Growth/ Endocrine Flashcards
Mechanism of T2DM
Insulin resistance followed by B cell failure
Mechanism of T1DM
Autoimmune damage to pancreatic B cells, leading to insulin deficiency
What are the markers to B cell destruction?
Islet cell antibodies Antibodies to glutamic acid decarboxylase
S+S DM
Polydipsia Polyuria Weight loss
S+S DKA
Vomiting Dehydration Abdo pain Hyperventilation due to acidosis (Kussmaul breathing) Hypovolaemic shock Drowsiness
What glucose results would indicate DM?
Random BM >11.1 Fasting BM >7
Types of insulin with onset of action, peak + duration, + when to give
Short acting human regular: 30-60 min action, peak 2-4 hours, 8hr duration, give 15-30 mins before meals Immediate acting: onset 1-2hrs, peak 4-12hrs
What is a basal bolus regime?
3-4 times a day Short acting insulin (bolus) before meals + long acting insulin before bed (basal)
S+S hypoglycaemia
Symptoms occur below 4 Hunger, abdo pain, sweatiness, fainting, seizures, irritability
What is mild vs severe FTT?
Mild = fall across 2 centiles Severe = fall across 3 centiles
What makes males genitalia?
Testis determining gene on Y chromosome (SRY) Production of testosterone produces male genitalia
Reasons for ambiguous genitalia at birth
Excess androgens causing growth of female genitals = congenital adrenal hyperplasia Inadequate androgen production in males = inability to respond to androgens or inadequate synthesis from cholesterol
How to determine sex
Karyotyping Adrenal + sex hormones measured USS of internal structures
Pathology of congenital adrenal hyperplasia
Autosomal recessive disorder Common in consanginous couples Cortisol deficiency stimulates pituitary to produce ACTH, driving production of androgens
Presentation of congenital adrenal hyperplasia
Virilisation of female genitals = clitoral hypertrophy, fusion of labia Enlarged penis + pigmented scrotum Salt-loosing adrenal crisis at 1-3 weeks (vomiting, ewight loss, floppiness) Precocious puberty
Diagnosis of congenital adrenal hyperplasia
Made by finding raised precursor 17α-hydroxyprogesterone in blood In salt losers: Metabolic acidosis Hypoglycaemia
Management of ambiguous genitalia
Corrective surgery Males in salt-losing crisis need saline, dextrose + hydrocortisone IV Long term glucocorticoids to suppress ACTH Mineralcorticoids if there is salt loss
What is classed as precocious puberty?
Development of secondary sexual characteristics before 8 in females + 9 in males
Causes of precocious puberty
Growth spurts Breast development (thelarche) Pubic hair devleopment (pubarche) Intracranial tumours, hydrocephalus, menigitis
What is true vs pseudo precocious puberty?
True = gonadotrophin dependant - from premature activation of HPG axis Pseudo - from excess sex steroids
Is precocious puberty common in males or females?
Common in females - likely to have enlarged uterus + polycystic ovaries Uncommon in males, usually has an organic cause
How can examining testes in males help identify cause of precocious puberty?
Bilateral enlargement = gonadotrophin release, usually due to intracranial lesions Small testes = adrenal cause (tumour or hyperplasia) Unilateral enlarged testes = gonadal tumour
What is the definition of delayed puberty?
Absence of pubertal development by 14 in girls + 15 in boys
Causes of delayed puberty
Constitutional delay of growth
Low gonadotrophin secretion due to CF, asthma, Crohns, anorexia, HPG disorders
High gonadotrophin secretion (chromosomal abnormalities, steroid hormone deficiency, gonadal damage)
Management of delayed puberty
Oral oxandrolone in young males, testosterone in older males Oestrodiol in females
Normal thyroxine production in infants
Fetal thyroid produces reverse T3 (inactive) Surge in TSH after birth, causes raised T3 + T4 levels TSH declines to normal in first week
What is juvenile hypothyroidism?
Commoner in females Growth failure accompanied by delayed bone age Goitre present
Congenital hypothyroidism causes?
Absence of thyroid Small thyroid Maldescent of thyroid
S+S of congenital hypothyroidism
Usually asymptomatic FTT, feeding problems, prolonged jaundice Constipation Umbilical hernia
S+S of acquired hypothyroidism
Short stature Cold intolerance Dry skin Bradycardia Thin hair Goitre Constipation
Management of hypothyroidism
Oral thyroxine
What is phenylketonuria?
Type 1: autosomal recessive genetic disorder Deficiency of enzyme which converts phenylalanine to tyrosine High conc is neurotoxic Type 2: cases of hyperphenylalaninaemia Malignant PKU = deficiency in THB (enzyme co factor
S+S phenylketonuria
Delayed development, poor growth, seizures
Develops at 6-12 months
Recurrent vomiting
Behavioural disturbances
Older children: hyperactive, rhythmic rocking, writhing movements
Investigations for phenylketonuria
Guithre test
Management of phenylketonuria
Low phenylalanine diet: no meat, cheese, poultry, egg, milk
What are the causes of short stature?
Familial IUGR Constitutional delay Hypothyroidism Growth hormone deficiency Corticosteroid excess, Cushings Nutritional/ chronic illness Chromosomal disorders
