Hyperparathyroidism Flashcards
Define hyperparathyroidism
Primary – increased secretion of PTH
Secondary – increased secretion of PTH secondary to hypocalcaemia
Tertiary – autonomous PTH secretion following chronic secondary HPT
What are the causes/risk factors of hyperparathyroidism?
Primary • Parathyroid adenoma • Parathyroid hyperplasia • Parathyroid carcinoma • Familial e.g. MEN
Secondary
• Chronic renal failure
• Vitamin D deficiency
• Malabsorption
What are the signs and symptoms of hyperparathyroidism?
ymptoms and Signs
• Asymptomatic
Primary Hypercalcaemia • Stones – renal, biliary • Bones – pain • Groans – abdominal pain, N&V • Thrones – polyuria, constipation • Psychic moans – depression, anxiety, lethargy • Paraesthesiae • Muscle cramps
Secondary (SPASMODIC)
• Spasms –Carpopedal Spasm = Trousseau’s sign.
• Perioral paraesthesia
• Anxious, irritable, irrational
• Seizures
• Muscle Tone Increase: Wheeze, colic and dysphagia.
• Orientation impairment and confusion
• Dermatitis
• Impetigo Herpetiformis
• Chvostek’s Sign; Choreoathetosis; Cataratcts.
What investigations are carried out for hyperparathyroidism?
• U&Es - often normal; may indicate CKD in secondary hyperparathyroidism
• Serum Calcium - raised in primary and tertiary hyperparathyroidism; low in secondary hyperparathyroidism
*Total serum calcium levels should be corrected for serum albumin. An ionised calcium level is preferred.
• Albumin - to calculate corrected serum calcium.
• Serum Intact Parathyroid Hormone (iPTH) - elevated; May be inappropriately normal (in upper half of normal range in 10 Hyperparathyroidism.
PTH should always be ordered with a paired calcium level so that the PTH level can be properly interpreted.
• ALP - elevated
Patients with elevated alkaline phosphatase with other normal liver enzymes have high turnover bone disease and are susceptible to post-parathyroidectomy hypocalcaemia.
• Vitamin D - may be low in secondary hyperparathyroidism
• ABG - primary hyperparathyroidism will show hyperchloraemic acidosis (normal anion gap) caused by PTH inhibition of renal tubular reabsorption of bicarbonate.
• Calcium: Creatinine - clearance Ratio
• Urine Calcium (mmol/l) x [Serum Creatinine (umol/l) / 1000]
• Serum Calcium (mmol/l) x Urine Creatinine (mmol/l)
• 24 hour urine collection should be sent for creatinine clearance and calcium measurement.
• Renal USS - to look for renal calculi
• Neck USS - preoperative Localisation
• Technetium Sestamibi Scan - preoperative localisation
Radiographic features • subperiosteal resorption - classically affects the radial aspects of the proximal and middle phalanges of the 2nd and 3rd fingers • Brown's tumours • Salt and pepper sign in skull • Rugger Jersey spine • Renal caluli
What is the management for hyperparathyroidism?
Primary Hyperparathyroidism
Conservative:
• Indicated for asymptomatic patients with no surgical indications.
• Regular Monitoring and Check-ups
• Avoid drugs that exacerbate hypercalcaemia: Thiazide Diuretics
• Maintain Adequate Hydration
• Vitamin D Supplements: Cholecalciferol and Ergocalciferol
• Bisphosphonates if indicated.
Surgical: Total (MEN) or Subtotal Parathyroidectomy Indications: • Symptomatic • Asymptomatic with: - Age < 50 - Bone Mineral Density: T-Score < - 2.5 - Calculi; Cr clearance reduced by 30%. - Difficulty in following up - Elevated serum calcium (>0.25 mmol/L above upper limit; 24hr urinary calcium > 10 mmol).
Secondary Hyperparathyroidism
Treat the underlying cause:
• CKD
• Vitamin Deficiency
What are the complications of hyperparathyroidism?
Primary Hyperparathyroidism PTH Leads to: • Bone Resorption • Renal Tubular Calcium Reabsorption • Intestinal Calcium Reabsorption secondary to 1a-hydroxylation of Vit D.
Secondary Hyperparathyroidism
• Stimulation of osteoclast leads to the increased resorption of bone and high bone turnover. This leads to osteitis fibrosa cystica (OFC), or brown tumours seen on X-rays.
Surgery
• Hypocalcaemia
• Damage to the recurrent laryngeal nerve.
