Pathophys/DDx/RF
List at least 3 DDx for hyperparathyroidism. (300 pts)
Familial Hypocalciuric Hypercalcemia (FHH)
Malignancy-Related Hypercalcemia
Medication-Induced Hypercalcemia (Lithium or Thiazides)
Granulomatous Disorders (e.g., Sarcoidosis, Tuberculosis)
Vitamin D or A Toxicity / Milk-Alkali Syndrome
List at least 3 clinical features or physical exam findings for hyperparathyroidism. (300 pts)
Neuromuscular / Motor Exam: Reduced deep tendon reflexes and proximal motor muscle weakness. High ionized calcium raises the resting membrane potential threshold, blunting neuromuscular action potential generation
Neck Examination (Non-Palpable Mass): Parathyroid adenomas are soft and small (~1 gram), making them non-palpable on physical exams. A firm, fixed, palpable neck mass in a hypercalcemic patient strongly suggests rare parathyroid carcinoma
Cardiovascular Exam: Elevated blood pressure (hypertension from hypercalcemia-induced vascular smooth muscle contraction), short QT interval on ECG, or cardiac arrhythmias
Dermatologic / Ocular Signs (primarily in SHPT): Band keratopathy ("red-eye syndrome" from corneal calcium deposits), intense pruritus (skin deposits), or calciphylaxis (painful ischemic skin necrosis)
What was the purpose of a Tc-99m Sestamibi and what were the findings? (400 pts)
Purpose: Preoperative functional imaging that takes advantage of mitochondrial radiotracer retention in overactive chief cells to locate the hyperfunctioning gland.
Findings: Confirmed a solitary left inferior parathyroid adenoma showing persistent uptake below the left thyroid lobe
What is the purpose of a parathyroidectomy and how is it conducted? (400 pts)
Purpose: Curative removal of overactive parathyroid tissue to normalize serum calcium and PTH, prevent progressive osteoporosis, stop kidney stone formation, and relieve symptoms (e.g., muscle weakness and constipation).
How It’s Conducted:
Localization: Guided preoperatively by Tc-99m Sestamibi scans and ultrasound.
Approaches: Minimally Invasive Parathyroidectomy (2–3 cm targeted incision) or Bilateral Neck Exploration (evaluates all 4 glands).
Intraoperative PTH Monitoring: Requires a ≥ 50% drop in PTH 10–20 minutes post-excision to confirm complete cure.
Frozen Section Pathology: Real-time intraoperative biopsy confirming parathyroid tissue and ruling out malignancy
What is the normal pathophysiology of PTH? (400 pts)
Parathyroid chief cells monitor extracellular ionized calcium via calcium-sensing receptors (CaSR). A drop in calcium triggers PTH release, which acts on bone (osteoclastic resorption), kidneys (distal tubular calcium reabsorption and phosphaturia), and intestines (via renal 1-alpha-hydroxylase activation converting 25-OH Vitamin D to active 1,25-OH2 Vitamin D).
Explain what occurs to the levels of calcium, phosphate and vitamin D in hyperparathyroidism. (400 pts)
Primary Hyperparathyroidism: Serum calcium is elevated, phosphate is low or low-normal, and active 1,25-dihydroxyvitamin D is elevated (while precursor 25-OH vitamin D is often low).
Secondary Hyperparathyroidism: Serum calcium is low or normal, phosphate is high (in chronic kidney disease) or low (in vitamin D deficiency), and active 1,25-dihydroxyvitamin D is low.
Tertiary Hyperparathyroidism: Serum calcium is elevated, phosphate is high or normal, and active 1,25-dihydroxyvitamin D is low or variable
What was the purpose of a point-of-care ultrasound and what were the findings? (300 pts)
Purpose: First-line, radiation-free anatomical imaging to screen the neck for enlarged parathyroid glands.
Findings: Non-diagnostic; no mass could be visualized on ultrasound
Explain the use of giving calcium and vitamin D supplementation for a patient with hyperparathyroidism. (300 pts)
Prevent Post-Op Hypocalcemia: Prevents rapid blood calcium drops and Hungry Bone Syndrome caused by sudden osteoblastic calcium influx into remineralizing bones after surgery.
Correct Pre-Op Deficiencies: Restores depleted precursor 25-OH vitamin D stores (consumed by high PTH-driven conversion to calcitriol).
Support Bone Building: Provides essential mineral raw materials (with vitamin K2, vitamin C, and magnesium) for osteoblastic matrix assembly
What is the pathophysiology for primary vs secondary hyperparathyroidism? (400 pts)
Bonus! What is the pathophysiology for tertiary hyperparathyroidism? (100 pts)
Primary (PHPT): Intrinsic, autonomous PTH hypersecretion (usually a solitary adenoma) due to an upward shift in the CaSR set-point.
Secondary (SHPT): Compensatory parathyroid hyperplasia triggered by chronic hypocalcemia, severe vitamin D deficiency, or chronic kidney disease (CKD).
Tertiary (THPT): Occurs when prolonged secondary hyperparathyroidism (e.g., end-stage renal disease) leads to irreversible nodular glandular hyperplasia. The enlarged glands secrete excess PTH autonomously, regardless of calcium levels.
What is the purpose of obtaining the random urine calcium creatinine ratio? (400 pts)
Rule Out FHH: Differentiates PHPT from Familial Hypocalciuric Hypercalcemia (FHH). A ratio < 0.01 indicates FHH (surgery contraindicated), whereas a ratio > 0.02 (or 0.36 in Catherine) confirms PHPT and hypercalciuria, justifying surgery.
Assess Stone Risk: Evaluates filtered calcium load to determine risk for nephrolithiasis.
What was the purpose of a DEXA scan and what were the findings? (400 pts)
Purpose: Measures Bone Mineral Density (BMD) to assess end-organ bone loss and determine if the patient meets criteria for surgery (T-score ≤ -2.5).
Findings: Confirmed osteoporosis with T-scores of -2.5 (femoral neck) and -2.7 (lumbar spine).
What are the benefits of weight bearing exercises for treating hyperparathyroidism? (300 pts)
Stimulates Bone Remodeling: Mechanical strain activates osteocyte mechanoreceptors, triggering osteoblasts to deposit bone matrix and rebuild density lost to hyperparathyroidism.
Strengthens Muscle & Reduces Fractures: Increases motor strength (targeting lower extremity weakness like Catherine's 4/5 strength) and balance, reducing fall and fracture risk.
What are risk factors associated with hyperparathyroidism? (300 pts)
Demographics: Postmenopausal women aged 50–60 (3–4x higher risk); Black/African Americans.
Medical Conditions: Chronic kidney disease, severe vitamin D or calcium deficiency.
Treatments & Drugs: Prior head/neck radiation therapy, chronic lithium use.
Genetics: Inherited syndromes like MEN1, MEN2A, or CaSR gene mutations.
What are the different vitamin D and calcium forms? (500 pts)
Vitamin D Forms:
Precursors: Vitamin D2 (Ergocalciferol) and D3 (Cholecalciferol).
Storage Form: 25-Hydroxyvitamin D (Calcidiol; measured for nutritional status).
Active Form: 1,25-Dihydroxyvitamin D (Calcitriol; active hormone).
Serum Calcium Forms:
Ionized Calcium (~50%): Physiologically active free fraction.
Protein-Bound Calcium (~40%): Inactive; bound to albumin.
Complexed Calcium (~10%): Bound to phosphate, citrate, or bicarbonate.
What are the T-score ranges for the DEXA scan to determine osteoporosis vs osteopenia? (500 pts)
Normal: T-score ≥ -1.0
Osteopenia: T-score between -1.0 and -2.5 (-1.1 to -2.4)
Osteoporosis: T-score ≤ -2.5
Severe Osteoporosis: T-score ≤ -2.5 plus a fragility fracture
What are the benefits of relaxation techniques for treating hyperparathyroidism? (300 pts)
Lowers Cortisol: Reduces stress-induced adrenal cortisol release; elevated cortisol impairs osteoblast function and worsens bone loss.
Symptom Relief: Reduces neuropsychiatric fatigue, anxiety, muscle tension, and joint pain associated with hypercalcemia.
What are the sequelae of hyperparathyroidism? (300 pts)
Bonus! Explain why osteoporosis develops in a patient with hyperparathyroidism. (100 pts)
Osteoporosis: Continuous, non-pulsatile PTH elevation binds to osteoblasts, strongly upregulating RANKL expression. RANKL activates osteoclasts, causing uncoupled bone resorption where osteoclastic bone degradation rapidly outpaces osteoblastic bone formation across cortical and trabecular bone.
Skeletal System: Progressive loss of bone mineral density, osteopenia, osteoporosis, fragility fractures, bone aches, and osteitis fibrosa cystica ("brown tumors")
Renal System: Filtered calcium overloads the renal tubules (hypercalciuria), causing nephrolithiasis (kidney stones), nephrocalcinosis (calcium deposits in kidney tissue), polyuria, polydipsia, and impaired renal function
Gastrointestinal System: Hypercalcemia depresses smooth muscle excitability, leading to severe constipation, anorexia, nausea, vomiting, abdominal pain, and an increased risk of peptic ulcers or pancreatitis
Neuropsychiatric System: Depressed neuronal excitability causes chronic fatigue, proximal muscle weakness, depression, difficulty concentrating, memory changes, and confusion
Cardiovascular System: High serum calcium promotes vascular smooth muscle contraction and calcification, leading to hypertension, short QT intervals, cardiac arrhythmias, and left ventricular hypertrophy
Extraosseous Calcifications (in SHPT): Calcium-phosphate deposits in non-bone tissues causing intense pruritus, band keratopathy ("red-eye syndrome"), or calciphylaxis (painful skin necrosis from vascular calcification)
What is the purpose of measuring the bone alkaline phosphatase? (400 pts)
Specific Bone Turnover Marker: Isolates the osteoblast-specific isoenzyme to quantify active skeletal remodeling driven by PTH.
Skeletal Risk Assessment: An elevated level confirms accelerated bone breakdown (osteoporosis) and alerts clinicians to the risk of post-surgical Hungry Bone Syndrome.
What was the purpose of the frozen section sampling? (500 pts)
Purpose: Intraoperative biopsy to confirm parathyroid tissue, verify that non-excised glands are normal, and rule out malignancy.
Findings: Confirmed 3 normal glands remaining in situ and verified that the removed enlarged gland was a benign chief cell adenoma without malignant invasion
How does intermittent injections of synthetic PTH help treat osteoporosis and prophylactically treat post surgical hypoparathyroidism? (400 pts)
Treats Osteoporosis (Anabolic Effect): Unlike continuous PTH elevation (which destroys bone via RANKL), daily intermittent PTH spikes preferentially stimulate osteoblasts over osteoclasts to actively build new bone matrix.
Prevents Post-Op Hypoparathyroidism: Functions as temporary hormone replacement, keeping calcium levels stable while suppressed remaining parathyroid glands recover after surgery