Calcium Disorders Lecture Powerpoint Flashcards
Role of parathyroid hormone
Maintain extracellular fluid ca2+ balance, acts directly on bone and kidney, acts indirectly on gut thru vit d production
Differential for hypercalcemia (6)
- PTH related
- Malignancy
- Vit D intoxication
- Hyperthyroidism
- thiazide diuretics
- Excessive alkaline agent ingestion
Hypercalcemia clinical features (4)
- asymptomatic
- fatigue, depression
- N/V
- stone formation
Primary hyperparathyroidism
Inappropriate elevation of PTH levels in relation to elevated Ca2+ levels, most often caused by a solitary adenoma
Treatment indications for primary hyperparathyroidism in asymptomatic patients (4)
- Only if serum Ca2+ >1.0mg/dL above normal
- or if osteoporosis development
- or if age less than 50
- or if kidney impairment
Treatment for primary hyperparathyroidism first choice and backup option
- Surgical removal using intraoperative rapid PTH assays between removing one parathyroid gland or in the case of 4 gland hyperplasia remove 3.5 glands and autotransplant remnant into forearm
- Cinacalcet (sensipar) that is a calcimimetic agent that lowers PTH levels
Chvostek sign
Light tap on facial nerve sees corner of mouth twitch in response, common in normal individuals but bilateral can indicate hypocalcemia
Trousseau’s sign
Pump blood pressure cuff above systolic and retain it until the patient cramps up due to acidosis, indicative of hypocalcemia
Differential for hypocalcemia (4)
- chronic renal failure
- hypoparathyroidism
- vit D deficiency
- transient
Hypocalcemia signs and symptoms (3)
- muscle spasms, convulsions
- mental status change
- positive chvostek and trousseau sign
Vit D action
Increases intestinal ca2+ absorption and increases effect of PTH on the bone, sourced from sunlight or from fortified foods, converted to active form at liver and kidney and acts on gut
Common causes of vit D deficiency (3)
- GI malabsorption
- Cirrhosis or kidney failure
- steroids/anticonvulsants
Vit D insufficiency value vs deficiency value
Insufficiency >20 but <30 ng/mL and deficiency <20 ng/mL
Vit D deficiency screening (3)
- Those without regular sun exposure
- Gastric surgery
- osteoporosis eval
Vitamin D replacement therapy
Vit D3 50,000 IU weekly for 4-6 weeks, then maintenance 800-2000 IU daily