Disorders of Parathyroid and Calcium MCQs

All the options contribute to a decreased incidence of osteoporosis. However, the fact that she is overweight suggests that her estrone levels are high due to higher expression of aromatase enzyme present in adipose tissue. Estrone is the main sex hormone produced after the menopause. Ovarian thecal androgens are converted to estrone in adipose tissue by the enzyme aromatase. High levels of estrone in this woman may thus be the main factor preventing the occurrence of bone resorption and osteoporosis. Reference: Harrison's Principles of Internal Medicine 21 st edition Page 3195

Amiodarone is structurally related to thyroid hormone & contains 37% iodine by weight. 1 tablet of 200 mg Amiodarone contains around 75 mg of iodine. Reference: Harrison's Principles of Internal Medicine 21 st edition Pg:2945

Ans. is 'd' i.e., Seen in teratoma o Psammoma bodies represent a process of dystrophic calcification. o Single necrotic cells may constitute seed crystals that become encrusted by the mineral deposits. The progressive acquisition of outer layers may create lamellated configurations, called psammoma bodies because of their resemblance to grains of sand. o Psammoma bodies are seen in : papillary cancer of thyroid, meningioma, papillary serous cystadenocarcinoma of ovary.

Calcium oxalate crystal formation in urine occurs independent of urine pH. You should not get confused as Urine alkalinization used for treatment of calcium oxalate stones is not intended to increase the urine pH, but to improve citrate excretion which prevents stone formation. Uric acid stones form at Ph Calcium phosphate stones at pH>6.5. Reference: Harrison's principles of internal medicine, 21 st ed, Ch: 318, Pg: 2369.

Management of osteoporotic fractures are treatment of the fractures along with management of osteoporosis. The management of osteoporosis involves: Reduction of risk factors: smoking cessation, weight reduction etc Nutritional: Calcium and Vitamin D supplements, Proteins adequately Pharmacological measures: Bisphosphonates are the mainstay. Reference: Harrison's Principles of Internal Medicine 21 st Ed, Ch:411 Pg: 3201-3203

Drugs like Iron, calcium, PPIs and H2 receptor blockers, cholestyramine, sucralfate can interfere with thyroxine drug absorption from GIT Therefore, a minimum of 4-6 hours gap to be ensured in patients taking these drugs along with thyroxine Reference: William's textbook of Endocrinology 14 th edition Page 427

Hypo-estrogenization, as in this case, is usually characterized by predominantly trabecular bone loss. Involutional bone loss of old age is characterized by a mixed picture of trabecular and cortical bone loss. In the presence of normal calcium and parathyroid hormone levels, parathyroid disease is ruled out. Hormone replacement therapy was formerly the mainstay of treatment, but this has fallen out of favor due to increased thromboembolic disease and the risk of breast carcinoma. The current line of therapy for osteoporosis include either anti-resorption agents like bisphosphonates and denosumab or anabolic agents like Teriparatide. Reference: Harrison's Principles of Internal Medicine 21 st edition Page 3192-93

PTH shares a receptor with PTH-related peptide (PTHrP), and this receptor is a member of the G protein–coupled receptor (GPCR) family. PTH/PTHrP receptors are expressed by kidney and bone cells, and PTH acts directly on renal and bone cells. PTH acts indirectly on intestinal cells to enhance calcium absorption as follows: PTH stimulates renal 1α-hydroxylase activity to promote synthesis of the active form of vitamin D (1,25-dihydroxyvitamin D), which then acts on the intestine to enhance calcium absorption. Reference: Harrison's Principles of Internal Medicine 21st edition, page number 3171