October 13, 2010

Q&A: Concerning Complications of Diabetes

The term diabetes mellitus describes diseases of abnormal carbohydrate metabolism that are characterized by hyperglycemia. It is associated with a relative or absolute impairment in insulin secretion, along with varying degrees of peripheral resistance to the action of insulin. Every few years, the diabetes community reevaluates the current recommendations for the classification, diagnosis, and screening of diabetes, reflecting new information from research and clinical practice.

This article is for Medical Students & Professionals
This is a Question & Answer revision article designed for medical students and professionals preparing for the PLAB, MRCP or USMLE examinations. They are based on actual questions from these examinations. You may find the Diabetes article more useful, or one of our many articles on Diseases & Conditions, Medical Syndromes, Health & Wellness or Home Remedies.
In this article:
Diagnostic tests for diabetes
MCQ: clinical scenario
MCQ: answer
MCQ: explanation

Diagnostic tests for diabetes

Fasting plasma glucose (FPG), oral glucose tolerance test (OGTT), and HbA1C represent different physiologic phenomena, and each of the tests will identify different proportions of the population with diabetes. Compared with HbA1C and FPG cutpoints, the OGTT diagnoses more people with prediabetes and diabetes. However, HbA1C and FPG are more convenient, the former perhaps the most convenient since fasting is not required. Because of its inconvenience, the OGTT is not commonly used clinically, except in pregnancy. OGTT is also used in research trials of diabetes prevention owing to its greater sensitivity.

MCQ: clinical scenario

An insulin dependendent diabetic uses an insulin pump to control his blood sugar levels. He is obsessed with strict control of his blood sugar level and makes sure his blood sugar level never exceeds the normal level. He now presents with a seizure without any prior warning.

This complication of diabetes is best described as:

a) keto acidosis
b) Nonketotic Hyperosmolarity
c) autonomic neuropathy
d) Hypoglycaemia unawareness
e) peripheral neuropathy
f) infection
g) Amytrophy
h) Focal nerve palsy
i) retinopathy
j) nephropathy

MCQ questions & answers on medicalnotes.info

MCQ: answer

The correct answer is D

MCQ: explanation

Whilst most patients with diabetes are aware of the symptoms of a hypoglycaemic reaction, there are some in whom the first sign may be a seizure or unconsciousness. It would appear that in these patients there is little adrenaline secreted in response to the falling blood glucose and the body's ability to raise the blood glucose level is impaired.

Hypoglycaemia unawareness occurs more frequently in those attempting very tight control of their diabetes especially if on an insulin pump (frequent episodes of hypoglycaemia leads to a blunting of the counter-regulatory hormonal responses due to low blood glucose). Patients who have this problem are at particular risk of developing severe hypoglycaemic reactions and their doctors must take this into account in setting somewhat higher target levels of blood glucose control. Increased blood glucose monitoring is helpful in reducing the number of hypoglycaemic episodes in these patients, especially when unaccustomed or special activities are undertaken.

Hypoglycaemia unawareness may be brought on by frequent, undiagnosed, hypoglycaemic events which leads to autonomic failure. Scrupulous prevention of these hypoglycaemic events may restore the hypoglycaemic awareness. Further, it is important to be aware that undiagnosed hypoglycaemic events often occur during the night.

Reference(s)
1). UpToDate: Clinical presentation, diagnosis, and initial evaluation of diabetes mellitus in adults. Available online: https://www.uptodate.com/contents/clinical-presentation-diagnosis-and-initial-evaluation-of-diabetes-mellitus-in-adults

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