Primary, secondary and tertiary hyperparathyroidism

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

PTH raises extracellular calcium by coordinating bone turnover, renal calcium retention, phosphate excretion and activation of vitamin D. In primary hyperparathyroidism, PTH is high or inappropriately normal despite hypercalcaemia. NICE advises repeating albumin-adjusted calcium, then measuring PTH concurrently with calcium and assessing renal and skeletal end organs. Symptoms include thirst, stone disease, constipation, cognitive or mood change and bone pain, but many people are asymptomatic. Differentiate FHH through family history and calcium excretion interpreted carefully around thiazides, CKD and vitamin D deficiency. Once surgery is indicated and accepted, imaging is used to plan the operation. A discordant scan should prompt expert localisation or exploration planning, not cancellation of the biochemical diagnosis.

Secondary disease preserves feedback logic. In CKD, phosphate retention, reduced calcitriol production, falling calcium signal and skeletal resistance drive progressive PTH elevation as part of CKD-mineral bone disorder. Vitamin D deficiency and malabsorption can produce a similar compensatory PTH pattern with normal or low calcium. Correct the driver and follow trends rather than treating a PTH number alone. Persistent gland hyperplasia can become autonomous, producing tertiary hyperparathyroidism with hypercalcaemia despite correction of the original stimulus or after kidney transplantation. Renal teams integrate dietary phosphate, dialysis adequacy, binders, native or activated vitamin D, calcimimetics and parathyroidectomy. NICE restricts cinacalcet for refractory dialysis-associated secondary disease to defined circumstances, and local renal protocols may be more specific. Pregnancy, young age, multi-gland disease and a family history of endocrine tumours lower the threshold for endocrine-genetic assessment.

Key points

Primary hyperparathyroidism is autonomous PTH secretion, usually with hypercalcaemia and low or low-normal phosphate, from a single adenoma more often than multi-gland disease.
Secondary hyperparathyroidism is an appropriate compensatory response to hypocalcaemic stimuli such as CKD, vitamin D deficiency, malabsorption or low calcium intake.
Tertiary hyperparathyroidism is autonomous secretion after prolonged secondary stimulation, classically in advanced CKD or after transplantation, and usually produces hypercalcaemia.
PTH is interpreted against simultaneous calcium, phosphate, eGFR, vitamin D and the longitudinal trend; an isolated concentration cannot name the subtype.
Exclude familial hypocalciuric hypercalcaemia before primary parathyroid surgery when the phenotype or urinary calcium suggests it, because surgery does not correct FHH.
NICE recommends surgical referral for primary disease with hypercalcaemic symptoms, renal or skeletal end-organ disease, or adjusted calcium at least 2.85 mmol/L, while individual factors still matter.
Neck ultrasound and sestamibi imaging localise abnormal glands after a surgical decision; negative imaging does not disprove biochemical primary disease.
CKD-mineral bone disorder is managed from serial phosphate, calcium and PTH patterns with renal specialists; indiscriminate PTH normalisation can cause adynamic bone disease.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Primary gland autonomy

A parathyroid adenoma or multigland disease produces PTH despite hypercalcaemia, making the hormone inappropriately non-suppressed for the calcium.

Compensatory secondary hyperparathyroidism

Chronic kidney disease, vitamin D deficiency or malabsorption lowers calcium signalling or impairs phosphate and vitamin D physiology, appropriately raising PTH.

Tertiary gland autonomy

Prolonged secondary stimulation can produce persistent hyperplastic gland secretion despite correction of the original stimulus, commonly with hypercalcaemia.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
PTH activity increases
Raised hormone stimulates bone turnover, renal calcium conservation, phosphate excretion and activation of vitamin D according to remaining kidney function.
2
Calcium-phosphate patterns diverge
Primary disease usually raises calcium, while renal secondary disease retains phosphate and may leave calcium low or normal despite high PTH.
3
Chronic stimulation enlarges glands
Persistent feedback drive causes parathyroid hyperplasia, which can eventually become partly autonomous and produce tertiary disease.
4
Bone and kidney injury accumulates
Sustained PTH-related turnover and abnormal mineral balance weaken skeleton and contribute to stones, calcification or renal morbidity.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Primary pattern

Repeated hypercalcaemia with PTH that is raised or not appropriately suppressed, preserved or reduced phosphate and no advanced CKD supports primary hyperparathyroidism.

Secondary pattern

Raised PTH with low or normal calcium in CKD, vitamin D deficiency, malabsorption or low calcium intake reflects compensation until the cause and serial biochemistry show otherwise.

Tertiary pattern

Marked persistent PTH excess with hypercalcaemia after prolonged advanced CKD or following renal transplantation suggests autonomous hyperplastic glands.

End-organ primary disease

Renal stones, fragility fracture, osteoporosis or declining renal function increases the benefit of specialist surgical assessment even when classic symptoms are limited.

Familial or syndromic clue

Young onset, multi-gland recurrence, jaw, pituitary or pancreatic tumours, or relatives with calcium abnormalities raises MEN, CDC73-related disease or FHH and needs specialist genetics.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Concurrent albumin-adjusted calcium and PTHFirst step
Why
Establish whether PTH response is appropriate at the time of confirmed calcium disturbance.
Interpretation and limitations
Non-suppressed PTH during hypercalcaemia is autonomous or PTH-dependent; raised PTH with low-normal calcium is usually secondary and requires renal, vitamin D and absorption context.
02
Phosphate, magnesium, eGFR and 25-hydroxyvitamin D
Why
Identify renal and nutritional drivers and interpret the biochemical phenotype safely.
Interpretation and limitations
Low vitamin D or advanced CKD can elevate PTH and alter urinary calcium. Hyperphosphataemia strongly supports advanced CKD physiology, while magnesium deficiency can disrupt PTH secretion and action.
03
Urine calcium excretion
Why
Help distinguish FHH from primary hyperparathyroidism before irreversible surgery.
Interpretation and limitations
Low calcium clearance supports FHH but overlaps with CKD, thiazides and deficiency; borderline values need endocrine and sometimes genetic review rather than a rigid cut-off.
04
Renal imaging and eGFR
Why
Detect calculi, nephrocalcinosis and renal impairment as end-organ effects of primary disease.
Interpretation and limitations
Stones or reduced kidney function influence NICE surgical referral. Imaging should be selected from symptoms and guideline assessment rather than repeated indiscriminately.
05
DXA including distal radius
Why
Assess cortical and axial bone loss caused by sustained PTH excess and quantify fracture risk.
Interpretation and limitations
Osteoporosis or fragility fracture supports parathyroid surgery; a normal result does not negate biochemical disease or renal indications.
06
Parathyroid localisation imaging
Why
Plan focused or bilateral surgical exploration after the diagnosis and decision for operation are established.
Interpretation and limitations
Concordant ultrasound and functional imaging may enable a focused approach. Negative or discordant imaging requires expert surgical strategy, not biochemical reclassification.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Familial hypocalciuric hypercalcaemia

Lifelong mild hypercalcaemia, family history and relatively low urinary calcium suggest altered calcium sensing rather than primary gland autonomy.

Malignancy-related hypercalcaemia

Tumour-mediated calcium elevation usually suppresses native PTH, unlike the inappropriately maintained hormone of primary hyperparathyroidism when combined with the history and other findings.

Vitamin D deficiency

Low vitamin D with normal or low calcium and raised PTH supports a compensatory secondary response that may resolve with cause correction.

Renal mineral-bone disorder

Reduced filtration, phosphate retention and altered vitamin D activation distinguish kidney-driven secondary disease from primary parathyroid secretion.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01PrimaryConfirm and assess end organsFirst stepRepeated hypercalcaemia has a non-suppressed PTH without advanced CKD.

1Review medicines and family history, correct relevant vitamin D deficiency carefully, and assess urinary calcium before labelling sporadic primary disease.
2Measure renal function, renal stone burden and DXA including the forearm, documenting symptoms and pregnancy or hereditary considerations.
3Refer for parathyroid surgery using NICE indications and patient preference; use localisation imaging only after surgery is being pursued.

02SecondaryCorrect the compensatory stimulusPTH is raised while calcium is low or normal in CKD, vitamin D deficiency or malabsorption.

1Determine eGFR, phosphate, calcium, alkaline phosphatase, magnesium, vitamin D, diet and malabsorption or medicine contributors.
2Treat native vitamin D deficiency and nutritional causes; in advanced CKD optimise phosphate intake, binder use and dialysis through the renal pathway.
3Follow serial calcium-phosphate-PTH trends and use activated vitamin D or calcimimetic treatment only under current renal guidance, avoiding oversuppression.

03TertiaryControl autonomous renal diseaseLongstanding CKD-related PTH excess becomes persistent and hypercalcaemic despite correction of reversible drivers.

1Confirm the trend and exclude other hypercalcaemia causes, reviewing transplant function, phosphate exposure, vitamin D analogues and calcimimetic adherence.
2Discuss calcimimetic, activated vitamin D adjustment and surgical candidacy in a renal-endocrine multidisciplinary team.
3After parathyroidectomy, anticipate hungry bone syndrome with intensive calcium, magnesium, phosphate and replacement planning rather than routine postoperative observation.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

Activates the calcium-sensing receptor to suppress PTH and lower calcium in selected inoperable primary, secondary or tertiary hyperparathyroid states.

Cinacalcet

Initiate and titrate through the relevant endocrine or renal specialist protocol according to the licensed indication, calcium, PTH response and tolerability; NICE commissioning criteria apply in refractory dialysis-associated secondary disease.

Hypocalcaemia, nausea and vomiting are common concerns. Check calcium soon after initiation or dose changes, review interactions, and do not allow biochemical improvement to replace surgery when a curative operation is appropriate.

Restores active vitamin D signalling and can suppress secondary PTH secretion in advanced CKD when renal activation is inadequate.

Activated vitamin D analogue

Use alfacalcidol or calcitriol only within the renal or hypoparathyroid protocol, titrating small regimen changes against calcium, phosphate and PTH after native vitamin D deficiency has been addressed where appropriate.

Hypercalcaemia and hyperphosphataemia promote vascular and soft-tissue calcification. Do not prescribe as interchangeable with nutritional colecalciferol, and monitor frequently during titration.

Reduces gastrointestinal phosphate absorption, addressing a major stimulus of secondary hyperparathyroidism in CKD stages 4 and 5.

Phosphate binder

Select the calcium-containing or non-calcium preparation under NICE CKD guidance and local renal formulary, taken with phosphate-containing food at the prescribed meal-specific regimen.

Pill burden impairs adherence; calcium-containing products can worsen hypercalcaemia and low PTH, while other agents have gastrointestinal and interaction risks. Diet and dialysis should be optimised first.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Kidney stones and renal decline

Hypercalciuria and hypercalcaemia promote stones and nephrocalcinosis, while dehydration and recurrent obstruction can further impair kidney function.

Fragility fracture

Persistent high bone turnover reduces cortical and trabecular strength, increasing osteoporosis and fragility-fracture risk, particularly when disease remains uncontrolled.

Vascular and soft-tissue calcification

Chronic calcium-phosphate imbalance in kidney disease promotes vascular and soft-tissue mineral deposition, adding cardiovascular and local tissue morbidity.

Hungry bone syndrome

After surgery for severe high-turnover disease, rapid skeletal mineral uptake can cause prolonged hypocalcaemia, hypophosphataemia and hypomagnesaemia.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

For non-operative primary disease, follow adjusted calcium, renal function and fracture or stone status at the NICE-recommended intervals with prompt review after new symptoms.
In CKD, interpret serial PTH with calcium, phosphate and alkaline phosphatase rather than reacting to a single fluctuation.
After cinacalcet or activated vitamin D changes, recheck calcium promptly and phosphate-PTH according to the specialist protocol.
After parathyroid surgery, watch calcium, phosphate, magnesium, symptoms and ECG risk for hungry bone syndrome or recurrent laryngeal complications.
Revisit family history and genetic referral when disease is young, recurrent, multi-gland or associated with other endocrine tumours.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Same hormone, opposite logic

PTH excess during low calcium is compensatory; the same concentration during high calcium is inappropriate. Calcium context separates secondary from autonomous physiology.

Forearm DXA adds information

PTH has prominent cortical skeletal effects, so distal radius measurement can reveal disease not captured fully by spine and hip values.

FHH protects from unnecessary surgery

Inherited altered calcium sensing produces lifelong mild hypercalcaemia and low urinary calcium. Recognising it prevents a neck operation that will not normalise calcium.

Transplant does not reset glands instantly

Hyperplastic glands may remain autonomous after kidney function improves. Persistent post-transplant hypercalcaemia can therefore represent tertiary disease.

PTH oversuppression has harm

In advanced CKD, driving PTH too low can contribute to adynamic bone and calcium loading. Treatment follows trends and the whole mineral profile.

11Common pitfallsFrequent interpretation and management errors.

01
Diagnosing primary hyperparathyroidism from raised PTH without checking simultaneous calcium and renal-vitamin D context.
02
Sending localisation imaging before deciding that biochemical primary disease and surgery are established.
03
Operating on a low-urinary-calcium familial phenotype without specialist consideration of FHH.
04
Treating CKD secondary disease to a single normal PTH target and overlooking adynamic bone risk.
05
Using activated vitamin D like ordinary nutritional vitamin D without close calcium and phosphate monitoring.
06
Missing hungry bone syndrome after surgery in someone with very high preoperative bone turnover.