Hyperparathyroidism


- See:
      - Renal Osteodystrophy:
      - Remodeling of Bone

- Discussion:
    - caused by excessive production of parathyroid hormone which leads to hypercalcemia, recurrent nephrolithiasis, pancreatitis, peptic
             ulcers, and mental changes;
    - incidence of approx 5 /10,000 pts per year;
    - usually affects adults over 50 yrs & occurs more commonly in females;
    - causes:
             - in most cases is due to single parathyroid adenoma (80% of patients);
             - malignant tumor: occurs in about 1% of patients with hyperparathyroidism;
                     - occurs often in association w/ multiple endocrine neoplasia syndrome, and rarely to parathyroid carcinoma;
                     - hyperparathyoidism is sometimes seen in renal cell carcinoma and squamous cell carcinoma;
    - diff dx:
           - occult tumor;
           - multiple myeloma (often associated w/ hypercalcemia);
    - classification:
           - primary defect of the parathyroid gland w/ hypersecretion of PTH as seen w/ adenoma's of the parathyroid gland;
           - secondaray causes arise from conditions that produces abnormally low ionic plasma Ca levels and thereby stimulates
                      production of PTH (see renal disease: effects on bone):
           - tertiary conditions in which PTH secretion has become autonomous after prolonged stimulation of gland owing
                      to secondary parathyroidism;
    - references:
           - Primary hyperparathyroidism: incidence, morbidity, and potential economic impact in a community.   
           - Pathology of the parathyroids in hyperparathyroidism. Discussion of recent advances in pathology of the parathyroid glands.
           - Recent advances in parathyroid gland pathology.                                                    
           - Primary hyperparathyroidism: changing patterns in presentation and treatment decisions in the eighties


- Labratory Diagnosis of Hyperparathyroidism

- Histology of Hyperparthyroidism:

- Radiology of HyperParaThyroidism: Chondrocalcinosis


- Clinical Presentation:
    - General:
         - recurrent nephrolithiasis, peptic ulcers, mental changes which has led to the phrase: stones, bones, and groans;"
               - lethargy, somnolence, and polydipsia are also nonspecific findings;
    - Bone:
         - PTH mobilizes bone and phosphate;
         - releases osteocytic perilacunaar stores (fast)
         - increases osteocytic number and activity (slow)
         - activates & increases number of osteoclasts, which leads to osteomalacia and more acutely, releases Ca & Phos;
         - causes diffuse bone pain and tenderness;
         - stimulate bone remodeling, w/ increase in number of BMU;
         - brown tumor;
         - chondrocalcinosis and calcific periarthritis are common (ossification of soft tissue);
         - fractures secondary to diffuse skeletal osteoporosis;
         - NEJM: pseudoclubbing: images in medicine
         - references:
                - Fractures of the femoral neck in elderly patients with hyperparathyroidism.
                - Joint lesions of hyperparathyroidism.                       
                - Osteosclerosis in primary hyperparathyroidism.                                                    
                - Hyperparathyroidism: tumor of the parathyroid glands associated with osteitis fibrosa.    
                - Parathyroid hormone and bone.                                                            
                - A case of multiple skeletal lesions of brown tumors, mimicking carcinoma metastases 
    - Kidney:
         - increases resorption of calcium;
         - increases excretion of phosphate;
         - stimulates 1,25 (OH)2 vit D3 (calcitriol) production;
         - common occurrence of renal calculi (in untreated cases, calculi sometimes caused renal failure);
         - increase renal phosphate excretion by decreasing renal tubular reabsorption of phosphate;
    - Gut:
         - increases absorption thru vitamin D;
         - acting at level of gut (w/ vit D) to incr absorption of calcium;
         - gastric ulcers (seen in 25% of patients) & pancreatitis are common;
         - pancreatic calcifications;
    - Neuromuscular:
         - proximal weakness, easy fatigability, and atrophy of muscles;
    - Pyschiatric:
         - individuals w/ serum Ca level of > than 12 mg/dl (2.99 mm/lit) (see hypercalcemia) have mental aberrations, confusion,
                     and dementia;
         - references:
               - Neuropsychologic deficits associated with primary hyperparathyroidism.


- Treatment:
         - non operative treatment includes adequate calcium intake and avoidance of Vit D;
                 - w/ vague constitutional symptoms such as fatigue, weakness, and/or constipation associated w/ mild hypercalcemia then
                         surgery is not indicated;
         - note that in most patients w/ primary hyperparathyroidism there is little if any disease progression;
         - among asymptomatic patients, approximately 25 % will have progressive disease, which can be measured as a signficant
                 decrease in bone mass over a decade;
         - operative treatment indications:
                - surgical treatment is indicated when clinical symptoms occur along with laboratory or radiographic abnormalities;
                - clinical findings:
                         - osteitis fibrosa cystica
                         - nephrolithiasis
                         - classic neuromuscular symptoms (proximal muscle weakness, atrophy, hyperreflexia, and gait disturbances);
                         - hyperparathyroid crisis (a discrete episode of life-threatening hypercalcemia);
               - laboratory and radiographic data;
                         - serum calcium concentration of greater than 12 mg per deciliter (3 mmol per liter)
                         - marked hypercalciuria (urinary calcium excretion, greater than 400 mg per day [10 mmol per day])
                        - markedly reduced cortical bone density (z score for the distal third of the radius, less than -2;
                                 - z score: standard deviation from mean for sex-matched and age-matched reference population), an unexplained
                                         reduction in Cr clearance


References

Fractures of the femoral neck in elderly patients with hyperparathyroidism.

Joint lesions of hyperparathyroidism.                        

Osteosclerosis in primary hyperparathyroidism.   

Hyperparathyroidism: tumor of the parathyroid glands associated with osteitis fibrosa.                                                         

Parathyroid hormone and bone.                                                           

A 10-Year Prospective Study of Primary Hyperparathyroidism with or without Parathyroid Surgery.



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, December 2, 2016 9:05 am