12.4.1 Chronic Complications Of Diabetes Mellitus Flashcards
List chronic complications of DM
Vascular
- Microvas (type 1)
➡️ Nerves, retina, glomeruli
➡️ distinct pathogenesis
➡️ thickening of capillary basement membrane
- Macrovas (type 2)
➡️ atherosclerosis
Others
- Diabetic foot
- Infections
- GIT
- Skin
- Connective tissue and joint involvement
- Bone and mineral metabolism
Microvascular disease pathogenesis
- sensitive to injury from sustained hyperglycaemia
- This, and the body’s responses aimed to repair, accounts for tissue/ organ damage
- Affects quality and duration of PLWD Type 1/2
- All types of DM
- Improved glycemic control decreases incidence and severity of microvascular damage
- Body’s microvasculature is a diffuse target, properties differ between tissues and organs, and therefore damage/ repair differs
- Remember all organs are affected simultaneously, to lesser or more degree
- Interactions between metabolic abnormalities (hyperglycaemia, dyslipidaemia) also genetics and epigenetic modulators
Classic microvascular pathologies
- Retinopathy, nephropathy, neuropathy
- Also: brain, myocardium, skin and other tissue
Relation between A1C and Relative risk
= Glycemia
One goes up, other too
Slide 6 + 7 + 8
Risk factors for microvascular disease
- 8Glycaemic control8 - DCCT showed a 60% decrease in diabetic retinopathy, nephropathy and neuropathy in group with HbA1C < 7.2%
- Blood pressure control- decreased nephropathy and retinopathy
- Genetic susceptibility/ endogenous differences
3 factors where cells are influenced
Slide 11
- Cell signaling dysfunction
- Toxic metabolites
- Altered osmols and redox potential
Hyperglyceamia -> tissue damage -> cell tries to fix it but can’t
NB Microvascular complications classification
1. Diabetic retinopathy
Retinopathy
-Non-Proliferative
• Mild/Moderate/Severe
• Mild = microaneurysms ONLY
• Mod/Severe = anything more
- Proliferative
Cataracts (subcapsular {type 1}; sensile)
Glaucoma
{review page 13}
2. Diabetic nephropathy
- End stage diabetic nephropathy accounts for a significant proportion of ESRD pts worldwide
- Key characteristic of diabetic nephropathy = persistent proteinuria
- ~ 30 % of type 1 develop nephropathy after 15-25 years
- ~ 10% of type 2 diabetics already have proteinuria at time of diagnosis
- NB better glycaemic and BP control!
{Pathology page 17}
- microalbuminuria
3. Diabetic neuropathy
- Peripheral symmetrical sensorimotor neuropathy (common)
- Autonomic neuropathy
- Mononeuropathy (spontaneous; nerve entrapment; external pressure paralysis)
- Proximal motor neuropathy
Clinical presentations page 29
Microalbuminuria
Definition
Prognostic value
Reversible
Def
- Albumin excretion of 30 - 300 mg per 24 hours
- Not detected on routine dipstix (measures >0.5g proteinuria)
- Expressed as: albumin:creatinine ratio (mg/mmol)
- Posture, infection and exercise can give false positive results (have to repeat test before diagnosis)
Prognostic value
- predictor of developing nephropathy (basement membrane changes)
- Marker of macrovascular disease (General endothelial dysfunction; Other cardiovascular risk factors)
Reversible
- good BP control
Other causes of renal disease to consider if pt don’t have proteinuria?
- haematuria
- very short history of type 1 diabetes
- acute renal fail
- recurrent UTI’s (chronic pyelonephritis)
- small kidney in renal ultrasound
- papillary necrosis (rare)
What is the hallmark for diabetic nephropathy?
Proteinuria
Sensorimotor neuropathy
Acute vs Chronic
Prevalence increases with age and duration of illness
Acute
- Periods of poor control
⬇️
- typical symptoms
⬇️
- reversible with control
Chronic clinical picture
- Predominantly sensory
- Motor component late
- Symmetrical in a stocking-glove distribution
- Affects most distal parts of long nerves first - toes and foot soles
- Hands affected late
Sensorimotor neuropathy
Neuropathic symptoms
Clinical signs
Neuropathic symptoms: symptoms come first; clinical signs is only later
- Pain - sharp, burning, especially foot soles and shins
- Skin tender - hyperesthesia
- Paraesthesia - pins and needles or ‘dead’ feeling in feet
- Symptoms may be persistent and severe
- Worse at night and may keep the patient out of sleep
Clinical signs:
Early:
- Decreased vibration sense
- Absent ankle reflexes
- Also: loss of pain and temperature sense
Late:
- Muscle weakness and atrophy
Autonomic neuropathy
General
Major clinical implications
- Involves the small unmyelinised nerve fibres
- Sympathetic and parasympathetic
Cardiovascular system:
- Tachycardia without arrhythmia
- Postural hypotension (if pt get up; they fall over)
- Painless myocardial infarct (pt don’t get chest pain)
GIT:
- Gastroparesis nausea and vomiting + labile control
- Constipation / nocturnal diarrhoea
Major clinical implications
- Hypoglycaemia unawareness a life threatening complication
Proximal neuropathy
Diabetic amyotrophy:
- Severe pain and paraesthesia in thigh, asymmetrical
- Weakness and muscle atrophy - especially quadriceps
- Involves lower motor neuron of lumbo-sacral plexus
- Middle-aged and older patients
- Associated with periods of poor glycemic control
What is the most typical type of diabetic neuropathy?
Symmetrical sensory neuropathy
What are the microvascular complications in DM?
- diabetic neuropathy
- diabetic retinopathy
- diabetic nephropathy
