9- Paediatric Endocrinology (2/2) Flashcards
hypothyroidism background
- Can be:
o Congenital
o Acquired - Thyroid hormones are essential for development and functioning of the brain and body
o Undiagnosed: neurodevelopment and intellectual disability - Used to be known as cretinism
pathophysiology of congenital hypothyroidism
Where child is born with underactive thyroid gland
- 1 in 3000
Cause:
- Underdevelopment of gland (agenesis) or fully developed gland which doesn’t produce enough hormone (dysgenesis) - primary
- Iodine deficiency
- Rarely a problem with pituitary (secondary) or hypothalamus (tertiary)
RF
- Female
- Down syndrome
Diagnosis: Newborn blood spot screening test (day Presentation
- Prolonged neonatal jaundice
- Poor feeding
- Constipation
- Abdominal swelling
- Umbilical hernia
- Enlarged protruding tongue
- Increased sleeping
- Reduced activity
- Slow growth and development
- Developmental delay/ learning difficulties
Acquired hypothyroidism
Acquired hypothyroidism is where a child or adolescent develops an underactive thyroid gland when previously it was functioning normally
Cause
- Autoimmune thyroiditis (Hashimoto’s)
- Associated with anti-TPO antibodies and antithyroglobulin antibodies
- Associated with type 1 diabetes and coeliac disease
- Iodine deficiency in infancy
Presentation
- Fatigue and low energy
- Poor growth
- Weight gain
- Poor school performance
- Constipation
- Dry skin and hair loss
Investigations
- TFTs (TSH freeT4)
- Thyroid US
- Thyroid antibodies
thyroid hormonal axis
- The hypothalamus secretes Thyrotropin Releasing Hormone (TRH) which stimulates the anterior pituitary gland to release Thyroid Stimulating Hormone (TSH).
- TSH then binds to the TSH receptor (TSH-R) on the thyroid gland, stimulating the release of thyroid hormones T4 (thyroxine) and T3 (tri-iodothyronine) from the thyroid gland.
- To control the levels of circulating thyroid hormones, negative feedback is exerted by T4 and T3 onto the pituitary and hypothalamus, thus reducing the secretion of TRH and TSH.
managment of hypothyroidism
Management – DIAGNOSE AS EARLY AS POSSSIBLE
- If preterm will need new born screening repeat at 28 days of life
- Screen for congenital heart problems
- Levothyroxine taken once a day orally (start within 2 weeks of burtg)
- Doses titrated based on TFT
Hyperthyroidism
Background
- Hyperthyroidism: excess production and secretion of thyroid hormones by the thyroid gland.
- Thyrotoxicosis: the clinical manifestation of excess circulating thyroid hormones caused by hyperthyroidism or other causes (e.g. increased release of stored hormones from thyroiditis)
- Relatively uncommon in children
- Neonatal thyrotoxicosis affects 1-2% of babies born to mothers with autoimmune hyperthyroidism e.g. graves
Risk factors hyperthyroidism
- Girls
- Increases with age
- Family history
- Increased iodine intake
- Smoking
Pathophysiology of hyperthyroidism
- Primary hyperthyroidism- problem with thyroid gland
- Secondary- problem with pituitary gland
Specific causes
- Autoimmune e.g. Graves disease -> TSH receptor antibodies which mimic TSH
- Toxic multinodular goitre
- Thyroids cancer
- Neonatal hyperthyroidism
- Functioning pituitary adenoma
investigations of for hyperthyroidism
Examination
- Remember thyroid moves with swallowing
Blood tests
- TSH and free T4
- Free T3 too with hyper
- TPO antibodies
Neonatal thyrotoxicosis: if mother has Graves disease the baby will have TFTs done between day 5-14 to check their thyroid levels
Imaging
- US
- Radionuclide thyroid scan
Presentation
Symptoms of hyperthyroidism
- Weight loss / failure to thrive
- Increased appetite
- Rapid growth in height
- Sweating
- Heat intolerance
- Fatigue
- Anxiety, restlessness, irritability
- Diarrhoea
- Palpitations
- Warm, vasodilated peripheries
- Dyspnoea
- Insomnia
- Learning difficulties, behavioural problems, decreased concentration
- Deteriorating school performance
- Psychosis
- Delayed or accelerated puberty; oligo or amenorrhoea
presentation
signs of hyperthryoidism
- Goitre (bruit) that will move on swallowing but not on tongue protrusion (Figure 3)
- Fine tremor
- Hyperreflexia
- Moist, warm skin
- Tachycardia (rarely SVT), wide pulse pressure
- Proximal muscle wasting
- Hair loss
- Signs of thyroid eye disease – exophthalmos, ophthalmoplegia, lid retraction, lid lag (can cause dry eyes)
- Pretibial myxoedema – indicative of Graves’ disease
initial management of graves
Anti-thyroid drugs e.g. Carbimazole or propylthiouracil
- 2 methods of ATD admin
1) Titration
2) Block and replace i.e. completely suppress thyroid and replace with thyroxine
- Side effects:rashes, nausea, headache, agranulocytosis, hepatitis
Symptom relief: propranolol
Thyroid eye- ophthalmologist
management of neonatal hyperthyroidism
self-limiting within 1-3 months
management of transient thyroidtoxicosis
without hyperthyroidism (only need supportive management with beta-blockers)
definitive management of hyperthyroidism
1) radioiodine therapy
2) surgery
Radioiodine therapy
- Given as a tablet or drink
- Iodine taken up by thyroid gland and radiation kills the cells- need to avoid school due to radiation risk for a few weeks
- Will require lifelong levothyroxine
- Not recommend ed <6 or those with uncontrolled disease
surgery for hyperthyroidism
- Total thyroidectomy
- Will need lifelong levothyroxine
- Good for very young children, goitre, nodule, poorly controlled hyperthyroidism
- Damage to parathyroid or recurrent laryngeal nerves causing hoarseness
complications of hyperthyroidism
- thyroid storm
- thyrodi eye disease
- untreated hyperthryoidism
- future pregnancies
- side effect from treatment
Thyroid storm (emergency) 3
- Presentation: fever, hyperthermia, tachycardia, hypertension leading to high output cardiac failure, GI dysfunction, CNS dysfunction and seizures
- Treatment: IV fluids, ATD (large doses of propylthiouracil +/- iodide), propranolol (minimise adrenergic effects), hydrocortisone (high risk of adrenal insufficiency), treat precipitating factor (e.g. infection)
Thyroid eye disease
1/3 children with thyrotoxicosis have significant eye disease which might not improve with treatment of the hyperthyroidism
Complications of untreated hyperthyroidism
o Weight loss
o Hypercalcaemia
o Osteoporosis and fragility fractures
o Cardiovascular dysfunction, atrial fibrillation, embolic events
Future pregnancies and hyperthyroidism
antibodies that cause Graves’ disease can be passed onto the foetus even when treatment is no longer required, causing neonatal hyperthyroidism
Side effect from treatment - carbimazole
- Agranulocytosis: report signs of infection (e.g. fever, sore throat). Check WBC and stop ATD
- Others: hepatitis, acute pancreatitis, hypothyroidism
Obesity
Background
- 20% of children and adolescents are either overweight or obese
- Strongly predicts adult obesity
- Risk factor for
o T2DM
o HTN
o CAD
o Cancer - Obesity implies increased central (abdominal) fat mass,
- and can be quantified using a number of clinical surrogate markers.
- BMI is the most convenient indicator of body fat mass
measures of obesity
- BMI
- Waist circumference
- Waist: hip ratio
pathophysiology of obesity in children
- Genetic predisposition
- Sedentary lifestyle
- Increasing consumption and availability of high energy foods
- Endocrine
o Hypothyroidism
o Cushings syndrome
o GH deficiency
o Pseudohypoparathyroidism’s
o PCOS
o Acquire hypothalamic injury e.g. CNS tumour - Genetic
o Prader-Willi syndrome
o Bardet-Biedl syndrome
o Monogenic cause: leptin deficiency
Risk factors for obesity
- Parental/family history of obesity.
- Afro-Caribbean/Indian–Asian ethnic origins.
- Catch-up growth (weight) in early childhood (0–2yrs): infants born small for gestational age who demonstrate significant weight catch up (>2SDs) in first 2yrs of life.
Investigations for obesity
- History
o Birthweight
o Feeding habits and behaviour
o Weight gain/growth pattern
o Physical activity
o Neurodevelopment and school performance
o Comorbid factors
o Family history: T2DM and CVD - Bloods
o Blood biochemistry – TFTs, serum cortisol, liver function test, fasting lipid profile
o Genetic studies e.g. prader willi syndrome
o OGGT
Complications of obesity
- Psychological: low self-esteem, depression
- ENT/ respiratory: obstructive sleep apnoea, obesity-hypoventilation syndrome
- Orthopaedic: bowing of legs, slipped femoral epiphysis, OA
- Metabolic: impaired glucose tolerance/ T2DM, HTN, dyslipidaemia, PCOS
- Hepatic: non-alcoholic steatohepatitis
Management
No consensus about the best approach to treating childhood obesity. MDT approach.
- Nutrition and lifestyle education/counselling: important.
- Decreasing calorie intake/increasing exercise.
- Behaviour modification and family therapy strategies.
- Drug therapies (currently limited, not licensed for children).
- Obesity (bariatric) surgery (rarely).
- Population-based intervention and prevention strategies may be more effective than approaches targeted at the obese individual.
- Symptoms of rickets
- Pain esp in lower limbs
- Development: delay in walking
- Muscle pain
- Calcium imbalance : tetany, cardiomyopathy, seizures
Risk factors for Vit D def
- Darker skin
- Insufficient exposure to sunlight
- Nutritional deficiency
- Malabsorption
- Steroids
- Obesity
investigations for vit D deficiency
- Measuring 25-hydroxyvitamin D (25[OH]D) levels
Other tests
- Radiological assessment if rickets
- Bone profile (calcium, phosphate, ALP)
- Renal, liver ,thyroid, parathyroid levels
- FBC and ferritin
- Malabsorption screen
- Rheumatoid and other autoimmune screening and inflammatory markers
management of - Adequate/ Sufficiency >50nmol/L Vit D
No treatment required
management of insufficient vit D - 20-50nmol/l
Advise measures to prevent deficiency e.g. taking supplements
management of vit D deficiency (<30mmol/L)
o Treat for deficiency
o Prescribe loading dose followed by daily supplementation
o Check calcium intake and calcium levels before treatment
Differential diagnoses for Vit D deficiency
- Certain cancers.
- Fibromyalgia.
- Fracture.
- Osteomyelitis
- Paget’s disease of the bone
- Parathyroid disease
- Rheumatoid arthritis.
- Polymyositis and dermatomyositis.
- Thyroid disease
- Muscular dystrophies
Vitamin D toxicity
Rarely occurs unless the vitamin D dose is very high.
Manifests mainly through chronic hypercalcaemia:
- Nausea and vomiting.
- Diarrhoea.
- Constipation.
- Anorexia and weight loss.
- Lethargy.
- Polyuria and thirst.
- Sweating.
Rickets Background
- Rickets is deficient mineralisation at the growth plate of long bones, resulting in growth retardation.
- If the underlying condition is not treated, bone deformity occurs, typically causing bowed legs and thickening of the ends of long bones.
- Only occurs in children before fusion of epiphyses
- Typically affects
o Wrists
o Knees
o Costochondral junctions
pathophysiology of rickets
1) Nutritional vitamin D deficiency
- Vitamin D plays an important role in calcium absorption-> low vit D= low calcium levels (calcium key to bone development)
Cause
- Low VitD in diet
- Low exposure to UV
2) Also associated with deficiency in calcium or phosphorous
- Genetic cause of rickets: hypophosphatemia rickets
RF for rickets
- Dark skin children
- Babies born prematurely
- Spend a lot of time indoors
- Always wear sunscreen
- Lactose free or strict plant based diet
- Celiac disease
- Genetic – hypophopshatemic rickets
presentation of rickets
- Shortened height and stature
- Bowed legs
- Painful walking
- Skeletal deformity- thickening of ankles, wrists and knees
- Fragile bones
- Bones which break easy
- Large forehead or abdomen
- Unusual shape of ribs or breastbone
- Dental cavities
management of rickets
1)Correct vitamin D and ensure adequate calcium intake
- Vitamin D supplements
- Calcium supplements
2) Lifestyle
- Spend time outdoors
- Diet (eggs, cod liver oil, oily fish, fortidied food e.g. milk, cereals, beef liver
