Human diseases 3 Flashcards
What is diabetes mellitus?
abnormality of glucose regulation
What is diabetes insipidous?
abnormality of renal function
What is the major characteristic of diabetes mellitus, both type 1 and 2?
hyperglycaemia
What is the intermediate zone between normal and overt diabetes called and what is it indicative of?
pre-diabetes
indicator of future diabetes development
A random plasma glucose measurement of what is diagnostic of diabetes?
> 11.1mmol/L on 2 occasions
What HbA1c measurement is diagnostic of diabetes?
> 48mmol/mol
What is HbA1c a measure of?
average blood glucose (sugar) levels for the last two to three months.
A fasting plasma glucose test can be done to investigate possible diabetes, which values are considered normal, impaired fasting glucose and diabetes?
<6.1 normal
6.1-7.0 impaired fasting glucose
>7.0 diabetes
A two hour plasma glucose test can be done to investigate diabetes, what values are considered normal, impaired glucose tolerance and diabetes?
<7.8 normal
7.8-11.1 impaired fasting glucose
>11.1 diabetes
What is Type I diabetes?
insulin deficiency
What causes the insulin deficiency in type I diabetes?
autoimmune destruction of pancreatic B cells
What is ketoacidosis?
body cells cannot access glucose for metabolism so start to metabolise fat which results in high levels of ketones causing the blood to become more acidic
What are the circulating antibodies present in Type I diabetes?
GAD - glutamic acid decarboxylase
ICA - islet cell antibodies
IAA - insulin antibodies
When is the onset of type I diabetes?
childhood/adolescence
What are the features of type I diabetes with adult onset?
LADA - late autoimmune diabetes in adults
GAD (glutamic acid decarboxylase) associated, generally low AB levels, less weight loss and less ketoacidosis
may masquerade as ‘non-obese’ type II
What are the diabetic symptoms in Type I diabetes?
polyuria
polydipsia - thirsty
tiredness
What are the characteristics of an acute presentation of Type I diabetes?
hyperglycaemia with diabetic symptoms
ketoacidosis (medical emergency)
From what point do Type I diabetics require insulin?
from diagnosis
What is type II diabetes strongly associated with?
obesity and inactivity
What is type II diabetes characterised by?
defective and delayed insulin secretion and abnormal post prandial suppression of glucagon
What kind of surgery has shown positive signs of remission in type II diabetes?
Bariatric surgery - most people go into partial or complete remission after surgery
What is the role of glucagon?
increases plasma glucose level
Collectively, the symptoms of type II diabetes are described as what?
“insulin resistance”
What are the effects of Type II diabetes?
multisystem impairment
impaired glucose tolerance
hyperinsulinaemia
hypertension
obesity with abdominal distribution
dyslipidaemia
early and accelerated atherosclerosis
What type of diabetes is hyperinsulinaemia associated with?
Type II
What medications can be linked to medication induced diabetes?
corticosteroids
immune suppressants - cyclosporin
cancer medication
antipsychotic medications - clozapine
antivirals - protease inhibitors
What other medical conditions can be linked to diabetes?
endocrine disease - Cushings, acromegaly
Pregnancy - gestational diabetes
What do Type II diabetics usually present with and is there a common FH?
present with complications
strong FH
Do type I or type II diabetics suffer from ketoacidosis?
Type I - easily get ketoacidosis
Type II - rarely get ketoacidosis
Why is the site of insulin injection often rotated around the body?
leads to fat atrophy at site used repeatedly
What are the two types of insulin regime?
1) basal-bolus more injections - better control, single long acting dose for whole day with intakes of short acting for meals and exercise
2) split-mixed fewer injections - poorer control, 2 injections per day, breakfast and tea containing rapid and med acting
In type I diabetic management what % of calories should come form saturated fat and what should they be counting in their diet?
<10% saturated fat
carbohydrate counting if on basal bolus regimen
What are the two newer T1DM insulin monitoring options?
continuous glucose monitoring - small needle attaches to skin and relays to monitor
closed loop glucose monitoring - monitor attached to insulin pump subcutaneously placed
How is type II diabetes managed?
weight loss
diet restriction - avoid CHO, high fibre diet, reduce fat
medication
surgery - bariatric surgery
What medications are used in the management of T2DM?
biguanides - ‘metformin’
gliptins
sulphonylureas
How does metformin help with T2DM management?
enhances cell sensitivity to insulin
reduces hepatic gluconeogenesis
How do gliptins work in T2DM management?
block the enzyme metabolising incretin
improves insulin response to glucose
reduces liver gluconeogenesis and delays stomach emptying
How do sulphonylureas work in T2DM management?
INCREASE pancreatic insulin secretion
can cause hypoglycaemia!
What is an acute complication of diabetes?
Hypoglycaemia
caused by insulin or sulphonylurea medications in Type II diabetes
insulin or drug without food
What are some chronic complications of diabetes?
cardiovascular risk - macrovascular changes to vessels and increased risk of atherosclerosis
infection risk
neuropathy
How does autonomic dysfunction in diabetes impact acute hypoglycaemia?
microvascular changes in nutrient supply to autonomic nerves mean they are less able to send signals, so patients get little warning when they are going to go hypo
Name a large vessel diabetic complication of diabetes
atheroma causing angina, MI, claudication, anneurysm
Name some diseases/impacts considered as diabetic complications
poor wound healing
easy wound infections
renal disease
eye disease
neuropathy - numbness
What symptoms can be seen in diabetic eye disease?
cataracts
maculopathy - lose high density cone section of retina, losing detailed vision
proliferative retinopathy - new blood vessels and scar tissue have formed on your retina, which can cause significant bleeding and lead to retinal detachment, where the retina pulls away from the back of the eye
What are the features associated with diabetic neuropathy?
general sensation - “glove and stocking” numbness
motor neuropathy - weakness and wasting of muscles
autonomic regulation - postural reflexes reduced, bladder and bowel dysfunction, less awareness of hypoglycaemia
Why is fasting before surgery an issue for type I diabetics?
need insulin to prevent ketoacidosis
need carbohydrates to prevent hypoglycaemia
What metabolic changes in surgery can cause complications with diabetes?
hormone changes aggravate diabetes
more glucose production and less muscle uptake
metabolic acidosis more likely
What are the features of bacterial conjunctivitis?
sticky, purulent discharge
bilateral, sequential
gritty, uncomfortable
What are the features of viral conjunctivitis?
watery, “streaming”
bilateral
pre-auricular lymphadenopathy
What is subconjunctival haemorrhage?
caused by a bleeding blood vessel under the conjunctiva
What are the features of subconjunctival haemorrhage?
asymptomatic, but terrifying to patient!
effectively a bruise, often spontaneous
only of concern in trauma
high bp and anticoagulants can increase incidence
What two things can increase incidence of subconjunctival haemorrhage?
anticoagulants
high blood pressure
What is a corneal ulcer?
an open sore in the outer layer of the cornea. It is often caused by corneal infection.
What are the features and causes of corneal ulcer?
very light sensitive (photophobia)
corneal inflammation
not always visible to naked eye
CONTACT LENSES - high risk
preventable blindness
URGENT (<24hrs)
Who are at high risk of corneal ulcer?
contact lense users
Is a corneal ulcer a medical issue?
Yes - risk of blindness
What does photophobia generally indicate a problem of?
problem of the cornea
What does redness of the inner lower eyelid with redness AWAY from the sclera of the eye indicate?
usually conjunctivitis
What does redness of the lower eyelid, into the sclera and in a concentrated circle round the cornea indicate?
corneal problem (which can scar) or a problem inside the eye itself
What can cause facial nerve palsy?
IANB
Parotidectomy
Damage or swelling of the facial nerve
What is the risk of facial palsy rendering a patient unable to close their eye?
if cornea dries out it can break down and cause scarring
What first aid management should be carried out following a facial nerve palsy where the eye cannot close?
tape eye closed
generous lubrication
optometrist
safety net advice
What is Bell’s phenomenon and how do you test it?
innate reflex in eye which protects cornea from damage. To test hold eyelid up and ask pt to squeeze eyes, eye should roll up.
What is peri(orbital) cellulitis?
infective oedema of the eyelids and periorbital skin (anterior portion of eye) with no involvement of the orbit
What is the most useful and important barrier to intra-orbital infection?
orbital septum
At what age does the orbital septum fully develop?
around 5-6yrs
What are the characteristics of preseptal (periorbital) cellulitis?
hot, red, swollen, tender lids
?preceding sinusitis/cold
?preceding facial injury/surgery
white eye
vision unchanged
full range of eye movements
pupil reacts normally
What is orbital cellulitis?
infection of the soft tissues of the eye socket behind the orbital septum, a thin tissue which divides the eyelid from the eye socket but not the globe
What are the characteristics of orbital cellulitis?
hot, red, swollen, tender lids
?preceding sinusitis/cold
?preceding facial injury/surgery
red, injected eye
blurred, reduced vision
eye movements restricted
sluggish pupil
What is the difference between preseptal (periorbital) cellulitis and orbital cellulitis?
Orbital cellulitis = behind the orbital septum
Preseptal cellulitis = Infection isolated anterior to the orbital septum
What are the four major questions to ask a patient with red eye?
- do you wear contact lenses?
- has vision been affected?
- appearance of the pupil
- pain?
What changes in appearance of the pupil should you look for?
round?
reactive to light compared to other side?
List the structures of the eye which light hits in order of first to last
-cornea
-anterior chamber
-lense
-vitrius
-retina
-optic nerve
Name five common eye conditions
1) Cataract
2) ARMD - Age-related macular degeneration
3) glaucoma
4) retinal detachment
5) giant cell arteritis
What is a cataract?
when the lens, a small transparent disc inside your eye, develops cloudy patches.
What are the symptoms of cataracts and how can they be treated?
gradual, painless, hazy/misty vision, near/total blindness
Phacoemulsification surgery - quick, safe, painless
What is ARMD?
Age related macular degeneration
What kind of vision is affected by ARMD?
Central vision - blurred, distorted, holes/gaps
seeing faces, reading
What are the two types of ARMD and what are their characteristics?
wet type - faster onset and progression, treatable by anti-VEGF injections
dry type - gradual, slowly progressing, no specific treatment
What is glaucoma?
condition of the optic nerve usually caused by fluid building up in the front part of the eye, which increases pressure inside the eye
What happens in glaucoma?
gradual, progressive loss of axons from the optic nerve
What are the characteristics of chronic open angle glaucoma?
peripheral vision affected first, central vision lost very late
mostly asymptomatic, painless
largely treated with pressure-lowering eyedrops, life-long
What are the characteristics of acute closed angle glaucoma?
red, painful eye, unreactive pupil, severe headache, unwell pt
What is retinal detachment?
retina becomes loose
What are the symptoms of retinal detachment?
flashing lights, floaters
“shadow in the corner of my vision”
painless, no external features on eye
Is surgery urgent in retinal detachment?
Yes - urgent surgery (<2 days) to salvage vision
What is the dental consideration of patients with retinal detachment?
NO INHALATION SEDATION
causes acute eye pressure rise and permanent sight loss
What is giant cell arteritis?
type of vasculitis (group of diseases whose main feature is inflammation of blood vessels) especially branches of external carotid artery
true medical emergency
Why is giant cell arteritis classed as a medical emergency?
can cause: possible sudden blindness in one or both eyes. Damage to blood vessels, such as an aneurysm (a ballooning blood vessel that may burst). Other disorders, including stroke or transient ischemic attacks (“mini-strokes”)
What are the symptoms of giant cell arteritis?
> 50yrs
tender scalp skin
feeling rotten
(transient) vision disturbance
jaw/tongue claudication pain
headache
losing weight
How does diabetes affect the eyes?
insulin deficiency/resistance - hyperglycaemia, sugary blood is toxic to blood vessels
diabetic retinopathy - vitreous haemorrhage, retinal detachment
maculopathy - retinal oedema
What is a diabetic vitreous haemorrhage?
main chamber of the eyeball is called the vitreous cavity and this is normally filled with a clear jelly called vitreous. If bleeding into the vitreous occurs with diabeters this is called a diabetic vitreous haemorrhage
What is diabetic retinopathy?
sugary blood damages vessels causing haemorrhage and oedema (especially at macula)
retinal ischaemia
vitreous haemorrhage, retinal detachment
What are the two main ways diabetics lose vision?
1) proliferative retinopathy - sugary blood damaging vessels causing retinal detachment and vitreous haemorrhage
2) Maculopathy (swelling) - leakage of substance into retina, retina soaks up fluid lifting it away from surface i.e. retinal detachment
What is maculopathy?
blood vessels in the part of the eye called the macula (the central area of the retina) can also become leaky or blocked
Where is the most common site of fracture maxillofacially?
floor of orbit
What are the two main questions to ask yourself when examining orbital fractures?
1) is there evidence of muscle entrapment?
2) is there evidence of orbital compartment syndrome?
What are the symptoms of an orbital fracture?
- bruising, pain, subconjunctival haemorrhage, “sunken eye” due to volume loss, periorbital oedema, double vision, infraorbital anaesthesia
Who are muscle entrapments upon orbital fracture most common in?
Children - “bend and snap”
What is the danger of muscle entrapment upon orbital fracture and what must be done to treat it?
warrants urgent surgery to prevent muscle necrosis - long term double vision if missed
oculocardiac reflex if muscle trapped - slowed heart rate, nausea/vomiting, syncope/fainting
What can cause a oculocardiac reflex and what does this reflex do?
muscle entrapment in orbital floor fracture
slowed heart rate, nausea/vomiting, syncope/fainting because muscle is stimulating parasympathetic nervous system
What is orbital compartment syndrome?
acute rise in intra-orbital pressure, and if not treated immediately, damage to the optic disc and retina will lead to irreversible vision loss. medical emergency
What is retrobulbar haemorrhage?
rapidly progressive, sight-threatening emergency that results in an accumulation of blood in the retrobulbar space
What can cause orbital compartment syndrome?
retrobulbar syndrome results in a compartment syndrome which can lead to compression or ischemia of the optic nerve, blockage of the optic nerve venous drainage, or a central retinal arterial occlusion leading to vision loss
What are the symptoms of retrobulbar haemorrhage?
severe pain, reduced vision, slow/unreactive pupil, restricted movement in all directions, large subconjunctival haemorrhage, “hard eye” compared to other
How is orbital compartment syndrome treated?
lateral canthotomy and cantholysis - emergency procedure, cut tendon to provide space and reduce eye pressure
What is hyphema?
Accumulation of red blood cells within the anterior chamber between the cornea and iris
What should be done to manage a chemical injury to the eye?
irrigate
tap water, saline
aim = prevent corneal scarring
What is worse for the eyes, acid or alkali?
alkali
Name three ways of administering respiratory drugs
1) inhalation
2) oral
3) IV
How do inhalers work?
topical to the bronchial tree, reduce systemic effects of drug
Which drugs improve ventilation by improving airway patency?
1) bronchodilators - B2 antagonist, anticholinergic
2) anti-inflammatory - corticosteroid
X
X
What drugs impair ventilation?
1) Beta blockers - make airways narrower by increasing affects of smooth muscle constriction
2) respiratory depressants - benzodiazepines (reduce ventilation rate by muscle relaxation), opioids (reduce stimulus for patient to breath)
What drug improves gas exchange?
oxygen
What are the two main modalities for inhaled drug therapy?
1) meter dose inhaler - “puffer”
2) Breath activated device - spinhaler, turbohaler
Name two aids to drug delivery in respiratory disease
1) nebuliser - uses liquid drug in small chamber, air blows through tube causing bubbling & then breathed in
2) spacer - allows pt to activate MDI into chamber and breathe through chamber
What do B2 antagonists do?
respiratory disease
relieve symptoms of bronchoconstrictions of smooth muscle
Name the two types of B2 antagonists
1) short acting - salbutamol, terbutaline (blue inhaler) “reliever drugs”
2) long acting - salmeterol (green inhaler)
What are the features of short acting B2 agonists?
- quick onset 2-3mins
- last 4-6hrs
- administration - inhaled, oral or IV
- used to TREAT acute bronchial constriction
What are the features of long acting B2 agonists?
- slow onset 1-2hrs
- last 12-15hrs
- administration - inhaled
- used to PREVENT acute bronchial constriction
What are anticholinergics and what are their purpose in respiratory medicine?
inhibit muscarinic nerve transmission in autonomic nerves, additive effect in bronchial dilatation with beta agonists and effective in reducing mucous secretion
What is an example of an anticholinergic medication and what colour of inhaler do they come in?
ipratropium
grey inhaler
How do corticosteroids function in respiratory medicine?
reduce inflammation in the bronchial walls
Name four corticosteroids used in respiratory medicine and their inhaler colours
1) beclomethasone (brown inhaler)
2) Budesonide (brown)
3) fluticosone (orange)
4) Mometasone (pink)
What does MART mean in respiratory medicine?
Maintenance and reliever therapy