ANATPATH - DM Flashcards
Name an acute metabolic complication of diabetes (1)
Hyperosmolar, hyperglycaemic non-ketotic coma
Name two (2) organisms to which diabetics are particularly prone (1)
Pyogenic organisms (e.g. Strep pneumonia, Staph aureus), TB, Clostridium perfringens, Candida
Outline why a diabetic patient would be at risk for pyelonephritis and TB
Pyelonephritis (1) Sugar in urine - culture media for organisms
Tuberculosis (1) Function of inflammatory cells compromised
List four (4) chronic complications of diabetes (2)
Nephropathy, Neuropathy, Accelerated atherosclerosis, Myocardial infarctions, Diabetic foot/ gangrene, Infections, mainly of skin/ kidney (pyelonephritis)
Briefly outline the possible major long-term (pathological) cardiovascular/ vascular complications of diabetes mellitus (12)/ Name two major classes of vascular complication in DM [½ each] and give one example for each of them [2] [3] (Super NB)
Macrovascular complications: Accelerated Atherosclerosis, with any mixture of:
o Coronary artery involvement ischaemic heart disease/ myocardial infarction
o Carotid/cerebral artery involvement ischaemic “stroke”/ cerebral infarction (CVA)
o Peripheral (especially lower limb) artery involvement peripheral vascular disease (claudication/gangrene)
o Aneurysm formation/rupture - Especially abdominal aorta
o Atherothrombotic embolisation with resultant infarction in the relevant arterial territory.
Microvascular complications
o Glomerulopathy (Kimelstiehl-Wilson kidney)/Renal failure
o Retinopathy (/cataracts) leading to blindness
List two (2)/ four (4) macrovascular complications of uncontrolled diabetes (2-4)
Accelerated atherosclerosis leading to any or all of: Coronary artery atherosclerosis, Cerebral artery atherosclerosis, Peripheral arterial atherosclerosis (especially the major lower limb arteries), Coeliac axis atherosclerosis
Outline the likely clinical syndromes that this patient might develop as a result of each of the major macro-vascular pathological complications (of diabetes mellitus) that you mentioned in the previous question [4]
Coronary atherosclerosis): Ischaemic heart disease: Angina/myocardial infarction
(Cerebral atherosclerosis): Atherothrombotic cerebral infarction (“ischaemic stroke”)
(Peripheral vascular disease): Intermittent claudication: Rest-pain; Gangrene
(Coeliac atherosclerosis): Intestinal angina
Discuss the cardiac complications seen in diabetes mellitus (2½)
Increased incidence of atherosclerosis (½) Earlier onset (½), More severe (½)
Coronary atheroma (½) predisposes to risk of myocardial infarction (½)
Give two likely explanations for her deteriorating vision [1]
Diabetic retinopathy (on the basis of a microangiopathy); cataracts.
Patient has hypertension and severe atheroma, particularly affecting one renal artery. It is determined that the unilateral renal artery atheroma is the cause of his hypertension. Explain how the hypertension comes about (5)
Diabetes accelerated atheroma partial blockage of 1 renal vessel hypotension in that kidney renin secretion by the kidney on that side renin-angiotensin cycle continues until BP in affected kidney normalizes. The remainder of the body becomes hypertensive.
List four (4) renal complications of diabetes mellitus which could be diagnosed on a kidney biopsy (4)
Nodular glomerulosclerosis, Hyalinised efferent and afferent arterioles, Pyelonephritis, Papillary necrosis, Vacuolisation of tubules
Explain the mechanism for microproteinuria in diabetics (1)
There is glycosylation of the basement membrane of the glomerulus making it more permeable to proteins.
Explain why diabetic patient is at risk for ascending urinary tract infections (2)
Raised urinary sugar culture medium for organisms ++
Obstruction of ureters from papillary necrosis
List two (2) complications of uncontrolled diabetes involving the eye (2) (NB)
Diabetic retinopathy with neovascularization, Retinal haemorrhage, Glaucoma, Diabetic cataracts
List three (3) lesions that can occur in the eye in diabetes (1½)
Aneurysms, cotton wool spots, haemorrhages, cataracts
List six (6) microvascular complications of diabetes that may be encountered in the retina in longstanding diabetes (6x½ = 3)
Pre-proliferative changes: Thickening of BM of retinal blood vessels, Microaneurysms, Macular oedema, Exudates
Proliferative changes: Neovascularisation – neovascular membrane, Posterior vitreous detachment, Haemorrhage, Retinal detachment
List two (2) long term complications that might occur in the leg/foot in the presence of poorly controlled diabetes (1)
Gangrene of the limbs due to macroangiopathy, Diabetic foot, Peripheral neuropathy
List three (3) possible lesions which may be present to explain the pain and parasthesia in both feet. For each lesion, briefly explain its pathogenesis (4½)
Ischaemia due to macroangiopathy in iliofemoral arteries due to severe atheroma of these vessels
Diabetic neuropathy due to microangiopathy [thickened BM] or macroangiopathy iliofemorals [atheroma]
Early gangrene of the feet due to thromboemboli or atheromatous emboli from iliofemoral vessels
Outline four (4) factors which are operative in the causation of the diabetic foot (4)
Nerve dysfunction, Thickened vascular basement membrane, Poor polymorph function (decreased intracellular glucose), Raised blood glucose, Stress/ steroids/ poor immune function
Outline five (5) factors that contribute to the development & persistence of the ulcer on a diabetic patient’s foot (5)/ Explain why the foot ulcers have a tendency not to heal (5)
Diabetes Peripheral neuropathy decreased pain sensation repeated trauma and damage
Macroangiopathy & Microangiopathy poor blood flow to feet poor healing, poor acute inflammation
Microangiopathy poor efflux of neutrophils from vessels
Raised glucose > proliferation of bacteria
Low glucose in polymorphs poor intracellular killing of organisms
Outline the factors that predispose a patient to the pathogenesis of a diabetic foot (3)
Sensory neuropathy resulting in traumatic injury
Macrovascular – accelerated atherosclerosis
Hyperglycaemia predisposes to infection
Explain the mechanism of diabetic foot ulcers (4)
Poor blood flow to nerves in the foot neuropathy [1]
Macroangiopathy i.e. atheroma in large vessels [femoral and iliac] [1]
Microangiopathy [thickening of basement membranes in small vessels and capillaries]
Poor function of nerves
Small episodes of trauma not felt significant ulcers [2]
Describe the pathogenesis of a diabetic foot (3) (NB)
Combination of tissue ischaemia secondary to microvascular injury (thickening of capillary basement membranes with tissue ischaemia) and neuropathic ulceration.
Superimposed infection: Superficial (cellulitis), Deep (Osteomyelitis)
Impaired wound healing and repair
Describe the pathogenesis of a diabetic foot (5)
- Trauma
- Decreased flow, poor acute inflammatory response, thick BM
- Persistence of agent due to above and high blood sugar
- Poor healing because of poor flow and low intracellular glucose
- Peripheral neuropathy
Explain the pathogenesis of the foot ulcers in a diabetic patient [3
A mixture of:
- (Macrovascular) Peripheral vascular disease
- (Microvascular) (Predominantly sensory) Peripheral neuropathy
- General increased susceptibility to infection of diabetics.
Indicate the macroscopic appearances of the ulcer and the local features that would suggest the ulcer is malignant (2)
Raised rolled edges Malignant ulcer.
Enlarged inguinal nodes Metastatic squamous carcinoma
