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Clinical Investigations And Tests Of Parathyroid Functions: Urinary Tests

Updated on February 9, 2014

A Urine Sample

These investigations include urinary calcium, phosphate, hydroxyproline, cyclic-AMP and other relevant tests such as the thiazide and cortisone tests.
These investigations include urinary calcium, phosphate, hydroxyproline, cyclic-AMP and other relevant tests such as the thiazide and cortisone tests. | Source

Urine Phosphate Analysis

Parathyroid hormone facilitates the excretion of phosphate in urine. When the dietary intake of phosphate is 1-1.5 g/day, the daily urinary loss is less than 1g. Dietary phosphate is mostly absorbed and it tends to raise serum phosphate level.
Parathyroid hormone facilitates the excretion of phosphate in urine. When the dietary intake of phosphate is 1-1.5 g/day, the daily urinary loss is less than 1g. Dietary phosphate is mostly absorbed and it tends to raise serum phosphate level. | Source

Urine Analysis

These investigations include urinary calcium, phosphate, hydroxyproline, cyclic-AMP and other relevant tests such as the thiazide and cortisone tests.

Urinary calcium: In health, more than 95.0% of filtered calcium is reabsorbed by the tubules. If the intake of calcium is steady, urinary loss of calcium is less than 3-4 mg/Kg of ideal body weight in 24 hours. In hyperparathyroidism, with sustained hypercalcemia, the dialy urinary loss of calcium exceeds 300 mg. This gives a positive Sulkowitch test.

Urinary Phosphate: Parathyroid hormone facilitates the excretion of phosphate in urine. When the dietary intake of phosphate is 1-1.5 g/day, the daily urinary loss is less than 1g. Dietary phosphate is mostly absorbed and it tends to raise serum phosphate level. The urinary excretion, therefore, varies directly with dietary intake. Normal phosphate clearance (determined by simultaneous measurement of urinary and serum phosphate) is 10.8+2.7 ml/min. The tubular reabsorption of phosphates exceeds 75-85% of the filtered load. Tubular reabsorption is reduced in hyperparathyroidism and thereby phosphate clearance is increased at least by 50%.

Urinary hydroxyproline: Normal adults eliminate 15-24 mg of hydroxyproline in 24 hours. This is increased in hyperparathyroidism and osteomalacia. Other conditions in which urinary hydroxyproline is altered include growth spurt and bone resorption.

Urinary cyclic-AMP: Measurement of urinary c-AMP levels gives useful clues regarding parathyroid function. Normal adults pass 10 micromoles of c-AMP in 24 hours (1.8 to 4.5 nanomoles/dl of glomerular filtrate). In primary hyperparathyroidism, urinary c-AMP levels are high. Administration of PTH raises urinary c-AMP levels are elevated in hypercalcemia secondary to boney metastases.

Ellsworth-Howard Test

Normal subjects respond to administration of bovine PTH (200- 400 USP units or 50- 80 BPC units) by increasing the urinary phosphate and c-AMP by about 100%. Subjects with hypoparathyroidism show exaggerated increase in these parameters
Normal subjects respond to administration of bovine PTH (200- 400 USP units or 50- 80 BPC units) by increasing the urinary phosphate and c-AMP by about 100%. Subjects with hypoparathyroidism show exaggerated increase in these parameters | Source

Other Analysis

Thiazide test: This test helps to establish the diagnosis in patients with intermittent hypercalcemia, sometimes seen in primary or ectopic hyperparathyroidism. In normal subjects, administration of 100mg hydrochlorothiazide daily for ten days does not elevate serum calcium level, but in subjects with hyperparathyroidism it is persistently elevated above 11 mg/dl or more.

Stimulation tests of parathyroid function: These tests are employed to distinguish hypoparathyroidism from pseudohypoparathyroidism.

Ellsworth-Howard test: Normal subjects respond to administration of bovine PTH (200- 400 USP units or 50- 80 BPC units) by increasing the urinary phosphate and c-AMP by about 100%. Subjects with hypoparathyroidism show exaggerated increase in these parameters. In patients with pseudohypoparathyroidism, this response is blunted.

Other indirect tests of parathyroid function: Radiographic assessement of the skeleton and bone scans using 99m technetium help to detect abnormal areas.

Cortisone test: Oral administration of prednisolone in a dose of 30 mg/day for ten days suppresses serum calcium levels in hypercalcemia of malignancy, ectopic hyperparathyroidism, vitamin D intoxication, tuberculosis and sarcoidosis. In primary hyperparathyroidism, serum calcium level does not fall.

© 2014 Funom Theophilus Makama

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      Mayra 2 years ago

      While many of us know that the obvious sign of prarmiy hyperparathyroidism is hypercalcemia, few of us, perhaps, are familiar with the symptoms of this disease. These symptoms are often summarized as: stones, bones, abdominal groans and psychiatric moans .• Stones refers to kidney stones, nephrocalcinosis, and diabetes insipidus (polyuria and polydipsia). These can ultimately lead to renal failure.• Bones refers to bone-related complications. The classic bone disease in hyperparathyroidism is osteitis fibrosa cystica, which results in pain and sometimes pathological fractures. Other bone diseases associated with hyperparathyroidism are osteoporosis, osteomalacia, and arthritis.• Abdominal groans refers to gastrointestinal symptoms of constipation, indigestion, nausea and vomiting. Hypercalcemia can lead to peptic ulcers and acute pancreatitis. The peptic ulcers can be an effect of increased gastric acid secretion by hypercalcemia,[4] but may also be part of a multiple endocrine neoplasia type 1 syndrome of both hyperparathyroid neoplasia and a gastrinoma.•Psychiatric moans refers to effects on the central nervous system. Symptoms include lethargy, fatigue, depression, memory loss, psychosis, ataxia, delirium, and coma.(BTW—I cannot take credit for knowing these symptoms. I referred to the much maligned Wikipedia for this data. As we all know, I’m not a physician nor am I a healthcare professional. I’m simply someone with an interest in health and well being—especially with respect to the master hormone: D).I do know a few people who suffer from this disease. It isn’t pleasant. It interferes with them living their lives to the fullest extent possible. Therefore, the choice of graphics for this article is very appropriate. Those suffering from this disease often must compartmentalize their lives according to how the illness impacts them from day-to-day. A compartmentalized life is no life to live, for sure! I was happy to read Brant’s closing statement: “…it looks like vitamin D supplementation shouldn’t necessarily be avoided in prarmiy hyperparathyroidism, as long as the condition and supplementation regimen is closely monitored by a qualified health professional. “ Optimal 25(OH)D levels are necessary, in my opinion, not only for bone health and protection from autoimmune diseases and (at least) 17 different types of cancer, but also for psychological and emotional health and well being.I choose to keep my 25(OH)D level at the higher end of the optimal range.Be well!!!Rita