Diagnostic Radiology/Musculoskeletal Imaging/Metabolic Basic/Primary hyperparathyroidism

Parathyroid hormone is the main hormone that maintains a balance of calcium and phosphate in our bodies. When released, parathyroid hormone increases the release of calcium from the bone, reabsorption from the kidney, and secondarily stimulates absorption of calcium from the intestines. It also stimulates secretion of phosphate in the kidney. Hyperparathyroidism is the abnormal secretion of parathyroid hormone. Clinical Findings The classic medical school clinical findings are "Stones, Bones, abdominal moans, and psychiatric overtones," referring to renal calculi, bone pain, peptic ulcers, pancreatitis, and CNS symptoms (confusion lethargy, weakness). Depending on the etiology, the serum calcium may be elevated and phosphate may be decreased. Etiology Excessive parathyroid hormone due to a parathyroid gland abnormality 80% parathyroid adenoma 12% parathyroid hyperplasia (rarely from Multiple endocrine neoplasia) 1-3% parathyroid carcinoma Radiology Osteopenia and bone demineralization Osteopenia and bone demineralization are present in all forms of hyperparathyroidism ===Subperiosteal .Subperiosteal resorption is virtually pathognomonic for hyperparathyroidism and is typically seen at the radial aspect of the middle phalanx of the index and middle fingers. Phalangeal tuff resorption/acroosteolysis Acroosteolysis differential diagnosis Mnemonic from The Primer: PINCH FO Psoriasis Injury (thermal/frostbite) Neuropathy (congenital insensitivity to pain, diabetes, leprosy, myelomeningocele) Collagen vascular disease (Scleroderma, Raynaud's) Hyperparathyroidism Familial (Hadju-Cheney) Other (Polyvinyl chloride exposure, snake/scorpion venom) Subchondral resorption Subchondral resorption Sacroiliac joints Distal clavicle Pubic symphysis Salt and Pepper Skull Brown Tumors Brown tumor are more common in patients with primary hyperparathyroidism, however, due to the increased prevalence of secondary hyperparathyroidism, there are more brown tumors from secondary hyperparathyroidism than from primary hyperparathyroidism. It is difficult to differentiate a Brown Tumor from a giant cell tumor or fibrous dysplasia; however, other signs of hyperparathyroidism should be present. Soft Tissue Calcification Primary > Secondary Chondrocalcinosis Secondary > Primary Knee Triangular fibrocartilage Symphysis Pubis Osteosclerosis Secondary > Primary Periostitis Secondary > Primary Tendon and ligament laxity May lead to rupture Renal osteodystrophy General term for the radiology changes associated with renal failure Secondary hyperparathyroidism (as describe above) Also includes: Osteomalacia (Normal osteoid, abnormal mineralization) Demineralized coarsened bones Looser's zones Axillary margin of the scapula Inner femoral neck Ribs Pubic and ischial rami Looser's zones in the inferior femoral neck Fig. 9 Looser's zones in the inferior femoral neck Osteosclerosis Rugger Jersey spine Rugger Jersey spine Fig. 10 Rugger Jersey spine Soft tissue calcification Vascular calcification References Hyperparathyroidism by Adam Myhre, M.D., University of Washington Department of Radiology Cooper KL. Radiology of metabolic bone disease. Endocrinology Metabolism Clinics of North America. 1989; 18(4): 955-76. Manaster BJ, et al. Musculoskeletal Imaging: the Requisites. Second Edition. Mosby, 2002. Weissleder R, et al. xxxxxxxxPrimer of Diagnostic Imaging. Second Edition. Mosby, 1997.