Endocrinology Flashcards
What are the paediatric endocrine disorders?
Diabetes mellitus Hypoglycemia Hypothyroidism Hyperthyroidism Parathyroid disorders Adrenal cortical insufficiency Cushing syndrome Inborn errors of metabolism Hyperlipidemia
What is the most common cause of hypothyroidism in children?
Congenital
What is the prevalence of diabetes in children?
2:1000 by 16 years age
What are the causes for diabetes in children?
Type 1 - most common (autoimmune beta destruction) Type 2 - insulin resistance (obesity, ethnicity) Type 3 - MODY (beta/insulin defects, rubella, steroids, Cushing, Down, Turner, pancreatic exocrine failure/CF) Type 4 (GDM)
What are the genetic associations of diabetes?
Identical twin has 40% risk
If type 1 DM in father, 1:40 risk for child
If type 1 DM in mother, 1:80 risk for child
Risk high in HLA DR3 and DR4
Protected in DR2 and DR5
What is the pathogenesis of beta cell destruction in T1DM?
Environmental trigger for autoimmunity
Molecular mimicry of beta cell antigen
Eg; Enteroviral infection, Cows milk protein allergy
What are the other autoimmune diseases associated with T1DM?
Hypothyroidism Addison disease Coeliac disease Rheumatoid arthritis (check in FHx as well)
What are the markers of beta cell destruction?
Anti Islet cell Ab
Anti Glutamic acid decarboxylase Ab
Anti Insulin Ab
What are the clinical features of T1DM?
2 peaks, preschooler or teen. Seasonal as well
Few weeks of polyuria, polydipsia, weight loss
(classic triad)
Secondary nocturnal enuresis
Skin sepsis
Candida
What are the clinical features of DKA?
Kussmaul hyperventilation Acetone breath Abdominal pain Dehydration Vomiting Drowsiness Hypoveolemic shock Coma/death
How is T1DM diagnosed?
RBS > 11.1 mM + Glycosuria + Ketonuria
FBS > 7 MM
HbA1c 3 times a year with FBC >7.5%
What are the signs of insulin resistance / T2DM?
Acanthosis nigricans
Skin tags
PCOM in girls
How is T1DM managed?
Treat DKA first Rehydrate Admit if dehydrated needing IV MDT (Paed, diet, psycho, social, support) Teach insulin injection, storage Low refined carb diet Basal bolus regimen Sick day rules Self monitoring of CBS (target 4-10 mM) How to recognise hypoglycaemia Keep sugar on hand Emergency contact Plot growth charts
What are the types of insulin?
Soluble insulin Fast analogs (aspart, lispro, glulisine) Long acting analogs (detemir, glargine) Intermediate isophane Mixed
What is the honeymoon period?
Shortly after symptomatic, when beta cells are still functioning, insulin need is low/none
Subsequently increase to 1-2 U/kg
What are the symptoms of hypoglycaemia?
When BG <4 mM
Hunger, sweating, dizziness, fainting, irritable
Seizures
How is hypoglycaemia treated?
Mild - sugary drink/food
Moderate - IV 10%D 2 mL/kg then infusion
Severe - IM Glucagon 1 mg + 5D + food/drink
What is the management of DKA?
Ix
RBG, S ketones, U+E, Cr, ABG, U glucose, U ketones, BCx, UCx, CRP, FBC, ECG for hypokalaemia, weight
Mx
SC insulin only if mild
If vomiting or worse
IV NS, resuscitate then over 48 hours drip, IpOp chart
Monitor E, SCr, ABG, prevent aspiration
IVI insulin, 0.1 U/kg/h after 1 hour, titrate with regular CBS
CBS chart lower 2 mM/h, dextrose IV when CBS 14 mM
Continuous cardiac monitoring, K+ chart
Convert to oral feeds and SC insulin
Treat cause, prevent future recurrence
What are the long term aims in managing diabetes?
Normal growth and development Normal life Good control Self management Prevent hypos Prevent long term complications HbA1c <7.5%
Why is there an increased insulin need in puberty?
Growth hormone, estrogen and testosterone are insulin antagonists
Increases from 1U/kg to 2 U/kg per day
What are the long term complications of DM?
Growth and pubertal delays Obesity Hypertension Microalbuminuria and nephropathy Retinopathy or cataract Foot care Yearly TSH
What is the cut off for hypoglycaemia?
< 2.6 mM in neonates
< 4 mM for children
What are the possible permanent complications of untreated hypoglycaemia?
Epilepsy
Severe learning difficulties
Microcephaly
Why are infants and neonates most at risk of hypoglycaemia?
High energy requirement
Poor gluconeogenesis and glycogenesis reserves
Cant independently feed
Never starve for more than 4 hours
How is hypoglycaemia investigated?
Confirm low CBS with a RBS for exact value
Blood for GH, IGF1, Cortisol, Insulin, c peptide, fatty acids, ketones, glycerol, BCAA, lactate, pyruvate
Urine for organic acids
What are the causes of hypoglycaemia?
Transient neonatal hypoglycaemia (in utero insulin)
Recurrent severe neonatal hypoglycemia (high insulin)
-Iatrogenic insulin
-Insulinoma
-Sulfonylurea
-Insulin receptor antibodies
Ketotic hypoglycaemia (low reserves)
-Liver disease
-Glycogen storage disorders (inborn errors)
-Low GH, ACTH, Addison, CAH
How to investigate hyperlipidemia?
If Random serum cholesterol > 5.3 mM
Do Fasting serum cholesterol, triglyceride, LDL and HDL cholesterols (fasting lipid profile)
What are the secondary causes of hyperlipidemia?
Obesity Hypothyroidism Diabetes mellitus Nephrotic syndrome Obstructive jaundice
What is familial hypercholesterolemia?
AD LDL receptor defect 1:500 LDL>3.3 mM Skin and tendon xanthomas Fix of premature CAD
How is hypercholesterolemia treated?
Statins
Bile acid sequestrants
Fibrates
What is Cushing Syndrome?
Clinical state of glucocorticoid excess
ACTH–>Glucocorticoids
ACTH dependent (pituitary adenoma/ectopic ACTHoma, exogenous ACTH)
ACTH independent (adrenal tumours, exogenous glucocorticoids)
What are the clinical features of Cushing Syndrome?
Short stature Obese Hirsutism Striae Bruising Hypertension Glucose intolerance
How is Cushing syndrome investigated?
- Confirm with a suppression test (fail to suppress)
- screen with ODST (1 mg at 2300 then sample at 0900)
- confirm with LDDST (0.5 mg 6 hourly * 8 doses) - DDx with HDDST (2 mg 6 hourly * 8 doses)
How to diagnose inborn errors of metabolism?
Before birth (FHx, unexplained deaths) After birth -Screening (PKU, familial hyperchol) -Normal newborn becoming severely ill -Infant or child with severe hypoglucemia -Subacute regression (storage disease) -Dysmorphism
What are the common inborn errors of metabolism?
Galactosemia (poor feeding when given milk)
Glycogen storage disease (hypoglycaemia)
Phenylketonuria (DD with blue eyes at 6 months)
Homocystinuria (DD with lens subluxation)
Tyrosinemia (Liver failure)
What are the causes of adrenal insufficiency?
Primary -CAH -Addison disease Secondary -hypopituitarism -long term glucocorticoid withdrawal
What are the clinical features of adrenal insufficiency?
Acute salt losing crisis -Hyponatremia -Hyperkalemia -Hypoglycemia -Dehydration -Hypotension -Shock Chronic -Vomiting -Lethargy -Brown pigmentation -Growth failure -salt craving
How is adrenal insufficiency diagnosed?
Screen
(low Na high K, low CBS, acidosis)
Confirm
(short synacthen test)
How is adrenal crisis managed?
IV NS, 10%D and hydrocortisone
Emergency IM hydrocortisone kit
What are the features of hypocalcemia (hypoparathyroidism)?
Spasms
fits
stridor
diarrhoea
(Prematures, severe rickets, hypoparathyroidism, DiGeorge Xd)
Rx Diluted IV 10% cal gluconate, PO Ca and Vit D
What are the features of hyperparathyroidism?
High calcium Constipation Anorexia Lethargy Polyuria Polydipsia (Rx Rehydrate, diuretics, bisphosphonates) Occurs with adenomas, MEN
What is pseudohypoparathyroidism?
PTH normal but defective receptors. Short 4th metacarpal Learning difficulties short stature obesity subcutaneous nodules calcified basal ganglia
What are the features of hyperthyroidism?
Systemic signs and Eye signs
In teen girls or neonates of Graves mothers
Exopthalmos, ophthalmoplegia, lid retraction, lid lag
Anxiety, hunger, sweating, diarrhoea, LOW, tremor
Rx - Carbimazole, propylthiouracil, beta blockers
SE- neutropenia
What is the newborn thyroid physiology?
Fetus depends on mothers T4
After birth there is a TSH surge which normalises within a week
(prematures have low T4 and normal TSH)
What are the causes of congenital hypothyroidism?
Iodine deficiency
Maldescent of thyroid/athyrosis
Dyshormonogenesis
Panhypopituitarism (micropenis, no testes descent)
Why is it important to screen newborn for hypothyroidism?
Preventable cause of severe learning difficulties Common 1:4000 Minimal clinical features (Heel prick test - high TSH) Rx T4 after 2 weeks age Needs lifelong T4
What are the causes of juvenile hypothyroidism?
Down/Turner syndrome
Autoimmune thyroiditis
Females with growth failure and delayed bone age
What are the clinical features of hypothyroidism?
Congenital
FTT, feeding problems, prolonged jaundice, constipation, dry skin, coarse facies, large tongue, hoarse cry, goiter, umbilical hernia, DD
Acquired
Short females with delayed puberty, dry skin and hair, cold intolerance, slipped femoral epiphysis, learning difficulties, puffy eyes
