Editing Hyperparathyroidism (section)

== '''Secondary: appropriate elevation in PTH levels due to a separate source of hypocalcaemia e.g. renal failure''' ==

* Aetiology
** CKD - 90% of patients on      dialysis have SHPT
*** Chronic hypocalcaemia       secondary to hyperphosphataemia and low levels of biologically active       vitamin D
*** Leads to PTH       hypersecretion, parathyroid cell proliferation, and parathyroid gland       hyperplasia
** Vitamin D deficiency -      causes increased secretion PTH
** GIT malabsorption due to      chronic disease
*** Coeliac
*** CF
*** Short gut syndrome
*** Bariatric procedures
** Medications
*** Lithium
*** Diuretics
** Metabolic abnormalities
*** Hypermagnesaemia
*** Hyperphosphataemia
** Congenital disorders
*** Transient neonatal       hyperparathyroidism
*** DiGeorge syndrome
* Symptoms
** As above - also      calciphylaxis - painful cutaneous purpuric lesions - if this is present,      severe HPT is probably present, and parathyroidectomy should be offered
* Treatment
** Initially managed medically
*** Vitamin D       deficiency/hypocalcaemia
**** 1000-1200mg calcium per        day + vitamin D supplementation to maintain serum 25(OH)D >30ng/mL
*** CKD - most can be managed       medically
**** Dietary phosphate        reduction, phosphate binders, oral calcium and calcitriol        supplementation, IV vitamin D analogues, and dialysis
**** Calcium and calcitriol        slow progression of HPT until patient can undergo renal transplantation
**** Calcimimetics - cinacalcet        - reduces PTH secretion through direct action on parathyroid gland.        Used in non-transplant candidates, but not generally used on transplant        candidates.
** Parathyroidectomy
*** Required in almost half of       dialysis patients eventually, if they live long enough
*** Indications (highly       variable between surgeons)
**** PTH > 800pg/mL
**** Sustained hypercalcaemia
**** Refractory        hyperphosphataemia
**** Elevation of        calcium-phosphorus product > 55mg/dL
**** Severe symptomatic bone        disease
**** Calciphylaxis
***** Calcific uraemic         arteriolopathy
***** Microvascular         calcification, intimal proliferation, fibrosis, and thrombotic         occlusion of small subcutaneous vessels
***** Predominantly seen in         ESKD and secondary HPT
***** Painful non-healing         wounds with areas of skin necrosis, which can lead to secondary         infection, sepsis and death
***** Debride only to control         sepsis, but not dry eschar
**** Consider for intractable        pruritis, profound muscle weakness, intolerance to cinacalcet, and        symptomatic ectopic extraosseous calcification (calcinosis)
*** Pre-op
**** Should have pre-op        localisation to ensure no supernumerary glands
*** Choice of procedure
**** Total parathyroidectomy
**** Total parathyroidectomy        with autologous transplantation
**** Subtotal parathyroidectomy        - preferred
***** Higher rate of         recurrence, but lower rate of hypoparathyroidism