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Phase 2 2. Repro, renal and urology > Cryptochordism > Flashcards

Cryptochordism Flashcards

1
Q

What determines genetic sex?

A

Genetic sex is fixed at fertilisation by the male gamete

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2
Q

How is the human embryo bipotential?

A

Whether 46XY or 46XX, the internal (Mullerian / Wolffian) and external (genital tubercle and urethral and
genital folds) look the same
until 40 days gestation (7 weeks)

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3
Q

How do the internal and external genitalia begin to differentiate?

A

After 40 days, these begin to differentiate: testis produces AMH then T or ovaries
o AMH is produced by Sertoli cells
o Causes regression of mullerian structures
o Leydig cells secrete testosterone and DHT
o DHT is about 10 times more potent than testosterone
 Responsible for the differentiation of the external genitalia
 Testosterone is more concerned with development of the internal genitalia

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4
Q

Describe the genetic influence in gender differentiation

A

 Needs activation of specific gene cascades, challenging ‘female development by default’
 Presence of Y chromo containing normal SRY will result in male differentiation (sex determining region of
the Y chromosome)
 SOX (SRY related HMG Box)  involved in sex determination
 WT-1 (Wilms tumour 1)  needed for testis determination
 SF-1 (steroidogenic factor 1)  needed for testis determination
 WNT-4 (Wingless type member 4)  pathway needed for ovarian differentiation

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5
Q

Describe the migration of primordial germ cells during differentiation

A

 Primordial germ cells are extragonadal in origin
o arise from the epiblast, passing through the primitive streak.
 For a period, they are kept in the wall of the yolk sac (perhaps to maintain pluripotency)
 At hindgut formation, they migrate to the genital ridge.

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6
Q

Where is the genital ridge found?

A

lies along the medial border of an intermediate kidney called the mesonephros.

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7
Q

Where does the testis duct system develop from?

A

The duct system of the testis develops from the mesonephros

o The mesonephric duct becomes the ductus (vas) deferens.

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8
Q

How do sertoli cells influence testis development?

A

the Mullerian system involutes under the influence of AMH
secreted by the Sertoli cells
AMH acts in a paracrine fashion

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9
Q

How do leydig cells influence testis development?

A

the Wolffian system is stabilised by testosterone secreted by Leydig cells
Testosterone acts locally and in a classical endocrine way through the bloodstream

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10
Q

What do the wollfian ducts develop into?

A 
Wollfian ducts are stimulated by hCG into:
o the epididymis
o vas deferens
o seminal vesicles
o ejaculatory ducts.
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11
Q

What are the layers covering the testis?

A
  • skin
  • dartos fascia and muscle
  • external spermatic fascia
  • cremasteric fascia
  • tunica vaginalis
  • tunica albuginea
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12
Q

What is the external spermatic fascia

A

external oblique

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13
Q

What is the cremaster muscle (skeletal muscle) and cremasteric fascia

A

continuation of the internal oblique muscle

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14
Q

What is the role of the cremaster muscle

A

elevates the testes during sexual arousal and exposure to cold

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15
Q

What is the internal spermatic fascia

A

transversalis fascia

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16
Q

Describe the tunica

vaginalis

A

o derived from abdominal peritoneum during development => processus vaginalis
o has visceral and parietal layers
o The visceral layer overlies the tunica albuginea (middle layer of the tunica)
o parietal layer lines the scrotal cavity.
o A thin fluid layer separates the two sections of the tunica vaginalis and reduces friction between
the testes and the scrotum.
o Excess fluid in the tunica vaginalis can form a hydrocele.

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17
Q

Tunica albuginea

A

o fibrous capsule that encloses the testes.
o penetrates into the parenchyma of each testicle, dividing it into lobules.
o dense blue-grey membrane, composed of bundles of white fibrous connective tissue
o encases the testes and connects to the layers of fibres which surround theepididymis

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18
Q

What is a hydrocele?

A

swollen testicles in a baby

use a light:
=> Hydrocele (fluid) transilluminates

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19
Q

What can cause swollen testicles other than hydrocele?

A

Herniation of bowel contents through inguinal canal into testes

use a light:
=> Hernia (bowel) stays dark

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20
Q

Why do testes need to descend?

A

 Antenatally, the testes are intra-abdominal
 However, it ‘descends’ to the scrotum, as normal body temperature is harmful to spermatogenesis
o The testis requires a temperature 2 o C lower than body temperature.
 The process of testicular descent is complex and controlled by both physical and hormonal factors.
 It begins in the 10 th week of pregnancy.
 Occurs in two phases:
o Transabdominal phase
o Inguinoscrotal phase

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21
Q

Where do the testes develop?

A

 The testis develops beside the mesonephros (‘urogenital ridge’), as an intra-abdominal organ.

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22
Q

What is the transabdominal phase?

A

(8-15 weeks)
 The testes enlarge as the mesonephric kidneys regress.
 Each testis is anchored at its upper pole to a cranial suspensory ligament and at
its lower pole to the gubernaculum
o Both derived from the urogenital mesentery.
 The gubernaculum swells under the control of Insulin-like Peptide 3 (INSL-3)
(and its receptor LGR8) produced by Leydig cells
o Swelling stimulates migration of the testes
 Sertoli cells produce Anti-Mullerian Hormone (AMH) which brings about
atrophy of the Mullerian (paramesonephric) ducts
o This enables the testis to move transabdominally to the deep inguinal
ring

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23
Q

What is the inguinoscrotal phase?

A

 Controlled by androgens and by calcitonin gene-related peptide (CGRP)
released from the sensory nucleus of the genitofemoral nerve
o innervates the spermatic cord and round ligament
 Gubernaculums shortens and migrates.
 The testis usually arrives in the scrotum a few weeks before birth
o Slide down behind the processus vaginalis - an extension of the peritoneal cavity
o Accompanied by muscular and fascial layers of the body wall, forming the inguinal canal.

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24
Q

Why do premature babies have undescended testes?

A

because they have not gone through the final few weeks of

pregnancy, when testicular descent occurs

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25
Q

What are the walls of the inguinal canal?

A

Walls of the inguinal canal - MALT:

Upper wall: 2Muscles
Anterior wall: 2Aponeuroses
Lower wall: 2Ligaments
Posterior wall: 2Ts

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26
Q

What muscles contribute to the inguinal canal

A

Upper wall:
o internal obliqueMuscle
o transverse abdominusMuscle

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27
Q

What aponeuroses contribute to the inguinal canal

A

Anterior wall:
o Aponeurosis of external oblique
o Aponeurosis of internal oblique

28
Q

What aponeuroses contribute to the inguinal canal

A

Lower wall:
o inguinalLigament
o lacunarLigament

29
Q

What T’s contribute to the inguinal canal

A

Posterior wall:
o Transversalis fascia
o ConjointTendon

30
Q

Why is the inguinal canal clinically important?

A

This is important clinically because hernias are commonly associated with it.

31
Q

What does the inguinal canal transmit?

A

Lying between the muscles of the lower anterior abdominal wall, the inguinal canal transmits:
o the spermatic cord in the male
o the round ligament of the uterus (equivalent of the gubernaculum) in the female.

32
Q

Describe the layout of the inguinal canal

A

 It is 4cm long and lies above the medial half of the inguinal ligament running downwards, forwards and
medially from the deep inguinal ring – a gap in the transversalis fascia - to the superficial inguinal ring in
the aponeurosis of the external oblique muscle.
 The two rings are off-set with respect to each other, acting as a safety valve mechanism when intra-
abdominal pressure is raised.

33
Q

What is the Tunica albuginea

A

dense white fibrous capsule which extends inwards
o forms septa that divide each testis into lobules
o Lobules contain the seminiferous tubules (where sperm are produced)

34
Q

Describe the sertoli cells

A

o form the blood-testis barrier
o support and protect spermatogenic cells
o mediate the effects of testosterone and FSH
o secrete inhibin  helps regulate sperm production by inhibiting secretion of FSH

35
Q

What is the function of the leydig cells?

A

secrete testosterone

36
Q

Describe the spermatic cord

A

transmits important structures to and from the testis
o vas deferens
o arteries (3, testicular, ductus and cremaster)
o pampiniform plexus of up to 12 veins for cooling the blood supply
o nerves (genital branch of the genitofemoral nerve)
o lymphatic vessels (cancer spread)
o fibrous remnant of processus vaginalis.

37
Q

What controls the descent of testicles and testicular function?

A

hypothalamic-pituitary-gonadal axis

38
Q

How are the testes examined clinically?

A

 Wash hands, introduction, chaperone( utmost importance - more for your protection than anyone else’s)
 Full abdominal examination
o Goes hand in hand with abdominal examination
 Standing then lie flat, ask about pain
o Standing  gravity will bring herniated organs into the scrotum
 Palpation, warm hands!
 Describe masses felt
 Lymph nodes
 Think about differential diagnoses of lumps in the groin
o Hernias, hydrocele, varicocoele, tumours, etc.

39
Q

What is testicular dysgenesis and how can it result?

A

includes:

  • hypospadias
  • micropenis
  • reduced semun quality
  • testicular cancer

Can result from testes being in the abdomen for too long and overheating

40
Q

What is cryptorchordism?

A

 Also known as ‘impalpable’ or ‘undescended’ testes

NB: be careful with terminology
o Undescended testes may be palpable high in the inguinal canal
o Impalpable testes cannot be felt at all  very high in abdomen or missing altogether

Bilateral vs unilateral

41
Q

What can cause chryptorchordism?

A

 Majority of cases have no discernible aetiology – environmental factors have been implicated
 Long term consequences on testicular function, including spermatogenesis, and risk of testicular cancer
 Part of ‘testicular dysgenesis syndrome’
 Retained testis often smaller, suggesting prenatal testicular maldevelopment
 Changes caused by the position itself can add further damage
 More severe testicular dysgenesis = more severe cryptorchidism
o Higher in abdomen = higher temperature = more severe damage

42
Q

How is cryptorchidism classified?

A

 Position
 Position over time
 Aetiological factors
 Retractile

 May be along normal route of descent or ectopic
 Unilateral vs bilateral
 Palpable vs non palpable
 Spontaneous descent, spontaneous ascent

43
Q

How should cryptorchidism be treated?

A

Any undescended testis after the age of 6 months should be referred for orchidopexy
o Given 6 months because they may descend naturally
o NB: babies with abdominal testes will not be left as these will not descend properly within 6
months

 Cryptorchidism with ambiguous genitalia needs immediate work up – CAIS, 5ARD.
 Phenotypically male with cryptorchidism needs immediate work up

44
Q

Describe the location of the testis in different types of cryptorchidism

A

 Abdominal testes probably not palpable
 Inguinal testes => in inguinal canal
 Prescrotal => high in the scrotum, still not quite the right position
 Retractile testis is normal variant
o Sit slightly high in the prescrotal area but can be ‘milked’
down into the prescrotal area where they should be, but
retract back to their original position with time
o Not as concerning, but should be monitored so that they
do not become prescrotal testes

45
Q

Describe the prevalence of cryptorchidism

A

 Normal birthweight boys at term, varies from 2% to 8%
 Indicates yet unexplained geographical differences
 May resolve spontaneously during the first months of life when endogenous testosterone briefly
increases thus lower prevalence is reported from 3-12 months of life.
 Increased incidence in childhood may be due to retractile and ascensus testes
 Prevalence is increasing over time in line with increasing hypospadias, reduced semen quality and
testicular cancer in some Western countries suggesting that changes in lifestyle and environment have a
role to play

46
Q

Describe the risk factors for cryptorchidism

A

 Low birthweight <2.5kg
 Small for gestational age
 Prematurity (incomplete normal testicular descent)
 Maternal diabetes, including gestational diabetes
 Environmental factors may also play a role for the risk of cryptorchidism:
o OrganochlorineS
o phthalate monoesters
o smoking
o All have been linked to adverse effects in infant reproductive development
 Placental insufficiency / decreased HCG secretion / low maternal oestrogen levels

47
Q

What is the link between cryptorchidism and semen quality?

A

 Adult men with persistent bilateral cryptorchidism have azoospermia (semen contains no sperm)
o 28% after operation have normal sperm count
 49% of men with persistent unilateral cryptorchidism have a normal sperm concentration
o 71% after orchidopexy
 Earlier surgery (between 10 months and 4 years) preferable in bilateral cryptorchidism

48
Q

What is the link between cryptorchidism and testicular cancer?

A

 Well established risk factor for testicular neoplasia
 5% higher risk of testicular cancer compared to normal population
 Bilateral carries a higher risk of malignancy
 Risk greatest if testis is intra-abdominal
 Early orchidopexy / spontaneous descent not associated with increased risk

49
Q

What investigations are used to diagnose cryptorchidism

A

 Ultrasound  most useful
o Painless
o Noninvasive
o Well-tolerated by children
 CT
o Exposes child to high dose of radiation
 MRI
o Difficult to get child to sit still
 Laparoscopy
 Consider karyotype
o Make sure baby is 46XY and not a different chromosomal arrangement
 Biochemical tests
o To determine if the testes are going to function normally
o Testosterone levels  check baby’s capacity to produce testosterone

50
Q

Describe the operative treatment for cryptorchidism

A

 Operative treatment should be carried out whenever possible
o Should be done in centre with expertise
 Orchidopexy => involves first making an incision in the groin to locate the undescended testicle. The
testicle is then moved downwards and repositioned in the scrotum through a second incision.
 Laparoscopy for non-palpable testis
 One stage vs two stage
 Should be carried out at age 6-18 months
 Clinical examination 12 months post op / for bilateral cases follow up at puberty
o High recurrence rate

Should be performed one side at a time

51
Q

What are the complications of orchidopexy?

A 
 Immediate complications:
o Haematoma
o Pain
o wound infection
 Long term complications:
o testicular atrophy
o recurrent cryptorchidism
52
Q

What hormonal treatment can be given to patients with cryptorchidism?

A

Can be tried in children who cannot tolerate surgery
 hCG stimulation test => mimics LH produced by pituitary, causing a surge of testosterone
 LHRH (GnRH) test
o To diagnose hypothalamic-pituitary disease in precocious and delayed puberty in both sexes in
those children with low basal gonadotropins.
 Overall efficacy of approximately 20%
 Efficacy depends on initial position of testis
 Up to 25% re-ascend later on

53
Q

What are the side effects of hormonal treatment for cryptorchidism?

A

Side effects of hormonal treatment include:
o Pain
o penile growth
o groin pain
o behavioural problems
o temporary inflammatory changes in the testes
o reduced testicular volume in adulthood

Age dependent (most harm at 1-3 years)

54
Q

What is hypospadias?

A

Ectopically positioned urethral meatus lies proximal to the normal site and on the ventral aspect of the
penis, and in severe cases opens on to the scrotum

Most common congenital anomaly of the penis
Usually develops sporadically and without an obvious underlying cause

55
Q

What other features are associated with hypospadias?

A

 Chordee (bend in the penis) and hooded foreskin common
 Associated with cryptorchidism and inguinal hernia
 Frequency of associated anomalies increases with the severity of
hypospadias

56
Q

What is the cause of hypopadias?

A

 Cause not always clear
 Hormonal fluctuations – testosterone, progesterone
 Advanced maternal age
 Assisted pregnancies – IVF
o Particularly IVF regimes using a lot of progesterone
 Teratogenic drugs / endocrine disruptor chemicals
 Reduced sensitivity to androgens
 Genetic factors - runs in families

57
Q

How is hypospadias treated?

A

 Surgery
o Surgically very challenging to repair
 Scarring, curvature, strictures, fistula may occur
o Repaired using foreskin to form a new urethra
o Therefore advise against circumcision
o Multiple procedures, mucosal grafting
 Hormonal treatment prior to surgery

58
Q

What is a disorder of sex development?

A

Any congenital condition in which development of chromosomal, gonadal or anatomic sex is atypical

Rare disorders, but crucial to get it right

59
Q

How are disorders of sex development classified?

A
  • primary root = karyotype
  • secondary root = what the disorder effects
  • & actual diagnoses
60
Q

Briefly describe the adrenal gland functional anatomy

A

o outer = salt control
o middle = glucocorticoids
o innermost = androgens

61
Q

What is CAH?

A

Congenital adrenal hyperplasia is group of congenital inherited conditions where the adrenal gland is larger than usual (hyperplasia).
any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the
biochemical steps of production of mineralocorticoids, glucocorticoids or sex steroids from cholesterol by
the adrenal glands (steroidogenesis)

62
Q

What is the most common type of CAH?

A

Each form of CAH is associated with a specific defective gene. The most common type (95% of cases)
involves the gene for21-hydroxylase => antenatal deficiency of 21-hydoxylase
o This enzyme stimulates the adrenal glands to release cortisol.
o No cortisol produced

63
Q

What does a deficiency in 21-hydroxylase result in?

A

Lacking this hormone means that the body is less able to cope with stress, either emotionally or physically, which can be life threatening.

It also makes the level of androgen increase, which causes male characteristics to appear early in boys or
inappropriately in girls.
o Negative feedback causes increased synthesis => diverted down the pathway to produce massive
amounts of testosterone
o Causes masculinisation of female genitalia

64
Q

What is 5-alpha reductase deficiency?

A

Inability to convert testosterone to DHT
o Necessary to form external male genitalia
 Internal genitalia forms normally but no external masculinisation of genitalia
 Individuals with 5-ARD are born with male gonads, including testicles and Wolffian structures.
 They can have normal male external genitalia, ambiguous genitalia, or normal female genitalia, but
usually tend towards a female appearance.
 As a consequence, they are often raised as girls, but usually have a male gender identity
 At puberty, DTH is produced directly by the gonads => masculinisation
o primary amenorrhoea and virilization.
o This may include descending of the
testes, hirsutism (facial/body hair considered normal in males - not to be confused with hypertrichosis),
deepening of the voice, and
enlargement of the clitoris into what would then be classed as a penis.

65
Q

How is gender identity formed?

A

conditioned

66
Q

How should disorders of sex development be diagnosed?

A 
 All newborn infants should receive a male or female sex assignment
 Where there is doubt, hasty decisions should be avoided
 Need for multidisciplinary team
 Strict confidence
 Open communication
 Surgical management
 Sex steroid replacement
 Psychosocial management
67
Q

How do disorders of sex development present in the newborn?

A
  • overt genital ambiguity
  • apparent female genitalis => with enlarged clitoris, posterior labial fusion, inguinal/labial mass
  • apparent male genitalia => bilateral undescended testes, micropenis, hypospadias
  • family history of DSD such as CAIS
  • Discordance between genital appearance and karyotype

Phase 2 2. Repro, renal and urology (21 decks)

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