Diabetic Complications

Question 1

What is diabetic nephropathy

Answer 1

Progressive kidney disease caused by damage to capillaries in the glomeruli (nodular glomerulosclerosis)

Question 2

How is diabetic nephropathy characterised

Answer 2

Proteinuria
Diffuse scaring of glomeruli
Damage to capillaries in glomeruli

Question 3

Diabetic nephropathy investigations

Answer 3

Albumin:creatinine ratio & urine dipstick

If ACR <30 or PCR <50 = microalbuminuria
1. Repeat twice as false positive readings are common
2. Established microalbuminuria if 2/3 positive
3. Microalbuminuria will not show as proteinuria on dipstick

If ACR >30 or PCR >50 = proteinuria (overt nephropathy)
1. Repeat on EMU
2. Proteinuria will show up on a urine dipstick

Question 4

Diabetic nephropathy/ Microalbuminuria treatment

Answer 4

Diabetes & microalbuminuria
=> ACEi (or ARB) & SGLT2i
=> Allow for 20% decline in eGFR with ACEi
(dilate renal arterioles)

Question 5

Diabetic neuropathy 4 subtypes

Answer 5

• Peripheral neuropathy & Charcot foot
• Autonomic neuropathy
• Proximal neuropathy
• Focal neuropathy

Question 6

Describe peripheral neuropathy

Answer 6

Pain/loss of feeling in feet or hands in a ‘glove & stocking’ distribution

Question 7

Diabetic peripheral neuropathy clinical features

Answer 7

• Numbness/insensitivity
• Tingling/burning
• Sharp pains or cramps
• Sensitivity to touch
• Loss of balace and coordination

Question 8

Diabetic peripheral neuropathy complications

Answer 8

Painless trauma
Charcot’s foot
Venous ulcers
Claw foot & callus formation
Argyll Robertson pupil

Question 9

What is Charcot foot - Pathophysiology & clinical presentation

Answer 9

• Well perfused foot but severe neuropathy
• Hot & swollen foot with bone destruction & deformity

Question 10

Charcot foot management

Answer 10

MRI to differentiate from infection
Non weight bearing, full contact cast/boot

Question 11

Peripheral neuropathy pain management

Answer 11

Oral Amitriptyline, duloxetine, gabapentin, pregabalin
Topical capsaicin cream

Question 12

Autonomic (diabetic) neuropathy clinical features

Answer 12

• Sweat glands - profuse sweating
• Gastroparesis - Constipation, diarrhoea, N&V, bloating
• Oesophagus - Dysphagia
• Blood pressure - postural hypotension
• Heart - constant tachycardia
• ECG - loss of RR variability (complete loss of autonomic control over cardiac function)

Question 13

Treatment of profuse sweating associated with diabetic, autonomic neuropathy

Answer 13

topical glycopyrolate, clonidine, botulium toxin

Question 14

Treatment of gastroparesis associated with diabetic, autonomic neuropathy

Answer 14

• Conservative (diet, analgesia)
• Promotility drugs (metoclopramide)
• Anti-nausea drugs (procholrperazine/ ondansetron)
• Severe cases (Botox, gastric pacemaker)

Question 15

What cause proximal neuropathy in diabetic patients

Answer 15

Damage of nerves of the lumbosacral plexus

Question 16

Diabetic retinopathy pathophysiology

Answer 16

Hyperglycaemia =>
oxidative stress & inflammation =>

Vessels supplying retina dilate =>
microaneurysms & small haemorrhages

Increased vascular permeability & leakage =>
hard exudates

Retina oxygen starvation =>
Cotton wool spots

VEGF release =>
Neovascularisation

Neovascularisation in vitreous humor & retinal traction =>
Vitreous haemorrhage =>
Vision loss

Question 17

Diabetic retinopathy investigations

Answer 17

Fundoscopy - diabetic retinopathy
Optical coherence tomography - maculopathy
Fluorescein angiography - severe disease, neovascularisation

Question 18

Diabetic retinopathy grading

Answer 18

Micro-aneurysms & dot haemorrhages
(mild non proliferative DR)

+ Blot haemorrhages, hard exudates & cotton wool spots
(moderate non proliferative DR)

+ Beaded veins, IRMA, extensive retinal haemorrhage
(severe non proliferative DR )

+ Neovascularisation, fibrous proliferation of vitreous/retina
(proliferative DR)

Question 19

Diabetic maculopathy grading

Answer 19

Mild-moderate maculopathy - hard exudates within 1-2 discs diameter of fovea

Severe maculopathy - hard exudates or blot haemorrhages within less than 1 disc diameter of fovea

Question 20

Diabetic eye management

Answer 20

• Severe NPDR or PDR - Laser panretinal photocoagulation
• Vitreal haemorrhage - Vitrectomy
• Macular oedema & retinal traction - Vitrectomy
• Macular oedema - Anti-VEGF agents intra-vitreal injections
• Clinically significant macular oedema - Focal macular laser

Question 21

Panretinal photocoagulation laser risks

Answer 21

Peripheral vision loss
Night vision loss
Macular oedema

Question 22

Name three other eye pathologies other than retinopathy & maculopathy that are associated with diabetes

Answer 22

Cataract (lens clouding)
Glaucoma (optic nerve damage)
Reversible visual blurring in hyperglycaemic episodes

Question 23

What three screening tests are carried out annually for all diabetic patients

Answer 23

• Digital retinal screening
• Foot risk assessment
• Urine albumin-to-creatinine ratio and serum creatinine

Question 24

Microvascular complications (nephropathy, neuropathy, retinopathy) pathophysiology

Answer 24

Mitochondria can’t keep up with glucose levels & so glucose is used in harmful pathways including….
- Formation of advanced glycation end products (AGE)
- Increased glucose through the sorbitol-polyol pathway
- Increased flux of glucose through other pathways e.g. pentose phosphate pathway

Question 25

Why is formation of advanced Glycation end products a prodoblem

Answer 25

AGEs cause tissue injury and inflammation via stimulation of pro-inflammatory factors, such as complement and cytokines

Question 26

What is the orbital-polyol pathway & why is it a problem

Answer 26

• Glucose + aldose reductase → sorbitol
• Sorbitol and fructose accumulate
• This cause changes in vascular permeability (osmotic damage), cell proliferation and capillary structure via stimulation of protein kinase C and TGF-β

Question 27

Why is the Pentose phosphate pathway a problem

Answer 27

It generates ROS