Microvascular Complications of Diabetes Flashcards
Macrovascular complications of diabetes?
- Ischaemic heart disease
* Cerebrovascular disease, i.e: stroke
Microvascular complications of diabetes?
Neuropathy
Nephropathy
Retinopathy
Other chronic complications of diabetes?
- Cognitive dysfunction/diabetes
- Erectile dysfunction
- Psychiatric
Types of neuropathy and symptoms of each?
Peripheral (sensory) neuropathy, e.g: pain/loss of sensation in hands and feet
Autonomic neuropathy, e.g: changes in bowel, bladder function, sexual response, sweating, heart rate and BP
Proximal neuropathy, e.g: pain in the thighs, hip or buttocks leading to weakness in the legs (AKA Diabetic Amyotrophy)
Focal neuropathy, e.g: sudden weakness in one nerve/group of nerves causing muscle weakness or pain, e.g: carpal tunnel, ulnar mono neuropathy, foot drop, Bell’s palsy, cranial nerve palsy
Risk factors for neuropathy?
- Increased length of diabetes
- Poor glycaemic control
- T1DM (higher risk than T2DM)
- High cholesterol/lipids
- Smoking
- Alcohol
- Inherited traits, i.e: genes
- Mechanical injury
Signs of peripheral neuropathy?
- Numbness/insensitivity
- Tingling/burning that is worse at night
- Sharp pain or cramps
- Sensitivity to touch
- Loss of balance and coordination
Complications of peripheral neuropathy?
- Charcot foot (progressive degeneration and destruction of a weight-bearing joint, e.g: tarsal/metatarsals, and could lead to amputation; signs include a hot, red foot that that mimics cellulitis but does not respond to antibiotics
- Painless trauma
- Foot ulcers (painless)
Treatment options for painful neuropathy?
Combinations are not recommended and the doses are titrated up as required:
• Amitriptyline
• Duloxetine
• Gabapentin
• Pregablin
Choose based on patient preference and co-morbidites, e.g: depression
If there is localised pain and patient wishes to avoid/cannot tolerate oral drugs:
• Topical Capsaicin cream
Signs of peripheral neuropathy in relation to the part of the nervous system affected?
Autonomic (supplies sweat glands) - dry feet that crack
Sensory - loss of sensation in a stocking distribution, i.e: spreads upwards, rather than in a dermatomal distribution
Motor - loss of lateral arch and development of clawed foot (dorsiflexors take over) changes pressure so painless foot ulcers develop
Signs of focal neuropathy?
Occur suddenly and affect specific nerve, often the head, torso or leg: • Inability to focus eye • Double vision • Aching behind the eye • Bell's palsy • Pain in thigh/chest/lower back/pelvis • Pain on outside of the foot
What is entrapment neuropathy?
Weakness in one nerve/group of nerves causing muscle weakness or pain, e.g: carpal tunnel syndrome
These are not specific to diabetes but are more common
Other names for proximal neuropathy?
- Lumbosacral plexus neuropathy
- Femoral neuropathy
- Diabetic amyotrophy
Development of proximal neuropathy?
Starts with pain in the thighs, hips, buttocks or legs, usually on ONE SIDE of the body
Atrophy of the proximal muscle may be seen
Occurrence of proximal neuropathy?
Tends to be in elderly people, often with marked assoc. weight loss
Effects of autonomic neuropathy?
Affects nerves that regulate HR and BP as well as control of internal organs, e.g: those inv. in gastric motility, respiratory function, urination, sexual function and vision
Effects of autonomic neuropathy on the digestive system?
Gastric slowing/frequency:
• Constipation
• Diarrhoea
• Or both sometimes
Gastroparesis (slow stomach emptying due to affected vagus nerve to the stomach)
Oesophagus nerve damage:
• Dysphagia can cause weight loss
Symptoms of gastroparesis?
- Persistent nausea and vomiting
- Bloating
- Loss of appetite
- Bad taste in mouth
- BG levels can fluctuate, due to abnormal food digestion
Treatment of gastroparesis?
- Improve glycaemic control
- Diet alterations - smaller- more frequent food portions that are low in fat and low in fibre; if severe, may require liquid meals
- Pro-motility drugs
- Anti-emetic drugs
- Treatment for abdominal pain
- Botulimin toxin (to loosen the LOS)
- Gastric pacemaker
Why is fat intake reduced in gastroparesis?
Fat slows digestion
Examples of pro-motility drugs?
Metoclopramide, domperidone and erythromycin
Examples of anti-emetic drugs?
Prochloperazine and serotonin antagonists, such as ondansetron
Drugs that can treat abdominal pain in gastroparesis?
NSAIDs, low-dose tricyclic antidepressants, gabapentin, tramadol and fentanyl
Effect of autonomic neuropathy on sweat glands?
Hyperhidrosis (excessive sweat) - profuse sweating at night or while eating, i.e: gustatory sweating
Anhidrosis (no sweat)
Body cannot regulate temperature
Treatment of sweat gland problems in autonomic neuropathy?
- Topical glycopyrollate
- Clonidine
- Botulinim toxin
Cardiovascular effects of autonomic neuropathy?
Nerve damage interferes with the ability to control BP and HR, i.e:
• Postural hypotension
• HR may be high, instead of rising and falling in response to normal body functions and physical activity
Effects of autonomic neuropathy on the eyes?
Pupils are less responsive to light changes, so patient may not see well when a light is turned on or may have trouble driving at night
Tools to diagnosis neuropathy?
Nerve conduction studies or EMG (determine type and extent of nerve damage and how well muscles respond)
Heart rate variability (show how heart responds to deep breathing and changes in BP and posture)
Ultrasound of the bladder and other parts of the urinary tract (check if bladder empties completely after urination)
Gastric emptying studies (for gastroparesis)
What is diabetic nephropathy?
Progressive kidney disease cause by damage to the capillaries of the glomeruli
Characterised by:
• Nephrotic syndrome
• Diffuse scarring of the glomeruli (AKA Kimmelsteil-Wilson Syndrome or nodular glomerulosclerosis)
• Microvascular changes in the capillaries
Consequences of diabetic nephropathy?
- Hypertension
- Decline in renal function
- Accelerated vascular disease means that most people with this die from CV events
How to screen for nephropathy?
Urinalysis only detects macroalbuminaemia
Urinary Albumin : Creatinine ratio (ACR) screens for microalbuminaemia:
• Screen all patients 12 and over at diagnosis and annually
• Can use random rather than 1st pass urine sample as initial check
• Confirm abnormal result with EMU
• Also, do U&Es (eGFR)
What are the approximate equivalents between urine ACR and other measures of protein excretion?
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Steps after checking for microalbuminuria?
Monitor serum creatinine and Ix other causes of renal pathology
Screen for ischaemic heart disease, PVD and hypertension; assess fasting lipid profile
Tighten glycaemic control
Discourage smoking
Risk factors for nephropathy progression?
- Hypertension, cholesterol and glycaemic control
- Smoking
- Albuminuria
Recommendations for treatment of hypertension in diabetic nephropathy?
BP should be maintained <130/80 mmHg in all diabetics (SIGN target 130/70 mmHg)
Patients with microalbuminuria or proteinuria should commence on an ACEI or ARB
Recommendation for glycaemic control to reduce risk of diabetic nephropathy?
Good glycaemic control (HbA1c 53 mmol/mol) should be maintained
Drugs used in diabetic nephropathy?
Have to alter doses or stop drugs altogether, to prevent drug toxicity
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Eye problems in diabetics?
Diabetic retinopathy
Cataract (clouding of the lens - develops earlier in diabetics)
Glaucoma (increase in fluid pressure in the eye causes optic nerve damage - 2x more common in diabetes)
Acute hyperglycaemia can cause reversible visual blurring (osmotic effect on the eye)
Normal retina image?
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Stages of retinopathy?
- Mild non-proliferative (background)
- Moderate non-proliferative
- Severe non-proliferative
- Proliferative
Gross abnormalities that can be seen on the retina with retinopathy?
Haemorrhage:
• Dot
• Blot
• Flame
Cotton wool spots - ischaemic areas
Hard exudates - white spots that are lipid break down products
IRMA (Intra-retinal microvascular abnormalities) - abnormalities of blood vessels/precursor to neovascularisation but blood vessels are patents (do not leak)
Difference between retinopathy and maculopathy?
Maculopathy is damage to the macula, not to the retina
They are both graded separately
Signs of mild background retinopathy?
Haemorrhages and microaneurysms only
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Signs of pre-proliferative retinopathy?
Microaneurysms, hard exudates and haemorrhages
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Signs of severe non-proliferative retinopathy?
IRMA, venous bleeding and haemorrhages
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Signs of severe proliferative retinopathy?
New vessel formation - look life tangled branches
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Other eye problems in diabetics?
Pre-retinal fibrosis +/e tranction retinal detachment
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Signs of retinal bleeding (from fragile new vessels)?
Sudden change in vision and floaters; looks boat-like and requires urgent referral
Other complications of retinopathy?
Secondary glaucoma
Retinal detachment
Ix for maculopathy?
Optical coherence tomography
Treatment of retinopathy?
Laser
Vitrectomy
Anti-VEGF injections
Occurrence of erectile dysfunction in diabetes?
At least 50% of all diabetic men
Causes of erectile dysfunction in diabetes?
Vascular disease and neuropathy
Other causes of ED?
Chronic renal failure, hepatic failure
MS
Severe depression
Others, e.g: vascular disease, low HDL, high cholesterol and hormonal deficiency
Spinal cord injuries
Pelvic and urogenital surgery and radiation
Substance abuse, alcohol (>600 ml/week) and smoking (amplifies other risk factors)
Medications
Bicycle riding
Medications that can cause erectile dysfunction?
Anti-hypertensive drugs (all are capable but common causes are thiazides and beta-blockers; uncommon is CCBs, ACEIs)
CNS drugs, e.g: antidepressants, tricyclics, SSRIs, tranquilisers, sedatives and analgesics
Mx of erectile dysfunction in diabetes?
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Annual screening in diabetes?
For all diabetic patients, i.e: eyes, feet and kidneys (ACR and U&Es)
How to substantially reduce risk of complications in diabetes?
Good blood glycaemic control, BP control and blood lipid control
