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Flashcards in Paediatric Endocrine/Metabolic Deck (56):

Causes of a goitre

Congenital: Dyshormonogenesis Maternal antibodies Maternal antithyroid drug McCune Albright syndrome Thyroid Tumour Acquired: Inflammation (e.g. Hashimoto's, Graves) Infiltrative disease Iodine deficiency Thyroglossal duct cyst Adenoma Carcinoma


Causes of hyperthyroidism in children

Graves Disease (relatively rare in children) Neonatal Graves (transplacental antibodies) Sub-acute thyroiditis Exogenous thyroxine exposure


Presentation of congenital hypothyroidism

Excessive sleeping Poor muscle tone Low/hoarse cry Infrequent bowel movements Exaggerated jaundice Low body temperature Myxedematous facies Large anterior fontanel, persistent posterior fontanel, umbilical hernia, macroglossia


Complications of congenital hypothyroidism

Permanent intellectual disability Deafness Growth Failure No sequelae if treatment initiated by 4 weeks of age!


Side effects of antithyroid drugs

Common: Pruritus, rash, urticaria Arthralgias, arthritis Fever Abnormal taste sensation Nausea and vomiting Major side effects: Agranulocytosis Hepatotoxicity ANCA-positive vasculitis (PTU only) Pancreatitis


Management of hyperthyroidism

Anti-thyroid drugs (carbimazole, propylthiocuracil) Beta-blockers: to manage symptoms of adrenergic overactivity (atenolol is cardioselective) Radioactive iodine if recurrent/major side effects of medications


Delayed puberty definition

lack of pubertal changes by 13 years in girls and 14 years in boys


Causes of delayed puberty

constitutional delay (50%) Primary (hypergonadotropic) hypogonadism Chromosomal (TS, Klinefelter's) trauma, radiation, torsion of gonads Drug damage (e.g. Chemo) Congenital (cryptorchidism) LH receptor mutation (females) Secondary (hypogonadotropic) hypogonadism HYPOTHALAMIC: familial, illness, lesions, genetic abnormality (Kallmans) PITUITARY: tumours, trauma, genetic abnormalities


Hypogonadism management

Identify and treat underlying cause (karyotype, MRI brain etc.) Females: low dose oestrogen increased over 2 years _ progestogen when breakthrough bleeding or 20mcg equiv to ethinyloestradiol Males: oral androgen, change to monthly IM or 6 monthly SC testosterone +/- testicular prostheses


Congenital Adrenal Hyperplasia (Inheritance pattern, deficiency, 4 neonatal presentations, diagnosis and management)

Autosomal recessive Deficiency of 21-hydroxylase -> catalyses 17OHP to 11-deoxycortisol Virilised female infant: ambiguous genitalia (spectrum from minor clitoral enlargement to complete labial fusion etc.) Male neonate with metabolic and haem compromise: 1 weeks post birth, unusual pigment of scrotal skin, poor feeding, lethargy, weight loss with FTT, progressive vomiting, haemodynamic collapse, "salt losing" adrenal crisis Sig. metabolic derangement weeks 2-3: recurrent vomiting, weight loss, FTT, haem compromise, hyperkalemia, hyponatremia, met acidosis, hypoglycaemia Antenatal diagnosis with genetic testing due to previously affected sibling Inx: elevated 17OHP, electrolyte abnormalities, chromosomal analysis Mx: oraly hydrocortisone, fludrocortisone and salt replacement


Addison's disease (causes, presentation, investigations, management)

Causes: CAH, autoimmune, adrenal haemorrhage, infections (CMV, TB HIV), neoplastic destruction Presentation: weakness, fatigue, anorexia, weight loss, hyperpigmentation, hypotension, vomiting, nausea, salt craving Inx: hyperK+, hypoNa, met acidosis, norm anaemia, neutropenia, high ACTH Management: glucocorticoids (hydrocortisone/prednisolone), mineralocorticoids (fludrocortisone)


Acute adrenal crisis (presentation and management)

Occurs in trauma and sickness Weakness, fatigue, anorexia, weight loss, hyperpigmentation, hypotension, shock, hypoglycaemia, fever + hyperK, hypoNa, met acidosis Manage: high dose steroids, IV fluids, treat precipitating cause


What is galactosaemia

An inherited metabolic disorder characterised by elevated levels of galactose in the blood caused by altered metabolism due to deficiency enzyme activity or impaired liver function


What is the inheritance pattern for galactosaemia?

Autosomal recessive


What is PKU?

AKA phenylketonuria

Is a metabolic disorder in which there is a deficiency in the enzyme  (PAH - phenylalanine hydroxylase) responsible for the conversion of phenylalanine to tyrosine and is characterised by intellectual disability if left untreated


What is the inheritance pattern of PKU?

Autosomal recessive


Clinical features of PKU

  • Asymptomatic newborns prior to initation of feeds with phenylalanine (breast milk or standard formula)
  • May not cause symptoms until early infancy - insidious onset
  • Mental impariment - worsens in childhood with increasing exposure, stabilises when brain maturation is complete
  • Epilepsy is common
  • some patients have loss of motor function over time
  • gait, posture and stance abnormalities
  • Hyperactivity
  • Light pigmentation of skin and eczeamtous rash
  • Mousy/musty odour of body and urine


Management of PKU

Dietary restriction

  • use of foods including phenylalanine-free protein substitute
  • low-protein diet
    • formula, fruits, vegetables
    • Avoid meats, dairy, eggs, nuts, seeds, tofy/soy etc


  • May be appropriate in mild-moderate phenotypes
  • artificial BH4 (cofactor for PAH activity)
  • Not appropriate in classical PKU where there is total absence of PAH


  • Phenylalnine Concn
  • Weekly for first 12m
  • Fortnightly from 12-24m
  • Monthly thereafter


Complications of PKU

Osteopenia (40%)

Cognitive impairment

  • IQ in treated patients tends to be in average range, but lower than unaffected parents or siblings

Behavioural problems

Visual abnormlaities (usually subclinical visual impairment)


Main sources of galactose

Sugar found primarily in human and bovine milk and milk products


What are the 3 different deficiencies which cause galactosaemia and which is most common?

GALT (galactose-1-phosphate uridyl transferase) - most common and most severe form

Galactokinase (GALK) deficiency - first enzyme in pathway for galactose metabolism, only consequence of this form is the development of cataracts

UDP GALE deficiency - either generalised (similar to classic galactosaemia) or defect isoloated to RBCs (normal growth and development)


Presentation of classic galactosaemia (including onset)

Usually presents in first few days after birth and initiation of breast milk or cow's milk based formula

  • Jaundice
  • Vomiting
  • Hepatomegaly
  • Failure to thrive
  • Poor feeding
  • Lethargy
  • Diarrhoea
  • Sepsis (most commonly E. Coli)
  • Lenticular cataracts generally appear after 2 weeks (galactitol deposits)


Investigations in galactosaemia

  • Raised plasma galactose
  • Raised RBC galactose-1-P
  • Raised serum and urine galactiiol levels
  • Liver dysfunction
    • hyperbilirubinaemia
    • abnormal LFTs
    • coagulopathy
    • increasedplasma amino acids (phenylalanine, tyrosine, methionine)
  • Renal tubular dysfunction
    • metabolic acidosis
    • galactosuria
    • glycosuria
    • aminoaciduria
    • albuminuria
  • Haemolytic anaemia
  • quantitative assay of RBC GALT activity is necessary to confirm diagnosis


Management of galactosaemia

Neonatal juandice: treat as other types of neonatal jaundice



  • Nutritional therapy
    • Galactose restriction
      • exclude dairy and milk products
      • soy-based infant formulas
      • lactose-free formulas are not safe
    • Calcium supplementation 
      • enough usually supplied by formula, supplement after 1 year when formula use has declined
  • Monitoring
    • OPD follow up (3 monthly until 2 years, 6 monthly until 14y, annually therafter)
    • Girls may need more frequent to assess pubertal development
    • monitoring of complications


Complications of galactosaemia


Growth Delay

Premature Ovarian failure (measure FSH and oestradiol levels at 10 years)

Neurodevelopmental problems (intellectual deficits, speech and language problems, focal neurological findings e.g. tremor, ataxia)


Dietary modificaion usually results in the resolution of clinical features


Premature ovarian failure in galactosaemia

Occurs in most females after the age of 14

Unknown mehanism

Most develop menarche and then oligomenorrhoea or amenorrhoea (25% will have primary amenorrhoea)

Most affected women are thus infertile

Pubertal development is normal in males


Cataracts in galactosaemia

Due to deposition of galactitol

Occur in 30%

Are Sublenticular

Typically detected at 2 weeks of age

Dietary manaement will resolve approximately half


Most common cuase of early mortality in galactosaemia

Sepsis, most commonly E. coli


Prevalence of congenital hypothyroidism

1/3,500 births


Cause of DKA

Unregulated lipolysis secondary to insufficiency of insulin


Clinical features of hypoglycaemia in a child

Blurry vision
Weakness or fatigue
Rapid heartbeat


Diagnostic criteria for diabetes

Fasting BGL >7

Random BGL/2hr post glucose load >11


Investigations in type 1 diabetes

Circulating antibodies against beta cells

  • Anti-insulin
  • Anti-islet cell
  • Anti-GAD

High IgA



Insulin types for management of diabetes

Fast acting:

  • Soluble
    • Actrapid
    • 30 minute onset of action
    • peak 1-2 hours
    • Duration of action 6-8 hours
  • Insulin analogues
    • e.g. Humalog, Novorapid
    • Onset of action 15 minutes
    • Peak 30-70 minutes
    • Duration of action 2-5 hours

Long acting:

  • Insulin analogues:
    • Glargine (Lantus)
      • lasts 24 hours
      • once daily
      • acidic injection (stings)
      • poor pen device
    • Demetir (Levemir)
      • Lasts approx 20 hours
      • 1-2 daily
      • Reduction of nocturnal hypos
      • Good pen device


Insulin regimes for type 1 diabetes

BD insulin mixes:

  • convenient, well understood, lots of mixes available
  • Only 2 injections/day
  • Lack of flexibility 
    • have to be up by 9am
    • Have to eat 3 snacks and 3 meals a day

Basal Bolus:

  • More flexibility (alter doses according to size of meal, if child unwell and not eating, can omit doses of rapid insulin if needed)
  • 4 injections/day, need to inject at school



Things parents and chlidren must be educated about regarding diabetes

How to provide injections
How to monitor blood glucose
Basic dietary advice
Hypoglycaemia management
Ketone monitoring if sugar levels high



Management of hypoglycaemia in DM1

If conscious and cooperative: 10g fast carbohydrate followed by starchy snack

If conscious but uncooperative: Glucogel followed by starchy snack

If unconscious: Glucagon IM then starchy snack if possible and present to hospital



Aims of treatment of DKA

Slowly restore metabolic homeostasis

Correct lack of insulin

Correct dehydration over 48 hours

Reduce hyperglycaemia


Management of DKA

  1. IV fluids
    • begin before insulin
    • 20ml/kg bolus if shocked on arrival
    • 0.9% saline with 40mmol/KCl
      • Maintenance + deficit (calculate level of dehydration)
      • Give deficit over 48 hours
    • Once BSL drops to 15mmol/L, change to 0.9% saline/5% dextrose with KCl
  2. Insulin
    • Short acting as an IV infusion
      • Actrapid/Humalog/Novorapid
      • 50IU in 50mL normal saline
      • Run at 0.1mL/kg/hr (turns of ketosis)
    • Change from IV to SC once stabilised
      • Child tolerating oral intake
      • Start SC insulin prior to stopping IV insulin
      • If starting basal bolus, give basal insulin the night before stopping IV


Complications of DKA and its management

Gastric stasis



Cerebral oedema




Cerebral oedema when treating DKA

(epidemiology, cause, onset)

  • Occurs if rehydration or electrolyte correction occurs too rapidly
  • typically occurs 4-12 hours after starting treatment
  • 7/1000 episodes of DKA
  • 24% morbidity (learning and intellecutal fuctioning impaired long term)
  • High mortality


Risk factors for a child with DKA to develop cerebral oedema

  • Child presenting very unwell
  • Younger child
  • Newly diagnosed diabetes
  • Lower pH at presentation
  • High urea at presentation
  • Administration of bicarbonate
  • Administration of large fluid boluses


Symptoms and signs of cerebral oedema

  • Headache
  • Drowsiness
  • Incontinence
  • Vomiting recurrence
  • Reduced consciousness
  • bradycardia
  • Risking BP (cushing's triad)
  • Reduced oxygen saturation
  • Neurological signs
  • Abnormal pupil responses
  • Abnormal posturing


Treatment of cerebral oedema



3% saline (hypertonic saline)


Biochemical criteria for DKA

  1. Venous pH less than 7.3 
    Bicarbonate <15 mmol/L
  2. Presence of blood or urinary ketones


Symptoms of DKA

Flushed, hot, dry skin
Blurred vision
Polyuria and polydipsia
Reduced consciousness (drowsiness, difficulty waking up)
Rapid, deep breathing (Kussmaul's acidotic breathing)
Strong, fruity breath odor (ketone breath)
Loss of appetite
Abdominal pain


Other types of paediatric diabetes

  •  Permanent neonatal diabetes
    • familial form of DM
    • appears shortly after birth, continues for life
    • usually immunologic markers for DM1 are absent
    • Requires insulin, but resistant to ketosis
    • Often associated with other congenital abnormalities
  • Transient neonatal diabetes
    • Most common in preterm babies
    • caused by immaturity of islet B-cells
    • polyuria and dehydration are prominent - baby looks well
    • highly sensitive to insulin
    • resolves in 4-6 weeks
  • Maturity onset diabetes of the young (MODY)
    • affects older children
    • 5 subclasses identified
    • not associated with immunologic or genetic markers
    • insulin resistance present
  • Scondary diabetes
    • e.g. secondary to CF, Cushing syndrome etc.


Types of congenital GH deficiency

Type IA and IB - autosomal recessive

Type II - autosomal dominant

Type III - X-linked recessive


Presentation of GH deficiency

  • Growth progresses well for first 6-12 months then falls off chart (if congenital)
  • Phenotypic features:
    • small hands and feet
    • prominent forehead, small midface
    • truncal obesity
    • poor muscle bulk
    • micropenis
    • sparse hair
    • cryptorchidism
    • midline defects (single central incisor, closely spaced eyes)
    • CNS disease
  • Bone age delayed but consistent with heith age
  • In acquired:
    • "cherub or angel-like" fat distribution
    • Infantile voice
    • immature face with underdeveloped nasal bridge and frontal bossing


Investigations for GH deficiency

  • GH testing (stimulation tests required due to pulsatile release)
    • Physiological stimulus
      • serial blood tests during sleep
      • post exercise-to-the-point-of-exhaustion
    • Pharmacological stimulus
      • most common testing these days
      • Arginine (glucagon, clonidine or propanolol could also be used)
  • IGF-1 and IGFBP-3
    • reflect integrated concentration of secreted GH
    • Not pulsatile (stable serum levels)
  • MRI brain and pituitary if GHD confirmed 
    • ?tumour
    • ?morphological abnormalities


Management of GH deficiency


  • Treat underlying cause if any (including psychosocial cuase)
  • GH supplementation (recombinant human GH)
    • daily SC injection
  • Treatment of associated pituitary hormone deficiencies
    • TSH deficiency: levothyroxine
    • ACTH deficiency: glucocorticoids
    • Gonadotrophin deficiency: oestrogen or testosterone
    • DI: desmopressin


Side effects of growth hormone supplementation

  • Fluid retention
    • benign intracranial HTN
    • Carpal tunnel syndrome/oedema
  • Skeletal
    • SCFE
    • Scoliosis
  • Glucose intolerance
  • Risk of malignancy


Causes of congenital hypothyroidism

Thyroid agenesisi or hypoplasia


Iodine deficiency



Management of hypothyroidism (congenital or acquired) in a child

10-15mcg/kg/day thyroxine

+/- surgery as indicated

follow up to ensure thyroxine in normal range


Causes of acquired hypothyroidism in children

Hashimotos thyroiditis most common

Iodine deficiency