How Common is it?

• Affects 1 in 500-1,000 people
• More common in women (2-3:1 ratio)
• Incidence increases with age (peak age 50-60)
• Often discovered incidentally on routine blood work

Symptoms:

Many patients are asymptomatic (no symptoms). When symptoms occur, they relate to high calcium and are summarized by the classic phrase:

"Stones, Bones, Groans, and Psychiatric Overtones"

• Stones: Kidney stones (nephrolithiasis) due to excess calcium in urine
• Bones: Osteoporosis, bone pain, fractures (PTH pulls calcium from bones)
• Groans: Gastrointestinal symptoms—nausea, constipation, abdominal pain, peptic ulcers, pancreatitis
• Psychiatric Overtones: Fatigue, depression, cognitive impairment, anxiety, confusion

Other Symptoms:

• Muscle weakness
• Excessive thirst and urination (from high calcium)
• Heart palpitations, high blood pressure

Diagnosis:

Lab Findings (Classic Triad):

• Elevated Serum Calcium: Total calcium >10.5 mg/dL or ionized calcium >5.6 mg/dL
• Elevated or Inappropriately Normal PTH: Should be suppressed if calcium is high; in PHPT, it's elevated or "normal" (which is abnormal)
• Low or Low-Normal Phosphorus: PTH causes phosphate loss in urine

Additional Tests:

• 25-OH Vitamin D: Check for deficiency (can worsen hyperparathyroidism)
• 24-Hour Urine Calcium: Helps distinguish PHPT from Familial Hypocalciuric Hypercalcemia (FHH)
  • PHPT: High or normal urine calcium
  • FHH: Low urine calcium (calcium-to-creatinine clearance ratio <0.01)< /li>
• Kidney Function (Creatinine, eGFR)
• DEXA Scan: Assess bone density
• Kidney Ultrasound or CT: Check for kidney stones

Imaging to Locate Abnormal Gland(s) (Pre-Surgery):

• Sestamibi Scan (Parathyroid Scan): Nuclear medicine scan to localize adenoma
• Ultrasound of Neck
• 4D CT Scan (if sestamibi negative)

Treatment:

Surgery: Parathyroidectomy (Definitive Cure)

• Recommended for ALL symptomatic patients
• Asymptomatic patients should have surgery if:
  • Calcium >1 mg/dL above upper limit of normal
  • Age <50< /li>
  • Osteoporosis (T-score ≤ -2.5) or fragility fracture
  • Reduced kidney function (eGFR <60 mL/min)
  • Kidney stones or nephrocalcinosis
  • Increased 24-hour urine calcium (>400 mg/day)
• Cure rate: >95% in experienced hands
• Minimally invasive if adenoma localized (single gland removal)
• Bilateral neck exploration if hyperplasia or adenoma not localized

Medical Management (for those NOT undergoing surgery):

• Observation: Monitor calcium, PTH, bone density, kidney function yearly
• Hydration: Drink plenty of water to reduce kidney stone risk
• Avoid Thiazide Diuretics: Can worsen hypercalcemia
• Avoid High Calcium Intake: Don't restrict, but don't supplement
• Vitamin D Repletion: Correct deficiency (may paradoxically help)
• Bisphosphonates: Can improve bone density (do not lower calcium)
• Calcimimetics (Cinacalcet/Sensipar®): Lowers calcium by making parathyroid glands more sensitive to calcium; not a cure; expensive; used if surgery not possible

Post-Operative Monitoring:

• Hungry Bone Syndrome: Rapid drop in calcium post-surgery as bones "soak up" calcium; may need temporary calcium/Vitamin D supplementation
• Monitor Calcium and PTH: Check within days/weeks after surgery to confirm cure
• DEXA Scan: Repeat 1-2 years post-surgery (bone density often improves)

Complications of Untreated PHPT:

• Severe osteoporosis and fractures
• Kidney stones, kidney damage
• Cardiovascular disease
• Hypercalcemic crisis (rare but life-threatening)