Parathyroid Disorders PDF

Parathyroid disorders Calcium metabolism Physiology of calcium homeostasis  PTH ( parathyroid hormone )  Vitamin D  Calcitonin( parafollicular cells of thyroid gland ) : it opposes the effects of PTH by : inhibiting osteoclasts from breaking down bone It inhibits CA reabsorption in re...

Parathyroid disorders Calcium metabolism Physiology of calcium homeostasis  PTH ( parathyroid hormone )  Vitamin D  Calcitonin( parafollicular cells of thyroid gland ) : it opposes the effects of PTH by : inhibiting osteoclasts from breaking down bone It inhibits CA reabsorption in renal tubular cells Vitamin D metabolism Best time for sun exposure Summer : 9 am - 10:30 & 2-3 pm Winter : 10 am -2 pm  Hypercalcemic states Primary hyperparathyroidism  Most common presentation is asymptomatic hypercalcemia  “bones, stones”  Bone disease : osteoporosis and fractures.  Neuromuscular : fatigue and weakness  Neuropsychiatric : depressed mood, psychosis  Kidney : nephrocalcinosis , stones(ca oxalate)  Cardiovascular : hypertension, ventricular hypertrophy Primary hyperparathyroidism  Calcium is high  Phosphorus is low  PTH is high Other hypercalcemic states  Thyrotoxicosis  Adrenal insufficiency  Thiazides & lithium  Hypervitaminosis D  Familial hypocalciuric hypercalcemia (PTH IS NORMAL )  MALIGNANCY : Increased PTHrp : commonest cause( BREAST CANCER ),  MULTIPLE MYELOMA , : production of osteoclast activating factor  LYMPHOMA and SARCOIDOSIS : & 1,25 dihydroxyvitamin D  PTH IS NORMAL in malignancy induced hypercalcemia  Treatment of hyperparathyroidism  In primary hyperparathyroidism : if patient is symptomatic ( lithiasis , osteoporosis, pancreatitis) surgery is indicated: bilateral neck exploration or focused parathyroid exploartion if adenoma is localized preopeatively  Intraopertave PTH monitoring  endoscopic parathyroidectomy  Medical treatment : cinacalcet ( calcimemetic agent ) : if patient is a high surgical risk.  Preoperative localization : U/S , CT ,MRI ,sestamibi scan  Removal of adenoma If hyperplasia : subtotal (removal of 3 ½ of glands) SURGERY OF PRIMARY HYPERPARATHYROIDISM Secondary hyperparathyroidism  Chronic renal disease causing hypocalcemia  Severe vitamin D deficiency  Malabsorption Hypoparathyroidism Causes : hypoparathyroidism ( autoimmmune or post surgery , Hypomagnesaemia : Mg is important for the release of PTH and for its effect) Polyglandular autoimmune syndrome Type 1 ( moniliasis→hypoparathroidism→hypoadrenalism  Clinical presentations : acute tetany( post surgical )OR chronic :  Eye : cataract , CNS ( calcification of basal ganglia ) causing extrapyramidal disorders  Cardiac : prolonged QT interval. Hypocalcemia with high PTH :  Vitamin D deficiency  Renal impairment  Vitamin D dependent rickets ( 1-alpha- hydroxylase deficiency) and hereditary resistance to to vitamin D).  Pseudohypoparathyroidism ( resistance to the action of PTH ) Hypoparathyroidism  Low calcium  High phosphorus  Low PTH Clinical presentation  Numbness  If severe hypocalcemia : tetany  Trosseau sign  Chovstek sign  ECG : prolonged QT interval Treatment of hypocalcemia  Calcium :1-2 gm daily  vitamin D analogs : calcitriol or alfacalcidol  If severe and acute with tetany : give 10 cc of 10% calcium gluconate slowly ( careful in patients on digoxin ) DEFINITION OF OSTEOPOROSIS  Low bone mass resulting in fracture from minimal trauma. Causes of osteoporosis  Menopause  Old age  Calcium and vitamin D deficiency  Estrogen deficiency in women and androgen deficiency in men  Use of steroids Exclude secondary causes especially in younger individuals and men Diagnosis of osteoporosis  Dual-energy x-ray absoptiometry ( DXA) measuring bone minaeral density (BMD) and comparing it to BMD of a healthy woman  More than -2.5 SD below average : osteoporosis  Lumbar spine Femoral neck Bone density scanner Treatment of osteoporosis  Prevention  Public awareness  Adequate calcium and vitamin D supplements  Bisphphosnates : reducing bone breakdown  Denosumab : reduces bone break down  Teriparatide : anabolic Effects  Steroids for several days causes bone loss more on axial bones ( 40 %) than on peripheral bones ( 20%).  Muscle weakness  Prednisolone more than 5 mg /day for long time Management  Use smallest possible dose  Shortest possible duration  Physical activity  Calcium and vitamin D  Pharmacologic treatment: bisphosphontaes , ? PTH  1-MANAGEMENT OF OSTEOPOROSIS AND OSTEOPENIA The management could be divided into two parts 1. Non-pharmacological therapy 2. Pharmacological therapy  1-MANAGEMENT OF OSTEOPOROSIS AND OSTEOPENIA 1. Non-pharmacological therapy Diet: -Adequate calorie intake -enough of Vit D and Ca Exercise: weight-bearing exercises Smoking cessation: because smoking accelerates bone loss Eliminate or reduce alcohol Avoid drugs that affect the bone (glucocorticoids)  1-MANAGEMENT OF OSTEOPOROSIS AND OSTEOPENIA 2. Pharmacological therapy Who needs Pharmacological therapy? 1-Postmenopausal women with established osteoporosis(T score=-2.5 or less) 2-high-risk postmenopausal women (T score=-1.0 to -2.5) 2-ROLE OF MEDICATIONS What medications do we use for osteoporosis? 1) Bisphosphonates: -first-line of treatment -Example:alendronate.. drug of choice for management of adrenal glucocorticoid-induced osteoporosis -MOA: decrease the activity of osteoclast and increase their apoptosis -Watch out for jaw osteonecrosis 2) Selective estrogen receptor modulator(raloxifine): -Used if bisphosphonates are not tolerated or counterindicated -it does not increase the risk of endometrial or breast cancer 2-ROLE OF MEDICATIONS 3)calcitonin: used as a nasal spray 4)PTH therapy (teriparatide) -given subcutaneously -given once daily and not continuously why? -used for less than 2 years (risk of osteosarcoma) 5)Denusomab: Monoclonal antibody that decreases osteoclast activation 3-ROLE OF VITAMIN D AND CA Ca : building block of bones Vitamin D : Help in absorbing Ca. 3-ROLE OF VITAMIN D AND CA Ca: Normal serum calcium level=8.5-10.5 mg/Dl Ca Bone Blood 99% 1% Complexed 10% Bound Non- 40% Bound 60% free 50% 3-ROLE OF VITAMIN D AND CA 3-ROLE OF VITAMIN D AND CA Optimal intake of calcium: From national osteoporosis foundation 3-ROLE OF VITAMIN D AND CA Vitamin D: -Provides Ca and phosphate to ECF for bone mineralization. -deficiency can cause rickets or osteomalacia. 3-ROLE OF VITAMIN D AND CA Optimal intake of Vitamin D: From national osteoporosis foundation 4-VITAMIN DEFICIENCY DURING PREGNANCY Why do you we care about Vitamin D level during pregnancy? 1- The woman’s body needs vitamin D to maintain proper levels of Ca and phosphorus, which help build the baby's bones and teeth 2-Pregnancy is a negative Ca balance state 3-deficiency might cause abnormal bone growth, fractures, or rickets in newborns. 4-It may have an association to gestational diabetes 4-VITAMIN DEFICIENCY DURING PREGNANCY How much of vitamin D does a pregnant lady need? 600 international units (IU) of vitamin D or 15 micrograms (mcg) each day. 5-PREVENTION AND ADVICE 1-Adequate dietary intake of Ca : (1200-1300 mg per day) either from dairy food (yoghurt-fish) or supplements 2-Vitamin D deficiency and sunlight : we need significant sunlight exposure to the face,arms and hands(15-30 mins a day up to 50 mins in winter)or simply take supplements 5-PREVENTION AND ADVICE 3-Exercise: Moderate exercises against gravity (brisk walking for 30 mins four times a week) 4-Lifestyle modifications: Stop smoking..limit alcohol 5-Adequate nutrition: Keep BMI