a) Risk factors for diabetic foot infections
Discuss three key factors that contribute to the development of diabetic foot infections (DFI). (6 marks)
Note the examiner has specified three factors, and that you should discuss them rather than just list them out. 1 point for each factor listed, 1 point for explaining why each factor is significant in DFI. I have put down four below. The discussions could be simplified further in the exam.
Foot wound - Foot infections occur frequently in diabetics, almost always following trauma. Efforts to prevent infections should be targeted at people with traumatic foot wounds, especially those that are chronic, deep, recurrent, or associated with peripheral vascular disease. The presence of an ulcer is a risk factor.
Peripheral vascular disease is present in up to 40% of patients with diabetic foot infections, evaluation of the vascular (blood) supply is critical. PVD is a disorder where the peripheral blood vessels are narrowed or blocked, primarily due to atherosclerosis. DM is a risk factor for PVD, as is smoking, HT and dyslipidaemia. PVD causes reduced blood flow/supply to the affected area, which causes necrosis and impaired healing.
Diabetic peripheral neuropathy is where the nerves are damaged due to high glucose levels, causing loss of sensation so that if foot trauma were to occur, the patient may not realise it. Neuropathic ulcers can occur due to undetected microtraumas over pressure points on the foot.
Impaired immune response in diabetics. High blood glucose levels can impair the immune response, and diabetics are prone to increased risk of prolonged infections.
Refs:
https://www.aafp.org/afp/2013/0801/p177.html
http://care.diabetesjournals.org/content/29/6/1288
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5435321/