Endocrinology- Pathology Flashcards
Cushing syndrome
- Etiology
Exogenous corticosteroids— Most common cause.
Primary adrenal adenoma, hyperplasia, or carcinoma.
ACTH-secreting pituitary adenoma (Cushing disease); paraneoplastic ACTH secretion.
*Cushing disease is responsible for the majority of endogenous cases of Cushing syndrome.
Cushing syndrome
- Clinical manifestations
Hypertension, weight gain, moon facies, abdominal striae and truncal obesity, buffalo hump, skin changes (eg, thinning, striae), hirsutism, osteoporosis, hyperglycemia (insulin resistance), amenorrhea, immunosuppression
Cushing syndrome
- Diagnosis
- Screening tests include: free cortisol on 24-hr urinalysis, midnight salivary cortisol, and no suppression with overnight low-dose dexamethasone test.
- Measure serum ACTH. If low, suspect adrenal tumor or exogenous glucocorticoids. If high, distinguish between Cushing disease and ectopic ACTH secretion
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Adrenal insufficiency
- Sympots
- Treatment
Symptoms include weakness, fatigue, orthostatic hypotension, muscle aches, weight loss, GI disturbances, sugar and/ or salt cravings.
Treatment: glucocorticoid/ mineralocorticoid replacement.
Adrenal insufficiency
- Diagnosis
measurement of serum electrolytes, morning/random serum cortisol and ACTH, and response to ACTH stimulation test.
Alternatively, can use metyrapone stimulation test: metyrapone blocks last step of cortisol synthesis (In 1° adrenal insufficiency, ACTH is high but 11-deoxycortisol
remains low after test. In 2°/3° adrenal insufficiency, both ACTH and 11-deoxycortisol remain low after test).
Primary adrenal insufficiency
loss of gland function: hypotension, hyperkalemia, metabolic acidosis, skin and mucosal hyperpigmentation
Acute—sudden onset (eg, due to massive hemorrhage). May present with shock in acute adrenal crisis.
Chronic—Addison disease. Due to adrenal atrophy or destruction by disease (autoimmune destruction most common in the Western world; TB most common in the
developing world).
Waterhouse-Friderichsen syndrome
acute 1° adrenal insufficiency due to adrenal hemorrhage associated with septicemia (usually Neisseria meningitidis), DIC, endotoxic shock.
Secondary adrenal insufficiency
Tertiary adrenal insufficiency
Seen with pituitary ACTH production. No skin/mucosal hyperpigmentation, no hyperkalemia.
Seen in patients with chronic exogenous steroid use, precipitated by abrupt withdrawal.
Hyperaldosteronism
- Clinical manifestations
hypertension, low or normal K+, metabolic alkalosis. 1° hyperaldosteronism does not directly cause edema due
to aldosterone escape mechanism.
Primary hyperaldosteronism
adrenal adenoma (Conn syndrome) or bilateral adrenal hyperplasia. high aldosterone, low renin. Causes resistant hypertension.
Secondary hyperaldosteronism
Seen in patients with renovascular hypertension, juxtaglomerular cell tumors (renin-producing), and edema (eg, cirrhosis, heart failure, nephrotic syndrome).
Neuroendocrine
tumors
Heterogeneous group of neoplasms that begin in specialized cells called neuroendocrine cells.
Cells contain amine precursor uptake decarboxylase (APUD) and secrete different hormones.
Most tumors arise in the GI system (eg, carcinoid, gastrinoma), pancreas (eg, insulinoma, glucagonoma), and lungs (eg, small cell carcinoma).
Neuroblastoma
Most common tumor of the adrenal medulla in children, usually < 4 years old. Originates from Neural crest cells. Occurs anywhere along the sympathetic chain.
Neuroblastoma
- Clinical features
Most common presentation is abdominal distension and a firm, irregular mass that can cross the midline (vs Wilms tumor, which is smooth and unilateral). Less likely to develop hypertension than with pheochromocytoma.
Can also present with opsoclonus-myoclonus syndrome (“dancing eyes-dancing feet”).
Neuroblastoma
- Diagnosis
HVA and VMA (catecholamine metabolites) in urine. Homer-Wright rosettes characteristic of neuroblastoma and medulloblastoma. Bombesin and NSE ⊕.
Associated with overexpression of N-myc oncogene. Classified as an APUD tumor.
Pheochromocytoma
-Etiology
Most common tumor of the adrenal medulla in
adults. Derived from chromaffin cells (arise from neural crest).
May be associated with germline mutations (eg,
NF-1, VHL, RET [MEN 2A, 2B]).
Rule of 10’s: 10% malignant 10% bilateral 10% extra-adrenal (eg, bladder wall, organ of Zuckerkandl) 10% calcify 10% kids
Pheochromocytoma
- Symptoms
episodic hypertension. May also secrete EPO, polycythemia. Symptoms occur in “spells”—relapse and remit
Episodic hyperadrenergic symptoms (5 P’s): Pressure (high BP) Pain (headache) Perspiration Palpitations (tachycardia) Pallor
Pheochromocytoma
- Findings
- Treatment
High catecholamines and catecholamine metabolites (eg, metanephrines) in urine and plasma.
Irreversible α-antagonists (eg, phenoxybenzamine) followed by β-blockers prior to tumor resection. α blockade must be achieved before giving β-blockers to avoid a hypertensive crisis. A before B.
VIPoma
- Etiology
- Symptoms
Most commonly arises in pancreas. Associated with MEN-1. Primary symptom is secretory diarrhea.
WDHA (Watery Diarrhea, Hypokalemia, Achlorhydria) syndrome.
Hypothyroidism vs hyperthyroidism
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Hashimoto thyroiditis
- Etiology
Most common cause of hypothyroidism in iodine sufficient regions; an autoimmune disorder with antithyroid peroxidase (antimicrosomal) and antithyroglobulin antibodies.
Associated with HLADR3, risk of non-Hodgkin lymphoma.
Hashimoto thyroiditis
- Histology:
- Findings:
Hürthle cells, lymphoid aggregates with germinal centers.
moderately enlarged, nontender thyroid
*May be hyperthyroid early in course due to thyrotoxicosis during follicular rupture.
Postpartum thyroiditis
- Etiology
- Presentation
- Histology
Self-limited thyroiditis arising up to 1 year after delivery. Presents as transient hyperthyroidism, hypothyroidism, or hyperthyroidism followed by hypothyroidism.
Thyroid usually painless and normal in size.
Histology: lymphocytic infiltrate with occasional germinal center formation
Congenital hypothyroidism (cretinism) - Etiology
Severe fetal hypothyroidism due to antibody-mediated maternal hypothyroidism, thyroid agenesis, thyroid dysgenesis (most common cause in US), iodine deficiency, dyshormonogenetic goiter.
Congenital hypothyroidism (cretinism) - Findings
Pot-bellied, Pale, Puffy-faced child with Protruding umbilicus, Protuberant tongue, and Poor brain development:
the 6 P’s
Subacute granulomatous thyroiditis (de Quervain)
- Etiology
- Presentation
Self-limited disease often following a flu-like illness
May be hyperthyroid early in course, followed by hypothyroidism (permanent in ~15% of cases).
Subacute granulomatous thyroiditis (de Quervain)
- Histology
- Findinga
Granulomatous inflammation.
Increase ESR, jaw pain, very tender thyroid. (de Quervain is associated with pain.
Riedel thyroiditis (hypothiroidism)
- Etiology
- Findings
Thyroid replaced by fibrous tissue with inflammatory infiltrate. Fibrosis may extend to local structures (eg, trachea, esophagus), mimicking anaplastic carcinoma. 1⁄3 are hypothyroid.
Considered a manifestation of IgG4-related systemic disease.
Findings: fixed, hard (rock-like), painless goiter
Graves disease
- Etiology
Most common cause of hyperthyroidism. Thyroid stimulating immunoglobulin (IgG; type II hypersensitivity) stimulates TSH receptors on thyroid (hyperthyroidism, diffuse goiter) and dermal fibroblasts (pretibial myxedema).
Graves disease
- Presentation
- Histology
Often presents during stress (eg, pregnancy).
Associated with HLA-DR3 and HLA-B8.
Histology: tall, crowded follicular epithelial cells; scalloped colloid.
Toxic multinodular goiter
Focal patches of hyperfunctioning follicular cells distended with colloid working independently of TSH (due to TSH receptor mutations in 60% of cases).
Hot nodules are rarely malignant.
Thyroid storm
- Etiology
- findings
complication that occurs when hyperthyroidism is incompletely treated/untreated and then significantly worsens in the setting of acute stress
Presents with agitation, delirium, fever, diarrhea, coma, and tachyarrhythmia
Thyroid storm
- Treatment
Treat with the 4 P’s: β-blockers (eg, Propranolol), Propylthiouracil, corticosteroids (eg, Prednisolone), Potassium iodide (Lugol iodine).
Jod-Basedow phenomenon
Thyrotoxicosis if a patient with iodine deficiency and partially autonomous thyroid tissue (eg, autonomous nodule) is made iodine replete.
Opposite to Wolff-Chaikoff effect.
Causes of goiter
- Smooth/difusse
Graves disease
Hashimoto thyroiditis
Iodine deficiency
TSH-secreting pituitary adenoma
Causes of goiter
- Nodular
Toxic multinodular goiter
Thyroid adenoma
Thyroid cancer
Thyroid cyst
Thyroid adenoma
Benign solitary growth of the thyroid. Most are nonfunctional (“cold”).
Most common histology is follicular; absence of capsular or vascular invasion (unlike follicular carcinoma).
Thyroid cancer
diagnosed with fine needle aspiration; treated with thyroidectomy.
Thyroid cancer
- Papillary carcinoma
Most common, excellent prognosis. Empty-appearing nuclei with central clearing (“Orphan Annie” eyes), psamMoma bodies, nuclear grooves.
High risk with RET/PTC rearrangements and BRAF mutations, childhood irradiation.
Thyroid cancer
- Follicular carcinoma
Good prognosis. Invades thyroid capsule and vasculature (unlike follicular adenoma), uniform follicles; hematogenous spread is common.
Associated with RAS mutation and PAX8-PPAR-γ translocations.
Thyroid cancer
- Medullary carcinoma
From parafollicular “C cells”; produces calcitonin, sheets of cells in an amyloid stroma (stains with Congo red).
Associated with MEN 2A and 2B (RET mutations).
Thyroid cancer
- Undifferentiated/anaplastic carcinoma
Older patients; invades local structures, very poor prognosis
Thyroid cancer
- Lymphoma
Associated with Hashimoto thyroiditis.
