PAEDS - GENETICS/ENDOCRINE Flashcards
GENETICS OVERVIEW
What is non-disjunction?
What is the outcome?
Management?
Karyotype?
- Error in meiosis where pair of chromosomes fail to separate so one gamete has 2 chromosome copies and one has none
- Fertilisation of the gamete with 2 chromosomes gives rise to a trisomy
- Parental chromosomes do not need to be examined, related to maternal age
- 47 chromosomes
GENETICS OVERVIEW
What is Robertsonian translocation?
Karyotype?
- Extra copy of one chromosome is joined onto another chromosome
- 46 chromosomes but 3 copies of one chromosomes material
GENETICS OVERVIEW
What is the management of Robertsonian translocation?
- Parental chromosomes analysis is needed, one parent may be carrier
- Translocation carriers have 45 chromosomes on karyotype (one is in wrong place)
GENETICS OVERVIEW
What are the 3 types of Mendelian inheritance?
- Autosomal dominant
- Autosomal recessive
- X-linked (recessive)
GENETICS OVERVIEW
In terms of autosomal dominant inheritance…
i) inheritance chance?
ii) general rule?
iii) pattern of inheritance?
iv) examples?
i) 50%
ii) AD = structural protein defects
iii) No skipped generations, inherited regardless of sex
iv) Adult PCKD, familial hypercholesterolaemia, Marfan’s, Huntington’s disease, BRCA genes
GENETICS OVERVIEW
What are some reasons for autosomal dominant conditions presenting in families with no family history?
- # 1 = non-paternity
- New mutation
- Gonadal mosaicism
GENETICS OVERVIEW
In terms of autosomal recessive inheritance…
i) inheritance chance?
ii) general rule?
iii) requirements to develop disease?
iv) carrier risk in siblings?
v) examples?
i) 25% from 2 carrier parents
ii) AR = affects metabolic pathways
iii) Two germline mutations (2 carrier parents)
iv) 2 in 3 (66%) as you take away possibility of them having the disease
v) CF, phenylketonuria, haemochromatosis
GENETICS OVERVIEW
What is a big risk factor for autosomal recessive conditions?
What is the outcome?
- Consanguineous parents, esp. if many generations of it
- Can give appearance of AD pedigree for a recessive condition
- Particularly in people with Asian origin
GENETICS OVERVIEW
In terms of X-linked recessive inheritance…
i) who is affected?
ii) who transmits?
iii) what can occur in females?
iv) examples?
i) Males more than females
ii) NO male-male transmission but affected males can produce a carrier female
iii) Gonadal mosaicism may occur influenced by X inactivation (lyonisation)
iv) Haemophilia A, Duchenne’s + Becker’s, colour blindness
GENETICS OVERVIEW
What is genomic imprinting + uniparental disomy?
Give an example
- Most genes both copies are expressed, some genes are only maternally or paternally expressed (imprinting)
- Prader-Willi + Angelman’s syndrome both caused by either cytogenic deletions of the same region of chromosome 15q or by uniparental disomy of chromosome 15
GENETICS OVERVIEW
What do mitochondrial diseases lead to?
What is the inheritance?
Give some examples
- Responsible for ATP production so if abnormal > poor production + hence myopathies
- Exclusively maternally inherited from circular mitochondrial DNA in cytoplasm of ovum (sperm mitochondria in tail)
- Myoclonic epilepsy, ragged red fibres (MERRF), mitochondrially inherited DM + deafness (DIDMOAD)
GENETICS OVERVIEW
What is gonadal mosaicism?
- Some cells have mutations in genes giving rise to a particular phenotype e.g. birthmarks
- Gonadal mosaicism is when germ cells involved
GENETICS OVERVIEW
Explain the process of gonadal mosaicism
- Father = mosaic sperm (some sperm with mutated gene, some sperm normal)
- Mother = all eggs with normal gene
- Offspring = fertilised egg > union of male DNA (sperm) with mutated gene + female DNA (egg) with normal gene
- Every cell of embryo has one copy of mutated + one copy of normal
GENETICS OVERVIEW
What are 3 ways of testing genes?
- DNA analysis via polymerase chain reaction to amplify the DNA + determine the sequence of the relevant gene
- Karyotyping (look at # of chromosomes, their size + basic structure)
- Molecular cytogenic analysis = fluorescent in situ hybridisation (FISH) to detect presence, # + chromosomal location of specific sequences
GENETICS OVERVIEW
What is the purpose of DNA analysis?
- Antenatal Dx (amniocentesis or CVS)
- Confirm clinical Dx
- Detect female carriers for X-linked disorders
- Detect carriers of AR disorders
- Pre-symptomatic diagnosis of AD disorders like Huntington’s disease
GENETICS OVERVIEW
In the case of Huntington’s disease, can healthy children be tested if parents consent for them?
- No, have to be old enough to give informed consent themselves
DOWN’S SYNDROME
What is Down’s syndrome?
What is the life expectancy?
- Trisomy 21 (3x copies of chromosome 21)
- About 60y
DOWN’S SYNDROME
What are some risk factors?
- Increasing maternal age #1 (1 in 100 by 40y, increased nondisjunction),
- FHx
- mother has Down’s (rare)
DOWN’S SYNDROME
What are the causes of Down’s syndrome?
- Nondisjunction (95%) leaves cell with extra C21 so trisomy on fertilisation
- Robertsonian translocation (4%) = long arm of C21 translocate to C14 often
- Mosaicism (1%) = cells have mixed amounts of chromosomes
DOWN’S SYNDROME
What is the classical craniofacial appearance in Down’s syndrome?
- Flat occiput (brachycephaly) + flat bridge of nose
- Upward sloping palpebral fissures (eyes slant down + inwards)
- Prominent epicanthic folds (skin overlying medial portion of eye + eyelid)
- Short neck + stature
- Small mouth, protruding tongue, small ears
- Brushfield spots in iris (pigmented spots)
DOWN’S SYNDROME
Other than craniofacial anomalies, what other anomalies can be seen in Down’s syndrome?
- Widely separated first + second toe (sandal gap)
- Hypotonia
- Single transverse palmar (simian) crease
DOWN’S SYNDROME
What are some complications of Down’s syndrome?
- LDs + delayed motor milestones
- Complete AVSD
- Atlantoaxial instability = risk of neck dislocation during sports
- Hypothyroidism, duodenal atresia, Hirschsprung’s
- Hearing + visual impairment, strabismus
- Increased ALL + early-onset dementia
DOWN’S SYNDROME
How is Down’s syndrome diagnosed?
- Women offered antenatal screening/testing (combined test, CVS, amniocentesis)
- Clinical suspicion + then FISH for Dx when born
DOWN’S SYNDROME
What regular investigations are required for Down’s syndrome?
- Regular thyroid checks (every 2y)
- ECHO to Dx any cardiac defects
- Regular audiometry + eye checks
DOWN’S SYNDROME
What is the management of Down’s syndrome?
MDT –
- Specialist Dr’s (CHD, hypothyroid)
- Social services (social care + benefits)
- Optician + audiologist
- OT/physio/SALT
- Additional support with educational needs
- Charities like Down’s syndrome association
PATAU’S SYNDROME
What is Patau’s syndrome?
- Severe physical + mental congenital abnormalities due to trisomy 13
PATAU’S SYNDROME
What are some clinical features of Patau’s syndrome?
- Microcephalic, scalp lesions, small eyes + other eye defects
- Cleft lip + palate
- Polydactyly (think 13 fingers)
- Cardiac + renal malformations
EDWARD’S SYNDROME
What is Edward’s syndrome?
- Trisomy 18, mostly F
- Severe psychomotor + growth retardation if survive 1st year of life
EDWARD’S SYNDROME
What is the clinical presentation of Edward’s syndrome?
- Prominent occiput
- Small mouth + chin (micrognathia)
- Low set ears
- Flexed, overlapping fingers
- Rocker-bottom feet (flat)
- Cardiac + renal malformations
EDWARD’S SYNDROME
For both Patau’s and Edward’s syndrome, what are the investigations?
- Antenatal abnormalities detected on USS (foetal anomaly scan)
- Prenatal Dx with amniocentesis or CVS via DNA PCR
- Karyotyping genetic analysis confirms at birth
FRAGILE X SYNDROME
What is fragile X syndrome?
- Inherited condition, 2nd most common cause of LD
FRAGILE X SYNDROME
What causes it?
Trinucleotide expansion repeat of CGG caused by slipped mispairing = ≤44 normal, 60–200 = premutation carriers, >200 = fragile X
FRAGILE X SYNDROME
What does fragile X result in?
- Mutation in fragile X mental retardation 1 (FMR1) gene on X chromosome
- Inadequate FMRP which plays a role in cognitive development
FRAGILE X SYNDROME
What sex is affected by fragile X syndrome?
Always males but females vary
FRAGILE X SYNDROME
Why do females vary in how much they are affected by fragile X syndrome?
- Spare copy on other X chromosome + reduced penetrance
- Even with full mutation usually have fewer problems
- Number of CGG repeats often increases as it’s inherited so caution in future
FRAGILE X SYNDROME
What are some cognitive features of fragile X syndrome?
- Intellectual disability
- Delay speech + language
- Delayed motor development (may be secondary to hypotonia)
- Aggressive, hyperactive + poor impulse control
- “Cocktail personality” = happy bouncy children
FRAGILE X SYNDROME
What are some physical features of fragile X syndrome?
- Long narrow face + large ears
- Large testicles after puberty
- Hypermobile joints (esp. hands)
- Hypersensitivity to stimuli
FRAGILE X SYNDROME
What is associated with fragile X syndrome?
- Autism (up to 30%)
- Seizures
- ADHD
FRAGILE X SYNDROME
What issues can fragile X premutation carriers suffer from?
- Men can get Fragile X-associated tremor ataxia syndrome (FXTAS) = intention tremor, ataxia, memory + cognitive issues as adult, white matter changes on MRI
- Females can get FMR1-related POI (endocrinologist input)
FRAGILE X SYNDROME
What are the investigations for fragile X syndrome?
- Carrier testing in pregnancy women, can have CVS or amniocentesis
- FISH to look at content of cells, DNA testing once born to count # of CGG repeats
FRAGILE X SYNDROME
What is the management of fragile X syndrome?
- OT = daily tasks
- Social services = social care + benefits
- Special education = learning help
- Challenging behaviours may benefit from risperidone.
- PO lorazepam in acute agitation (after de-escalation strategies)
TURNER’S SYNDROME
What is Turner’s syndrome?
- Lack of a second X chromosome in a female leading to 45, XO
TURNER’S SYNDROME
What is the clinical presentation of Turner’s syndrome?
- Short stature, webbed neck, shield chest + widely spaced nipples (classic)
- Delayed puberty, underdeveloped ovaries > primary amenorrhoea + infertility
- Cubitus valgus
TURNER’S SYNDROME
What are some complications of Turner’s syndrome?
- Coarctation or bicuspid aortic valve
- Increased risk of CHD > HTN, obesity
- DM, osteoporosis, hypothyroidism
- Recurrent otitis media + UTIs
- Horseshoe kidney, susceptible to x-linked recessive conditions
TURNER’S SYNDROME
What is the investigation of choice for Turner’s syndrome?
- Karyotyping after clinical suspicion = 45XO
TURNER’S SYNDROME
What is the management of Turner’s syndrome?
- GH therapy to prevent short stature
- Oestrogen + progesterone replacement to establish 2ary sex characteristics, regulate menstrual cycle + prevent osteoporosis
- Fertility treatment like IVF
DUCHENNE’S
What is Duchenne’s muscular dystrophy?
- X-linked recessive chromosome 21 = gene deletion for dystrophin (connects muscle fibres to ECM)
DUCHENNE’S
What is the clinical presentation of Duchenne’s muscular dystrophy?
- Proximal muscle weakness from 5y
- Delayed milestones
- Waddling gait
- Gower sign +ve
- Calf pseudohypertrophy (replaced by fat + fibrous tissue)
DUCHENNE’S
What is Gower’s sign?
- Patient uses hands + arms to “walk” themselves upright from a squatting position due to lack of hip + thigh muscle strength
DUCHENNE’S
What are some complications of Duchenne’s muscular dystrophy?
- Wheelchair by 13y
- Cardiac involvement (dilated cardiomyopathy) in teenagers
- Resp involvement
- Survival >30y unusual
DUCHENNE’S
What are some investigations for Duchenne’s muscular dystrophy?
- Clinical exam = Gower’s sign
- Creatinine kinase markedly raised
- Genetic testing to confirm
DUCHENNE’S
What is the medical management of Duchenne’s muscular dystrophy?
- Steroids (prednisolone) appear best treatment as improves QOL, longer life expectancy + decreased progression of heart problems
- Manage congestive HF + arrhythmias with beta blocker, ACEi.
DUCHENNE’S
What is the supportive therapy for Duchenne’s muscular dystrophy?
- OT = aids + adaptations to help live with condition
- Physio = prevent contractures, scoliosis correction
- NIV for resp failure, gene therapy
DUCHENNE’S
What is another type of muscular dystrophy very similar to Duchenne’s?
How does it differ?
- Becker’s = some functional dystrophin produced
- Features similar but clinically progresses slower, average age of onset 11y with inability to walk from 20s
KLINEFELTER SYNDROME
What is Klinefelter syndrome?
- When a male has an additional X chromosome, making 47XXY
- Rarely even more X chromosomes like 48XXXY (more severe)
- Chief genetic cause of hypergonadotropic hypogonadism
KLINEFELTER SYNDROME
What is the clinical presentation of Klinefelter syndrome?
- Often appear normal until puberty
- Taller height + wider hips
- Delayed puberty (lack of pubic hair, poor beard growth)
- Gynaecomastia, small testicles/penis, infertility
- Weaker muscles, shyness, subtle learning difficulties (esp. speech + language)
KLINEFELTER SYNDROME
What are some complications of Klinefelter syndrome?
- Increased risk of breast cancer compared to other males
- Osteoporosis
- Diabetes
- Anxiety + depression
KLINEFELTER SYNDROME
What is the medical management of Klinefelter syndrome?
- Monthly testosterone injections to promote sexual characteristics
- Advanced IVF techniques for infertility
- Breast reduction surgery for cosmesis
KLINEFELTER SYNDROME
What is the MDT management for Klinefelter syndrome?
- SALT
- OT for day-day tasks
- Physio to strengthen muscles + joints
- Educational support if learning difficulties
PRADER-WILLI SYNDROME
What is Prader-Willi syndrome?
- Genetic imprinting disorder due to deletion of paternal chromosome 15 or maternal uniparental disomy
PRADER-WILLI SYNDROME
What is the clinical presentation of Prader-Willi syndrome?
- Constant, insatiable hunger > hyperphagia + obesity
- Initially failure to thrive due to hypotonia
- Small genitalia, hypogonadism + infertility
- Narrow forehead, almond eyes, strabismus
- LDs, MH issues
PRADER-WILLI SYNDROME
What causes the constant, insatiable hunger in Prader-Willi?
How can this be managed?
- Marked elevated levels of ghrelin (hormone associated with hunger)
- Dietician = careful limitation of access to food to control weight (may have to lock food cupboards or fridge)
PRADER-WILLI SYNDROME
What is the management of Prader-Willi syndrome?
- GH to improve muscle development + body composition
- MDT = education support, social workers, psychologists/CAMHS, physio + OT
ANGELMAN’S SYNDROME
What is Angelman’s syndrome?
What is it caused by?
- Genetic imprinting disorder due to deletion of maternal chromosome 15 or paternal uniparental disomy
- Loss of function of maternal UBE3A gene
ANGELMAN’S SYNDROME
What is the clinical presentation of Angelman’s syndrome?
- “Happy puppet” = unprovoked laughing, clapping, hand flapping, ADHD
- Fascination with water
- Epilepsy, ataxia, broad based gait
- Severe LD, delayed development
- Widely spaced teeth, microcephaly
ANGELMAN’S SYNDROME
What is the management of Angelman’s syndrome?
- Chromosomal analysis with FISH to detect deletions
- MDT approach = parental education, CAMHS, psychology, physio, SALT, OT
NOONAN’S SYNDROME
What is Noonan’s syndrome?
- Autosomal dominant condition with defect on chromosome 12, normal karyotype
NOONAN’S SYNDROME
What is the clinical presentation of Noonan’s syndrome?
- Short stature, webbed neck, widely spaced nipples (Male Turner’s)
- Pectus excavatum, low set ears
- Hypertelorism (wide space between eyes)
- Downward sloping eyes with ptosis
- Curly/woolly hair
NOONAN’S SYNDROME
What are some complications of Noonan’s syndrome?
- CHD = pulmonary valve stenosis
- Cryptorchidism which can lead to infertility (fertility in women normal)
- LDs, bleeding disorders (XI deficient)
NOONAN’S SYNDROME
What is the management of Noonan’s syndrome?
- MDT support
- Main complication CHD so may need surgical correction
WILLIAM’S SYNDROME
What is William’s syndrome?
- Random deletion of genetic material on one copy of chromosome 7 resulting in only single copy of genes from other chromosome 7
WILLIAM’S SYNDROME
What is the clinical presentation of William’s syndrome?
- Very friendly + sociable
- Starburst eyes (star-pattern on iris)
- Wide mouth, big smile + widely spaced teeth
- Broad forehead, short nose + small chin
- Mild LD, short stature
WILLIAM’S SYNDROME
What are some complications of William’s syndrome?
- Supravalvular aortic stenosis
- ADHD
- HTN + hypercalcaemia
WILLIAM’S SYNDROME
What is the management of William’s syndrome?
- MDT approach
- ECHO + BP monitoring for complications
- Low Ca2+ diet
- FISH to confirm Dx
CONGENITAL HYPOTHYROIDISM
What is congenital hypothyroidism?
- Affects 1 in 3000 births + causes severe neurological dysfunction which leads to severe learning difficulties later in life
CONGENITAL HYPOTHYROIDISM
What is the most common cause of congenital hypothyroidism…
i) worldwide?
ii) UK?
iii) consanguineous families?
i) Iodine deficiency
ii) Maldescent of the thyroid or an absent thyroid gland (athyrosis)
– Remains as a lingual mass or unilobular small gland
iii) Dyshormonogenesis (inborn error of thyroid hormone synthesis)
– Goitre due to TSH stimulation
CONGENITAL HYPOTHYROIDISM
What is the clinical presentation of congenital hypothyroidism?
- Prolonged neonatal jaundice
- Delayed mental + physical milestones
- Puffy face, macroglossia + hypotonia
- Failure to thrive + feeding problems
- Coarse facies + hoarse cry
CONGENITAL HYPOTHYROIDISM
What are some investigations for congenital hypothyroidism?
- Should be picked up on Guthrie neonatal bloodspot test
- TFTs = TSH high, may have USS neck or thyroid isotope scan
CONGEN HYPOTHYROIDISM
What is the management of congenital hypothyroidism?
What has this helped prevent?
How can it be monitored?
- Lifelong PO thyroxine 30m before breakfast
- Titrate dose to maintain normal growth, start at age 2–3w
- Severe neuro disability (spasticity, gait issues, dysarthria)
- Normal TSH levels is most important at indicating long-term well controlled thyroid disease
JUVENILE HYPOTHYROIDISM
What is associated with an increased risk of juvenile hypothyroidism?
- Increased risk with Down or Turner syndrome
JUVENILE HYPOTHYROIDISM
What causes it?
Most commonly autoimmune thyroiditis (e.g. Hashimoto’s)
JUVENILE HYPOTHYROIDISM
What is the clinical presentation of juvenile hypothyroidism?
(Same as adult)
- F>M, cold intolerance, dry skin, thin + dry hair
- Bradycardia, constipation, goitre
- Delayed puberty, obesity
JUVENILE HYPOTHYROIDISM
What are the investigations for juvenile hypothyroidism?
- TFTs will show high TSH, anti-thyroid peroxidase antibodies if hashimoto’s
JUVENILE HYPOTHYROIDISM
What is the management of juvenile hypothyroidism?
Lifelong PO thyroxine replacement
PUBERTY
In terms of female puberty…
i) age?
ii) first sign?
iii) other signs?
i) 8.5–12.5
ii) Thelarche (breast development)
iii) Pubarche (growth of pubic hair) + rapid height spurt occur rapidly after thelarche, menarche occurs roughly 2.5y after start of puberty (signals growth coming to an end)
PUBERTY
In terms of male puberty…
i) age?
ii) first sign?
iii) other signs?
i) 10–14
ii) Testicular enlargement >4ml (Prader orchidometer)
iii) Pubarche follows testicular enlargement, height spurt about 18m after puberty but greater magnitude than in females
PUBERTY
What features of puberty are consistent with both sexes?
- Adrenarche = maturation of adrenal gland leading to androgen production causing body odour + mild acne
- Development of acne, axillary hair, body odour + mood changes
PUBERTY
What can be used to measure puberty?
What are the components?
- Tanner staging
- B (breasts)
- PH (pubic hair)
- G (male genitals)
PUBERTY
Explain the tanner stages for…
i) breast?
ii) pubic hair?
iii) genitalia?
i) BI = pre-pubertal, BII = breast bud, BIII = juvenile smooth contour, BIV = areola + papilla project above breast, BV = adult
ii) PHI = none, PHII = sparse, PHIII = dark, coarser, curlier, PHIV = filling out, PHV = adult
iii) GI = pre-adolescent, GII = lengthens, GIII = growth in length + circumference, GIV = glans penis develops, GV = adult
PRECOCIOUS PUBERTY
What are the 2 main types of precocious puberty?
- Gonadotropin-dependent (central/true) = premature activation of hypothalamic-pituitary-gonadal axis
- Gonadotropin-independent (pseudo/false) = excess sex steroids
PRECOCIOUS PUBERTY
What is the pathophysiology and potential causes of central precocious puberty?
Pathophysiology: LH++, FSH+ > oestrogen from ovary ++ or testosterone from testis ++ & adrenal +
Causes:
- Familial,
- hypothyroidism,
- CNS (neurofibroma, tuberous sclerosis)
PRECOCIOUS PUBERTY
What is precocious puberty in females?
- Development of secondary sexual characteristics (thelarche) <8y
PRECOCIOUS PUBERTY
What is the management of precocious puberty in females?
- Full Hx, ages parents went into puberty, USS of uterus + ovaries
- If ok = reassure
- GnRH analogues stop puberty progressing further by suppressing pulsatile GnRH secretion until she is ready
PRECOCIOUS PUBERTY
What is precocious puberty in males?
- Development of secondary sexual characteristics <9y
- Less common, more worrying
PRECOCIOUS PUBERTY
What is the management of precocious puberty in males?
- Full Hx including ages parents went into puberty
- MRI head for ?tumour
- Treat underlying cause
PRECOCIOUS PUBERTY
What is premature thelarche?
Who does it normally affect?
- Breast enlargement (may be asymmetrical) rarely beyond stage 3 but absence of axillary/pubic hair or growth spurt (differentiating from precocious puberty)
- Females 6m–2y, non-progressive + self-limiting
PRECOCIOUS PUBERTY
What is premature pubarche (adrenarche)?
- Pubic hair development <8y (F), <9y (M) but no other signs of sexual development
PRECOCIOUS PUBERTY
What causes premature pubarche (adrenarche)?
How can you tell?
- Accentuation of normal maturation of androgen production by adrenal gland (adrenarche), can be late-onset CAH or adrenal tumour
- Urinary steroid profile to help differentiate
PRECOCIOUS PUBERTY
What is the pathophysiology of pseudo precocious puberty?
Low LH + FSH as gonadal or extra-gonadal source leads to increased testosterone or oestrogen
PRECOCIOUS PUBERTY
What are the causes of pseudo precocious puberty?
Causes:
– Adrenal (tumours, CAH)
– Granulosa cell tumour (ovary)
– Leydig cell tumour (testicular)
PRECOCIOUS PUBERTY
What are the risk factors with premature pubarche (adrenarche)?
- More common in Asian + Afro-Caribbean, increased risk of PCOS later in life
PRECOCIOUS PUBERTY
What is the management for premature pubarche (adrenarche)?
USS of ovaries + uterus with bone age to exclude central precocious puberty
PRECOCIOUS PUBERTY
What are the causes in females?
More common in girls, usually idiopathic or familial, occasionally late presenting CAH
PRECOCIOUS PUBERTY
What are the causes in males?
Less common, more worrying
– Pituitary adenoma (bilateral testicular enlargement suggests gonadotropin release)
– CAH or adrenal tumour (small testes)
– Gonadal tumour (unilateral testicular enlargement)
PRECOCIOUS PUBERTY
What is a genetic cause of precocious puberty?
McCune Albright syndrome (café-au-lait, short stature)
CAH
What is congenital adrenal hyperplasia (CAH)?
- Autosomal recessive condition with deficiency of 21-hydroxylase enzyme
- Small minority = 11-beta-hydroxylase
CAH
What is the normal physiology of the adrenal gland?
- Glucocorticoids (cortisol) deal with stress > raise glucose, reduce inflammation, suppresses immune system
- Mineralocorticoids (aldosterone) act on kidneys to control balance of salt (mineral) + Water in blood > increases Na+ reabsorption + K+ excretion
CAH
What is a major risk factor?
Consanguineous parents
CAH
What is the pathophysiology of CAH?
- 21-hydroxylase responsible for converting progesterone into cortisol + aldosterone
- Progesterone also used to create testosterone, but not with 21-hydroxylase
- Excess progesterone (as not converted to aldosterone or cortisol) gets converted into testosterone instead (high)
CAH
What is the clinical presentation of CAH in females?
- Tall for age, facial hair, absent periods, deep voice + precocious puberty
- Severe = virilised genitalia (ambiguous), labial fusion + enlarged clitoris
CAH
What is the clinical presentation of CAH in…
i) males?
ii) both sexes?
i) Tall for age, large penis + muscles, small testicles, deep voice + precocious puberty
ii) Skin hyperpigmentation as melanocyte stimulating hormone by-product of ACTH production (as low cortisol) > increased melanin
CAH
What is a critical complication of CAH?
- Male salt-losers present in salt-losing crisis shortly after birth
CAH
How does salt-losing crisis present?
– Vomiting, weight loss, floppiness + circulatory collapse
– Hyponatraemic, hyperkalaemic, metabolic acidosis, hypoglycaemic
CAH
What is the management of salt-losing crisis?
IV 0.9% NaCl + dextrose,
IV hydrocortisone
CAH
What are some investigations for CAH?
- Monitor growth, skeletal maturity, plasma androgens
- High metabolic precursor levels of 17alpha-hydroxyprogesterone (used to monitor disease too)
CAH
What management is needed for females with CAH?
- Corrective surgery to external genitalia within 1st year
- Definitive surgical reconstruction usually delayed until puberty
CAH
What is the general management of CAH?
- Lifelong glucocorticoids (hydrocortisone) to suppress ACTH > normal growth
- Lifelong mineralocorticoids (fludrocortisone) if there’s salt loss, infants may need NaCl
- Additional hydrocortisone to cover illness/surgery
- Antenatal dexamethasone controversial treatment, risks>benefits currently
SEXUAL DIFFERENTIATION
In embryology, when does sexual differentiation occur?
How does a male foetus not produce female sexual characteristics?
- Foetal gonad bipotential until 6w
- Sex-determining region on Y chromosome (SRY) gene present
- Production of anti-mullerian hormone inhibits Mullerian (paramesonephric) duct from persisting which > uterus + fallopian tubes
SEXUAL DIFFERENTIATION
How does a male foetus produce male sexual characteristics?
- Leydig cells produce testosterone causing Wolffian duct differentiation > vas, epididymis, seminal vesicles
- Later, dihydrotestosterone leads to virilised external genitalia
SEXUAL DIFFERENTIATION
What is the process of female sexual differentiation?
- No SRY gene present so no AMH
- Mullerian duct persists which develops into ovaries + female genitalia
SEXUAL DIFFERENTIATION
What are some causes of sexual differentiation disorders?
- CAH (#1)
- Congenital hypopituitarism (Prader-Willi)
- Ovotesticular disorder of sex development (true hermaphroditism) leading to both testicular + ovarian tissues as XX + XY containing cells present
SEXUAL DIFFERENTIATION
What is the management of sexual differentiation disorders?
- Do not guess sex
- Karyotyping, adrenal + sex hormone levels measured
- USS of internal structures + gonads
- Surgical reconstruction may be delayed so individual can make choice
DELAYED PUBERTY
What are the two categories for delayed puberty?
- Hypogonadotropic hypogonadism = deficiency of LH + FSH leading to deficiency of sex hormones
- Hypergonadotropic hypogonadism = gonads fail to respond to stimulation from gonadotrophins (LH + FSH), no -ve feedback from sex hormones so increased LH + FSH
DELAYED PUBERTY
What are some causes of hypogonadotropic hypogonadism?
- Constitutional delay in growth + puberty (FHx)
- Chronic diseases (IBD, CF, coeliac)
- Excess stress (anorexia, intense exercise, low weight)
- Hypothalamo-pituitary disorders (panhypopituitarism, Kallman’s + anosmia, GH deficiency)
DELAYED PUBERTY
What are some causes of hypergonadotropic hypogonadism?
- Chromosomal abnormalities (Turner’s XO, Klinefelter’s 47XXY)
- Acquired gonadal damage (post-surgery, chemo/radio, torsion)
- Congenital absence of the testes or ovaries
DELAYED PUBERTY
In delayed puberty, what are some causes of…
i) short stature (delayed + short)?
ii) normal stature (delayed + normal)?
i) Turner’s, Prader-Willi + Noonan’s
ii) PCOS, androgen insensitivity, Kallmann’s + Klinefelter’s
DELAYED PUBERTY
What is delayed puberty in…
i) females?
ii) males?
i) Absence of pubertal development by 14y
ii) Absence of pubertal development by 15y (more common in males)
DELAYED PUBERTY
What are some investigations for delayed puberty?
- FBC + ferritin (anaemia), U+E (CKD), coeliac antibodies
- Hormonal testing
- Genetic testing/karyotyping
- XR wrist to assess bone age (low in constitutional delay)
- Pelvic USS to assess ovaries + other pelvic organs
- MRI head if ?pituitary pathology + assess olfactory bulbs (Kallmann)
DELAYED PUBERTY
What are the hormonal tests you would do in delayed puberty?
- Early morning serum gonadotropins (FSH/LH)
- TFTs
- GH provocation testing (insulin, glucagon)
- IGF-1 levels
- Serum prolactin
DELAYED PUBERTY
What is the management of delayed puberty?
- Constitutional = reassure, can Tx if severe distress
- F = oestradiol
- Young M = PO oxandrolone (weak androgenic steroid will induce some catch-up growth but not 2ary sexual characteristics)
- Older M = low dose IM testosterone for growth + sexual characteristics
TESTICULAR TORSION
What is testicular torsion?
Who is it most common in?
- Twisting of the testis + spermatic cord resulting in testicular ischaemia
- Common in adolescents + neonatal but can happen at any age
TESTICULAR TORSION
What is the clinical presentation of testicular torsion?
- Tender, red, painful testicle which may be swollen + retracted upwards
- Loss of cremasteric reflex
- Elevation of testis does not ease pain (differentiates epididymitis)
- Acute abdo pain (lower abdo or scrotal), N+V
TESTICULAR TORSION
What is a very similar differential diagnosis of testicular torsion?
- Torsion of testicular appendage (hydatid)
- Remnant of Mullerian duct, can rapidly enlarge prior to puberty due to gonadotropins
- ‘Blue dot sign’
TESTICULAR TORSION
What are the investigations of testicular torsion?
- Doppler USS = decreased blood flow
- Surgical exploration unless torsion can be excluded
TESTICULAR TORSION
What is the management of testicular torsion?
- Emergency surgical intervention > needs operating to untort within 6h
- If testicle is dead > orchidectomy
PICA
what is it?
an eating disorders in which a person eats things that are not usually considered food
PICA
what is the clinical presentation?
craving/eating non-food items:
- dirt
- clay
- rocks
- paper
- ice
- crayons
- hair
- paint chips
- chalk
- faeces
PICA
what health problems can be caused?
- iron deficiency anaemia
- lead poisoning
- constipation or diarrhoea
- infections
- intestinal obstruction
- mouth or teeth injuries
PICA
what are the causes?
- developmental problems e.g. autism
- mental health problems e.g. OCD, schizophrenia
- malnutrition or hunger
- stress
PICA
how is it diagnosed?
eating non-food items and:
- doing so for 1 month
- behaviour is not normal for child’s age
- has risk factors for pica
PICA
what are the investigations?
- blood tests - anaemia, lead levels
- stool tests - parasites
- x-rays
PICA
what is the management?
- prevent child from getting to non-food items
- psychological support
CRYPTORCHIDISM
What are the 3 types of cryptorchidism?
- Retractile (normal variant in prepubescent boys)
- Palpable
- Impalpable
CRYPTORCHIDISM
What is retractile cryptorchidism?
- Testis can be manipulated into bottom of scrotum without tension but subsequently retracts into inguinal region (pulled by cremaster muscle)
- Usually present later as hard to notice on NIPE, eventually testes should permanently reside in scrotum (follow-up to check)
CRYPTORCHIDISM
What is palpable cryptorchidism?
- Testis palpated in groin but cannot be manipulated into scrotum
- Sometimes ectopic so lie outside the normal line of descent + may be found in perineum or femoral triangle
CRYPTORCHIDISM
What is impalpable cryptorchidism?
- No testis felt on detailed examination
- May be in the inguinal canal, intra-abdominal or absent
CRYPTORCHIDISM
What are some investigations for cryptorchidism?
- Genital exam = warm room + hands, relaxed child, try “milk” testes into scrotum
- USS in bilateral impalpable testes to verify internal pelvic organs
- Hormonal for bilateral impalpable testes to confirm presence of testicular tissue (record rise in serum testosterone in response to IM hCG)
- Laparoscopy = Ix of choice for impalpable
CRYPTORCHIDISM
What is the first line management of cryptorchidism?
- If unilateral monitor as most newborns descend
- Wait 3m then refer to paeds urologist so they’re seen by 6m
- If bilateral needs urgent senior review within 24h
CRYPTORCHIDISM
What is the management of cryptorchidism that has not resolved?
- Surgical placement of testis in scrotum (orchidopexy = before or around 1y)
- May need testosterone at age 10 to start puberty if absent altogether, ?prosthesis
CRYPTORCHIDISM
What are the reasons for performing orchidopexy around 1y?
- Fertility = optimises spermatogenesis as testis need to be below body temp
- Malignancy = massive risk of seminoma in undescended testes
- Cosmesis, psychological + avoid torsion
KALLMAN SYNDROME
what is it?
genetic disorder that can be inherited via autosomal dominant, autosomal recessive and x-linked
KALLMAN SYNDROME
what are the clinical features?
- hypogonadotropic hypogonadism
- anosmia
- synkinesia (mirror-image movements)
- renal agenesis
- visual problems
- craniofacial anomalies
KALLMAN SYNDROME
why do you get anosmia in this condition?
due to a defect in the co-migration of GnRH releasing neurons and olfactory neurons that occurs during early foetal development
ANDROGEN INSENSITIVITY SYNDROME
what is it?
a genetic condition in which there are defects in the androgen receptor
- is x-linked recessive
- patients are genetically male (46XY)but develop female phenotype
ANDROGEN INSENSITIVITY SYNDROME
what are the different types?
- complete AIS
- partial AIS
- true hermaphroditism
ANDROGEN INSENSITIVITY SYNDROME
what is complete AIS?
- karyotype = 46XY
- results in a completely female phenotype
- external genitalia are female (clitoris, hypoplastic labia majora + blind-ending vagina)
- testes may be present in abdomen
- absence of pubic + axillary hair
- normal breast development
ANDROGEN INSENSITIVITY SYNDROME
what is partial AIS?
- presents with a wide range of phenotypes
- can present as normal male with fertility issues
- sex assignment depends on the degree of genital ambiguity
ANDROGEN INSENSITIVITY SYNDROME
what is true hermaphroditism?
- have both ovarian tissue with follicles and testicular tissue with seminiferous tubules, either in the same organ or one on either side
- external genitalia are often ambiguous
ANDROGEN INSENSITIVITY SYNDROME
what is the inheritance pattern?
x-linked recessive
ANDROGEN INSENSITIVITY SYNDROME
what are the results of hormone tests?
- raised LH
- normal/raised FSH
- normal/raised testosterone
- raised oestrogen
ANDROGEN INSENSITIVITY SYNDROME
how does it typically present?
- present in infancy with an inguinal hernia
- present at puberty with primary amenorrhoea
ANDROGEN INSENSITIVITY SYNDROME
what is the management?
- bilateral orchidectomy to avoid testicular tumours
- oestrogen therapy
- vaginal dilators or vaginal surgery
- generally patients are raised as female
- offered support and counselling
HYPOGONADISM
Name the 3 types of hypogonadism?
Primary = hypergonadotropic hypogonadism
Secondary = hypogonadotropic hypogonadism
Tertiary = hypogonadotropic hypogonadism
GONADOTROPIN DEFICIENCY
What is Hypergonadotropic hypogonadism?
Primary gonadal failure - Testes or ovarian failure
GONADOTROPIN DEFICIENCY
Briefly describe the mechanism of Hypergonadotropic hypogonadism
Gonads not working properly so less oestrogen/testosterone
Increase in GnRH as less negative feedback
Increase in LH and FSH
Hypogonadism occurs
GONADOTROPIN DEFICIENCY
Give 2 causes of primary hypogonadism
Hypergonadotropic hypogonadism
Klinefelter’s Syndrome (47XXY)
Tuner’s Syndrome (45X)
GONADOTROPIN DEFICIENCY
What is the effect of Hypergonadotropic hypogonadism on FSH/LH and oestrogen/testosterone levels?
FSH/LH = high
Oestrogen/testosterone = low
GONADOTROPIN DEFICIENCY
What is Hypogonadotropic hypogonadism?
Secondary gonadal failure = problem with pituitary
OR
Tertiary gonadal failure = Problem with hypothalamus
GONADOTROPIN DEFICIENCY
Briefly describe the mechanism of secondary hypogonadism
Less FSH and LH
So less activation at gonads
Girls = no response to feedback so oestrogen decreases
Boys = no response to feedback so testosterone decreases
GONADOTROPIN DEFICIENCY
Briefly describe the mechanism of tertiary hypogonadism
Less GnRH produced
So less FSH and LH
So less activation at gonads
Girls = no response to feedback so oestrogen decreases
Boys = no response to feedback so testosterone decreases
GONADOTROPIN DEFICIENCY
Give 2 causes of Hypogonadotropic hypogonadism
- Kallmann’s Syndrome
- Tumours - craniopharyngiomas, germinomas
GONADOTROPIN DEFICIENCY
What is the effect of hypogonadotropic hypogonadism on FSH/LH and oestrogen/testosterone levels?
FSH/LH = low
Oestrogen/testosterone = low
GONADOTROPIN DEFICIENCY
What is the treatment for hypogonadism?
Hormone replacement therapy
Males = testosterone gel/injections
Females = Ethinyl oestradiol or oestrogen (tablet or transdermal), progesterone added once full oestrogen dose reached
HYPOTHALAMIC TUMOUR
what is it?
A hypothalamic tumour is an abnormal growth in the hypothalamus gland, which is located in the brain.
HYPOTHALAMIC TUMOUR
what are the causes?
The exact cause of hypothalamic tumours is not known. It is likely that they result from a combination of genetic and environmental factors.
HYPOTHALAMIC TUMOURS
what are the risk factors for developing hypothalamic tumours?
neurofibromatosis
undergone radiation therapy
HYPOTHALAMIC TUMOURS
what is the most common type of tumour to cause a hypothalamic tumour in children?
glioma
HYPOTHALAMIC TUMOUR
what is the clinical presentation?
- euphoric ‘high’ sensations
- failure to thrive
- headache
- hyperactivity
- loss of body fat and appetite
- vision loss
- precocious puberty
HYPOTHALAMIC TUMOUR
what are the investigations?
- full neurological examination
- blood tests for CRH, GH, GnRH, TRH, dopamine and somatostatin
- CT/MRI scan
- visual field testing
HYPOTHALAMIC TUMOURS
what is the management?
- surgery
- radiation
- chemotherapy
- steroids to treat brain swelling
- hormone replacement/imbalance corrected
OBESITY
when does NICE recommend intervention?
tailored intervention if >91st centile
assess for comorbidities if >98th centile
OBESITY
what is the most common cause?
lifestyle factors
OBESITY
what factors are associated with a higher rate of obesity?
- asian children
- female
- tall
OBESITY
what are the causes of obesity in children other than lifestyle factors?
- growth hormone deficiency
- hypothyroidism
- Down’s syndrome
- Cushing’s syndrome
- Prader-Willi syndrome
OBESITY
what are the consequences of obesity in children?
- orthopaedic problems: slipped upper femoral epiphyses, Blount’s disease (a development abnormality of the tibia resulting in bowing of the legs), musculoskeletal pains
- psychological consequences: poor self-esteem, bullying
sleep apnoea
benign intracranial hypertension - long-term consequences: increased incidence of type 2 diabetes mellitus, hypertension and ischaemic heart disease
TYPE 1 DIABETES
what is the most common presentation for new patients?
diabetic ketoacidosis
TYPE 1 DIABETES
what is the triad of symptoms?
what other symptoms may be present?
- polyuria
- polydipsia
- weight loss
- secondary enuresis
- recurrent infections
TYPE 1 DIABETES
what are the investigations for a new diagnosis?
- FBC, U+Es, glucose
- blood cultures
- HbA1c
- TFTs + TPO
- anti-TTG
- insulin antibodies, anti-GAD + islet cell antibodies
TYPE 1 DIABETES
what is the long term management?
- SC insulin
- monitoring carbohydrate intake
- monitoring for complications
TYPE 1 DIABETES
what are the short term complications?
- hypoglycaemia
- hyperglycaemia and DKA
TYPE 1 DIABETES
what are the long term complications?
macrovascular - coronary artery disease, stroke, HTN
microvascular - peripheral neuropathy, retinopathy, nephropathy
TYPE 1 DIABETES
why should insulin injection sites be rotated?
to prevent lipodystrophy
TYPE 1 DIABETES
what are the pros and cons of insulin pumps?
pros - better blood glucose control, more flexibility eating and less injections
cons - difficulties learning how to use, blockages in infusion set, having it attached at all times, infection risk
TYPE 1 DIABETES
how is hypoglycaemia treated?
- rapid acting glucose + longer acting carb
- if impaired consciousness use IV dextrose and IM glucagon
- 10% dextrose IV
DKA
what is the clinical presentation?
Polyuria
Polydipsia
Nausea and vomiting
Weight loss
Acetone smell to their breath
Dehydration and subsequent hypotension
Altered consciousness
Symptoms of an underlying trigger (i.e. sepsis)
DKA
what is required to diagnose DKA?
Hyperglycaemia (i.e. blood glucose > 11 mmol/l)
Ketosis (i.e. blood ketones > 3 mmol/l)
Acidosis (i.e. pH < 7.3)
DKA
what are the principles of DKA management in children?
- correct dehydration evenly over 48hrs
- give an initial bolus followed by ongoing fluids
- insulin should be delayed by 1-2hrs to reduce chance of cerebral oedema
- 0.05-0.1 units/kg/hr of insulin
DKA
what are the different classifications of DKA?
Mild - pH 7.2-7.29 or bicarb <15mmol/L, dehydration = 5%
moderate - pH 7.1-7.19 or bicarb <10mmol/L, dehydration = 7%
severe - pH <7.1 or bicarb <5mmol/L, dehydration = 10%
DKA
what fluids are given to children not in shock?
initial bolus - 10ml/kg 0.9% NaCl over 1 hour
ongoing fluids - 0.9% NaCl with 20mmol KCl in each 500ml bag
1. calculate fluid deficit based on % dehydration
2. subtract initial 10ml/kg bolus from this
3. add maintenance fluids
DKA
what are the complications?
cerebral oedema
hypokalaemia
aspiration pneumonia
hypoglycaemia