5. Metabolic + Endocrine Flashcards
What is the average birth weight and what rate should it increase at?
-Average = 3.3kg / 7lb 4
-Should double by 5 months
-Should triple by 1 year
-Between ages 1-10, expected weight in kg = age+4 x 2
What is the average head circumference at birth?
-35cm
-Should be 19% of bodyweight at birth compared to 9% at 15y/o
What is the peak age of onset for T1DM?
2 peaks:
-5-7 years
-Puberty (increased insulin requirement)
-90% destruction of beta cells before symptoms start
What glucose test results are diagnostic of diabetes?
-Random BG >11 mmol/L
-Fasting (6h) glucose >7 mmol/L
-OGTT 2h level >11 mmol/L
-HbA1c >48
How often should someone with diabetes check their BG?
4 times a day - before each meal and before bed
-More frequent if high frequency of hypoglycaemic episodes
How is hypoglycaemia defined?
BG <2.2-2.6 mmol/L
How does hypoglycaemia present and how is it managed?
Commonly occurs over night, high risk when starting treatment
-Fainting, dizziness
-Sweaty
-Lethargic
-Coma / seizures
MANAGEMENT:
-Glucogel
-Sugary drinks
-Bread
-Consider IV glucose / IM glucagon if symptomatic
What is the protocol for fluid resuscitation in paediatric DKA?
Reduced volume due to risk of cerebral oedema
1. If <10kg - 2ml/kg/hr
2. If 10-40kg - 1ml/kg/hr
3. If >40kg - 40ml/hr
What is MODY?
-Maturity Onset Diabetes of the Young
-Development of T2DM <25
-Autosomal dominant condition
-Less severe than T1DM
-Sulfonylureas often adequate for management but may require low dose insulin
What children are more at risk of developing T2DM?
-Obese children
-South Asian ethnicity
-IUGR
-LBW
How is failure to thrive defined?
-Less than expected growth over time during the first 3 years of life
-Weight gain is usually first affected
What commonly causes a child to fail to thrive?
-Psychosocial causes = most common
-Malabsorption eg coeliac disease, CF, reflux, pyloric stenosis
-Chornic illness
-Familial causes eg constitutionally small child, Turner’s syndrome
What should be looked for on examination of a child failing to thrive?
-Signs of dehydration
-Cleft lip / palate (swallowing issues)
-Signs of neglect
-Growth chart
What causes congenital adrenal hyperplasia / ambiguous genitalia?
-Y chromosome has sex determining gene so if absent, gonads become ovaries (female)
-Ambiguous genitalia is a consequence of CAH
-Can be an endocrinological emergency
PATHOPHYSIOLOGY:
-Inadequate production of cortisol
-Consequential rise in ACTH leads to adrenal hyperplasia and over-production of androgenic cortisol precursors
-Ovaries + male external genitalia
How is CAH managed?
-Glucocorticoid therapy and surgical correction at puberty (usually female gender assignment)
What features does androgen insensitivity syndrome have?
-46XY - testes present but external genitalia female / ambiguous
-X-linked recessive
-Male genotype, female phenotype
-No uterus
-Testosterone, oestrogen and LH all elevated
What features does 5-alpha reductase deficiency have?
-46CY - ambiguous genitalia, hypospadias
-Autosomal recessive
-Unable to convert testosterone into dihydrotestosterone
How would you examine a child with ambiguous genitalia?
-Palpable gonads? Bilateral?
-Penile length <2.5cm / Clitoris length >1cm
-Hypospadias? Undescended testes?
-Separation of scrotal sacs
How is precocious puberty defined and what are its features?
-Early onset and rapid progression of puberty
–Females <8yrs
–Males <9yrs
FEATURES
-Thelarche (development of breasts)
-Adrenarche (pubic hair development)
-Tall stature, boys testes >4ml
-Cafe au lair spots
What investigations would you consider in a child with precocious puberty?
-Bone age assessment
-FSH+LH
-Serum testosterone, oestrogen
-USS pelvis
What causes precocious puberty?
Can be either central or peripheral in origin:
Gonadotrophin-DEPENDENT (ie central)
-Raised FSH/LH due to early physiological activation of the hypothalamic-pituitary-gonadal axis
-Can treat with GnRH agonists
-NORMAL sequence of puberty observed
Gonadotrophin-INDEPENDENT
-Sex steroids sourced exogenously or endogenously
-So FSH/LH are low
-Managed with ketoconazole or cyproterone
-ABNORMAL sequence of puberty observed
How is delayed puberty defined?
-Lack of initiation and progress of puberty
-Females >13yrs
-Males >14 yrs
What can cause delayed puberty?
FUNCTIONAL - constitutional delay, malnutrition, excessive exercise
SHORT STATURE - Turner’s, Prader-Willi, Noonan’s
NORMAL STATURE - PCOS, androgen insensitivity, Kallman’s, Klinefelter’s
What features do Kallman’s and Klinefelter’s syndromes have?
KALLMAN’s = hypogonadotrophic hypogonadism
-X-linked recessive
-Failure of GnRH neurons to migrate to hypothalamus
KLINEFELTER’S = lack of secondary sexual characteristics
-47XXY
-Gynaecomastia and small, firm testes
