Renal hypoplasia

Last updated
Renal hypoplasia
Other namesHypoplastic kidneys
Ultrasound showing hypoplastic right kidney.png
An ultrasound scan of a hypoplastic right kidney in an adult male.
Specialty Nephrology
Complications Anuria, chronic kidney disease, glomerular hyperfiltration, hypertension, proteinuria, sepsis, urinary tract infection, urinary tract obstruction, urolithiasis [1] [2]
TypesSimple, oligomeganephronic, segmental, cortical
CausesMutation of the genes HNF1B, PAX2, PBX1 [1]
Diagnostic method Ultrasound
Differential diagnosis Renal dysplasia, oligomeganephronia [3]
Frequency1 in 400 births [4]

Renal hypoplasia is a congenital abnormality in which one or both of the kidneys are smaller than normal, [5] resulting in a reduced nephron number [1] but with normal morphology. [4]

Contents

It is defined as abnormally small kidneys, where the size is less than two standard deviations below the expected mean for the corresponding demographics, and the morphology is normal. [4] [1] The severity of the disease depends on whether hypoplasia is unilateral or bilateral, and the degree of reduction in the number of nephrons. [1]

Classification

Renal lobe (renal cortex green with renal pyramid below) Slide24iii.JPG
Renal lobe (renal cortex green with renal pyramid below)

Renal hypoplasia pertains to the reduction in the number of renal lobes. The classification of renal hypoplasia establishes four types, termed simple, oligomeganephronic, segmental, and cortical.

Simple hypoplasia

Simple hypoplasia is characterized by either one kidney weighing 50% or less of that of the normal, or the combined weight of both kidneys being less than 33% of that of the normal. Often accompanied by hypertension. The number of lobules and calyces is reduced to five or fewer, compared to the usual ten or more. Enlargement of the nephrons is not present in this type, considering it is associated with oligomeganephronia. The histology is normal. Cysts or dysplasia are absent and apart from its decreased size, every other facet of the kidneys is unaffected. If unilateral, the contralateral kidney can undergo hypertrophy to compensate for the affected kidney, and renal function stays normal. If bilateral, progressive renal insufficiency is expected. [6] [ additional citation(s) needed ]

Oligomeganephronia

Oligomeganephronia (or oligomeganephronic hypoplasia) is a rare pediatric renal disease where the number of nephrons is reduced but is distinctly enlarged. Tubules are also enlarged. This type of hypoplasia is more prevalent in males with a ratio of three-to-one and is caused by either renal-coloboma syndrome, branchiootorenal syndrome, acro renal syndrome, or wolf-hirschhorn syndrome. Both kidneys are affected symmetrically unless paired with unilateral agenesis, which is uncommon. Morphology is normal. The combined length of both kidneys is 80% or lower than a single normal kidney and the glomerular filtration rate is reduced to 30% of the normal. The number of renal lobes is reduced to five to six or occasionally as few as one or two. The number of nephrons per lobe is reduced as well. Malformations of the urinary tract and nephrosclerosis are absent and vesicoureteral reflux is insignificant. Unlike segmental hypoplasia, hypertension is rarely present in this type. The affected are generally born premature or small for their gestational age. Most cases are sporadic but some are inherited. It has been reported that the affected person can have a twin or sibling with the same condition. In the first few years of the affected individual's life, dehydration, polyuria and polydipsia are present, followed by hyperfiltration alongside proteinuria, with progressive renal failure to come after, its onset determined by the combined renal mass. The end-stage renal disease occurs between six months and seventeen years. [7] [ additional citation(s) needed ]

Segmental hypoplasia

Segmental hypoplasia or Ask-Upmark kidney is a rare renal disease where a part of the kidney has undergone hypoplasia. The number of renal lobes is reduced, and the kidney size is less than two standard deviations from the average, with the weight often being over 50g in adults and 12–25g in children. This type of hypoplasia can be either unilateral or bilateral and is more prevalent in females by 72%. The enzyme renin is overly secreted, causing hypertension and is often severe. Calyces are enlarged, glomeruli are absent in the cortex, and the medulla is either non-existent or underdeveloped. Vesicoureteral reflux and urinary tract infections are commonly present, while cysts, dysplasia, and proteinuria are absent. The surface of the kidney has a pelvic recess and one or more transverse cortical grooves, presumed to be a failed formation of a renal lobe. The renal parenchyma next to the hypoplastic part of the kidney is seemingly normal; however, it can undergo hypertrophy, making the grooves more noticeable.[ citation needed ]

Cortical hypoplasia

Cortical hypoplasia is a not widely known type of renal hypoplasia where the number of nephron generations is reduced, causing the renal medulla to reduce in size and the renal cortex to decrease in thickness throughout the person's life. This type of hypoplasia is frequently paired with other forms of renal hypoplasia and seems to portray an arrest of nephrogenesis, leading to fewer nephron generations, resulting in smaller renal size in general. The nephrogenesis before the arrest is normal. On the other hand, the medullary rays and renal pyramids have decreased in size with the radial glomerular count reduced to eight or less. [8]

Signs and symptoms

Kidney stone Nefrolit.jpg
Kidney stone

Hypoplastic kidneys have a reduced nephron number, [4] but normal corticomedullary differentiation. [1] [9] The condition is usually asymptomatic, [10] otherwise infection and kidney stone formation can occur. [5]

Complications

Renal hypoplasia is a common cause of kidney failure in children and also of adult-onset disease. [4]

Causes

We find the etiology of this condition is in the mutations in kidney-related genes, namely, HNF1B, PAX2, PBX1. However, environmental factors like maternal diseases such as diabetes, hypertension, and intoxication via smoking and alcohol are linked to renal hypoplasia. [10]

Diagnosis

In terms of the diagnosis of renal hypoplasia, we find that the following is done in its evaluation: [1] [10] [11]

Management

Hemodialysis Hemodialysismachine.jpg
Hemodialysis

In terms of the treatment of renal hypoplasia, we find it depends on the severity of the chronic kidney disease. Renal replacement therapy is a possibility. [10]

Epidemiology

Epidemiologic studies point to an estimated incidence of 1 in 400 births. [4]

Etymology

The word renal comes from the Late Latin word renalis (“related to the kidneys”), from the Latin word renes (“kidneys”). [12]

The prefix hypo- comes from the Ancient Greek word ὑπο hupo (“under”). [13]

The suffix -plasia comes from the Neo-Latin word plasia, from the Ancient Greek word πλάσις plásis (“molding, formation”). [14]

Related Research Articles

<span class="mw-page-title-main">Kidney</span> Organ that filters blood and produces urine

In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space, and in adult humans are about 12 centimetres in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.

<span class="mw-page-title-main">Proteinuria</span> Presence of an excess of serum proteins in the urine

Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein, less than 150 mg/day; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become foamy. Severe proteinuria can cause nephrotic syndrome in which there is worsening swelling of the body.

<span class="mw-page-title-main">Alport syndrome</span> Medical condition

Alport syndrome is a genetic disorder affecting around 1 in 5,000-10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affect vision, except when changes to the lens occur in later life. Blood in urine is universal. Proteinuria is a feature as kidney disease progresses.

<span class="mw-page-title-main">Diabetic nephropathy</span> Chronic loss of kidney function

Diabetic nephropathy, also known as diabetic kidney disease, is the chronic loss of kidney function occurring in those with diabetes mellitus. Diabetic nephropathy is the leading causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD) globally. The triad of protein leaking into the urine, rising blood pressure with hypertension and then falling renal function is common to many forms of CKD. Protein loss in the urine due to damage of the glomeruli may become massive, and cause a low serum albumin with resulting generalized body swelling (edema) so called nephrotic syndrome. Likewise, the estimated glomerular filtration rate (eGFR) may progressively fall from a normal of over 90 ml/min/1.73m2 to less than 15, at which point the patient is said to have end-stage renal disease. It usually is slowly progressive over years.

<span class="mw-page-title-main">Hypertensive kidney disease</span> Medical condition

Hypertensive kidney disease is a medical condition referring to damage to the kidney due to chronic high blood pressure. It manifests as hypertensive nephrosclerosis. It should be distinguished from renovascular hypertension, which is a form of secondary hypertension, and thus has opposite direction of causation.

Atresia is a condition in which an orifice or passage in the body is closed or absent.

Secondary hypertension is a type of hypertension which by definition is caused by an identifiable underlying primary cause. It is much less common than the other type, called essential hypertension, affecting only 5-10% of hypertensive patients. It has many different causes including endocrine diseases, kidney diseases, and tumors. It also can be a side effect of many medications.

<span class="mw-page-title-main">Renal tubular acidosis</span> Medical condition

Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine. In renal physiology, when blood is filtered by the kidney, the filtrate passes through the tubules of the nephron, allowing for exchange of salts, acid equivalents, and other solutes before it drains into the bladder as urine. The metabolic acidosis that results from RTA may be caused either by insufficient secretion of hydrogen ions into the latter portions of the nephron or by failure to reabsorb sufficient bicarbonate ions from the filtrate in the early portion of the nephron. Although a metabolic acidosis also occurs in those with chronic kidney disease, the term RTA is reserved for individuals with poor urinary acidification in otherwise well-functioning kidneys. Several different types of RTA exist, which all have different syndromes and different causes. RTA is usually an incidental finding based on routine blood draws that show abnormal results. Clinically, patients may present with vague symptoms such as dehydration, mental status changes, or delayed growth in adolescents.

<span class="mw-page-title-main">Vesicoureteral reflux</span> Medical condition

Vesicoureteral reflux (VUR), also known as vesicoureteric reflux, is a condition in which urine flows retrograde, or backward, from the bladder into one or both ureters and then to the renal calyx or kidneys. Urine normally travels in one direction from the kidneys to the bladder via the ureters, with a one-way valve at the vesicoureteral (ureteral-bladder) junction preventing backflow. The valve is formed by oblique tunneling of the distal ureter through the wall of the bladder, creating a short length of ureter (1–2 cm) that can be compressed as the bladder fills. Reflux occurs if the ureter enters the bladder without sufficient tunneling, i.e., too "end-on".

Kidney development, or nephrogenesis, describes the embryologic origins of the kidney, a major organ in the urinary system. This article covers a 3 part developmental process that is observed in most reptiles, birds and mammals, including humans. Nephrogenesis is often considered in the broader context of the development of the urinary and reproductive organs.

<span class="mw-page-title-main">Papillorenal syndrome</span> Medical condition

Papillorenal syndrome is an autosomal dominant genetic disorder marked by underdevelopment (hypoplasia) of the kidney and colobomas of the optic nerve.

<span class="mw-page-title-main">Multicystic dysplastic kidney</span> Medical condition

Multicystic dysplastic kidney (MCDK) is a condition that results from the malformation of the kidney during fetal development. The kidney consists of irregular cysts of varying sizes. Multicystic dysplastic kidney is a common type of renal cystic disease, and it is a cause of an abdominal mass in infants.

Glomerulonephrosis is a non-inflammatory disease of the kidney (nephrosis) presenting primarily in the glomerulus as nephrotic syndrome. The nephron is the functional unit of the kidney and it contains the glomerulus, which acts as a filter for blood to retain proteins and blood lipids. Damage to these filtration units results in important blood contents being released as waste in urine. This disease can be characterized by symptoms such as fatigue, swelling, and foamy urine, and can lead to chronic kidney disease and ultimately end-stage renal disease, as well as cardiovascular diseases. Glomerulonephrosis can present as either primary glomerulonephrosis or secondary glomerulonephrosis.

Sickle cell nephropathy is a type of nephropathy associated with sickle cell disease which causes kidney complications as a result of sickling of red blood cells in the small blood vessels. The hypertonic and relatively hypoxic environment of the renal medulla, coupled with the slow blood flow in the vasa recta, favors sickling of red blood cells, with resultant local infarction. Functional tubule defects in patients with sickle cell disease are likely the result of partial ischemic injury to the renal tubules.

<span class="mw-page-title-main">Renal cysts and diabetes syndrome</span> Medical condition

Renal cysts and diabetes syndrome (RCAD), also known as MODY 5 or HNF1B-MODY, is a form of maturity onset diabetes of the young.

<span class="mw-page-title-main">Fryns syndrome</span> Medical condition

Fryns syndrome is an autosomal recessive multiple congenital anomaly syndrome that is usually lethal in the neonatal period. Fryns (1987) reviewed the syndrome.

<span class="mw-page-title-main">Hand-foot-genital syndrome</span> Medical condition

Hand-foot-genital syndrome (HFGS) is characterized by limb malformations and urogenital defects. Mild bilateral shortening of the thumbs and great toes, caused primarily by shortening of the distal phalanx and/or the first metacarpal or metatarsal, is the most common limb malformation and results in impaired dexterity or apposition of the thumbs. Urogenital abnormalities include abnormalities of the ureters and urethra and various degrees of incomplete Müllerian fusion in females and hypospadias of variable severity with or without chordee in males. Vesicoureteral reflux, recurrent urinary tract infections, and chronic pyelonephritis are common; fertility is normal.

<span class="mw-page-title-main">Renal ultrasonography</span> Examination of one or both kidneys using medical ultrasound

Renal ultrasonography is the examination of one or both kidneys using medical ultrasound.

The kidneys are a pair of organs of the excretory system in vertebrates, which maintains the balance of water and electrolytes in the body (osmoregulation), filters the blood, removes metabolic waste products, and in many vertebrates also produces hormones and maintains blood pressure. In healthy vertebrates, the kidneys maintain homeostasis of extracellular fluid in the body. When the blood is being filtered, the kidneys form urine, which consists of water and excess or unnecessary substances, the urine is then excreted from the body through other organs, which in vertebrates, depending on the species, may include the ureter, urinary bladder, cloaca, and urethra.

<span class="mw-page-title-main">Mammalian kidney</span> Paired organ in the urinary system of mammals

The mammalian kidneys are a pair of excretory organs of the urinary system of mammals, a type of metanephric kidney. The kidneys in mammals are usually bean-shaped, located behind the peritoneum (retroperitoneally) on the back (dorsal) wall of the body. Each kidney consists of a renal capsule, peripheral cortex, internal medulla, calices, and renal pelvis, although the calices or renal pelvis may be absent in some species. Urine is excreted from the kidney through the ureter. The structure of the kidney may differ between species depending on the environment, in particular on its aridity. The cortex is responsible for filtering the blood, this part of the kidney is similar to the typical kidneys of less developed vertebrates. Nitrogen-containing waste products are excreted by the kidneys in mammals mainly in the form of urea.

References

  1. 1 2 3 4 5 6 7 "S. Kohl, M. Liebau - Renal hypoplasia". www.orpha.net.
  2. ↑ Gadelkareem, Rabea Ahmed; Mohammed, Nasreldin (25 January 2022). "Unilateral hypoplastic kidney in adults: An experience of a tertiary-level urology center". World Journal of Nephrology. 11 (1): 30–38. doi: 10.5527/wjn.v11.i1.30 . PMC   8790306 . PMID   35117977.
  3. ↑ Copelovitch, Lawrence; Kaplan, Bernard S. (2012). "Developmental Abnormalities of the Kidneys". Avery's Diseases of the Newborn. pp. 1182–1190. doi:10.1016/B978-1-4377-0134-0.10083-6. ISBN   978-1-4377-0134-0.
  4. 1 2 3 4 5 6 Cain, Jason E; Di Giovanni, Valeria; Smeeton, Joanna; Rosenblum, Norman D (August 2010). "Genetics of Renal Hypoplasia: Insights Into the Mechanisms Controlling Nephron Endowment". Pediatric Research. 68 (2): 91–98. doi: 10.1203/PDR.0b013e3181e35a88 . PMID   20421843.
  5. 1 2 Lote, Christopher J. (2012). Principles of Renal Physiology, 5th edition. Springer. p. 22.
  6. ↑ Bonsib, Stephen M. (September 2020). "Renal Hypoplasia, From Grossly Insufficient to Not Quite Enough: Consideration for Expanded Concepts Based Upon the Author's Perspective With Historical Review". Advances in Anatomic Pathology. 27 (5): 311–330. doi: 10.1097/PAP.0000000000000269 . ISSN   1533-4031. PMC   7458098 . PMID   32520748.
  7. ↑ Wang, XH; Pan, L; He, S; Kong, DL; Wang, W (2022). "A Case Report and Literature Review of Oligomeganephronia". Frontiers in Medicine. 9: 811992. doi: 10.3389/fmed.2022.811992 . PMC   8980273 . PMID   35391889.
  8. ↑ Bonsib, Stephen M. (September 2020). "Renal Hypoplasia, From Grossly Insufficient to Not Quite Enough: Consideration for Expanded Concepts Based Upon the Author's Perspective With Historical Review". Advances in Anatomic Pathology. 27 (5): 311–330. doi:10.1097/PAP.0000000000000269. PMC   7458098 . PMID   32520748.
  9. ↑ Schreuder, Michiel F. (2015). "Renal hypoplasia". In Turner, Neil N.; Turner, Neil N.; Lameire, Norbert; Goldsmith, David J.; Winearls, Christopher G.; Himmelfarb, Jonathan; Remuzzi, Giuseppe (eds.). Oxford Textbook of Clinical Nephrology. p. 2832. doi:10.1093/med/9780199592548.003.0348. ISBN   978-0-19-959254-8.
  10. 1 2 3 4 RESERVED, INSERM US14-- ALL RIGHTS. "Orphanet: Renal hypoplasia". www.orpha.net. Retrieved 16 August 2023.{{cite web}}: CS1 maint: numeric names: authors list (link)
  11. ↑ "Renal Agenesis/Hypoplasia". Centers for Disease Control and Prevention. 17 March 2021. Retrieved 16 August 2023.
  12. ↑ "renal | Etymology, origin and meaning of renal by etymonline". www.etymonline.com. Retrieved 26 August 2023.
  13. ↑ "hypo | Search Online Etymology Dictionary". www.etymonline.com. Retrieved 26 August 2023.
  14. ↑ "plasia | Search Online Etymology Dictionary". www.etymonline.com. Retrieved 26 August 2023.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.