Cryptorchidism overview: Difference between revisions
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A 2006 study showed that regular alcohol consumption during pregnancy (5 or more drinks per week) is associated with a 3x increase in cryptorchidism, when compared to non-drinking mothers. Other previously known risk factors include exposure to [[pesticides]], low birth weight (including premature birth), gestational diabetes and being a twin[http://www.sciencenews.org/articles/20070106/food.asp]. | A 2006 study showed that regular alcohol consumption during pregnancy (5 or more drinks per week) is associated with a 3x increase in cryptorchidism, when compared to non-drinking mothers. Other previously known risk factors include exposure to [[pesticides]], low birth weight (including premature birth), gestational diabetes and being a twin[http://www.sciencenews.org/articles/20070106/food.asp]. | ||
==References== | ==References== | ||
Revision as of 00:13, 13 April 2013
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Cryptorchidism Microchapters |
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Cryptorchidism overview On the Web |
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Risk calculators and risk factors for Cryptorchidism overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Saumya Easaw, M.B.B.S.[2]
Overview
Cryptorchidism is the absence of one or both testes from the scrotum. This usually represents failure of the testis to move, or descend, during fetal development from an abdominal position, through the inguinal canal, into the ipsilateral scrotum. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis, making cryptorchidism the most common birth defect of male genitalia. However, most testes descend by the first year of life (the majority within three months), making the true incidence of cryptorchidism around 1% overall.
A testis absent from the normal scrotal position can be:
- found anywhere along the "path of descent" from high in the posterior (retroperitoneal) abdomen, just below the kidney, to the inguinal ring;
- found in the inguinal canal;
- ''ectopic'', that is, found to have "wandered" from that path, usually outside the inguinal canal and sometimes even under the skin of the thigh, the perineum, the opposite scrotum, and femoral canal;
- found to be undeveloped (hypoplastic) or severely abnormal (dysgenetic);
- found to have vanished (also see Anorchia).
About two thirds of cases without other abnormalities are unilateral; 1/3 involve both testes. In 90% of cases an undescended testis can be palpated (felt) in the inguinal canal; in a minority the testis or testes are in the abdomen or nonexistent (truly "hidden").
Undescended testes are associated with reduced fertility, increased risk of testicular germ cell tumors and psychological problems when the boy is grown. Undescended testes are also more susceptible to testicular torsion and infarction and inguinal hernias. To reduce these risks, undescended testes are usually brought into the scrotum in infancy by a surgical procedure called an orchiopexy.
Although cryptorchidism nearly always refers to congenital absence or maldescent, a testis observed in the scrotum in early infancy can occasionally "reascend" (move back up) into the inguinal canal. A testis which can readily move or be moved between the scrotum and canal is referred to as retractile.
Historical Perspective
Cryptorchidism is derived from the Greek words "crypto" (meaning "hidden") and "orchid" (meaning "testicle"). During the last century, cryptorchidism was sometimes restricted to the subset of undescended testes that were not palpable above the scrotum or in the inguinal canal — those that were truly hidden in the abdomen or completely absent. In recent decades the distinction is no longer made in most contexts, and the two terms are used interchangeably. Cryptorchism is an older variant of the same term.
Causes
In most full-term infant boys with cryptorchidism but no other genital abnormalities, a cause cannot be found, making this a common, sporadic, unexplained (idiopathic) birth defect.
Although severely premature infants can be born before descent of testes, there is a strong association of cryptorchidism with low birthweight due to either prematurity or intrauterine growth retardation. In these infants there is usually no evidence of hormonal malfunction. Associated inguinal hernias are common.
Hormonal abnormalities (deficiency or insensitivity to androgens or anti-müllerian hormone) can be demonstrated in a high proportion of those with evidence of undervirilization or ambiguity such as hypospadias or micropenis.
A contributing role of environmental chemicals — endocrine disruptors — that interfere with normal fetal hormone balance has been proposed as well, similar to the effects of diethylstilbestrol exposure. It is rarely possible to implicate a specific chemical exposure for an individual child.
Occasional instances of other genetic defects involving development or function of the gubernaculum have been reported. Homeobox gene mutations can cause cryptorchidism in animals but remain a largely theoretical possibility in humans.
Rare iatrogenic cases have also been reported in which hernia repair or other surgery in the inguinal area resulted in trapping of a testis above the scrotum.
A 2006 study showed that regular alcohol consumption during pregnancy (5 or more drinks per week) is associated with a 3x increase in cryptorchidism, when compared to non-drinking mothers. Other previously known risk factors include exposure to pesticides, low birth weight (including premature birth), gestational diabetes and being a twin[3].