Endocrine Flashcards
What is acute adrenal insufficiency (adrenal crisis)?
Etiology: adrenal hemorrhage or infarction; acute illness/injury/surgery in pt w/ chronic adrenal insufficiency or long-term glucocorticoid use
RF: underlying primary adrenal insufficiency (Addison disease) or suppression of HPA axis due to chronic glucocorticoid use
Presentation: hypotension/shock; nausea, vomiting, abdominal pain; weakness, fever
Tx: hydrocortisone or dexamethasone; high flow IVF
What is primary hyperparathyroidism?
Etiology: parathyroid adenoma (most common), hyperplasia, carcinoma, increased in MEN1 and 2A
Presentation: asymptomatic (most common); mild, nonspecific symptoms (eg fatigue, constipation), abdominal pain, renal stones, bone pain, neuropsychiatric symptoms
Dx: hypercalcemia, hypophosphatemia, elevated or inappropriately normal PTH, elevated 24h urinary ca excretion
Indications for parathyroidectomy: age <50yo, symptomatic hypercalcemia; complications - osteoporosis (T score < -2.5, fragility fracture), nephrolithiasis/calcinosis, CKD (GFR <60);
elevated risk of complications - calcium >/= 1mg/dl above normal, urinary ca excretion >400mg/day
What is thyroid storm/hyperthyroidism?
Precipitating factors: thyroid or non-thyroid surgery, acute illness (eg trauma, infection), childbirth; acute iodine load (eg iodine contrast)
Presentation: fever as high as 40-41.1C (104-106F); tachycardia, hypertension, CHF, cardiac arrhythmias (eg atrial fibrillation); agitation, delirium, seizure, coma; goiter, lid lag, tremor, warm and moist skin; nausea, vomiting, diarrhea, jaundice
Tx: beta blocker (eg propranolol) to decrease adrenergic manifestations; PTU (to block new hormone synthesis) followed by iodine solution (SSKI) (to block release; given 1h later to prevent excess I incorporation into TH); glucocorticoids (eg hydrocortisone) to decrease peripheral T4 to T3 conversion and improve vasomotor stability; identify trigger and treat, supportive care
What is hypocalcemia?
After confirmation, next step is to check PTH level to distinguish between low PTH-assoc. conditions (eg parathyroid surgery, polylglandular autoimmune) and elevated PTH-assoc. conditions (eg vit D deficiency, chronic kidney disease).
Causes: neck sugery (parathyroidectomy), pancreatitis, sepsis, tumor lysis syndrome, acute alkalosis, chelation: blood (citrate binds ionized ca) transfusion, EDTA, foscarnet
Presentation: muscle cramps, Chvostek and Trousseau signs, paresthesias (tingling and numbness), hyperreflexia/tetany, seizures; QT interval prolongation
Pts w/ impaired hepatic function are at increased risk due to decreased clearance of citrate by the liver.
Lactate, foscarnet, and EDTA can chelate calcium in the blood
Tx: IV calcium gluconate/chloride
What is papillary thyroid cancer?
Most common thyroid epithelial malignancy
Characterized by slow spread into local tissues and regional lymph nodes
Pathology: large cells w/ ground glass cytoplasm; pale nuclei w/ inclusion bodies and central grooving; and grainy, lamellated calcification known as psammoma bodies
Tx: surgical resection; postoperative adjuvant therapies for pts at increased risk of recurrence include radioiodine ablation and suppressive doses of thyroid hormone
What is follicular thyroid cancer?
Second most common thyroid epithelial malignancy
Peak incidence of 40-60yo
Presentation: firm thyroid nodule
Thyroid scintigraphy usually shows a nonmetabolically active “cold” nodule
Dx: surgically excised nodule - invasion of tumor capsule and/or blood vessels; invasion pattern accounts for tendency of FTC to metastasize via hematogenous spread and to distant tissues (eg bone, lung)
What is thyroid lymphoma?
Uncommon, though high incidence in pts w/ pre-existing chronic lymphocytic (Hashimoto) thyroiditis (ie chronic hypothyroidism, positive antithyroid peroxidase antibody)
Presentation: rapidly enlarging, firm goiter assoc. w/ compressive symptoms (eg dysphagia, hoarseness); systemic B sxs (fever, night sweats, wt loss); retrosternal extension (prominent venous distension, facial redness=Pemberton sign)
What is Riedel thyroiditis?
Progressive fibrosis of thyroid gland and surrounding tissues
Resulting fibrotic mass may resemble malignancy, but sxs are chronic and slowly progressive rather than acute
What is constitutional growth delay?
Characterized by delayed growth spurt, delayed puberty, and delayed bone age.
What is glucose 6 phosphatase deficiency (type 1 glycogen storage disease/von Gierke disease)?
Caused by deficient glucose 6 phosphatase in liver, kidney, intestinal mucosa which results in impaired conversion of glycogen to glucose, leading to glycogen accumulation in affected organs
Presentation: 3-4mo, hypoglycemia (seizures), lactic acidosis (due to buildup in liver); DOLL LIKE FACE, thin extremities, short stature, LARGE LIVER
No spleen and heart involvement
Labs: hyperuricemia, hyperlipidemia
What is euthyroid sick syndrome?
AKA “low T3 syndrome”; any pt w/ acute, severe illness
Labs: decreased total and free T3 levels, normal TSH and T4
What is subclinical hypothyroidism?
Elevated TSH
Normal T4, T3 (until late stages)
What is chronic lymphocytic (Hashimoto) thyroiditis?
Form of hypothyroidism; subclincal hypothyroidism may convert to overt hypothyroidism
Presentation: symmetrically enlarged non-tender thyroid
Labs: antithyroid peroxidase and anti-thyroglobulin antibodies
High titers of anti-tpo assoc. w/ increased risk of miscarriage
Tx: levothyroxine
Estrogen and TH.
Oral E decreases clearance of thyroxine-binding globulin, leading to elevated TBG levels.
Pt w/ nl thyroid fxn can readily increase thyroxine production to saturate increased number of TBG binding sites.
Hypothyroid pts are dependent on exogenous thyroid replacement and cannot compensate resulting in decreased free thyroxine and increased TSH. So, higher dosing of levothyroxine may be required.
Radioactive iodine uptake (RAIU) scintigraphy
Increased in cases of hormone overproduction (graves)
Low/undetectable in cases of release of preformed hormone (painless thyroiditis)
Water deprivation test.
Urine osm >600 suggest primary polydipsia due to intact ADH and ability to concentrate urine in absence of water intake.
Less than 600 = diabetes insipidous
Desmopression distinguishes between central and nephrogenic DI.
Central DI: >50% increase in urine osmolality w/ desmopressin; Tx: intranasal desmopressin
Nephrogenic DI: minimal change in urine osmolality w/ desmopression
Thyrotoxicosis.
Causes increased sensitivity to catecholamines due to increased expression of beta-1 adrenergic receptors as well as changes in proteins controlling post beta-1 adrenergic receptor activity.
It DOES NOT stimulate catecholamine production.
What is metabolic syndrome?
At least 3/5 are met: BP >130/80 Fasting glucose >100-110 Abdominal obesity (M: waist circum >40in; W: >35in) Triglycerides >150 HDL (M: <40, W: <50)
Diabetic neuropathy.
Small fiber injury: predominance of positive sxs (eg pain, paresthesias, allodynia)
Large fiber injury: predominance of negative sxs (numbness, loss of proprioception and vibration sense, diminished ankle reflexes)
Hypercalcemia.
Nephrolitihiasis, osteoporosis, nausea, constipation, neuropsychiatric symptoms (confusion, stupor, coma); (“stones, bones, abdominal moans, psychic groans”)
Tx: severe - calcitonin (inhibits osteoclast-mediated bone resorption, quickly reduces serum Ca concentrations and can be admnistered w/ saline)
Bisphosphonates also inhibit bone resorption and provide a sustained reduction in ca levels. however their effect is delayed usually occuring over 2-4d and they are typically given after initial administeration of saline and calcitonin
What is painless (silent) thyroiditis?
Variant of chronic lymphocytic (Hashimoto) thyroiditis
Presentation: self-limited hyperthyroid phase, then hypothyroid phase
Low uptake on RAIU scan
Labs: thyroid peroxidase autoantibodies
Tx: beta blocker for hyperthyroid symptoms
What is methimazole?
Decreases TH production
Used in thyrotoxicosis
What is radioactive iodine?
Causes radiation-induced destruction of thyroid follicular cells
Leads to clincial and biochemical resolution of hyperthyroidism over the subsequent 6-18 weeks
Can lead to permanent hypothyroidism w/in months in >90% of pts (Graves)
In contrast, when used to treat toxic nodular goiter and toxic adenoma, the radioisotope is taken up only by the autonomous thyroid tissue, and the function of the remaining normal tissue is usually adequate to prevent permanent hypothyroidism
Used in thyrotoxicosis
What is Gauchers disease?
Most common lysosomal storage disease Due to GLUCOcerebrosidase deficiency resulting in accumulation of glucocerebrosidase in lipid-laden MACROPHAGES of different tissues - BM: anemia + thrombocytopenia Splenomegaly > hepatomegaly Bone: bone pain FFT, delayed puberty Tx: enzyme replacement
Primary hyperparathyroidism and HTN.
Primary hyperparathyroidism can cause HTN, arrhythmias, ventricular hypertrophy, and vascular and valvular calcification.
Hypothyroidism and metabolic abnormalities.
Causes-
Hyperlidemia: due to decreased LDL surface receptors and/or decreased LDL receptor activity
Hypertriglyceridemia: due to decreased lipoprotein lipase activity
Hyponatremia: due to decreased free water clearance
Asx elevation of creatinine and serum transaminases
Glucose control in DM.
Pts who have an elevated HbA1c despite good control of fasting glucose may have POSTPRANDIAL hyperglycemia.
Combined regimen including a long-acting basal insulin (to control baseline/fasting glucose) and a rapid-acting mealtime insulin (to control postprandial glucose) may be needed to provide optimal control.
Hyperthyroid drugs.
Antithyroid drugs (methimazole, PTU) are used in pts w/ mild disease who are likely to have a permanent remission. Also used in preparation for treatment w/ radioactive iodine in pts w/ significant hyperthyroidism or who are at increased risk of complications.
What is acute thyrotoxic myopathy?
Presentation: severe distal or proximal muscle weakness; muscle atrophy
DTR are frequently normal
Tx: treatment of hyperthyroidism usually improves the myopathy
