Renal management of phosphate is impaired in secondary hyperparathyroidism which results in hyperphosphatemia.Primary hyperplasia of the parathyroid gland, results from both hypocalcaemia and increased phosphate levels by decreasing expression of calcium sensing receptors and vitamin D receptors at the parathyroid gland. These decreases in receptor expression lead to hyperfunctioning of the parathyroid. Hyperfunction of the parathyroid gland is thought to exacerbate primary hyperplasia which evolves further to a secondary more aggressive hyperplasia. Histologically, these hyperplasic glands can be either diffuse or nodular. Primary hyperplasia, usually resulting in diffuse polyclonal growth is manly related to reversible secondary hyperparathyroidism. Secondary hyperplasia of the parathyroid gland is more often a nodular, monoclonal growth that sustains secondary hyperparathyroidism and is the catalyst in the progression to tertiary hyperparathyroidism. Nodular hyperplastic glands in tertiary hyperparathyroidism are distinctly larger in both absolute size and weight up to 20-40-fold increases have been reported. Parathyroid glands are normally composed of chief cells, adipocytes and scattered oxyphil cells. Chief cells are thought to be responsible for the production, storage and secretion of parathyroid hormone. These cells appear light and dark with a prominent Golgi body and endoplasmic reticulum. In electron micrographs, secretory vesicles can be seen in and around the Golgi and at the cell membrane. These cells also contain prominent cytoplasmic adipose. Upon onset of hyperplasia these cells are described as having a nodular pattern with enlargement of protein synthesis machinery such as the endoplasmic reticulum and Golgi. Increased secretory vesicles are seen and decreased intercellular fat is characteristic.
Pseudopterygium is the conjunctival adhesion to cornea caused by limbal or corneal inflammation or trauma. The pseudopterygium can be easily distinguished from pterygium by bowmans probe test. Because of the lack of adherence of pseudopterygium at every point, the probe can be passed beneath it at some point. Causes
Chemical burn
Marginal corneal ulcer
Cicatrizing conjunctivitis
Trauma
Surgery

Differential diagnosis
Treatment
Pseudopterygium can be removed by surgical excision. See also
Symblepharon
Pterygium


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