Diabetes

ABC of Diabetes
by Peter J. Watkins

Clinical presentation: why is diabetes so often missed?

Thirst, tiredness, pruritus vulvae or balanitis, polyuria, and weight loss are the familiar symptoms of diabetes. Why then is the diagnosis so often missed? Of 15 new patients with diabetes presenting in our diabetic ward for the first time with ketoacidosis, 14 had had no tests for diabetes after a total of 41 visits to their doctors. Almost all these serious cases of ketoacidosis could have been prevented.

Patients do not, of course, always describe their symptoms in the clearest possible terms, or else their complaints may occur only as an indirect consequence of the more common features. Many patients describe dry mouth rather than thirst, and patients have been investigated for dysphagia when dehydration was the cause. Polyuria is often treated blindly with antibiotics; it may cause enuresis in young people and incontinence in elderly people and the true diagnosis is often overlooked. Complex urological investigations and even circumcision are sometimes performed before diabetes is considered.

Confusion in diagnosis

Some diabetic patients present chiefly with weight loss, but even then the diagnosis is sometimes missed, and I have seen two teenagers referred for psychiatric management of anorexia nervosa before admission with ketoacidosis. Perhaps weakness, tiredness, and lethargy, which may be the dominant symptoms, are the most commonly misinterpreted; “tonics” and iron are sometimes given as the symptoms worsen.

Deteriorating vision is not uncommon as a presentation, due either to change of refraction causing myopia (mainly in Type 1 diabetes) or to the early development of retinopathy (mainly in Type 2 diabetes). Foot ulceration or sepsis in older patients brings them to accident and emergency departments and is nearly always due to diabetes. Occasionally painful neuropathy is the presenting symptom, causing extreme pain in the feet, thighs, or trunk.

Glycosuria itself is responsible for the monilial overgrowth which causes pruritus vulvae or balanitis; some older men are first aware of diabetes when they notice white spots on their trousers. In hot climates drops of sugary urine attract an interested population of ants, and at least one patient now attending the clinic at King’s College Hospital presented in this way before he came to England.

Patterns of presentation

Symptoms are similar in the two types of diabetes (Type 1 and Type 2), but they vary in their intensity. The presentation is most typical and the symptoms develop most rapidly in patients with Type 1 diabetes; they usually develop over some weeks, but the duration may be a few days to a few months. There is usually considerable weight loss and exhaustion. If the diagnosis is missed, diabetic ketoacidosis occurs. Type 1 diabetes occurs under 40 years of age in approximately 70% of cases but can occur at any age, and even in older people.

Symptoms in patients with Type 2 diabetes are similar but tend to be insidious in their onset; sometimes these patients deny any symptoms, although they often admit to feeling more energetic after treatment has been started. These patients are usually middle aged or elderly, but increasingly children, especially those of ethnic minorities, or those who are inert and overweight, are developing Type 2 diabetes. Microvascular and macrovascular complications are frequently already present when Type 2 diabetes is diagnosed. Type 2 diabetes is commonly detected at routine medical examinations or on admission to hospital with another illness.

Identifying patients in need of insulin

Patients in need of treatment with insulin must be identified early. This is done by judging the patient’s clinical features; blood glucose concentrations alone offer a relatively poor guide, although most patients with a blood glucose concentration greater than 25 mmol/l are likely to need insulin.

Features suggesting need for insulin are:

* a rapid development of symptoms
* substantial weight loss—patients are usually thin and
demonstrate a dry tongue or more severe dehydration
* weakness
* the presence of ketonuria.

Note: The rest of the chapter is omitted.