Endocrine 4 Flashcards
What are the causes of glucocorticoid excess from treatment?
a side effect of long-term glucocorticoid treatment (IV, oral or more rarely inhaled, nasal or topical) for treatment of conditions
such as nephrotic syndrome, asthma or severe bronchopulmonary dysplasia
What are the side effects of corticosteroids?
potent growth suppressors and prolonged use in high dosage will lead to reduced adult height and osteopenia
This is reduced when it’s taken in the morning on alternate days
What are the other causes of glucocorticoid excess?
ACTH driven from a pituitary adenoma
ectopic ACTH producing tumours
adrenocortical tumours (benign or malignant), when there may also be cirilisation
How does Cushing’s affect hormone levels?
normal diurnal variation of cortisol (high in morning, low at midnight) may be shown to be lost
24hr urine free cortisol is also high
• After the administration of dexamethasone, there is failure to suppress the plasma 9am cortisol levels
What are the clinical features of Cushing syndrome?
o Growth failure/short stature o Face & trunk obesity o Red cheeks o Hirsutism o Striae o Hypertension o Bruising o Carbohydrate intolerance o Muscle wasting and weakness o Osteopenia o Psychological problems
What is diabetes insidious?
failure to produce ADH resulting in polyuria and polydipsia, as the urine cannot be concentrated
patient may become extremely dehydrated or may present with nocturnal enuresis
Genetic link
What are the clinical features of diabetes insipidus?
FTT
Poor feeding
Irritability
earliest signs include vigorous suck with vomiting, fever without apparent cause, constipation and excessively wet nappies
How is diabetes insipidus diagnosed?
• 24hr assessment of urinary volume and osmolality under coniditions of ad libitum fluid intake should be undertaken- serum osmolality, U&Es and blood glucose should also be measured
• Blood hypertonicity (serum osmolality >300mOsm) with inappropriate urine hypotonicity (serum osmolality
<300mOsm) should be demonstrated- DM and renal failure should be excluded
• A water deprivation test and assessment of responses to exogenously administered ADH is required to diagnose the type of DI
What is the treatment for diabetes insipidus?
- Cranial DI- synthetic analogue of ADH (Desmopressin)- dose and frequency is adjusted to maintain 24hr urine output volume within the normal range
- Nephrogenic DI- correction of underlying metabolic or iatrogenic causes, maintenance of an adequate fluid input is essential- thiazides, amiloride and PG synthase inhibitors can be effective
- Primary polydipsia- treatment is often difficult, behaviour modification strategies are usually required
What can cause growth hormone deficiency?
May be an isolated defect or secondary to panhypopituitarism
• Pituitary function may be abnormal or congenital mid-facial defects or as a result of a craniopharyngioma (a tumour affecting the pituitary region), a hypothalamic tumour or trauma – such as head injury, meningitis and cranial irradiation
What is a craniopharyngioma?
usually presents in late childhood and may result in abnormal visual fields, optic atrophy or papiloedema on fundoscopy
visual field defects include bitemporal hemianopia as it impinges on the optic chiasm
Whta is laron syndrome?
condition due to defection growth hormone receptors resulting in growth hormone insensitivity, patients with this coniditon have high growth hormone levels, but low levels of the downstream active product of growth hormone (IGF-1) produced at the growth plate and in the liver
What are the investigations for GH deficiency?
GH provocation test using insulin, glucagon, clonidine or arginine
Bone age
What is the treatment for GH deficiency?
biosynthetic GF, which is given by subcutaneous injection, usually daily
Other indications are in Turner syndrome, Prader-Willi syndrome, chronic renal failure and IUGR
• Recently recombinant IGF-1 has been used to treat children with growth hormone resistance (Laron syndrome) and IGF-1 deficiency who would have previously not responded to GH treatment
What is gynaecomastia?
condition affecting boys in which there is hyperplasia of the glandular tissue of the breast- resulting in enlargement of one or both breasts
• Boys may notice a small, firm, tender mass under on or both nipples which eventually flatten out- the tenderness is only temporary and will go with time
