Endocrine Flashcards
What should the value of Serum Osmolality be?
290mOSm/kg
what should the value of urine osmolality be?
500-800mOsm/kg. Typically 1-3x serum osmolality.
12-24hrs fluid restriction= >850mOsm/kg
conditions that increase serum osmolality?
dehydration/sepsis/fever/burns DM (hyperglycaemia) Diabetes Insipidus Uraemia Hypernatremia Ethanol/methanol/ethylene glycol Mannitol Therapy Sweating
conditions that decrease serum osmolality?
excess hydration
hyponaetremia
syndrome of inapproproate ADH secretion
conditions that increases urine osmolality?
dehydration syndrome of inappropriate ADH secretion adrenal insufficiency glycosuria hypernateamia high protein diet
conditions that decreases urine osmolality?
diabetes insipiduc
excess hydration
acute renal insufficiency
glomerulonephritis
what is myopia?
short sightedness
long eye, steep cornea, lens too weak, distance clear, near blurred
what is hyperopia?
long sightedness
small eye, flat cornea, lens too weak, distance clear, near blurred
causes of corneal clouding?
Trauma
Keratoconus
Inherited dystrophy
infection: eg bacterial/viral keratitis, contact lens keratitis
causes of cataract?
Drugs: steroid, amiodarone,chlorpromazine,gold, busulphan
Trauma: direct, radiation, electricity, glassblowers, intra-occular surgery
Metabolic: diabetes, hypoglycaemia
Acquired: Senile, atopic
Presenile: myotonia dystrophy, NF2, retinitis pigmentosa
Congential: inherited, infective trisomy 3, metabolic
Inflammation
What is retinitis Pigmentosa?
Rare inherited disorder
Black Pigment on the retina
typically presents with tunnel vision and night blindness
What are the red flags for retinal detachment?
Floaters, loss of field vision and flashing lights.
Urgent surgical repair if macula is on.
What are the causes of retinal detachment?
Rhegmatogenous: break in retina+ vitreous liquification allows fluid to enter the sub-retinal space and seperate. Worse if superior.
Tractional: contracting, retinal membranes, abnormal adhesions and vitreous changes.
Exudatitve: damage to outer blood-retinal barrier allowing fluid into sub-retinal space.
What are the causes of retinal central vascular occlusion?
Atherosclerosis
`hyperviscoisty
vasculitis
glaucoma
What are the signs of central artery occlusion?
Cherry red spot
Embolic
Tx unsatiactory if <4hrs
exclude giant cell artiritis
TIA referal and Aspirin
Important differential for painless loss of unilateral vision?
Temporal Artiritis- Anterior Ischaemic Optic Neuropathay
Need to do ESR
Can go blind bilaterally within 10 days
Hypertensive retinopathy:
causes?
Signs?
arteriolar constriction
areriolosclerosis
signs: flame shaped retinal haemorrhage, cotton wool spots and macular stars
disc oedema
Explain the pathophysiology of diabetic retinopathy?
MACULOPATHY (M0-M1)= focal, diffuse oedema, ischamia caused by leakages from microaneurysms, exudates, loss of central vision
RETINOPATH& (R0-R1= pre-proliferative, R2-R3= proliferative).
microvascular occlusions= hypoxia= release of VEGF= new vessel stimulation.
New vessels are poor leading to vitreous haemorrhage + tractional retinal detachment. The new vessels i the iridocorneal angle= glaucoma.
How to you treat diabetic retinopathy?
OCCULAR: laser- prevents leakage and decreases retinal ischaemia
SYSTEMIC: good diabetic and HTN control stop smoking reduce weight and increase exercise Tx anaemia and renal disease ACE inhibitors and Statins
What is open angle glaucoma?
acquired optic neuropathy associated w/ raised IOP, characteristic pattern of field loss (arculate defect within central 30 degrees) and appearance of the optic disc (progressive disc cupping). Develops slowly over time and is painless.
What causes open angle glaucoma?
Raised pressure to due blocakge of outflow through the trabacular. open vs closed angle and primary vs secondary
Treatment of glaucoma?
Reduce the IO pressure
95% medically with drops
laser/selective trabeculoplasty
Signs of acute angle closure glaucoma?
Red Painfu Eye
Halos
reduced vision
unresponsive semi dialted pupil (from ischaemia)
Cause of acute angle closure glaucoma?
shallow AC
closed iridocorneal angle + rapid increase in IOP
Treatment of acute angle closure glaucoma?
Admit
systemic acetazolamide
miotics
laser- periperal iridotomies/ cataract removal.
