Endocrinology Flashcards
Diabetes, endocrine disorders, newborn screening, puberty problems, salt + water, bone + calcium
Diabetes types
Type 1: majority. autoimmune destruction of beta cells, higher risk if FH, likely an environmental trigger for the autoimmune process. a/w other autoimmune conditions in pt/their family like hypothyroidism, coeliac, RA, Addison disease
Type 2: insulin resistance then beta cell failure, usually obesity-related, positive FH, more in Black/Asian groups
MODY: strong FH, genetic defects in beta cell function
Drug induced: steroids
Pancreatic insufficiency: cystic fibrosis, iron overload in thalassaeamia
Genetic/chromosomal abnormalities
Neonatal diabetes: transient/permanent defective beta cell function
CF + diagnosis of diabetes
Early: polydipsia, polyuria, weight loss; may have enuresis/skin sepsis/candida
Late: DKA. acetone breath, vomiting, dehydration, abdo pain, hyperventilation due to acidosis, hypovolaemic shock, drowsy, coma, death
Diagnosis:
- Symptoms + random BG >11.1, glycosuria, ketosis
- Fasting BG >7 or raised HbA1c if doubt
T2DM: suspect when obesity, FH, signs of insulin resistance
Management of T1DM
MDT - Paediatrician, paediatric specialist diabetes nerve, dietician, clinical psychologist, adult diabetes team for joint adolescence clinics
Parent/patient support groups, voluntary orgs e.g. Diabetes UK
Intensive education
Insulin: SC into anterolateral thigh/buttock/abdomen (rotate to avoid lipohypertrophy/atrophy, pinch skin + inject at 45 degree)
- Rapid acting short duration e.g. insulin lispro (Humalog), insulin aspart (Novorapid)
- Short acting onset 30-60m, peak 2-4h. Give 15-30m before meals e.g. Actrapid, Humulin S
- Intermediate acting onset 1-2h, peak 4-12h e.g. Humulin I
- Very long acting e.g. glargine
Child insulin regimens: SC insulin pump, or a basal-bolus regime (boluses before meals, long acting in evening/early morning for background insulin). Aim for glucose 4-7 before meals
Blood glucose monitoring: keep a record, monitor frequently. Continuous SC/TC sensors help control insulin from a pump + detecting asymptomatic times of poor control
Blood ketones: measure with same meter during periods of illness or poor control
Acute complications of T1DM
Hypoglycaemia: usually symptoms when <4, individual but things like hunger/abdo pain/sweaty/faint/dizzy/unstable legs, infants pale + irritable. May progress to seizure + coma. Frequent hypos=less aware. M: glucose tablets/sugary drink, oral glucose gel, glucagon IM injection if severe, then give food like a sandwich/biscuits to prevent another drop, IV glucose if unconscious
DKA: hyperglycaemia >11.1 + blood ketones >3 + severe metabolic acidosis
- Also will have dehydration, monitor ECG for hypokalaemic T wave changes
- M: fluid resus/maintenance with saline then 5% glucose when its back to normal, insulin infusion, potassium in maintenance fluids, acidosis will correct with fluids + insulin, re-establish oral fluids +SC insulin+diet (wait 1h after the SC to stop IV)
- Find underlying cause - infection common
During illness: insulin requirements may be increased, but assess by BGL as may be eating less
Long-term complications of T1DM
Macrovascular: HTN, coronary HD, stroke/TIA
Microvascular: retinopathy, nephropathy, neuropathy
Puberty delay if control poor
Psychological: esp teenagers cos different to peers, in early adolescence concrete thinking means they know missing 1 injection/eating unhealthily doesn’t cause immediate illness so this is when control likely to go off, diabulimia (if insulin dose not reduced towards the end of puberty they can become obese and omit insulin to lose weight). Be enthusiastic, give clear short term goals
Hypoglycaemic events can be frightening
Higher risk from alcohol/drugs, some restriction in job choices
Problems with separation from parents e.g. school residential trips
Hypoglycaemia
Check BG in any child becoming seriously unwell, even tho is uncommon after neonatal except in DM
Causes:
- Fasting: insulin excess (exogenous, insulinoma, persistent hypoglycaemic hyperinsulinism of childhood), no insulin excess (liver disease, ketotic hypoglycaemia of childhood, IEM)
- Reactive (non-fasting): galactosemia, fructose intolerance, maternal DM, hormonal deficiency, aspirin/alcohol poisoning
Comps: neurological sequelae e.g. epilepsy/severe LD/microcephaly (esp in younger)
M: IV glucose (5ml/kg of 10% bolus, then 10% infusion) or oral glucose as in DM; IM glucagon if no IV access; corticosteroids if pituitary/adrenal dysfunction
Acquired hypothyroidism
Usually autoimmune
RF: Down syndrome, Turner syndrome, other autoimmune, females
CF: poor growth, cold intolerance, dry skin, cool peripheries, bradycardia, thin dry hair, pale puffy eyes, eyebrow loss, goitre, slow-relaxing reflexes, constipation, delayed puberty/amenorrhoea, obesity, SUFE, poor concentration, LD, deterioration in school work
M: thyroxine
Congenital hypothyroidism
Quite common, picked up on screening now (is a cause of severe LD)
Causes: maldescent of the thyroid from the base of the tongue, inborn error of thyroid hormone synthesis, iodine deficiency (rare in UK, commonest cause developing), TSH deficiency (rare but usually widespread pituitary dysfunction so other sx - not picked up on screening)
CF:
- Usually picked up on screening
- Other: faltering growth, feeding problems, prolonged jaundice, constipation, pale/mottled/cold/dry skin, coarse facies, large tongue, hoarse cry, goitre, umbilical hernia, delayed development, irreversible cognitive impairment
- May cause precocious puberty via TSH stimulation of FSH receptors
M: thyroxine before 2-3w old to prevent neurodevelopment issues
Newborn heelprick screening
To detect asymptomatic treatable conditions, within 5-7d, drops of blood onto filter paper:
- Cystic fibrosis
- Congenital hypothyroidism
- Haemoglobinopathis-thalassaemia
- 6 x IEM (PKU, MCAD, glutaric acuduria type 1, isovaleric acidaemia, homocystinuria, maple syrup urine disease)
Premature pubertal development
Development of secondary characteristics <8y in girls/<9y in boys
Precocious puberty: can be central (gonadotrophin dependent so HPG axis activated early, e.g. hydrocephlaus/tumors/hypothyroidism) or gonadotrophin-independent (excess sex steroids outside pituitary e.g. CAH, ovarian granulosa cell tumour, testicular Leydig cell tumour)
Premature thelarche: usually in infants with no other features
Premature adrenarche: no other signs, usually accentuation of normal androgen production
Isolated premature menarche
Delayed puberty
Absence of pubertal development by 14y in girls/15y in boys, M>F
Causes: constitutional (most common), low gonadotrophin secretion (severe systemic diseases, anorexia nervosa, intracranial tumours, Kallman syndrome [LH deficiency + anosmia), high gonadotrophin secretin (chromosomal abnormalities like Klinefelter or Turner, acquired damage to gonads e.g. from chemo or torsion)
Diabetes insipidus
Central - ADH deficiency. Causes polyuria but some children cant recognise thirst so get hypernatraemia
Nephrogenic - ADH insensitivity
SIADH
Hyponatraemia
Can be provoked by severe illness or neurosurgery
Congenital adrenal hyperplasia
AR disorder of adrenal steroid biosynthesis, due to a deficiency in a particular steroid (multiple types). Low cortisol - high ACTH in response - adrenal androgen overproduction
Around 75% also unable to produce aldosterone (salt losers) so low sodium + high potassium, metabolic acidosis, hypoglycaemia
CF: virilisation of female external genitalia (e.g. labial fusion, clitoral hypertrophy), male may have enlarged penis/pigmented scrotum, salt-losing crisis at 1-3w (vomiting, weight loss, hypotonia), tall stature in non-salt losers (also with adult BO, pubic hair, acne - excess androgens - precocious puberty)
M: surgery for females, lifelong glucocorticoids (hydrocortisone-suppresses ACTH-normal growth), mineralocorticoids (fludracortisone) for salt-losers, additional hormones during illness/surgery (as they can’t mount a cortisol response)
Primary adrenal insufficiency (Addisons disease)
Rare in childhood. Causes are autoimmune, haemorrhage/infarction e.g. meningococcal sepsis, X-linked disorders, secondary to HP disease or HPA suppression from long term steroids
CF:
- Acute: low sodium, high potassium, hypoglycaemia, dehydration, hypotension, circulatory collapse
- Chronic: vomiting, lethargy, brown pigmentation in gums/scars/skin creases
Ix: low plasma cortisol, high ACTH (unless pituitary issue!), Synacthen test (cortisol remains low when given exogenous ACTH)
M: glucocorticoid + mineralocorticoid replacement; in a crisis IV saline + glucose + hydrocortisone
