Hyperparathyroidism

 

Primary

It is caused by autonomus secretion of PTH from adenoma, carcinoma or hyperplasia of parathyroid gland

1. Single adenoma (90%)
2. Multiple adenomas (4%)
3. Nodular hyperplasia (5%)
4. Carcinoma (1%)

 

Secondary:

Prolonged hypocalcaemia (e.g. CRF, Malabsorption, Osteomalacia & rickets)

↓

Increase in PTH secretion

(Physiological response)

 

Tertiary:

Prolonged secondary hyperparathyroidism

(Continuous stimulation of parathyroid)

↓

Formation of adenoma

↓

Autonomous PTH secretion

 

                                E.g. Advanced CKD

 

Pseudohyperparathyroidism

Hyperparathyroidism occurs due to secretion of PTH from non parathyroid tumors e.g. kidney, lung

 

Clinical features:

Primary hyperparathyroidism 2-3 times more common in female & 90% over 50 years

• • General: Weakness, Weight loss
  • CNS: Fatigue, Lassitude, Headache, Depression, dementia, psychosis
  • GIT: nausea, vomiting, diarrhea/ constipation, PUD, cute pancreatitis

• Musculoskeletal: 

• atony of muscles

• back pain, bone pain, joint pain
• spontaneous fracture of long bones, ribs and spine
• body height may be diminished with progressive development of kyphosis
• bony cysts called osteitis fibrosa cystica (Brown tumor of bone)
• Chondrocalcinosis: Deposition of calcium pyrophosphate crystals within articular cartilage; Site: knee; Complications:  Secondary degenerative arthritis, Pseudogout

          

• • CVS: Hypertension
  • Eye: Band keratopathy on slit lamp examination

• Renal: 

• Polyuria with polydipsia (due to increased excretion of calcium)

• Nephrocalcinosis

• Nephrolithiasis (5% of first stone formers and 15% of recurrent stone formers have 10 hyperparathyroidism) → obstructive uropathy→   CRF

• Pyelonephritis

 

Stones Renal stones Nephrocalcinosis Polyuria, Polydipsia Uremia		Bones Osteitis fibrosa Radiologic osteoporosis Osteomalacia and rickets Arthritis, Chondrocalcinosis, Pseudogout
Abdominal groans Constipation Nausea, vomiting, Dyspepsia, PUD Pancreatitis		Psychic moans Lethargy, Fatigue Depression Memory loss, Psychosis Personality change Confusion, coma, stupor
Others Proximal muscle weakness Keratitis, Conjunctivitis Hypertension

 

Types	PTH	Calcium	Phosphate	ALP
Primary	↑	↑	↓	↑
Secondary	↑	↓ or N	↑ (CRF)	↑
Tertiary	↑	↑	↑ (CRF)	↑

Investigations:

       

Investigation	Finding
S. PTH, Ca++, PO4–, ALP
Hydrocortisone suppression test	100 mg 6 hourly for 10 days There is failure of suppression of calcium in hyperparathyroidism
24 hour urinary calcium, Ca clearance  Family member screening for hypercalcemia Genetic testing for CSR  gene mutation	To exclude FHH Low urinary Ca, Ca clearance →  FHH Hyperparathyroidism এর কোন case হলে দুইটা পয়েন্ট দেখতে হবে FHH → MEN
X Ray Skull lateral view	Pepper-pot [salt and pepper] appearance (multiple small lytic lesion) Multiple myeloma:   punched out lesion Secondary: irregular margin
X Ray long bones (OSPE)	Generalized osteopenia  Erosion/resorption of terminal phalanges Subperiosteal erosion of radial side of middle phalanges Fracture & Cysts (rare)
ECG	Long QT syndromes
USG of Parathyroid glands	adenoma, operator dependent
Parathyroid scintigraphy  99mTc-sestamibi scintigraphy  99mTc-SPECT/CT 18F- Fluorocholine PET/ CT.
X Ray, USG abdomen	Calcification within renal outlines, arterial wall
CXR, USG of KUB	to exclude Pseudohyperparathyroidism

 

Treatment: Primary 

Mild or vague symptoms or asymptomatic case

• No active therapy
• High oral fluid intake to prevent renal stone
• Follow up 6-12 monthly: 
  • Clinical (symptoms), 
  • Biochemical (calcium biochemistry, renal function), 
  • DEXA scan

 

Symptomatic patient

For life threatening hypercalcaemia:

• Rehydration: 4-6 liters/day NS for 2-3 days
• Bisphosphonates
• Forced diuresis by furosemide and normal saline
• Haemodialysis
• Urgent parathyroidectomy 

 

Surgery: Indications: (Q)

1. Clear cut symptoms
2. Complications: renal stone, renal impairment, osteoporosis
3. Corrected serum calcium > 11.4 mg/dl (2.8 mmol/L)

 

After surgery there is development of hypocalcaemia so calcium and vit D supplement   should be given in the immediate postoperative period.  

 

Cinacalcet: calcimimetic which enhances the sensitivity of the calcium-sensing receptor 

• for tertiary hyperparathyroidism
• for patients unwilling to surgery or unfit

 

Hypercalcemia in malignancy:

• Humoral hypercalcemia of malignancy

• Caused by PTHrP (solid tumors, adult T cell leukemia syndrome)
• Caused by 1,25(OH)2D (lymphomas) 
• Caused by ectopic secretion of PTH (rare)

• Local osteolytic hypercalcemia (multiple myeloma, leukemia, lymphoma)