Endocrine disorders

Question 1

Diabetes mellitus

Answer 1

Chronic
Interferes with carbohydrate, fat and protein metabolism
5-10% of population affected
Systemic disease

Question 2

Type 1

Answer 2

Aka insulin dependent, requires injections
1/10 Px
Autoimmune
Destruction of beta cells in pancreas
Triggered by viral infections (e.g., mumps)
Without active beta population no insulin can be released when glucose levels rise
With no glucose to bind to GLUT-4 glucose transporter stays in cytoplasm + doesn’t insert into plasma membrane
Without insertion of GLUT-4, glucose stays in blood- hyperglycaemia

Question 3

Type 2

Answer 3

Related to diet, lifestyle and obesity
Become resistant to insulin
Interferes with binding to receptors
Like type 1- without insulin GLUT-4 cannot be inserted into plasma membrane + glucose cannot enter cells - hyperglycaemia
9/10 cases

Question 4

Gestational diabetes

Answer 4

4% of pregnant women
High levels of placental hormone
Overall does not affect health of mother but excess glucose can cross placenta leading to increased fat deposition in foetus + high birth weight (often require assisted delivery)
Mothers have high chance of developing type 2

Question 5

Diagnosis of diabetes

Answer 5

OGTT- oral glucose tolerance test
Take fasting blood glucose levels, ask them to drink fixed amount of glucose, measure blood glucose concentration over 2 hour period
Healthy fasting- below 5.6 mol/l
Diabetic fasting is much higher than and remains high following consumption

Question 6

Polyuria

Answer 6

Increased urine output, osmotic pull due to glucose dissolving in water

Question 7

Glycosuria

Answer 7

Excess glucose overspills into urine (too much reabsorbed back into blood)

Question 8

Polydipsia

Answer 8

Excessive thirst
Blood becomes progressively more concentrated, hypothalamus detects higher plasma concentration
Thirst centres activated

Question 9

Ketoacidosis

Answer 9

Unable to take up glucose, body in state of starvation, stimulates cortisol production from adrenal cortex
Cortisol promotes breakdown of fat to provide energy for cells
This can produce ketones which is an alternate energy source for metabolism
Ketones are acidic, lower pH potentially leading to ketoacidosis and coma- medical emergency

Question 10

Associated pathologies- peripheral vascular disease

Answer 10

Can damage endothelial lining of blood vessels triggering fatty plaque deposition on vessel walls (atherosclerotic occlusion)
Leads to poor blood flow down arms and legs
PVD often revealed through P in calves during exercise
Claudication + P caused by poor blood flow, depriving calf muscles of oxygen forcing them into anaerobic respiration –> lactic acid

Question 11

Associated pathologies- diabetic foot

Answer 11

Diabetics highly susceptible to atherosclerotic occlusion which reduces blood flow to feet
Each nerve in foot has its own capillary supply
Atherosclerotic occlusion down major arteries of legs lead to poor perfusion of nerve fibres, gradually causing atrophy
Causes peripheral neuropathy aka lack of sensation
Particularly dangerous as Px may not notice injuries
Injuries provide route for pathogens to enter

Question 12

Autonomic neuropathy

Answer 12

Soles of feet have large number of sweat glands, necessary due to thick skin
Each sweat gland innervated by autonomic nerve fibre which is part of sympathetic branch of autonomic nervous system
If nerve fibre atrophy occurs due to neuropathy, skin of foot can no longer produce sweat and will dry out and crack
Cracked skin= entry route for pathogens

Question 13

Infection + inflammation

Answer 13

If loss of skin integrity skin-borne bacteria can access and cause infections such as cellulitis (inflammation of dermis of skin)
Infection in foot of Px with diabetes can progress quickly because excess sugar acts as substrate for bacterial replication
Infections cause inflammatory response where phagocytic leukocytes (e.g., neutrophils) migrate into infected skin and degranulate releasing digestive enzymes
Kills pathogens and can break down tissue, leading to maceration (break down) and ulceration

Question 14

Atherosclerotic occlusion of coronary arteries

Answer 14

Rapid occlusion if not dealt with efficiently
Can result in coronary artery disease
Associated with chest P due to poor blood supply to myocardium (angina)
In Px with sensory neuropathy chest P may not be present, even when arteries are occluded (silent angina)
If fatty plaque occluding arteries ruptures it can cause thrombosis resulting in myocardial infarction, which is most common cause of death in diabetics

Question 15

Diabetic nephropathy

Answer 15

Excess sugar in blood can damage filtration membrane in nephron
Rapidly reduces renal function, leads to failure
High molecular weight plasma proteins pass into renal filtrate before eventually collecting in urine
Presence of protein in urine can provide early renal injury warning

Question 16

Diabetic eye- retinopathy

Answer 16

Diabetes leading cause of blindness in UK
Chronic hyperglycaemia prone to diabetic retinopathy
Abnormal growth of blood vessels in retina
Vessels often leak resulting in accumulation of damaging exudates in retina
Px may experience dark spots which appear in field view and can gradually expand and join up leading to progressive blindness

Question 17

Diabetic cataracts

Answer 17

Poor glycemic control can also damage lenses of eyes leading to clouding and cataract formation

Question 18

Opportunistic infection

Answer 18

Presence of excess sugar in blood and bodily secretions such as mucus, provides ideal substrate for micro-organism growth
Px with diabetes very prone to bacterial and fungal infections