Diabetes mellitus

Diabetes mellitus is a medical disorder characterized by varying or persistent hyperglycemia (elevated blood sugar levels), especially after eating. All types of diabetes mellitus share similar symptoms and complications at advanced stages. Hyperglycemia itself can lead to dehydration and ketoacidosis. Longer-term complications include cardiovascular disease (doubled risk), chronic renal failure (it is the main cause for dialysis), retinal damage which can lead to blindness, nerve damage which can lead to erectile dysfunction (impotence), gangrene with risk of amputation of toes, feet, and even legs. The more serious complications are all more common in those with poor glycemic control.

Diagnosis

Signs and symptoms

Type 2 diabetes almost always has a slow onset (often years), but in type 1, particularly in children, onset may be quite fast (weeks or months). Early symptoms of type 1 diabetes are often polyuria (frequent urination) and polydipsia (increased thirst, and consequent increased fluid intake). There may also be weight loss (despite normal or increased eating), increased appetite, and irreducible fatigue. These symptoms may also manifest in Type 2 diabetes in patients who present with frank poorly controlled diabetes.

Related Topics:
Polyuria - Polydipsia

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Thirst develops because of osmotic effects — sufficiently high glucose (above the 'renal threshold') in the blood is excreted by the kidneys but this requires water to carry it and causes increased fluid loss, which must be replaced. The lost blood volume will be replaced from water held inside body cells, causing dehydration.

Related Topics:
Osmotic - Renal threshold - Dehydration

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Another common presenting symptom is altered vision. Prolonged high blood glucose causes changes in the shape of the lens in the eye, leading to blurred vision and, perhaps, a visit to an optometrist. All unexplained quick changes in eyesight should force a fasting blood glucose test. These are now quick (less than 5 minutes total), inexpensive (materials less than USD $1), and can be safely performed by almost anyone with trivial training.

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Especially dangerous symptoms in diabetics include the smell of acetone on the patient's breath (a sign of ketoacidosis), Kussmaul breathing (a rapid, deep breathing), and any altered state of consciousness or arousal (hostility and mania are both possible, as is confusion and lethargy). The most dangerous form of altered consciousness is the so-called "diabetic coma" which produces unconsciousness. Early symptoms of impending diabetic coma include polyuria, nausea, vomiting and abdominal pain, with lethargy and somnolence a later development, progressing to unconsciousness and death if untreated.

Related Topics:
Acetone - Ketoacidosis - Kussmaul breathing - Diabetic coma - Abdominal pain

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Diagnostic approach

The diagnosis of type 1 diabetes and many cases of type 2 is usually prompted by recent-onset symptoms of excessive urination (polyuria) and excessive thirst (polydipsia), often accompanied by weight loss. These symptoms typically worsen over days to weeks; about 25% of people with new type 1 diabetes have developed a degree of diabetic ketoacidosis by the time the diabetes is recognized.

Related Topics:
Polyuria - Polydipsia - Diabetic ketoacidosis

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The diagnosis of other types of diabetes is made in many other ways. The most common are (1) health screening, (2) detection of hyperglycemia when a doctor is investigating a complication of longstanding, unrecognized diabetes, and less commonly (3) new signs and symptoms attributable to the diabetes.

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• Diabetes screening is recommended for many types of people at various stages of life or with several different risk factors. The screening test varies according to circumstances and local policy and may be a random glucose, a fasting glucose and insulin, a glucose 2 hours after 75 g of glucose, or a formal glucose tolerance test. Many health care recommendations for adults recommend universal screening at age 40 or 50 years, and sometimes occasionally thereafter. Earlier screening is recommended for those with risk factors such as obesity, family history of diabetes, high risk ethnicity (Hispanic , American Indian, African American, Pacific Island, and South Asian ancestry).
• Many medical conditions are associated with a higher risk of various types of diabetes and warrant screening. A partial list includes: high blood pressure, elevated cholesterol levels, coronary artery disease, past gestational diabetes, polycystic ovary syndrome, chronic pancreatitis, hepatic steatosis (fatty liver), cystic fibrosis, several mitochondrial neuropathies and myopathies, myotonic dystrophy, Friedreich's ataxia, some of the inherited forms of neonatal hyperinsulinism and many others. Risk of diabetes is higher with chronic use of several medications, including high dose glucocorticoids, some chemotherapy agents (especially L-asparaginase), and some of the antipsychotics and mood stabilizers (especially phenothiazines and some atypical antipsychotics).
• Diabetes is often detected when a person suffers a problem frequently caused by diabetes, such as a heart attack, stroke, neuropathy, poor wound healing or a foot ulcer, certain eye problems, certain fungal infections, or delivering a baby with macrosomia or hypoglycemia.

Criteria for diagnosis

Diabetes mellitus is characterized by recurrent or persistent hyperglycemia, and is diagnosed by demonstrating any one of

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• two fasting plasma glucose levels above 7 mmol/l (125 mg/dl) on different days;
• plasma glucose above 11.1 mmol/l (200 mg/dl) two hours after a 75 g glucose load; or
• symptoms of diabetes and a random glucose above 11.1 mmol/l (200 mg/dl).

While not used for diagnosis, an elevated glucose bound to hemoglobin, HbA1c, of 6.0% or higher (2003 revised US standard); is a screening and treatment-tracking test reflecting average blood glucose levels over the preceding 90 days (approximately).

Related Topics:
Hemoglobin - HbA1c

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Diabetic ketoacidosis and coma

See more detail in the articles diabetic ketoacidosis and diabetic coma

Related Topics:
Diabetic ketoacidosis - Diabetic coma

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Diabetic ketoacidosis (DKA) is an acute, dangerous complication and is always a medical emergency. Prompt proper treatment usually results in full recovery, though death can result from inadequate treatment or a variety of complications.

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Hyperosmotic diabetic coma is another acute problem associated with improper management of diabetes mellitus. It has some symptoms in common with DKA, but a different cause, and requires different treatment. In anyone with very high blood glucose levels (usually considered to be above 16.6 mmol/l (300 mg/dl)) water will be osmotically driven out of cells into the blood. The kidneys will also be "dumping" glucose into the urine, resulting in concomitant loss of water, causing an increase in blood osmolality. The osmotic effect of high glucose levels combined with the loss of water will eventually result in such a high serum osmolality that the body's cells may become directly affected as water is drawn out from them. Electrolyte imbalances are also common. This combination of changes, especially if prolonged, will result in symptoms similar to ketoacidosis, including loss of consciousness. As with DKA, urgent medical treatment is necessary. This is the diabetic coma to which type 2 diabetics are prone; it is less common in type 1 diabetics.

Related Topics:
Diabetic coma - Osmolality

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Hypoglycemia

Hypoglycemia in patients with diabetes almost always arises as a result of poor management of the disease either from too much or poorly timed insulin or oral hypoglycemics or too much exercise, not enough food, or poor timing of either. If blood glucose levels are low enough, the patient may become agitated, sweaty, and have many symptoms of sympathetic activation of the autonomic nervous system - they may experience feelings similar to dread and immobilized panic. Consciousness can be altered, or even lost, in extreme cases, leading to coma and/or seizures or even death and brain damage. Experienced diabetics can often recognise the symptoms early on - all diabetics should always carry something sugary to eat or drink as these symptoms can be rapidly reduced if treated early enough. In the case of children, this can be a type of candy disliked by the patient, to prevent concerns about unnecessary use.

Related Topics:
Hypoglycemia - Sympathetic - Seizure

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Other ways of treating hypoglycemia include an injection of glucagon which causes the liver to convert its internal stores of glycogen to be released as glucose into the blood. Oral or intravenous dextrose can also be given. In most cases, recovery is rapid and troublefree. Longstanding hypoglycemia may require hospital admission to allow supervised recovery and adjustment of diabetic medications.

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