Paediatric Endocrine/Metabolic Flashcards
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
Pharmacotherapy
- 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
Monitoring
- 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)