Misdiagnosis of Diabetes

The most likely diagnostic problem with diabetes is failure to diagnose it early because patients do not recognize its early mild symptoms. Once a doctor is seen, diabetes is not often completely misdiagnosed because it is well-known to physicians and has fairly definitive diagnostic tests (blood glucose test; urine glucose test). However, more difficulty is found in determining the correct type of diabetes, diagnosing any complications of diabetes, or associated diseases.

Undiagnosed Diabetes. The most likely misdiagnosis related to diabetes is that it remains undiagnosed in many people. This mostly refers to Type 2 Diabetes, where the disease can take years to progress to major symptoms, but undiagnosed Type 1 Diabetes can occur (though usually becomes visible within weeks or months). Read more about: Symptoms of Diabetes.

Undiagnosed Pre-Diabetes: The milder precursor to Type 2 Diabetes called “pre-diabetes” is often so mild that it can remain undiagnosed for years. Read more about: Pre-Diabetes.

Undiagnosed Gestational Diabetes: Gestational Diabetes can also remain undiagnosed in a pregnant woman. Read more about: Gestational Diabetes.

Acute Complications of Undiagnosed Diabetes: If diabetes is undiagnosed, some of the symptoms and complications can become very dangerous. These can often remain undiagnosed until too late, or can be misdiagnosed as something else. Fatality is possible. The complications include:

Most Dangerous Misdiagnosis: One of the most dangerous errors in diagnosis is to incorrectly diagnose a person with Type 2 Diabetes, sending them home with instructions about diet and how to monitor their blood sugar levels. If they actually have Type 1 Diabetes, insulin is required, and trying to treat it with diet changes alone is likely to result in DKA and even death.

There are real-world examples of this diagnostic mistake. A six-year-old girl died after being sent home in this way, with a Type 2 Diabetes diagnosis, and a diet treatment plan (insulin was required; DKA was the result).

But Type 2 Diabetes is extremely rare in children under 10; it’s almost certainly Type 1 Diabetes in that age group. And an older child or a teenager is actually the most likely age to get Type 1 Diabetes requiring insulin (although the reverse misdiagnosis is possible since some teens are being diagnosed correctly with Type 2 Diabetes).

Another example case is a 29-year-old man sent home with instructions about dieting and monitoring, with a diagnosis of Type 2 Diabetes. Although it’s more likely for a 29-year-old than a 6-year-old to have Type 2 Diabetes, the age is still an unusual age for Type 2 Diabetes. And at 29, the possibility of Type 1 Diabetes is still there, and this was the actual correct diagnosis (insulin was required).

MODY Diabetes is another possibility for a younger adult in their 20’s or 30’s with Type 2 Diabetes, rather than the classic ages of onset for Type 2 Diabetes (40’s or 50’s or later).

Misdiagnosed: The list of conditions that mimic diabetes is not really that long. A total misdiagnosis is highly unlikely.

  • Fructosuria. A rare condition that causes the appearance of fructose in the urine that may trigger a false positive on a urine glucose test. But a blood glucose test should not be high in this case.
  • Xylulosuria. Another rare disease that causes some forms of sugar in the urine, but which also shouldn’t cause glucose in the blood.
  • Renal glycosuria: This is where there is glycosuria due to a kidney disease (i.e. renal causes), where the kidneys are not properly filtering glucose out of the urine, but usually there is not also high blood sugars.
  • Fanconi syndrome: May cause glycosuria (renal glycosuria) due to a kidney disorder, but will not have high blood glucose.
  • Glucagonoma. A rare endocrine tumor of the endocrine pancreas, that over-produces glucagon, which can stimulate the liver to create too much sugar in the blood. (Note that the better known type of Pancreatic Cancer is not similar to this disorder; however, a pancreas disorder can sometimes lead to reduced insulin production and diabetes.)
  • Diabetes Insipidus: Despite its similar name, this rare disease has almost no relationship to common diabetes, except that its hallmark symptom is excessive urination. This disease is a kidney disease (due to a pituitary disorder) and is extremely unlikely to be misdiagnosed as diabetes.

There are other disorders that cause glycosuria (usually without hyperglycemia). See other uncommon causes of glycosuria.

Hidden Causes (Secondary Diabetes): There are a number of medical conditions that can cause hyperglycemia, diabetes symptoms, or diabetes-like conditions, mainly due to their impact on the pancreas. These conditions may cause disorders that mimic either “insulin deficiency” or “insulin resistance”.

  • Hyperthyroidism. An excess of thyroid hormone may sometimes cause diabetes-like conditions.
  • Pancreatitis. An inflammation of the pancreas can sometimes cause the insulin-related part of the pancreas (endocrine pancreas) to fail, causing insulin deficiency. However, pancreatitis more commonly causes digestive symptoms than diabetes-like symptoms.
  • Hemochromatosis (“bronze diabetes”). This disease causes insulin deficiency due to pancreas damage. A genetic disease that is often overlooked, occurring in about 1 in 200 to 300 people, which damages the pancreas, liver, heart, and joints, among other symptoms. If you are diagnosed with diabetes, then a second diagnosis of hidden hemochromatosis is one of those rare cases where it’s good to get a second disease! Hemochromatosis is often readily treatable, and doing so can often improve diabetes symptoms, or at least stall any further diabetes progression. (Read more about: Hemochromatosis.)
  • Pancreas disorders. Other disorders of the pancreas can affect it in a way to cause diabetes-like symptoms. Pancreas injury of any type, or any pancreas surgery, may also cause insulin deficiency.
  • Acromegaly. A rare and insidious disorder of the growth hormone that can cause a form of secondary diabetes.
  • Gigantism. An overgrowth disorder in children, similar to acromegaly in adults.
  • Cushing’s syndrome. Another endocrine disorder that can cause secondary diabetes. Cushing’s syndrome involves the adrenal glands producing too much corticosteroid hormones (hypercortisolism), so the effect is similar to “steroid diabetes”. There are usually various other symptoms.
  • Pheochromocytoma. A form of adrenal gland cancer that may have secondary diabetes as one of its symptoms; other symptoms are likely.
  • Somatostatinoma. An extremely rare form of cancer that may cause over-production of statins, and show the effects of secondary diabetes. Other gastrointestinal symptoms are typical.
  • Glucagonoma (endocrine pancreatic tumor). Over-production of the glucagon hormone (due to a pancreatic tumor) stimulates the liver to continually output extra glucose into the bloodstream, resulting in hyperglycemia.

Drug-Related Diabetes: There are a number of drug medications that can sometimes cause diabetes or diabetes-like conditions.

Genetic Syndromes with Increased Diabetic Risk: There are a number of genetic diseases or disorders where the person is at higher risk of diabetes.

Wrong Type of Diabetes: Sometimes people are correctly diagnosed with diabetes, but the wrong subtype is diagnosed. There are two main types of diabetes and a few rare types.

Subtypes of Type 2 Diabetes: There are actually subtypes of the main Type 2 Diabetes, which can affect how to treat it. The main issue is whether your body is producing too much insulin but resisting it (called “insulin-resistant”), or the less common case where your body is producing too little insulin (called “insulin-deficient” type). Detection of insulin resistance (and hyperinsulinemia) makes it very likely that the diabetes is classic Type 2 Diabetes, but the detection of an insulin-deficient type may increase the suspicion of another rarer type of diabetes or secondary diabetes.

Undiagnosed Chronic Complications of Diabetes. The onset of Type 2 Diabetes can be so slow that the complications of diabetes can have time to develop prior to the diabetes being discovered. And once diagnosed, the careful watching for any signs of diabetes complications becomes an ongoing management concern. Read more about diabetes complications, but some of the complications more likely to be undiagnosed include:

Associated (Comorbid) Conditions: Not only is there diabetes, and the various complications of diabetes, but people with diabetes can often have additional diseases. People with Type 1 Diabetes are more likely to have other types of Autoimmune Diseases (e.g. Addison’s Disease). A list of comorbid disorders for Type 1 diabetes includes:

People with Type 2 Diabetes often have three other disorders: hypertension, obesity, and high cholesterol, which is a cluster of four diseases (including diabetes) which is called Metabolic Syndrome (Syndrome X). There are various other associated diseases for diabetes. A list of these comorbid disorders for Type 2 diabetes includes:

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.