MET3 Revision: Diabetes II Flashcards
Describe why diabetic complications occur [3]
Long term exposure to hyperglycaemia:
- causes mircroaneurysms and venous beading (where the walls of the veins are no longer straight and parallel and look more like a string of beads or sausages)
- vessel closure: hypoxia & nutrients decreased
- vessel permeability: damaged vessels dilate and leak
Which is the strongest risk factor for diabetic complications? [1]
Name 3 others [3]
1st: Smoking
2nd: HTN
3rd: Dysplidaemia
4th: Hyperglycaemia
Describe the pathophysiology of diabetic retinopathy [3]
Chronic hyperglycemia causes:
- basement membrane thickening
- loss of pericytes
- endothelial cell damage in retinal blood vessels (microaneurysms & venous beeding
Describe the three classifications of diabetic retinopathy? [2]
non-proliferative diabetic retinopathy (NPDR) marked by:
- microaneurysms
- retinal haemorrhages (dot haemorrhages)
- hard exudates (yellowish deposits of lipid due to vessel leakage)
proliferative diabetic retinopathy (PDR) (more advanced and severe stage), is characterized by:
- the proliferation of new, fragile blood vessels that can bleed into the vitreous, leading to vision loss due to VEGF upregulation
- can be new vessels on disc (NVD) OR new vessels everywhere (NVE)
Diabetic maculopathy:
- Presence of any retinopathy within 1 disc diameter around macula:
Can be:
- Focal
- Diffuse
- Ischaemic
How can you prevent diabetic retinopathy? [3]
Good BP control - most important
Good glycaemic control
Annual screening
What does this yellow arrow depict in non-proliferative diabetic retinopathy? [1]
Hard exudates
What does the yellow arrow on the image of non-proliferative retinopathy depict? [1]
Lipid exudates
Describe what the arrows & circle depict on this image of non proliferative diabetic retinopathy [3]
intraretinal microvascular abnormality (IRMA; green arrow)
venous beading and segmentation (blue arrow)
cluster haemorrhage (red circle)
featureless retina suggestive of capillary non-perfusion (white ellipse)
How can PDR lead to blindness? [4]
- New blood vessels are very fragile; easily break and leak
- Retinal haemorrhage can lead to acute blindness
- If repeated; leads to fibrosis & scarring
- Can lead to: tractional retinal detachment: when scar tissue or other tissue grows on your retina and pulls it away from the layer underneath
Which pathology is depicted? [1]
Diabetic maculopathy: hard exudates near to the macula
What is depicted in this image? [1]
Proliferative diabetic retinopathy:
extensive vitreous haemorrhage obscuring most of fundus (white circle)}
What is the management of diabetic retinopathy? [5]
Laser photocoagulation
Anti-VEGF medications such as ranibizumab, bevacizumab & Aflibercept
Vitreoretinal surgery (keyhole surgery on the eye) may be required in severe disease or a vitrectomy may be necessary to clear severe vitreous hemorrhage or to relieve tractional retinal detachment.
Corticosteroids: (triamcinolone, dexamethasone implant) can also be used, particularly in refractory DME.
Pan-retinal photocoagulation (PRP): laser used to make small burns evenly across the peripheral retina - should make blood vessels shrink and dissapear
What are the different types of diabetic neuropathy? [5]
- Periperal sensory neuropathy
- Autonomic neuropathy
- Proximal motor neuropathy (amyotrophy; femoral nerve neuropathy - severe pain in anterior thigh & quadricep wasting)
- Cranial nerve palsies (CN III, VI & VII)
- Median nerve / Carpal tunnel syndrome
Which cranial nerves are particularly effected by diabetes? [3]
Cranial nerve palsies: CN III, VI & VII
Describe the treatment regime for diabetic peripheral neuropathy [4]
What are two additonal therapies if these don’t work? [2]
first-line treatment: amitriptyline, duloxetine, gabapentin or pregabalin
if the first-line drug treatment does not work try one of the other 3 drugs
tramadol may be used as ‘rescue therapy’ for exacerbations of neuropathic pain
topical capsaicin may be used for localised neuropathic pain
pain management clinics may be useful in patients with resistant problem
Describe the effects of diabetic autonomic neuropathy on genito-urinary [2]; GI [3] & CV [1] systems
Genito-urinary
- ED
- Atonic bladder: difficulty voiding / urinary incontinence
Gastrointestinal [3]:
- Gastroparesis: stomach doesn’t empty properly, causing outflow problems: recurrent vomiting & early satiety
- Chronic constipation & diarrhoea
- Gustatory sweating: severe sweating on eating
CV [1]:
- Postural hypotension
What is the clinical presentation triad of diabetic nephropathy? [3]
Hypertension
Albuminuria
Decline renal function
What does the green arrows point to? [1]
Kimmelstein-Wilson lesion
Describe the pathophysiology of diabetic nephropathy [4]
Oxidative stress consumes nitric oxide, which prevents flow-mediated dilation of blood vessels (endothelial dysfunction): subjecting the endothelium to injury
Leads to production of cytokines, acceleration of inflammation, worsening of blood vessel rigidity due to atherosclerosis, and further impairment of FMD and susceptibility to oxidative stress.
Platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) mediate mesangial expansion and fibrosis via the stimulation of matrix protein (collagen and fibronectin) synthesis and decreased matrix degradation
Angiotensin II (ATII), elevated in DKD, constricts the efferent arteriole in the glomerulus, causing high glomerular capillary pressures, and also stimulates fibrosis and glomerular inflammation
How do you screen for microalbuminuria for suspected diabetic nephropathy patients? [2]
Measure urine albumin:creatinine ratio (ACR):
- Normal is < 2.5mg/mmol men; < 3.5 mg/mmol in women
- If evelated repeated x2: 2/3 positive microalbuminuria present
- (can be elevated by meat; running)
Describe the treatment regime for nephropathy (have microalbuminuria) [7]
Control BP:
- ACE inhibitor: captopril; elanapril; lisinopril; ramipril
- ARB if ACE inhibitor not tolerated; losartan; valsartan
- Add calcium-channel blocker amlodopine; felopdipine; nifedipine and/or thiazide-like diuretic: hydrochlorothiazide; and/or beta-blocker carvedilol; metaprolol
Optomise blood glucose control
Manage CV risk factors aggressivey
Manage lipid levels: atorvostatin
Stop metformin when eGFR < 30 mls/min
Refer to specialist if eGFR < 45 mls/min
Renal transplant if giving pancreatic transplant
When should you stop prescribing metformin a patient suffering from diabetic nephropathy? [1]
Stop metformin when eGFR < 30 mls/min
Refer to specialist if eGFR < 45 mls/min
What are common skin presentations of diabetes? [6]
- Oral / genital candidiasis
- Skin abcesses
- Rhinocerebral mucormycosis infection
- Fungal nail infections
- Aconthosis nigricans (sign of insulin resistance)
- Bullosis Diabeticorum (blisterng)
- Granuloma annulare
- Necrobiosis Lipoidica Diabeticorum (pink skin lesion on lower legs)
What is this skin condition associated with diabetes? [1]
Necrobiosis Lipoidica Diabeticorum
What is the name of this skin complication of diabetes? [1]
Granuloma annulare