaldosteronism associated with high plasma renin levels?
All the causes of secondary hyperaldosteronism cause the kidney to perceive a low intravascular volume state, causing up-regulation of the renin-angiotensin pathway
Which hormones are deficient in patients with Addisons disease?
Cortisol and aldosterone
What pathologic findings would be expected in the adrenal glands of a patient with Addisons disease?
Adrenal Atrophy affecting All three cortical divisions and Absence of hormone production
Name three findings associated with Addisons disease (primary adrenal insufficiency).
Hypotension, skin hyperpigmentation, hyperkalemia
Is primary or secondary hypoaldosteronism associated with skin hyperpigmentation?
Primary
Is low adrenocorticotropic hormone production associated with primary or secondary hypoaldosteronism?
Secondary
Why is skin pigmentation a finding of Addisons?
In Addisons, there is increased adrenocorticotropic hormone; proopiomelanocortin is the precursor of adrenocorticotropic hormone and melanocyte-stimulating hormone; melanocyte-stimulating hormone leads to skin hyperpigmentation
How is primary adrenal insufficiency distinguished from secondary adrenal insufficiency?
Secondary adrenal insufficiency has decreased adrenocorticotropic hormone, no skin hyperpigmentation, and no hyperkalemia
What processes can cause primary adrenal insufficiency?
Atrophy or destruction by autoimmune disease, tuberculosis infection, or metastatic malignancy
A patient with meningococcal septicemia suddenly becomes severely hypotensive, with disseminated intravascular coagulation and endotoxic shock; what is the likely diagnosis?
Waterhouse-Friderichsen syndrome, or acute adrenocortical insufficiency caused by adrenal hemorrhage
From what cells does a pheochromocytoma develop?
Chromaffin cells of the adrenal medulla, which are of neural crest origin
Based on a history suggestive of pheochromocytoma, you order serum and urine tests for confirmation; what would be consistent with this diagnosis?
Increased plasma catecholamines and urinary vanillylmandelic acid
List three genetic syndromes that are associated with pheochromocytoma.
Multiple endocrine neoplasia types IIA and IIB, neurofibromatosis
What category of drugs is often used to treat pheochromocytoma?
α-Antagonists
Why is phenoxybenzamine a good choice in the treatment of pheochromocytoma?
It is a nonselective, irreversible -blocker
What are five common symptoms associated with pheochromocytoma?
Pressure (elevated blood pressure), Pain (headache), Perspiration, Palpitations (tachycardia), Pallor (remember: the 5 Ps)
List the six components of “the pheochromocytoma rule of tens.”
10% malignant, 10% bilateral, 10% extra-adrenal, 10% calcify, 10% kids, 10% familial
What characteristic of pheochromocytoma distinguishes it from chronic, poorly controlled hypertension?
Symptoms occur in “spells” and are thus relapsing and remitting
From which two amino acids are catecholamines synthesized?
Phenylalanine and tyrosine
The most common adrenal tumor is _____ in adults and _____ in children.
Pheochromocytoma; neuroblastoma
Where in the body can a neuroblastoma develop?
Anywhere along the sympathetic chain
What product is increased in the urine of children with neuroblastoma?
Homovanillic acid (a breakdown product of dopamine)
What oncogene is associated with neuroblastoma?
N-myc
How do hypo- and hyperthyroidism each affect temperature tolerance?
Hypothyroidism causes cold intolerance; hyperthyroidism causes heat intolerance
How do hypo- and hyperthyroidism each affect body weight?
Hypothyroidism causes weight gain; hyperthyroidism causes weight loss
How do hypo- and hyperthyroidism each affect bowel movements?
Hypothyroidism causes constipation; hyperthyroidism causes diarrhea
What cardiac symptoms can hyperthyroidism cause?
Chest pain and palpitations
Which serologic marker is a sensitive test for primary hypothyroidism?
Elevated thyroid-stimulating hormone
A patient is lethargic and has swelling in the face and periorbital region; you diagnose myxedema resulting from what condition?
Hypothyroidism
How do hypo- and hyperthyroidism each affect the skin?
Hypothyroidism causes dry, cool skin; hyperthyroidism causes warm, moist skin
How do hypo- and hyperthyroidism each affect the hair?
Hypothyroidism causes coarse, brittle hair; hyperthyroidism causes fine hair
What potentially fatal cardiac process is hyperthyroidism known to induce?
Arrhythmia
What are the lab findings in hypothyroidism?
Elevated thyroid-stimulating hormone with a low total T4, free T4, and T3 uptake
What are the lab findings in hyperthyroidism?
Decreased thyroid-stimulating hormone with elevated total T4, free T4, and T3uptake
What is the most common cause of hypothyroidism?
Hashimotos thyroiditis, an autoimmune disorder
In the presence of hypothyroidism, what historical and physical exam findings would be consistent with Hashimotos thyroiditis?
Hashimotos thyroiditis follows a slow course and produces a moderately enlarged, nontender thyroid
Describe the course of Hashimotos thyroiditis.
A slow course; it can have an initial period of hyperthyroidism before hypothyroidism due to follicular rupture causing thyrotoxicosis
What histologic findings are suggestive of Hashimotos thyroiditis?
A lymphocytic infiltrate with germinal centers and Hürthle cells
Which two autoantibodies are associated with Hashimotos thyroiditis?
Antimicrosomal antibodies and antithyroglobulin antibodies
What condition is a result of severe fetal hypothyroidism?
Cretinism (meaning “Christlike,” these children were considered so mentally retarded as to be incapable of sinning)
What are causes of sporadic congenital hypothyroidism?
Defect in T4formation or developmental failure in thyroid formation (congenital hypothyroidism)
While traveling in China, you learn that there is a high prevalence of cretinism; what intervention would decrease the prevalence of this disease?
This is likely endemic cretinism, found wherever endemic goiter occurs; it could be treated by dietary iodine supplementation
What physical exam findings would suggest congenital hypothyroidism in an infant?
Pot belly, protruding umbilicus, pale skin, and a puffy face with protuberant tongue
Following a flu-like illness, a patient is found to be hypothyroid and to have a tender thyroid gland; what is the prognosis?
This is most consistent with subacute thyroiditis, which has a self-limited course
Name four findings, other than hypothyroidism, associated with subacute (de Quervains) thyroiditis.
Elevated erythrocyte sedimentation rate, jaw pain, early inflammation, and a tender thyroid gland
What are histological findings of subacute (de Quervains) thyroiditis?
Granulomatous inflammation
What is the pathophysiology of Reidels thyroiditis?
Thyroid tissue is replaced by fibrous tissue
A patient with hypothyroidism has a fixed, hard (rock-like), painless goiter; what is the likely diagnosis?
Riedels thyroiditis
What is the pathophysiology of Graves disease?
It is an autoimmune disorder associated with thyroid-stimulating hormone receptor antibodies that stimulate thyroid hormone release
What physical exam findings would suggest that Graves disease is the cause of a case of hyperthyroidism?
Exophthalmos, pretibial myxedema, diffuse goiter
When does Graves disease most often present?
During stress (eg, childbirth)
What is a potentially fatal complication of hyperthyroidism?
A stress-induced catecholamine surge, which can lead to death by cardiac arrhythmia
What type of hypersensitivity reaction is Graves disease?
Type II hypersensitivity
A patient with hyperthyroidism has a thyroid scan that shows several highly active nodules; what is the diagnosis?
Toxic multinodular goiter, in which patches of follicular cells work independently of thyroid-stimulating hormone
On physical exam of a 40-year-old woman you find protruding eyes and a goiter. What do you expect on examination of her legs?
Pretibial myxedema; exophthalmos, diffuse goiter, and pretibial myxedema are three physical findings of Graves’ disease
CT of a man shows lesions indicating renal osteodystrophy. What is the diagnosis and what would the calcium and PTH levels be?
Secondary hyperparathyroidism due to chronic renal failure
;
Low calcium and high PTH
A man with renal stones has bone pain. He has increased urine cAMP. What is the diagnosis and what would the calcium and PTH levels be?
Primary hyperparathyroidism (stones, bones and groans)
;
High calcium and high PTH
A man with DiGeorge syndrome presents to your office. How would this affect his parathyroid and what levels would you expect for calcium and PTH?
Hypoparathyroidism due to DiGeorge syndrome
;
Low calcium and low PTH
