Ch 25 - Endocrine & metabolic disorders Flashcards
Classification of Diabetes:
Type 1, 2, 3, 4
- Autoimmune B cell destruction > insulin deficiency (miost childhood diabetes)
- Insulin resistance which eventually leads to b cell failure; usually obesity related, +ve FH, Indians
- Other specific types e.g. MODY (genetic defect in B-cell function due to glucokinase or TF mutations), genetic insulin defects, infections, drugs etc.
- GDM
DM features (3)
- polyuria + polydipsia
- weight loss
- DKA
DM Ix (4)
- Random blood sugar > 11.1
- Fasting blood sugar > 7
- Raised HbA1c
- Signs of IR e.g. acanthosis nigricans (dark velvety skin on neck and armpits)
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DM: management (always education 1st): insulin types (2), admin (2), regimens (2)
Insulin:
- Short acting soluble human insulin e.g. actrapid, Humulin S, novorapid (before meals)
- Intermediate acting e.g. insulatard, humulin I
- Long acting e.g. Lantus
Admin:
- subcut > rotate sites to prevent lipoatrophy
- insulin pumps
Regimens:
- twice daily: mixed in morning & evening (short + intermediate)
- Thrice daily: long acting at night, mixed in morning, short in evening
DKA: features (5), management (4)
Features:
- dehydration, vomiting
- sweet smelling breath
- abdo pain
- Kussmaul breathing - due to acidosis
- coma/ shock
Management:
Admit > IV 0.9% saline 10ml/kg (not 20 because of risk of cerebral oedema) + insulin infusion + potassium
Re-establish oral fluids + subcut insulin + treat underlying cause
Hypoglycaemia: features (4), Rx (3)
<4 mmol/l:
- hunger, stomache ache, sweatiness, faintess, ‘wobbly legs’
- pallor, irritability, seizures
Rx:
- glucose tabs/ sugary drink if severe give IM glucagon
- Then give complex carb e.g. biscuit/ sandwich
Causes of hypoglycaemia (4)
insulin excess:
- e.g. DM
- insulinoma
without hyperinsulinaemia:
- ketotic hypoglycaemia of childhood (due to short period of starvation)
- in born errors of metabolism e.g. glycogen storage disorder
- hormonal def e.g. low GH, low ACTH, CAH, Addison
Ix of hypoglycaemia (4), management (2)
GH, IGF-1, cortisol, insulin, C-peptide, ketones, lactate, pyruvate
Rx:
- IV 10% dextrose slowly (prevent cerebral oedema)
- if fail to respond > IM glucagon
Congenital hypothyroidism: causes (4), features (5), Ix (1), Rx (1)
Causes: agenesis/maldescent, dyshormonegenesis, idodine def, TSH def
Features: hoarse cry, goitre, coarse facies, cool peripheries, constipation, macroglossia, jaundice
Ix: Guthrie test (raised TSH)
Rx: T4
Hyperthyroidism: cause (1), features, Ix (2), Rx (4)
Cause - graves
F - similar to adults; exopthalmus less common
Ix - raised T4/3, low TSH, anti-TPO/ TG abs
Rx:
- propyluracil/ carbimazole
- BB
- thyroidectomy
- radioidoine
Hypoparathyroidism: main cause in infants (1), chilren (1)
Pseudohypoparathyroidism: serum Ca/PO4 & PTH (high/low or normal), features (4)
Pseduopseudohypoparathyroidism: serum Ca/PO4 & PTH (high/low or normal)
Usually due to DiGeorge in infants & Addisons in children (high Ca low PO4 > spasms fits, diarrhoea)
Pseudo - end organ resistance to PTH (mutation in signaling molecule) > serum Ca/ PO4 abnormal, PTH may be normal/high. Features include: short stature, obesity, subcut nodules, short 4th/5th metacarpals.
Pseudopseudo - clin features of pseudoHPT, but Ca/PO4/PTH all normal
Rx of Hypocalcaemia (3)
- Iv 10% Ca gluconate
- oral Ca
- high dose vit D
Hyperparathyroidism features (4), Rx (3)
F: constipation, lethargy, anorexia, polyuria, polydipsia, bony phalange erosions
Rx - bisphosphonates, rehydration, diuretics
Adrenal cortical insufficiency: causes (3), features (5)
CAH, Addisons, hypopituitarism
Features
- salt losing crisis
- hypotension
- hypoglycaemia
- chronic ill health + pigmentation
- undescended testicle - CAH
Adrenal cortical insufficency: Ix ( 5), Rx (4)
Hyponatremia, hyperkalaemia, acidosis, hypoglycaemia
Low plasma cortisol, high plasma ACTH (unless hypopituitarism), SynACTHen test - plasma cortisol remains low
Rx: crisis > IV saline + glucose + glucocorticoid + mineralocorticoid
Cushing syndrome: Causes (3), features (5), Ix (3), Rx (3)
C:
- long term glucocorticoids e.g. for asthma/ nephrotic syndrome
- pituitary adenoma
- ectopic tumours
- adrenocortical tumour
F: short stature, obesity, striate, HTN, bruishing, mypoathy, osteopenia
Ix:
- 24hr urinary free cortisol high
- high dose Dex suppression failure
- CT/ MRI
Rx:
- unilateral adrenalectomy
- radiotherapy
- transphenoidal resection
PKU: cause (1), features (4), Rx (1)
Cause: deficiency in phenylalanine hydroxylase
F: usually picked up in guithrie test; else present within 1st year with developmental delay, musty odour, usually blue-eyed fair haired, seizures, eczema
Rx - restriction of dietary phenylalanine (but enough to ensure neuro development)
Homocystinuria: cause (1), features (5), Rx (2)
Cause - cystathionine synthetase def; which results in failure of methionine metabolism > homocysteine accumulation
F - developmental delay, ocular lens subluxation (ectopia lentis), LD, psych disorders, convulsions, marfanoid habitus, thromboembolic episodes, malar flush
Rx: pyridoxine (50% respond) if not > low methionine diet + supplement with cysteine + betanine
Tyrosinaemia (type 1): cause, features (2), Rx (2)
Cause - autosomal recessive def in fumarylacetoacetase
F - accumulation of toxic metabolites > liver failure + renal damage > Fanconi syndrome
Rx - NTBC (a drug) which inhbitis enzyme that catabolizes tyrosine so must have a low tyrosine & phenylalanine diet
Galactosaemia: definition, features (5), rx(1)
D - Gal-1-PUT deficiency - essential for galactose metabolism
F - so when lactose-containing milk feeds introduced affected infants feed poorly, vomit, develop jaundice, hepatosplenomegaly & liver failure. Cataracts if untreated. LDs even if treated early
M - lactose + galactose free diet for life
Familial hypercholesterolaemia: definition, features (3), Ix (1), Rx (2)
D - autosomal dominant disorder due to LDL receptor defect
F - xanthomata on skin + tendon; CHD by 50-60, if homozygous CVD in 2nd decade
Ix - serum cholesterol > 3.3
Rx - statins if LDL high + FH of CVD; fibrates
What is Glycogen storage disorder
Recessive disorder whih have specific enzyme defects that prevent mobilization of glucose from glycogen > resulting in abnormal accumulation of glycogen in liver and/or muslce.
Glycogen storage disorders: type 1, 2, 3, 5
Type 1 (von Gierke): G6P deficiency > enlarged liver and kidneys (which causes truncal obesity), growth failure, hypoglycaemia, doll facies, hypotrophic muscles (good prognosis)
Type 2 (pompe): lysosomal alpha glucosidase def: hypotonia, cardiomegaly, death from HF. Can be management with enzyme replacement myzozyme
Type 3 (cori): amylo 1,6 glucosidase def: milder features of type 1. managed with high protein diet to prevent growth retardation
Type 5 (mcardle): presentas in childhood, temp weakness, muscle cramps post-exercise, myoglobulinuria
