ABNORMALITIES OF KIDNEY
1. AGENESIS OF KIDNEY-
Development abnormality which consists of a complete absence of kidney and usually of its ureter which can be unilateral or bilateral.
2. MALROTATION OF THE KIDNEY-
A defect resulting in failure of kidney to rotate completely during development which can rotate in reverse direction with consequent persistent ventral orientation of the pelvis and ureter. It may result in pelvic obstruction. Most of malrotated kidneys are also ectopic.
3. OLIGOMEGANEPPHRONIC HYPOPLASIA-
This is a form of bilateral renal hypoplasia which is characterized by severe reduction in renal mass, as both kidneysdo not weigh more than 50% of the normal. Because of this, renal function is impaired. Even there are fewer nephrons than is normal and those, which are present, show gross hypertrophy.
4. RENAL HYPOPLASIA-
The is a developmental abnormality in which the mass of kidney is less than normal and there is decrease of renal lobes, Renal function is normal. In this most of reported cases are infact cases of acquired forms of renal atrophy. If one kidney is affected, it is unilateral simple renal hypoplasia and if both are affected, the condition is termed bilateral renal hypoplasia.
5. RENAL ECTOPIA-
A development defect consisting in malpositioning of one or both of kidneys in a location other than the normal lumbar site.
(a) Ectopic kidneys are commonly fused, the location of kidney may be specified by the use of pelvic kidney.
(b) The term “isolated renal ectopia”; is applied to ectopia in which the kidney, though abnormally positioned, is located on the correct side of body, which may be unilateral or bilateral.
(c) The term “Crossed renal ectopia”; is applied to ectopia in which a kidney is located on the side of the body opposite to that of its ureter, both kidneys being on the same side of the body. Kidneys are often but not invariably fused.
6. RENAL FUSION-
This is a developmental abnormality which consists in joining of two kidneys with continuous parenchyma or fibrous tissue. Renal fusion may be of several different types. The most common form of renal fusion is in which both kidneys are fused usually at lower or at upper poles. The kidneys are normally lower than normal and incompletely rotated.
RENAL FUSION, Ring Type-
This is a form of renal fusion in which both of kidneys are fused at both poles.
RENAL FUSION, Entire- A form of renal fusion in which both of kidneys are fused along their entire length to produce an organ of irregular shape.
RENAL FUSION, Sigmoid type- A form of renal fusion in which the upper pole of one of kidneys is fused to the lower pole of the other kidney.
7. SUPERNUMERARY KIDNEY-
A kidney in addition to the normal two because of defective development. Such kidneys are without parenchymal continuity and each has its own collecting system.
8. RENAL DYSPLASIA-
This is general term for defective development of tissues of the metanephros with consequent abnormality of the renal parenchyma, which affects either the medulla alone or both the medulla and the cortex which can be unilateral or bilateral. Pertitubular fibromuscular mesenchymal cells and metaplastic cartilage are important histological features of the disorder.
(1) The term medullary renal dysplasia and corticomedullary renal dysplasia are used,when the lesions may be focal, segmental or generalized
(2) The two main types of renal dysplasia are multicystic and aplastic dysplasia
9. MULTICYSTIC RENAL DYSPLASIA-
This is a severe form of generalized renal dysplasia in which there is nephromegaly with no functional renal parenchyma, most of the latter being occupied by cysts. The larger ones showing a peripheral distribution, it can be bilateral but it is more frequently unilateral. The pelvis and calyces are occluded or absent.
Renal agenesis- dysplasia syndrome – It is usually unilateral but sometimes bilateral.
Renal tubular dysgenesis- This is a hereditary abnormality of metanephric differentiation that gives rise to abnormal tubular development and naturation. The abnormality which is apparently of autosomal recessive inheritance is associated with oligohydramnios and prenatal death.