A common complication with Diabetes Mellitus is prolonged exposure to hyperglycaemia. Uncontrolled blood sugar levels can result in pathophysiology on a cellular level that causes chronic complications. Prolonged exposure to hyperglycaemia causes protein structures to change shape, which alters their function and effects on other organs and structures throughout the body. This can be seen in the circulatory system where micro and macro vascular changes occur. Excess blood glucose attaches itself to circulating proteins, which are then deposited onto vascular walls, resulting in atherosclerosis. This can lead to peripheral vascular disease, transient ischaemic attacks and myocardial infarctions (American Heart Association, 2014; Hoy & Walding, 2015).
Other chronic complications that arise from prolonged hyperglycaemia are:
Diabetic retinopathy: Changes to the blood vessels can cause retinal ischaemia leading to blurred vision and vision loss Retinopathy is a progressive complication that has three stages: background retinopathy, pre-proliferative retinopathy and proliferative retinopathy. This complication arises due to microvascular damage. Background retinopathy involves micro-infarction (an area of necrosis in tissue) and micro-aneurysms (enlargement of a retinal capillary at the venous end). Vision is not impacted at this stage. Pre-proliferative retinopathy is a result of microvascular obstruction and infarctions of retinal nerve fibres. Neovascularization occurs in proliferative retinopathy. This is the formation of a function microvascular network. Vessels in the network may bleed, causing vision disturbances (Donaghue et al., 2007). Diabetic patients will need to be educated on the importance of having regular eye check -ups to identify retinopathy in the early stages before it progresses.
Renal failure: The changed shape of protein damages glomeruli causes enlargement, thickening basement membrane and increased multiplication of support cells. As glomerular filtration rate decreases, acidosis, nausea, hypertension and anaemia occur. Nephropathy is a result of microvascular destruction in the kidneys and can lead to kidney failure. This can result in glomerular enlargement, thickening glomerular basement membrane, and a decrease filtration rate. Micro-albumin (albumin present in urine) is a sign that the kidney is going into failure (Donaghue et al., 2007; Hoy & Walding, 2015). Symptoms of nephropathy include nausea, hypertension, lethargy and acidosis. It is important that urinalysis be incorporated into the care plan for patients where nephropathy is suspected.
Neuropathy: As neurons do not need insulin to transport glucose, an increased amount of glucose enters the neuron resulting in nerve degradation, delayed conduction and decreased sensation. Neuropathy is the name commonly given to sensorimotor polyneuropathy. Damage occurs to all peripheral neurons. Firstly, sensory and then secondly, motor neurons are damaged. Autonomic nerve dysfunction is also included in the generalized name neuropathy. Damage to the autonomic nervous system can result in impotence, sweating dysfunction, and postural hypotension. Neuropathy is a microvascular complication of diabetes. Signs and symptoms of neuropathy are a loss of sensation, numbness, and tingling. Due to the decreased sensation, diabetic patients are at risk of developing sores that they are unaware of. This can lead to infection and ulceration. Feet especially are at risk of ulceration. Patients should be educated about the importance of seeing a podiatrist and regularly wearing footwear to protect from possible sores (Donaghue et al., 2007; Hoy & Walding, 2015).
Infection: Impaired vision, touch, and pain sensation alongside decreased blood supply from micro/macro vascular changes increase the risk of infection. Another factor is the proliferation of pathogens in an environment of increased blood glucose.
Together, neuropathy and increased risk of infection can lead to gangrene and possibly lower limb amputation. With the above complications areas of damage result in tissue death. The area can then become ulcerous leading to osteomyelitis which may require amputation of the affected limb (Hoy & Walding, 2015).
Cardiovascular disease is a macrovascular complication of diabetes. There is an increase in triglycerides and low density lipoprotein (LDL) and a decrease in high density lipoprotein (HDL) which attribute to atherosclerosis. Narrowing of the vessel lumen can result in hypertension, further placing the cardiovascular system under strain. Educating the patient about maintaining a healthy diet, low in saturated fat and sodium will help to keep hypertension and atherosclerosis under control (Health Navigator, 2016; Hoy & Walding, 2015).
American Heart Association. (2014). Atherosclerosis. Retrieved March 7, 2016, from http://www.heart.org/HEARTORG/Conditions/Cholesterol/WhyCholesterolMatters/Atherosclerosis_UCM_305564_Article.jsp#.Vt3ALvkrLIU
Donaghue, K., Chiarelli, F., Trotta, D., Allgrove, J., & Dahl-Jorgensen, K. (2007). Microvascular and macrovascular complications. Pediatric Diabetes, 8, 163–170. Retrieved from https://www.researchgate.net/profile/Knut_Dahl-Jorgensen2/publication/6287052_ISPAD_Clinical_Practice_Consensus_Guidelines_20062007._Microvascular_and_macrovascular_complications/links/557abc9408aef90db60d791c.pdf
Health Navigator. (2016). Type 2 diabetes. Retrieved March 7, 2016 from http://www.healthnavigator.org.nz/health-a-z/d/diabetes-type-2/
Hoy, A., & Walding, M. (2015). Obesity and diabetes mellitus. In J. Craft & C. Gordon (Eds.), Understanding pathophysiology (2nd ed., pp. 1028–1060). Sydney, Australia: Mosby Elsevier.
Khanacademymedicine. (2015, May 14). What is diabetes mellitus? [Video file]. Retrieved from https://www.youtube.com/watch?v=ulxyWZf7BWc&list=PLbKSbFnKYVY3MhJvcNo4uUqFX8vs8AzAF
The World Health Organisation (2016). About diabetes. Retrieved March 7, 2016 from http://www.who.int/diabetes/action_online/basics/en/index3.html