Endocrine disorders Flashcards
Discuss the development of the endocrine system in children
Differentiation of cells -> hormone producing cells able to secrete
Just before birth, incr ACTH secretion -> incr cortisol -> rapid maturation of enzyme systems
Birth -> incr ADH, renin + angiotensin
Postbirth
-> incr noradrenaline -> blood glucose maintained by metabolism of brown fat
-> incr thyrotropin (birth stress) -> incr thyroid hormones
-> high GT and sex hormone output
Name risk factors for infants at risk of hypoglycemia
Premature IUGR Maternal diabetes Septicemia Severe illness
Name causes of infant hypoglycemia
Defects in - hepatic glycogen release/storage - carnitine metabolism - fatty acid oxidation Hyperinsulinism Cortisol deficiency GH deficiency
Name symptoms of hypoglycemia
Poor feeding Lethargy Apnoea Cyanotic spells Hypothermia Seizure Coma
What tests should be ordered when evaluating hypoglycemia?
Critical
- true blood glucose
- LFT
- electrolytes
- serum bicarb
- urinalysis
Archival
- serum for insulin, ketones, GH, cortisol
- C peptide
- carnitine profile
- amino acids
- toxins
- urine amino + organic acids
What are the 3 phases of growth and what do they depend on?
Infantile - nutrition
Childhood - GH
Pubertal - sex hormones
What investigations are important when evaluating a child with short stature?
Urine dipstix Stool microscopy Hb Serum albumin Blood urea T4 and TSH Radiological bone age
Discuss a differential for familial short stature
Prenatal onset
- IUGR
- Silver-Russell syndrome
- Turner syndrome
Postnatal onset
- psychosocial dwarfism
- malnutrition
- GIT disorder
- renal disorder
- cardiopulmonary disease
- chronic anemia
- endocrine disease
Which children should be evaluated for a growth disturbance?
- Height
Discuss a differential for endocrine causes of short stature
Hypopituitarism Hypothyroidism Precocious puberty CAH Cushing's syndrome Pseudohypoparathyroidism Poorly controlled DM
Name causes of pituitary gland malfunction
Cranial
- holoprosencephaly
- septooptic dysplasia
- midline craniocerebral abnormality
- midfacial abnormality
Embryonic
- pituitary hypoplasia
- pituitary aplasia
- congenital absence of pituitary gland
Childhood cancer (radiation)
Infectious (meningitis, encephalitis)
Infiltrative (histiocytosis)
Trauma
What is the clinical presentation of pseudohypoparathyroidism?
Short stature Truncal obesity Short metacarpals Round face Mental retardation
What is Silver-Russell syndrome?
A rare disorder characterized by IUGR, poor postnatal growth, a relatively large head size, a triangular facial appearance, a prominent forehead (looking from the side of the face), body asymmetry and significant feeding difficulties
What is Mauriac syndrome?
Severe growth failure and HSM due to hepatic deposition of glycogen in poorly controlled diabetics
Give a differential diagnosis for tall statue
Familial tall stature Obesity Thyrotoxicosis Precocious puberty Marfan's syndrome Klinefelter's syndrome Excess GH
Name disorders that are classified as 46, XY DSD
Disorder of gonadal development
Disorder of androgen synthesis/action
Cloacal extrophy
Severe hypospadia
Name disorders that are classified as 46, XX DSD
Disorder of gonadal development
Androgen excess
Cloacal extrophy
Vaginal atresia
What should you evaluate when approaching ambiguous genitalia?
Clinical examination U/S Exploratory laparotomy Chromosome analysis Na/K balance Plasma 17-OH Gonadal biopsy
Name disorders of puberty
Premature thelarce Premature adrenarche Adolescent gynecomastia Precocious puberty Pseudoprecocious puberty Delayed puberty
Name disorders of water balance
SIADH Diabetes insipidus - central - nephrogenic DM type I DM type II
Name causes of SIADH
Severe meningitis
Head injury
Pulmonary disorders
Vincristine therapy
Name the clinical features of SIADH
N+V Mm weakness Neurological irritability Convulsions Coma Oedema
How do you manage SIADH?
Restrict water intake
3% saline 5ml/kg
Furosemide therapy 0.5-1mg/kg
Name the clinical features of diabetes insipidus
Polyuria
Polydipsia
Chronic dehydration
Growth failure
How do you make the diagnosis of diabetes insipidus in children?
Urine osmolality <300mOsm/kg
Serum osmolality >300mOsm/kg
Water deprivation test
When should you not perform water deprivation tests?
Night time - inadequate monitoring
How do you manage central diabetes insipidus?
Lysine vasopressin/DDAVP
What is DDAVP?
Desamino D-arginine vasopressin
What is the inheritance pattern of nephrogenic diabetes insipidus?
X linked dominant
How do infants with nephrogenic diabetes insipidus present?
Vomiting Constipation Hypotonia FTT Recurrent hypertonic dehydration
How do you manage a child with nephrogenic diabetes insipidus?
High water intake with frequent feeds
Low salt diet
Hydrochlorothiazide 3mg/kg/d
Indomethacin 1.5-3mg/kg/d
What is the cause of type I DM?
T-cell mediated pancreatic islet beta cell destruction
Name clinical features of DM type I
Polyuria Polydipsia Vision blurring Weight loss Glycosuria Ketonuria
How do you diagnose DM type I?
Clinically
Fasting glucoe >7mmol/l
2hr ppg >11.1mmol/l
When should hyperglycemia not be regarded as diagnostic of diabetes?
Acute stress situation
Incidental finding
How does diabetic ketoacidosis occur?
Insulin deficiency -> incr levels of catecholamines, glucagon, cortisol and GH -> catabolism
Name the clinical features of diabetic ketoacidosis
Acidotic breathing N+V Abdominal pain Decr LOC Coma
What should you always consider in a dehydrated, acidotic patient?
Diabetic ketoacidosis
What is the criteria to diagnose diabetic ketoacidosis?
BG >11 mmol/l
Venous pH <7.3
Serum bicarb <15mmol/l
Ketonuria
Discuss management of a DKA child
0.9% saline IV 10-20ml/kg bolus
Continue infusion for 36-48hrs (replace fluid deficit)
Insulin 0.1unit/kg/hr
When glucose <11mmol/l, add dextrose
Give potassium
2 hours before discontinuing IV insulin, give 1st insulin maintenance dose (0.5-0.7units/kg/24hr)
How do you calculate corrected Na?
Measure Na + 2(glucose -5.5)/5.5
How do you calculate fluid deficit?
7.5% -10% body weight
What is a serious complication of DKA?
Cerebral oedema
Name clinical signs of cerebral oedema
Headache Altered mental status Vomiting Hypertension Inappropriate HR decrease
Name clinical signs of newborn hypothyroidism
Open posterior fontanelle >1cm Umbilical hernia Coarse facial features Poor sucking Prolonged UC hyperbilirubinaemia
Which score is used to recognise congenital hypothyroidism?
Congenital hypothyroidism score
Name factors in the congenital hypothyroidism score
Umbilical hernia Coarse facial features Constipation Hypothermia Enlarged tongue Hypotonia Jaundice >3days Dry skin Wide post fontanelle GA >40wk BW >3.5kg Female
Name causes of congenital hypothyroidism
Dysgenesis Aplasia Maldescent Iodine deficiency Familial enzyme defect Ingestion of goitrogens
Give examples of goitrogens
Iodine-containing cough mixtures
Antithyroid drugs
Para-amino-salicylic acid
What is the most common use of para-amino salicylic acid?
Treat XDR TB
How is congenital hypothyroidism treated?
Thyroxine 10-15ug/kg/day in 1st year
Name clinical features of congenital hyperthyroidism
Emotional lability Nervousness Behavioural disturbances Sweating Nocturnal enuresis
Name clinical features of acute adrenal insufficiency
Circulatory collapse Low Na Hypoglycemia High K Metabolic acidosis
Name causes of adrenocortical insufficiency in children
Aplasia Hypoplaia CAH Haemorrhage Infection WF syndrome Autoimmune X-linked adrenoleukodystrophy Steroid therapy Hypothalamic damage Pituitary damage
Discuss the acute management of adrenocortical insufficiency in children
Bloods (electrolytes, acid base, urea, glucose, plasma cortisol assay)
Replace fluids and electrolytes
- Ringer’s lactate/plasma/Haemaccel
- 0.9%NaCl 5% dextrose at 10-20mg/kg over 1st hour then 60ml/kg over following 24hrs
Hydrocortisone sodium succinate
- as IV bolus 50mg small child, 100mg large child, then
- 50-100mg/24hr maintenace
Florinef 0.05-0.1mg//d orally
Monitor patient
What is CAH?
AR condition due to partial/severe deficiency of enzyme in the biosynthetic pathway of cortisol (and aldosterone in 50% of cases)
Discuss management of CAH
Oral hydrocortisone 20-25mg/m2/d
Oral florinef 0.05-01mg/d
Dietary salt if needed
Name clinical signs of Addison’s disease
Weak Anorectic Vomiting Diarrhoea Hydration Hypotension Skin pigmentation
Discuss management of Addison’s disease
Oral hydrocortisone 20-25mg/m2/d
Oral florinef 0.05-01mg/d
Name the cause of Cushing syndrome
- Excess steroid therapy
- Adrenal tumour
- Cushing’s disease
Name the clinical signs of Cushing’s syndrome
Moon face Truncal obesity Buffalo hump Purple striae Mm wasting Hypertension Virilisation
Name investigations you would perform in a child with signs of Cushing’s syndrome
24hr urinary free cortisol excretion
Overnight dexamethasone adrenal suppression test
Tumour:
U/S
IVP
CT
Name causes of hypocalcemia in infancy
Prematurity Asphyxia Gestational diabetes Hypoparathyroidism High P intake Hypomagnesemia Chronic alkalosis Maternal hyperparathyroidism
Name causes of hypocalcemia in childhood
Vitamin D deficiency Rickets Chronic renal failure Hypoparathyroidism Pseudohypoparathyroidism
Name investigations you would perform in a child with signs of hypocalcemia?
Calcium Phosphate Alkaline phosphatase PTH 25-hydroxyvitamin D
Name parathyroid-related causes of hypocalcemia
Congenital
- transient neonatal hypoparathyroidism
- PTH synthesis defect
- aplasia
- CaSR
Acquired
- autoimmune
- surgical
- magnesium deficiency
- nutritional
- bisphosphonate ingestion
- PTH resistance
Discuss management of chronic hypoparathyroidism
Calcium supplements
1,25 hydroxyvitamin D
Name clinical features of Albright’s hereditary osteodystrophy
Short stature Mental retardation Skeletal changes Subcutaneous ossifications Brachydactyly
What is the Frankfort plane?
Line of sight (hole in ear to bottom of eye socket)
