Endocrinology

Published on 24/06/2015 by admin

Filed under Internal Medicine

Last modified 24/06/2015

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DIABETES MELLITUS

Case vignette

A 58-year-old female presents with nausea and vomiting in the background of progressive exertional dyspnoea.She is a smoker with a 10-pack per year history. She was diagnosed with diabetes 2 years ago and has been managed on metformin 500 mg twice daily. On examination she has coarse crepitations in the lung bases bilaterally. She has an S3 gallop in the precordium. She is obese and has moderate bipedal pitting oedema. Blood pressure is 140/90 mmHg. On the ECG, ST segment depression is observed in the lateral leads. Her fasting blood sugar levels are 11.2 mmo/L with an Hb A1c of 8.2%. Serum troponin level is not elevated.

Approach to the patient

Diabetes is a very commonly encountered condition in the long case setting. Most diabetic patients have multiple associated medical conditions, and this makes them favourite long case material. A candidate is expected to be able to address diabetic cases thoroughly and extensively. Ascertain whether the patient has the metabolic syndrome (see box) that is associated with high cardiovascular risk. The following is a discussion of the integral issues that should never be missed in any diabetic case.

History

Ask about:

when and how the diagnosis was made, and symptoms at presentation, such as loss of weight, polyuria, polydypsia, and other associated presenting features such as diabetic ketoacidosis, hyperosmolar coma and infection

initial treatment, subsequent treatment and the current medical regimen

age at disease onset

the type of diabetes the patient has—this has implications for the risk of diabetic ketoacidosis and for the therapeutic regimens

the insulin treatment, such as previous and/or current regimens, types of insulin, dose and frequency of administration, who injects the insulin, the method of delivery (pen or syringe) and adverse effects associated with insulin treatment

medication history, in detail—note the different classes of drugs that have been used to treat the diabetes, and also other medications that would interfere with adequate glycaemic control

the patient’s knowledge of and compliance with the diabetic diet, and knowledge of the concept of the glycaemic index of various carbohydrate-containing foods

who monitors the blood sugar levels and how often this is done—ask for the most recent readings

episodes of ketoacidosis, hyperosmolar coma and other acute events that have necessitated hospitalisation

whether the patient suffers from hypoglycaemic episodes and how he or she recognises early warning signs, and what remedial measures the patient takes in such situations

other vascular risk factors, such as smoking, hyperlipidaemia and hypertension

The social and occupational impact of diabetes on the patient should be discussed in detail. Talk about impotence, if relevant to the patient. Social and marital issues associated with this condition should be dealt with in detail. Check for a family history of diabetes mellitus and obtain details thereof.
Exclude possible secondary causes for the diabetes, such as chronic pancreatitis, cystic fibrosis, Cushing’s syndrome, acromegaly, polycystic ovary syndrome and consumption of drugs such as corticosteroids, thiazides and the oral contraceptive pill (see box).

Examination

Management

Discussion of therapeutic options revolves around the diabetic diet, regular physical exercise, oral hypoglycaemic agents and their side effects, and insulin therapy. Objectives of diabetes management include: 1) adequate control of the blood sugar level (fasting levels to be maintained below 6.1 mmol/L and postprandial levels below 7.8 mmol/L) and the glycosylated haemoglobin level (should be maintained below 7% in most cases, based on the patient’s clinical status); 2) prevention of end-organ complications; and 3) control of other vascular risk factors.

1. Hypoglycaemic agents—If the diabetic diet and physical exercise fail to provide adequate glycaemic control in the patient with type 2 diabetes, consider commencing an oral hypoglycaemic agent. Commonly used agents are:

biguanides—metformin is the most common and the first line of pharmacotherapy in type 2 diabetes. Act to enhance peripheral insulin sensitivity. Side effects of this class of drugs include diarrhoea, nausea, impaired vitamin B12 absorption and lactic acidosis, particularly in patients with hepatic or renal failure.

sulfonylureas—act via stimulation of pancreatic insulin secretion. Side effects of this class of drugs include hypoglycaemia, weight gain, rash and, very rarely, bone marrow suppression and cholestasis. Sulfonylureas have been associated with an increased mortality rate in post myocardial infarction patients.

meglitinides—repaglinide is a short-acting agent that acts by stimulating pancreatic insulin secretion, but can cause weight gain and hypoglycaemia. This agent can be given in combination with metformin.

alpha-glucosidase inhibitor agents such as acarbose act to inhibit the activity of intestinal glucosidase enzymes. Their side effect profile includes bloating, abdominal discomfort, diarrhoea and flatulence.