Perioperative & Surgical Care

Parathyroidectomy: indications and management

Clinical Overview and When to Suspect Parathyroid Disease

— PHPT prevalence: ~1 in 1,000 adults; peaks in postmenopausal women (3:1 female predominance)

— Caused by single adenoma (~85%), four-gland hyperplasia (~10–15%), or carcinoma (<1%)

— Classic mnemonic still tested: "stones, bones, abdominal groans, psychiatric overtones, fatigue overdrive"

— Nephrolithiasis, osteoporosis/fragility fracture, constipation, peptic ulcer, pancreatitis, depression, polyuria

— MEN1 (parathyroid + pituitary + pancreas)

— MEN2A (medullary thyroid CA + pheo + parathyroid)

— Familial hypocalciuric hypercalcemia (FHH) — do NOT operate; calcium-sensing receptor mutation

Board pearl: Hypercalcemia + inappropriately normal or elevated PTH = PHPT until proven otherwise. Hypercalcemia + suppressed PTH = malignancy, granulomatous disease, vitamin D toxicity, or thiazide — workup pivots entirely. Always check 24-hour urine calcium before referring for surgery to exclude FHH (urine Ca <100 mg/day, Ca/Cr clearance ratio <0.01).

Parathyroidectomy is the only definitive cure for primary hyperparathyroidism (PHPT), the dominant indication encountered on Step 3.

Suspect PHPT when an outpatient chemistry panel shows incidental hypercalcemia — the modern presentation in >80% of US cases (asymptomatic biochemical disease)

Secondary HPT: appropriate PTH elevation from CKD, vitamin D deficiency, malabsorption — corrects with medical therapy, NOT surgical unless tertiary

Tertiary HPT: autonomous parathyroid hyperfunction after prolonged secondary stimulation (long-standing CKD or post–renal transplant with persistent hypercalcemia) — frequently requires subtotal parathyroidectomy

Familial syndromes raise suspicion in younger patients:

Step 3 outpatient trigger: a 62-year-old woman with osteopenia on DXA and Ca 10.9 — next step is intact PTH, not repeat calcium alone

Presentation Patterns and Key History

— Patient may volunteer vague fatigue, mild cognitive fog, constipation only on directed questioning

— Renal: nephrolithiasis (calcium oxalate or phosphate), nephrocalcinosis, polyuria/polydipsia from nephrogenic DI effect

— Skeletal: osteoporosis (especially cortical bone — distal 1/3 radius), fragility fracture, bone pain; rarely osteitis fibrosa cystica with brown tumors (advanced disease)

— GI: anorexia, nausea, constipation, PUD (gastrin stimulation), acute pancreatitis

— Neuropsychiatric: depression, anxiety, poor concentration, proximal muscle weakness

— Cardiac: shortened QT, HTN, LVH

— Lithium use — induces PTH-like hypercalcemia, may unmask underlying adenoma

— Thiazides — reduce urine calcium; hold for 2–4 weeks then recheck

— Family history of hypercalcemia, kidney stones, pituitary/pancreatic tumors → screen for MEN1

— Prior neck irradiation (childhood) — risk factor for parathyroid adenoma

— CKD stage, transplant history — distinguishes secondary/tertiary

— Calcium and vitamin D supplement intake — milk-alkali considerations

Step 3 management: Before labeling PHPT, stop the thiazide, replete vitamin D to >30 ng/mL, and confirm hypercalcemia on two separate occasions with ionized or albumin-corrected calcium. Premature surgical referral on a single mildly elevated calcium is a common test trap and a real-world misstep that triggers unnecessary imaging and patient anxiety.

Asymptomatic biochemical hypercalcemia is now the most common presentation — found on routine CMP ordered for unrelated reasons (HTN visit, preop screening)

Symptomatic classical presentations still appear on exams:

Critical history elements:

Timeline matters: chronic, slowly rising calcium with stable PTH suggests adenoma; rapidly rising Ca >14 with weight loss suggests malignancy-associated hypercalcemia (PTHrP-mediated)

Physical Exam Findings and Preoperative Assessment

— Neck: palpate for thyroid nodules, lymphadenopathy. A palpable parathyroid mass is rare and raises concern for parathyroid carcinoma (especially with Ca >14, PTH >5× normal)

— Musculoskeletal: proximal muscle weakness, bone tenderness, kyphosis from vertebral compression

— Neurocognitive: subtle memory/concentration deficits; depression screen (PHQ-2)

— Abdomen: epigastric tenderness (pancreatitis, PUD), CVA tenderness (stones)

— Skin: band keratopathy (chronic hypercalcemia), pruritus (especially in secondary HPT)

— Laryngoscopy to document vocal cord function if prior neck surgery, voice changes, or suspected invasion — medicolegal protection regarding recurrent laryngeal nerve (RLN)

— Cardiac exam: HTN control, JVP; consider ECG for QT

— Volume status — many patients are dehydrated from polyuria

Key distinction: A palpable neck mass + severe hypercalcemia + markedly elevated PTH should prompt suspicion for parathyroid carcinoma, which requires en bloc resection with ipsilateral thyroid lobectomy — NOT a minimally invasive approach. Misclassifying carcinoma as adenoma and performing limited surgery results in local recurrence and is a recurrent test theme. Also examine for signs of MEN syndromes (lipomas, angiofibromas in MEN1; marfanoid habitus, mucosal neuromas in MEN2B).

PHPT is largely a biochemical diagnosis — physical exam is often unremarkable, which is itself a board cue

Targeted exam in suspected hyperparathyroidism:

Preoperative anatomic and functional assessment:

Frailty and functional assessment in elderly: predicts perioperative outcomes more than chronologic age; bone density (DXA) guides surgical urgency

Document baseline calcium, PTH, 25-OH vitamin D, creatinine, and 24-hour urine calcium — these become the biochemical fingerprint for postoperative comparison

Diagnostic Workup — Initial Labs and Imaging

— Correction: add 0.8 mg/dL for every 1 g/dL albumin <4.0

— Intact PTH — the pivotal test

— 25-hydroxyvitamin D (replete to ≥30 ng/mL before final interpretation)

— Serum phosphate (low in PHPT, high in secondary HPT from CKD)

— Magnesium (low Mg can blunt PTH; correct first)

— Creatinine and eGFR

— Alkaline phosphatase (elevated suggests bone involvement)

— 24-hour urine calcium and creatinine to calculate calcium/creatinine clearance ratio (CCCR)

— High Ca + high or inappropriately normal PTH + urine Ca elevated → PHPT

— High Ca + high PTH + CCCR <0.01 → FHH (do NOT operate; confirm with CASR genetic testing)

— High Ca + suppressed PTH → check PTHrP (malignancy), 1,25-OH vitamin D (granulomatous, lymphoma), SPEP (myeloma), TSH

Board pearl: Always measure 24-hour urine calcium before parathyroidectomy. A low value (CCCR <0.01) flips the diagnosis to FHH, where surgery is contraindicated and ineffective — a classic Step 3 distractor. Vitamin D repletion is mandatory before surgical decision-making because deficiency artificially elevates PTH and can mask or mimic findings.

Confirm hypercalcemia on two occasions with albumin-corrected calcium or ionized calcium

Core biochemical panel for hypercalcemia workup:

Interpretation tree:

DXA scan at lumbar spine, hip, and distal 1/3 radius — PHPT preferentially attacks cortical bone; radius site is essential and often forgotten

Renal imaging: non-contrast CT or ultrasound to detect silent nephrolithiasis or nephrocalcinosis — finding either upgrades the patient to a surgical indication

ECG: shortened QT, possible heart block in severe hypercalcemia

Diagnostic Workup — Localization Studies

— Neck ultrasound — operator-dependent, no radiation, simultaneously evaluates thyroid; sensitivity ~75% for adenomas

— Sestamibi (Tc-99m) scintigraphy with SPECT/CT — sensitivity 80–90% for single adenomas; identifies ectopic glands (mediastinum, retroesophageal, intrathyroidal)

— 4D-CT — high spatial and temporal resolution, increasingly first-line at high-volume centers, particularly for reoperative cases or discordant studies

— Concordant ultrasound + sestamibi → enables minimally invasive parathyroidectomy (MIP) with focused unilateral exploration

— Discordant or negative → 4D-CT, MRI, or proceed to bilateral neck exploration (BNE)

— Reoperative cases → 4D-CT ± selective venous sampling for PTH gradient

CCS pearl: On a simulated case of biochemically confirmed PHPT with negative ultrasound, do not repeatedly order more localization tests — advance to sestamibi-SPECT/CT or 4D-CT, and if still negative, refer to an experienced parathyroid surgeon for bilateral neck exploration. Excessive imaging delays definitive care and inflates cost; over-ordering scans is penalized on CCS.

Localization is for surgical planning, NOT diagnosis — PHPT is diagnosed biochemically. Negative imaging does not refute PHPT in a biochemically confirmed patient

First-line localization modalities:

Imaging strategy:

Intraoperative PTH (ioPTH) monitoring — half-life ~3–5 min; >50% drop from baseline at 10 min post-excision (and into the normal range) confirms successful resection (Miami criterion)

Genetic testing indications: age <40, multiglandular disease, family history, syndromic features — test for MEN1, RET, CDC73 (HPT-jaw tumor), CASR

Bone turnover markers and FGF23 are rarely tested but appear in academic stems

Indications for Parathyroidectomy — Decision Logic

— Serum calcium >1 mg/dL above upper limit of normal

— Age <50 years

— Skeletal: T-score ≤ −2.5 at spine, hip, or distal 1/3 radius; or vertebral fracture on imaging (VFA/XR)

— Renal: eGFR <60 mL/min; 24-hour urine calcium >400 mg/day with increased stone risk; nephrolithiasis or nephrocalcinosis on imaging

Step 3 management: Memorize the "<50, >1, ≤−2.5, <60, >400" mnemonic for asymptomatic PHPT surgical criteria. Postmenopausal women with osteopenia but T-score >−2.5 still qualify if calcium is >1 above ULN or any stone is found on renal imaging — which is why renal imaging is part of the standard workup, not optional.

All symptomatic PHPT is a surgical indication: nephrolithiasis, fragility fracture, osteoporosis, neuromuscular symptoms, overt hypercalcemic symptoms

Asymptomatic PHPT — surgery indicated if any of the following (4th International Workshop / AAES 2016 guidelines):

Patients not meeting criteria may undergo observation with annual Ca/PTH/Cr and DXA every 1–2 years — but surgery is still reasonable if patient prefers cure, given high success rate (>95%) and low morbidity at high-volume centers

Secondary HPT (CKD): surgical indications include severe symptoms (pruritus, bone pain, calciphylaxis), persistent PTH >800 pg/mL refractory to cinacalcet/vitamin D analogs, severe hyperphosphatemia

Tertiary HPT: persistent hypercalcemia >1 year post–renal transplant, or symptomatic — typically subtotal (3.5-gland) parathyroidectomy or total parathyroidectomy with autotransplantation

Parathyroid carcinoma: always surgical — en bloc resection

Lithium-associated: trial off lithium if feasible; surgery if persists

Medical Management — When Surgery Is Deferred or Bridging

— Adequate hydration (≥2 L/day)

— Moderate dietary calcium 800–1000 mg/day — restriction worsens PTH drive

— Vitamin D repletion to 25-OH D >30 ng/mL (low-dose to avoid bolus hypercalcemia)

— Avoid thiazides and lithium when feasible

— Weight-bearing exercise

— Cinacalcet (calcimimetic): activates calcium-sensing receptor on parathyroid cells → lowers PTH and calcium; does NOT improve bone density; used when surgery contraindicated or for parathyroid carcinoma/inoperable disease and secondary HPT in dialysis

— Bisphosphonates (alendronate, zoledronate): improve bone density but do not lower calcium meaningfully long-term; useful when osteoporosis is the dominant issue and patient declines surgery

— Denosumab: alternative in CKD where bisphosphonates contraindicated

— HRT or raloxifene: modest benefit in postmenopausal women

— Aggressive IV normal saline 200–300 mL/hr (titrate to UOP 100–150 mL/hr)

— Calcitonin 4 IU/kg SC/IM q12h — rapid onset within hours, tachyphylaxis by 48 h

— IV bisphosphonate (zoledronic acid 4 mg IV) — peak effect 2–4 days; avoid if eGFR <30

— Denosumab if bisphosphonate-refractory or severe renal impairment

— Hemodialysis with low-calcium bath for crisis with renal failure or heart failure

— Loop diuretics only after volume repletion and for fluid overload — NOT routine

Board pearl: Cinacalcet lowers calcium and PTH but does NOT improve bone mineral density — so it is not a substitute for parathyroidectomy when osteoporosis is the surgical indication. Bisphosphonates do the opposite. Use both knowingly; surgery does both.

Medical therapy is bridging or palliative, never curative in PHPT

General measures for chronic mild PHPT under observation:

Pharmacologic options for non-operative patients:

Acute severe hypercalcemia (Ca >14 or symptomatic):

Surgical Approach — Parathyroidectomy Techniques and Operative Management

— Small (2–4 cm) focused incision, unilateral exploration

— Intraoperative PTH (ioPTH) monitoring required; Miami criterion: >50% drop from highest pre-excision value at 10 min post-resection and into normal range

— Outpatient or 23-hour observation

— Lower morbidity, similar cure rate (>95%) compared to BNE

— Imaging negative or discordant

— Suspected four-gland hyperplasia (MEN, lithium, secondary/tertiary HPT)

— Concomitant thyroid pathology requiring resection

— Familial syndromes

— Subtotal parathyroidectomy (3.5 glands) — standard for hyperplasia/MEN1/tertiary; leaves ~50 mg vascularized remnant marked with clip

— Total parathyroidectomy with autotransplantation — all four glands removed, fragments implanted in non-dominant forearm or SCM; preferred in MEN1 and dialysis-dependent secondary HPT (easier to revise if recurrence)

— En bloc resection with ipsilateral thyroid lobectomy — parathyroid carcinoma

— Transcervical mediastinal exploration or VATS — ectopic mediastinal adenomas (~1–2%)

— Damage to recurrent laryngeal nerve → vocal cord paralysis (intraoperative nerve monitoring increasingly used)

— Superior laryngeal nerve injury → voice fatigue/pitch loss (Amelita Galli-Curci sign)

— Devascularization of remaining glands → hypoparathyroidism

— Missed second adenoma (~5%) → persistent disease

Step 3 management: A successful operation is defined by eucalcemia 6 months postoperatively. Persistent hyperparathyroidism = hypercalcemia within 6 months; recurrent = after 6 months of normocalcemia. Both warrant repeat localization (4D-CT, selective venous sampling) and referral to a high-volume reoperative center — not immediate re-exploration locally.

Minimally invasive parathyroidectomy (MIP) — preferred when preoperative imaging localizes a single adenoma

Bilateral neck exploration (BNE) — gold standard when:

Operative variants:

Anesthesia: general or cervical block; consider regional in high-risk cardiopulmonary patients

Key intraoperative pitfalls:

Special Populations — Elderly and Renal/Hepatic Impairment

— Parathyroidectomy is safe and effective at any age at experienced centers; chronologic age alone is not a contraindication

— Symptomatic improvement in cognition, depression, fatigue, and bone density is well documented

— Frailty assessment (gait speed, grip strength, comprehensive geriatric assessment) better predicts outcome than age

— Preop optimization: cardiac risk stratification (RCRI), pulmonary assessment, medication reconciliation (anticoagulants, antiplatelets — bridge per ACCP)

— Outpatient MIP under local/cervical block is often feasible

— Most managed medically first: active vitamin D analogs (calcitriol, paricalcitol), phosphate binders (non-calcium-based preferred — sevelamer, lanthanum), cinacalcet/etelcalcetide

— KDIGO surgical indications: severe symptoms, PTH persistently >800 despite optimal medical therapy, calciphylaxis, tumoral calcinosis

— Preferred procedure: subtotal parathyroidectomy or total + autotransplantation

— Expect profound postoperative hypocalcemia ("hungry bone syndrome") — admit for IV calcium gluconate, calcitriol, oral calcium

— Observe for 12 months post-transplant — many resolve

— Operate if persistent hypercalcemia, declining graft function from hypercalcemic nephropathy, or symptomatic

Key distinction: Hungry bone syndrome (prolonged severe hypocalcemia, hypophosphatemia, hypomagnesemia from rapid bone remineralization) occurs predominantly after parathyroidectomy for secondary/tertiary HPT or PHPT with severe bone disease (high ALP, brown tumors). Contrast with transient postoperative hypocalcemia from remaining gland stunning, which resolves within days with oral calcium ± calcitriol.

Elderly patients (>75 years):

Chronic kidney disease (secondary HPT):

Post-transplant tertiary HPT:

Hepatic impairment: rarely directly relevant; vitamin D metabolism preserved (25-hydroxylation hepatic, but rarely limiting); cinacalcet undergoes hepatic metabolism — caution in severe cirrhosis

Special Populations — Pregnancy, Pediatrics, and Genetic Syndromes

— PHPT in pregnancy is rare but high-stakes — fetal risks include neonatal hypocalcemic tetany (from fetal parathyroid suppression by maternal hypercalcemia), IUGR, preterm labor, miscarriage

— Maternal risks: hyperemesis, nephrolithiasis, pancreatitis, hypertensive crisis

— Surgery indicated in second trimester (14–26 weeks) for moderate-severe disease — safest window

— Avoid bisphosphonates (cross placenta, embryotoxic) and cinacalcet (limited data, pregnancy category C)

— Mild cases: hydration, low-dose oral phosphate, careful monitoring

— Neonatal calcium monitoring for 2 weeks post-delivery

— Rare; strong genetic underpinning — screen for MEN1, MEN2A, FHH, neonatal severe HPT (CASR homozygous)

— Bilateral neck exploration often preferred given higher rate of multigland disease

— Refer to pediatric endocrine surgery centers

— Autosomal dominant, MEN1 gene chromosome 11

— Parathyroid disease in >90% — typically four-gland hyperplasia, recurrence common

— Standard operation: subtotal parathyroidectomy with cervical thymectomy (supernumerary glands in thymus)

— Lifetime surveillance for pituitary and pancreatic neuroendocrine tumors

— RET proto-oncogene mutation

— Parathyroid involvement less aggressive (~20–30%); only enlarged glands removed

— Prophylactic thyroidectomy for medullary thyroid carcinoma is the priority

— CASR loss-of-function mutation; lifelong mild asymptomatic hypercalcemia

— Surgery contraindicated — does not cure disease

Board pearl: A 22-year-old with hypercalcemia and a family history of "calcium problems" → check 24-hour urine calcium before booking the OR. CCCR <0.01 = FHH = no surgery. This is one of the most consistently tested traps across Step 2 and Step 3.

Pregnancy:

Pediatric PHPT:

MEN1:

MEN2A:

Familial Hypocalciuric Hypercalcemia (FHH):

Complications and Adverse Outcomes of Parathyroidectomy

— Transient (10–50%): gland stunning; symptoms include perioral numbness, Chvostek and Trousseau signs, paresthesias, tetany

— Permanent hypoparathyroidism (1–3%): more common after BNE, total parathyroidectomy, or reoperation

— Monitor Ca and PTH at 6 h, 24 h, and outpatient

— Treat with oral calcium carbonate/citrate + calcitriol; severe → IV calcium gluconate

— Profound, prolonged hypocalcemia with hypophosphatemia, hypomagnesemia, low ALP recovery period

— Risk factors: severe bone disease, high preop ALP, large adenoma, secondary HPT

— Requires inpatient management with continuous IV calcium gluconate infusion, oral calcium 2–4 g/day elemental, calcitriol 0.5–2 µg/day, Mg repletion

— Unilateral: hoarseness, weak voice

— Bilateral: airway emergency requiring tracheostomy

— Immediate bedside opening of incision is first step before transfer to OR — classic CCS scenario

CCS pearl: Post-thyroid/parathyroid surgery patient with neck swelling, stridor, and respiratory distress → immediately open the incision at bedside to evacuate hematoma, then call surgery and transfer to OR. Securing the airway and decompressing pressure trumps imaging or labs. Document neuro and voice exam preoperatively and postoperatively at every visit.

Postoperative hypocalcemia — most common complication

Hungry bone syndrome (HBS):

Recurrent laryngeal nerve (RLN) injury (~1%):

Superior laryngeal nerve injury: subtle voice changes, loss of high pitch — important for singers, teachers (consent issue)

Neck hematoma: rare but life-threatening from airway compression

Persistent (within 6 months) or recurrent (after 6 months) hyperparathyroidism: missed adenoma, ectopic gland, multiglandular disease

Parathyromatosis: seeding from capsule rupture during prior surgery

Wound infection, seroma, scar issues — uncommon

When to Escalate — ICU, Consult, and Inpatient Triage

— Admit; telemetry for QT shortening and arrhythmia

— Aggressive IV NS, calcitonin, IV bisphosphonate or denosumab

— Endocrinology and surgery consults; urgent (not emergent) parathyroidectomy after stabilization

— ICU for altered mental status, hemodynamic instability, severe AKI requiring HD

— Stridor, expanding neck swelling → open incision, airway management, OR

— Symptomatic hypocalcemia (tetany, seizure, laryngospasm, QT prolongation) → IV calcium gluconate 1–2 g over 10–20 min, then infusion

— Cardiac arrhythmia

— Persistent hypotension or fever — assess for sepsis, bleeding

— Endocrinology — diagnostic ambiguity, MEN syndromes, secondary/tertiary HPT management, severe osteoporosis

— Endocrine/parathyroid surgery (high-volume, ≥50 cases/year) — operative planning; reoperative cases mandate experienced surgeon

— Nephrology — CKD-related HPT, calciphylaxis, transplant

— Genetics — suspected MEN, FHH, HPT-jaw tumor syndrome (age <40, family history, multiglandular)

— Otolaryngology — preop laryngoscopy with prior neck surgery; postop vocal cord paralysis

— Anesthesia preop — frail elderly, severe cardiopulmonary disease

— Stable calcium (often discharged with empiric oral calcium ± calcitriol)

— No expanding hematoma, stable voice

— Tolerating PO, ambulating, pain controlled

— Same-day or next-morning discharge typical

Step 3 management: Hypercalcemia + altered mental status + AKI = medical emergency. Admit, telemetry, aggressive IVF, calcitonin (fastest onset), schedule definitive parathyroidectomy after stabilization. Do not rush to OR while patient is dehydrated and electrolytically deranged — this is a recurrent trap testing perioperative judgment.

Hypercalcemic crisis (Ca >14 mg/dL or symptomatic at any level):

Postoperative red flags requiring escalation:

Consult triggers:

Discharge criteria after MIP:

Key Differentials — Other Causes of PTH-Mediated Hypercalcemia

— Autosomal dominant CASR mutation

— Lifelong mild hypercalcemia, normal or mildly elevated PTH, low urine calcium (CCCR <0.01)

— Asymptomatic, no end-organ damage

— Surgery contraindicated

— Lithium shifts CASR set-point upward → PTH rises

— Can unmask underlying adenoma in long-term users

— Management: trial off lithium if psychiatrically feasible; surgery for persistent disease (often bilateral exploration due to high rate of multiglandular involvement)

— Autonomous PTH secretion after prolonged secondary stimulation

— Long-standing CKD or post-renal transplant

— Hypercalcemia + high PTH + history of CKD

— Subtotal or total parathyroidectomy with autotransplantation

— Appropriate response to low calcium or vitamin D deficiency or CKD

— Calcium is low or normal, PTH is high

— Treat underlying cause; not surgical unless tertiary develops

— Extremely rare; small cell lung CA, ovarian, others — distinguishable by imaging

— Very high Ca (often >14), very high PTH (5–10× ULN), palpable neck mass

— Surgical: en bloc resection; refractory disease → cinacalcet, denosumab

Key distinction: All "PTH-driven" hypercalcemias share inappropriately normal-to-high PTH, but urine calcium and clinical context separate them. PHPT = high urine Ca; FHH = low urine Ca; tertiary = CKD context; lithium = drug history. Always confirm with CCCR and family history before booking the OR.

Familial Hypocalciuric Hypercalcemia (FHH):

Lithium-induced hyperparathyroidism:

Tertiary hyperparathyroidism:

Secondary hyperparathyroidism (NOT hypercalcemic):

Ectopic PTH secretion:

Parathyroid carcinoma:

Key Differentials — Non-PTH-Mediated Hypercalcemia

— PTHrP-mediated (humoral hypercalcemia of malignancy): squamous cell carcinomas (lung, head/neck, esophagus), renal cell, breast, bladder, ovarian

— Osteolytic metastases: breast cancer, multiple myeloma — direct bone resorption

— 1,25-(OH)₂-vitamin D production: lymphomas (Hodgkin and non-Hodgkin)

— Typically rapid onset, weight loss, performance decline; calcium often >14

— Sarcoidosis, TB, histoplasmosis, berylliosis — macrophages convert 25-OH D to 1,25-OH D

— Elevated 1,25-vitamin D, normal/elevated ACE in sarcoid

— Treatment: low-dose corticosteroids

— Hyperthyroidism — bone turnover

— Adrenal insufficiency — volume depletion mechanism

— Pheochromocytoma — consider in MEN2A context

— Thiazides — decrease urine calcium excretion

— Lithium — primarily PTH-mediated

— Calcium-based antacids (milk-alkali syndrome) — calcium + bicarbonate + AKI triad

— Theophylline toxicity

Board pearl: The first fork in hypercalcemia workup is PTH high vs. low. PTH suppressed → think malignancy (PTHrP, lytic mets, vitamin D from lymphoma), granulomatous disease, vitamin D/A toxicity, milk-alkali, thyrotoxicosis. PTH high or inappropriately normal → think PHPT, FHH, lithium, tertiary HPT. Do not order parathyroid imaging until this fork is resolved.

Suppressed PTH in the setting of hypercalcemia redirects the entire workup

Malignancy-associated hypercalcemia (most common inpatient cause):

Granulomatous disease:

Vitamin D toxicity: supplements, OTC megadosing — elevated 25-OH D

Vitamin A toxicity: rare; bone resorption

Endocrinopathies:

Medications:

Immobilization — especially adolescents and Paget's disease

Hyperparathyroidism-jaw tumor syndrome (CDC73/HRPT2) — also associated with parathyroid carcinoma

Postoperative Long-Term Plan and Secondary Prevention

— Oral calcium carbonate or citrate 1500–3000 mg elemental/day divided TID — empiric for many patients

— Calcitriol 0.25–0.5 µg BID if symptomatic hypocalcemia or HBS risk

— Magnesium oxide if Mg low

— Taper over 2–4 weeks as PTH and Ca normalize

— Continue cholecalciferol 1000–2000 IU/day to maintain 25-OH D >30

— Lifelong calcium + calcitriol

— Consider recombinant PTH (1-84) — palopegteriparatide in refractory cases

— Monitor 24-hour urine calcium to avoid nephrocalcinosis (goal <300 mg/day)

— DXA at 1 year postop — expect 5–10% improvement at spine/hip; cortical (radius) lags

— Continue weight-bearing exercise, vitamin D, adequate dietary calcium

— Bisphosphonate if osteoporosis persists or fracture history

— Hydration ≥2.5 L/day, dietary sodium <2.3 g/day, moderate animal protein

— Repeat renal imaging at 1 year if prior stones

— Annual calcium and PTH for life

— Earlier and more frequent if MEN syndrome, hyperplasia, or autotransplant

— Rising PTH with normal calcium suggests vitamin D deficiency or early recurrence

Step 3 management: A patient 6 weeks postop with calcium 8.2 and PTH 75 with mild paresthesias → increase oral calcium and calcitriol, check 25-OH vitamin D and magnesium, not immediately diagnose recurrence. Postop PTH can transiently rise during gland recovery. Reserve the term "persistent disease" for documented hypercalcemia within 6 months.

Discharge medications after parathyroidectomy:

Patients with permanent hypoparathyroidism (rare):

Bone health follow-up:

Renal stone prevention:

Surveillance for recurrence:

MEN1 patients: lifelong screening — pituitary MRI, prolactin, IGF-1, gastrin, fasting insulin/proinsulin, pancreatic imaging

MEN2A: annual calcitonin, CEA, plasma metanephrines

Follow-Up Cadence, Monitoring, and Counseling

— Day of/next day: wound check, voice exam, ionized or total calcium

— Week 1–2: calcium, albumin, magnesium, phosphate; titrate supplements

— Month 3: calcium, intact PTH, 25-OH vitamin D, creatinine

— Month 6: repeat — confirms cure (eucalcemia at 6 months)

— Annual lifelong: calcium, PTH, creatinine, DXA every 1–2 years until stable, then less frequently

— Symptoms of hypocalcemia: perioral tingling, finger/toe paresthesias, muscle cramps, carpopedal spasm — go to ED if severe or chest pain/palpitations

— Symptoms of recurrent hypercalcemia: fatigue, constipation, polyuria, mental fog

— Wound care: keep dry 48 h, watch for expanding swelling, fever, drainage

— Voice changes: report hoarseness lasting >2 weeks → laryngoscopy

— Activity: resume normal activity within days; avoid heavy lifting for 1 week

— Return-to-work: typically 3–7 days for desk jobs; longer for manual labor

— Maintain dietary calcium 1000–1200 mg/day — do not restrict

— Hydration, sun-safe vitamin D, weight-bearing exercise

— Smoking cessation, alcohol moderation for bone health

— Avoid thiazides and lithium when alternatives exist

— Communicate clearly with PCP and endocrinology; provide pathology report, ioPTH curve, postop calcium/PTH trajectory

— Ensure DXA scheduled at 12 months; flag pending labs

CCS pearl: Schedule the 3- and 6-month postop labs at the time of discharge in CCS — failure to set follow-up monitoring after parathyroidectomy is a documented loss of points. Always order both calcium and PTH together; one without the other yields incomplete information about cure status or recurrence.

Postop visit schedule:

Counseling points at discharge:

Lifestyle counseling:

Transitions of care:

Ethical, Legal, and Patient Safety Considerations

— Recurrent laryngeal nerve injury with vocal cord paralysis (uni- or bilateral) — especially crucial for professional voice users (singers, teachers, attorneys, broadcasters); document occupational considerations

— Permanent hypoparathyroidism with lifelong calcium/vitamin D requirements

— Failure to cure / persistent disease — patient must understand cure rate (~95% at high-volume centers, lower at low-volume) and need for reoperation

— Bleeding/airway hematoma, infection, scar

— Alternative of observation or medical therapy with cinacalcet/bisphosphonates

— Outcomes correlate with surgeon volume (≥50 parathyroidectomies/year)

— Patients have a right to ask about case volume; in complex/reoperative cases, referral to high-volume center is the standard of care and a defensible ethical choice

— MEN1 testing has implications for first-degree relatives — pretest counseling, cascade testing, GINA protections

— Discuss insurance implications and confidentiality

— Read-back of calcium and PTH critical values by lab to clinician — institutional protocol

— Same-day discharge after MIP requires explicit symptom education and a 24-hour contact pathway; patients sent home with subclinical hypocalcemia and no follow-up plan can present in tetany or with QT prolongation

— Medication reconciliation at discharge: continue holding thiazides? Restart anticoagulants when?

Board pearl: Obtaining surgical consent from a patient with acute hypercalcemia-induced delirium is not valid. Stabilize medically first, reassess capacity, then consent. If permanent incapacity exists, engage the legal surrogate per the institution's hierarchy (POA → spouse → adult children).

Informed consent for parathyroidectomy must explicitly include:

Surgeon volume and disclosure:

Genetic testing ethics:

Patient safety / transitions of care:

Capacity and surrogate decision-making: severe hypercalcemia causes delirium; defer non-emergent operative consent until cognition clears with rehydration and calcium-lowering therapy — operating during hypercalcemic delirium violates valid consent

High-Yield Associations and Rapid-Fire Facts

Key distinction: PHPT affects cortical bone (distal radius) preferentially; osteoporosis affects trabecular bone (spine) preferentially. Always include the distal 1/3 radius site on DXA when PHPT is suspected.

Most common cause of outpatient hypercalcemia: primary hyperparathyroidism

Most common cause of inpatient hypercalcemia: malignancy

Most common parathyroid pathology in PHPT: single adenoma (~85%)

Inferior parathyroids derive from 3rd pharyngeal pouch (more variable location, can descend to mediastinum)

Superior parathyroids derive from 4th pharyngeal pouch (more consistent location, posterior to thyroid)

Ectopic locations: thymus, mediastinum, retroesophageal, intrathyroidal, carotid sheath

Number of glands: 4 in 84%, supernumerary (5+) in ~13%, only 3 in ~3%

MEN1 mnemonic — "3 P's": Parathyroid, Pituitary, Pancreas (gastrinoma > insulinoma)

MEN2A: Medullary thyroid CA + Pheochromocytoma + Parathyroid hyperplasia

MEN2B: Medullary thyroid CA + Pheo + Mucosal neuromas + Marfanoid (NO parathyroid)

Brown tumors = osteoclastic lesions of advanced PHPT

Osteitis fibrosa cystica = severe skeletal manifestation; rare in US today

Subperiosteal resorption of radial side of middle phalanges — classic XR finding

"Salt and pepper" skull on plain films

Sestamibi = Tc-99m sestamibi, taken up by mitochondria-rich oxyphil cells in adenoma

Miami criterion: ioPTH drop >50% at 10 minutes

Cure rate: >95% at high-volume centers

Cinacalcet: activates calcium-sensing receptor; lowers Ca and PTH; no bone benefit

Etelcalcetide: IV calcimimetic for dialysis patients

Hungry bone syndrome: post-parathyroidectomy hypocalcemia + hypophosphatemia + hypomagnesemia

Surgical indication threshold: Ca >1 mg/dL above ULN, age <50, T-score ≤−2.5 (any site including 1/3 radius), eGFR <60, urine Ca >400, stones/fractures

FHH: CCCR <0.01, normal urine Ca, do NOT operate

Thiazides falsely lower urine Ca — hold 2–4 weeks before urine collection

Calcium correction: + 0.8 mg/dL per 1 g/dL albumin <4.0

Board Question Stem Patterns

— 58F on routine labs, Ca 11.0, asymptomatic → check PTH, vitamin D, urine Ca → if PTH inappropriately normal/elevated and urine Ca normal → PHPT → apply surgical criteria

— 24F mild hypercalcemia, "calcium issues" in family → CCCR <0.01 → FHH → reassurance, NO surgery

— 65F with T-score −2.7 spine, Ca 10.6, PTH 95 → meets surgical criteria → parathyroidectomy (not just bisphosphonate)

— Ca 15.2, altered mental status, AKI → IV NS first, then calcitonin + IV bisphosphonate; surgery after stabilization

— Day 1 post-parathyroidectomy with perioral numbness, Trousseau positive → IV calcium gluconate, then oral calcium + calcitriol; check Mg

— Stridor, neck swelling 4 h postop → open incision at bedside → OR

— Ca elevated at 3 months postop → localization (4D-CT, sestamibi) + refer to high-volume reoperative center

— Post-renal transplant 18 months, persistent Ca 11.5, PTH 250 → subtotal parathyroidectomy

— Bipolar patient on lithium 15 years with hypercalcemia → trial off lithium if feasible, evaluate for surgery if persistent (often multiglandular)

— Young patient with PHPT + pituitary adenoma + gastrinoma → subtotal parathyroidectomy with cervical thymectomy + lifetime surveillance

— Palpable neck mass, Ca 14.8, PTH 1200 → en bloc resection with thyroid lobectomy

— 2nd trimester PHPT with stones → parathyroidectomy in 2nd trimester

— Suppressed PTH + elevated Ca + weight loss → check PTHrP, imaging for occult malignancy — NOT parathyroid imaging

Step 3 management: When a stem provides a localization study without first establishing a biochemical diagnosis (calcium + PTH + urine Ca), the next best step is almost always to obtain the missing biochemical workup — not to order more imaging or proceed to surgery.

Stem 1: Incidental hypercalcemia

Stem 2: Family history trap

Stem 3: Postmenopausal osteoporosis

Stem 4: Hypercalcemic crisis

Stem 5: Postop tetany

Stem 6: Postop expanding neck mass

Stem 7: Persistent hypercalcemia

Stem 8: Tertiary HPT

Stem 9: Lithium-induced

Stem 10: MEN1 patient

Stem 11: Suspected carcinoma

Stem 12: Pregnancy

Stem 13: Malignancy mimic

One-Line Recap

Parathyroidectomy is the only curative therapy for primary hyperparathyroidism, indicated in all symptomatic patients and in asymptomatic patients meeting Ca >1 mg/dL above ULN, age <50, T-score ≤−2.5 at any site (including distal 1/3 radius), eGFR <60, or 24-hour urine Ca >400 with stones/nephrocalcinosis — but only after FHH is excluded by urinary calcium and vitamin D is repleted.

Diagnosis is biochemical, not radiologic — confirm hypercalcemia + inappropriately normal/high PTH + 24-hour urine calcium (CCCR >0.01) before any imaging; sestamibi-SPECT/CT, ultrasound, or 4D-CT serve to plan the operation, not establish the disease

Minimally invasive parathyroidectomy with intraoperative PTH (Miami criterion: >50% drop at 10 min) is preferred for localized single adenomas; bilateral neck exploration with subtotal parathyroidectomy is standard for MEN1, hyperplasia, lithium-induced, and reoperative cases — refer reoperations and complex syndromes to high-volume centers

Postoperative management centers on monitoring for transient hypocalcemia, hungry bone syndrome, recurrent laryngeal nerve injury, and airway hematoma, with empiric oral calcium ± calcitriol, structured 1-week / 3-month / 6-month / annual follow-up labs, and DXA at 12 months; cure is defined by eucalcemia at 6 months

Step 3 traps to memorize: FHH (low urine Ca, no surgery), hypercalcemic delirium invalidating consent (stabilize first), thiazides falsely lowering urine Ca (hold before collection), vitamin D deficiency falsely elevating PTH (replete first), cinacalcet not improving bone density, and the bedside opening of a postop neck hematoma as the immediate airway-saving maneuver