Diabetes: chronic lesions
- Lesion
Long-standing diabetes leaves recognisable marks in vessels, kidneys, eyes and nerves. These cause heart attacks, kidney failure, blindness and amputations.
What it is
The morphology of chronic diabetes is the morphology of its vessels. Large arteries develop accelerated atherosclerosis; small arterioles show hyaline arteriolosclerosis; capillaries everywhere develop thick basement membranes but become leaky. These changes, together with neuropathy and impaired healing, explain myocardial infarction, stroke, renal failure, blindness and the diabetic foot.
Structure
- Pancreas: smaller islets with insulitis (type 1) or amyloid (type 2); beta-cell hyperplasia in infants of diabetic mothers.
- Arteries: early, severe, often calcified atherosclerosis, including distal leg arteries.
- Arterioles: hyaline (PAS-positive) wall thickening with narrowed lumen.
- Glomeruli: PAS-positive mesangial nodules with peripheral capillary loops; capsular drops and fibrin caps.
- Retina: microaneurysms, dot-blot haemorrhages, cotton-wool spots (microinfarcts), new fragile vessels.
- Nerve: axonal degeneration with segmental demyelination; vasa nervorum show hyaline thickening.
Organs and what diabetes does to them
| Organ | Lesion | Clinical result |
|---|---|---|
| Heart and large arteries | Accelerated atherosclerosis | Myocardial infarction, stroke, peripheral artery disease |
| Kidney | Basement membrane thickening, mesangial and nodular sclerosis, arteriolosclerosis | Albuminuria, nephrotic syndrome, chronic kidney disease |
| Retina | Microaneurysms, haemorrhages, neovascularisation | Visual loss, vitreous haemorrhage, retinal detachment |
| Peripheral nerve | Axonal loss, demyelination | Stocking-glove numbness, foot ulcers, autonomic failure |
| Foot | Neuropathy plus ischaemia plus infection | Ulcers, osteomyelitis, gangrene, amputation |
| Immune defence | Impaired neutrophil function, poor blood flow | Infections: pyelonephritis, mucormycosis, malignant otitis externa |
Clinical notes
- Albuminuria is the earliest sign of diabetic kidney disease.
- Daily foot inspection and annual retinal examination are basic prevention.
- Diabetic retinopathy is a leading cause of preventable blindness in Latin America.
Test yourself
Think of the answer, then tap the question to see it.
What is the commonest cause of death in diabetes?
Myocardial infarction from accelerated atherosclerosis.
Why is diabetic microangiopathy leaky despite thicker basement membranes?
The glycated, abnormal basement membrane is structurally defective and more permeable to plasma proteins.
Which arterioles show hyaline arteriolosclerosis in the diabetic kidney?
Both the afferent and the efferent arterioles.
Elsewhere in DurgiPedia
- What delays healing: infection, diabetes, nutrition, glucocorticoids, poor blood flow
- Arterial vs venous thrombi; mural thrombi and lines of Zahn
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Diabetes Complications (MedlinePlus, US National Library of Medicine, 2025); Diabetic Retinopathy (StatPearls (NCBI Bookshelf), 2025).
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Representative model, for educational purposes only.