Paediatrics 2 ( Opth, Resp, ENT, Genetics, Endocrine) Flashcards
Explain the Hypothalamic-Pituitary Gonadal Axis?
- Hypothalamus = release GnRH
- Anterior pituitary gland = FSH and LH
- acts on testes and Ovaries
- Sex hormone action
what is the first sign of puberty for males and females?
Females = breast buds 8-13 yrs
Males = testicular enlargement 9-14 yrs
What are the different categories for delay in puberty causes?
Tertiary = problem in hypothalamus
Secondary = problem in pituitary
Primary = problem in gonads
Define: Klinefelter syndrome
male has an additional X chromosome making them 47 XXY
Presentation: Kleinfelder syndrome
appear as normal males until puberty
Taller height
Wider hips
Gynaecomastia
Weaker muscles
Small testicles
Reduced libido
Shyness
Infertility
Subtle learning difficulties (particularly affecting speech and language)
Management: Klinefelter syndrome
No cure
- Testosterone injections = improve many of the symptoms
- Advanced IVF techniques have the potential to allow fertility
- Breast reduction surgery for cosmetic purposes
Multidisciplinary team input:
- Speech and language therapy to improve speech and language
- Occupational therapy to assist in day to day tasks
- Physiotherapy to strengthen muscles and joints
- Educational support where required for dyslexia and other learning difficulties
What does Klinefelter syndrome increase your risk of?
- Breast cancer compared with other males (but still less than females)
- Osteoporosis
- Diabetes
- Anxiety and depression
Infertility = can be treated with advanced IVF
Define: Turner syndrome
Female has a single X chromosome making them 45 X0
Presentation: Turner’s syndrome
Short stature
Webbed neck
Broad chest with widely spaced nipples
High arching palate
Downward sloping eyes with ptosis
Cubitus valgus (elbow when extended is exaggerated away from the body)
Underdeveloped ovaries with reduced function
Late or incomplete puberty
Most women are infertile
What are the effects of Turner’s syndrome on prenatal, neonatal, adults and fertility?
Prenatal: increased nuchal translucency
Neonatal: Lymphoedema
Cardiac: Aortic coarctation
Fertility: dysplastic ovaries (risk of malignancy)
What are seem associated conditions with Turner’s syndrome?
Recurrent otitis media
Recurrent urinary tract infections
Coarctation of the aorta
Hypothyroidism
Hypertension
Obesity
Diabetes
Osteoporosis
Various specific learning disabilities
Management: Turner’s syndrome
No cure
Growth hormone therapy = can be used to prevent short stature
Oestrogen and progesterone replacement = can help establish female secondary sex characteristics, regulate the menstrual cycle and prevent osteoporosis
Fertility treatment = can increase the chances of becoming pregnant
What are the most common causes of primary hypogonadism?
Males = Klinefelter’s syndrome
Both = chemo/radiotherapy
Galactosemia
Trauma/surgery
Females = Turner’s syndrome
What are the most common causes of secondary + tertiary hypogonadism?
Intracranial tumours
Chemotherapy / Radiotherapy
Congenital enzyme / receptor mutations
Prader-Willi syndrome
Sport
Eating disorders
Malnutrition
Chronic disease
Marijuana
What are the 2 types of hypogonadism?
lack of sex hormones, oestrogen and testosterone
- Hypogonadotrophic hypogonadism = deficiency of LH and FSH
- hypergonadotrophic hypogonadism = lack of response to LH and FSH by the gonads
What are the causes of hypogonadotrophic hypogonadism?
Abnormal functioning of hypothalamus or pituitary gland due to:
- Previous damage to the hypothalamus or pituitary, for example by radiotherapy or surgery for previous cancer
- Growth hormone deficiency
- Hypothyroidism
- Hyperprolactinaemia (high prolactin)
- Serious chronic conditions can temporarily delay puberty (e.g. cystic fibrosis or inflammatory bowel disease)
- Excessive exercise or dieting can delay the onset of menstruation in girls
- Constitutional delay in growth and development is a temporary delay in growth and puberty without underlying physical pathology
- Kallman syndrome
What are the causes of hypergonadotrophic hypogonadism?
Gonads fail to respond to stimulation so increasing amounts of LH and FSH are produced by pituitary (no negative feedback)
- Previous damage to the gonads (e.g. testicular torsion, cancer or infections, such as mumps)
- Congenital absence of the testes or ovaries
- Kleinfelter’s Syndrome (XXY)
- Turner’s Syndrome (XO)
Define: Kallman syndrome
genetic condition causing hypogonadotrophic hypogonadism
- resulting in failure to start puberty
- associated with reduced or absent sense of smell (anosmia)
Investigations: hypogonadism
No evidence of puberty in a girl aged 13 or a boy aged 14
initial:
- Full blood count and ferritin for anaemia
- U&E for chronic kidney disease
- Anti-TTG or anti-EMA antibodies for coeliac disease
Hormonal blood tests:
- Early morning serum FSH and LH (the gonadotropins). These will be low in hypogonadotrophic hypogonadism and high in hypergonadotrophic hypogonadism.
- Thyroid function tests
- Growth hormone testing. - Insulin-like growth factor I is often used as a screening test for GH deficiency.
- Serum prolactin
Genetic testing
What imaging investigations can be done for hypogonadism?
Xray of the wrist = to assess bone age and inform a diagnosis of constitutional delay
Pelvic ultrasound = in girls to assess the ovaries and other pelvic organs
MRI = of the brain to look for pituitary pathology and assess the olfactory bulbs in possible Kallman syndrome
Management: hypogonadism
treat underlying condition
- replacement sex hormones can be used to induce puberty under guidance
Define: precocious puberty
Puberty at an abnormally young age
Girls before 8 yrs
Boys before age 9
What are the 2 types of precocious puberty?
- Central precocious puberty ‘true’
- gonadotrophin dependent types
- premature activation of hypothalamic pituitary gonadal - Peripheral/ pseudo precocious puberty
- independent of gonadotrophin release
- increased production of female or male hormones
- oestrogen and testosterone high, FSH and LH suppressed
What are the causes of central precocious puberty?
- idiopathic 80% of girls and 40% of boys
- abnormalities of CNS
- tumours
- CNS trauma or injury
- harartomas og hypothalamus
- congenital disorders e.g. hydrocephalus