Diabetes Mellitus
Consequences of Chronic High Blood Glucose (Hyperglycemia) in Other Systems
Jennifer Kong
Learning Objectives
By the end of this section, you will be able to:
- Explain how manifestations of diabetes mellitus affects other organ systems in the body.
- Identify the consequences of having high blood sugar levels in the body.
All types of diabetes mellitus manifest as high blood glucose circulating in the body for a long time. Hyperglycemia damage blood vessels in the body – ESPECIALLY the very small microvasculature. Thus, the most common consequences of poorly controlled diabetes are impaired blood flow and damage in the eyes, kidneys, and nerves.
- Nerves: decreased blood flow cause loss of neural response for sensation (paresthesia) and movement (i.e. tripping while walking due to foot drop). As the nerve dies, tingling and pain develops (diabetic neuropathy). These problems can manifest in any part of the nervous system – but are more common in the hands, shins, and feet. Nerves serving the GI system will cause symptoms like gastric paralysis.
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Limbs & digits: blood vessel damage causes poor circulation to limbs and digits, which can cause tissue death. As well, hands and feet have a higher risk of injury and wound infection. In the presence of hyperglycemia and loss of neural response it might result in healing complications and the possible need of amputations.
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Eyes: damage to the retina microvasculature of the eye leads to blindness
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Blood vessels: Injury & inflammation of the lining of arteries can lead to atherosclerosis, ischemic heart disease, heart attacks and strokes (see Atherosclerosis chapter for more background).
- Kidneys: damage to microvasculature leads to a loss of the filtering ability in the kidneys resulting in renal disease and eventual renal failure.
DHPLC Specimen PATH 425-053 – Diabetic glomerulosclerosis – kidney stained with Periodic acid -Schiff stain. Created by Jennifer Kong, licensed under All rights reserved
- Urinary & oral infections: there are many pathogens in the genitourinary & oral cavities and high sugar in urine/saliva will encourage pathogen growth.
- Open wounds: high blood sugar promotes bacterial growth in the wound, thus delaying healing. As well, diabetes causes poor blood flow thus leading to slow or poor wound healing.
- Liver disease (non-alcoholic fatty liver disease): constantly high blood glucose wreaks havoc on nutrient processing and storage in the liver. The liver is the storage site for glucose in the form of glycogen in response to insulin. It also converts excessive nutrients like sugars into fats where it is stored locally. As a result, diabetes can lead to liver lipid accumulation and liver disease as excessive storage of these nutrients are harmful to the liver cells.
Critical thinking Exercises
Section Review
Diabetes involves chronic hyperglycemia and it will cause tissues to change anatomically and functionally, particularly the walls of small blood vessels. As a result, less blood is delivered to tissues. Thus, chronic hyperglycemia affects all tissues but is most noticeable in the kidneys, peripheral nervous system, eyes, and fingers/toes. As glucose metabolism is disturbed, fat metabolism is dominant causing high circulating levels of fat metabolism byproducts which will also affect the blood vessels, blood pH, and the liver.
Review Questions
1. Manifestations of diabetes mellitus can affect organ systems in the body. Fill in the blanks on the mechanism of how manifestations of diabetes mellitus affect each organ or system._____: _____ blood flow causes _____ damage resulting in tingling and/or painful sensations common in hands and feet.
Limbs & Digits: blood _____ damage causes poor circulation which can result in _____ death in limbs & digits.
_____: retinas can be damaged leading to _____.
Blood _____: _____ and _____ of the lining of arteries can lead to circulatory diseases.
_____: damaged microvasculature can lead to a loss of _____ which may lead to renal disease and renal _____.
_____: excessive storage of nutrients which is harmful to the organ.
2. High blood sugar levels in the blood and other bodily fluids may cause harm to the body since this allows a favorable environment for bacteria to growth. This may cause infections and delay healing.
- True
- False
Answer Key
- nerves, decreased/lower, nerve, vessel, tissue, eyes, blindness, vessels, injury/injuries, inflammation, kidneys, filtering, failure, liver
- True
Media Attributions
- Diabetes Nephropathy © Bruce Blaus is licensed under a CC BY (Attribution) license
