What is Type 1 Diabetes?
Type 1 diabetes is a medical condition characterized by autoimmune destruction of beta islets cells in the pancreas, resulting in impaired insulin production and hyperglycemia. Patients often present for the first time to the emergency department with diabetic ketoacidosis – this potentially fatal condition is characterized by metabolic acidosis, ketoacids in the serum and urine, severe dehydration, cardiovascular instability, and respiratory distress. If left untreated, patients will typically die.
Type 1 diabetes is very difficult to control and typically requires the help of an Endocrinology specialist. Chronically poorly controlled diabetes is a leading cause of cardiovascular, kidney disease, and retinal disease.
What is Type 2 Diabetes?
Type 2 Diabetes is a disorder characterized by abnormally high blood sugar levels usually caused by insensitivity to insulin. Insulin production is normal in type 2 diabetics. The condition is frequently associated with a family history and is seen in obese individuals. It is a leading risk factor for the development of heart attack, stroke, and peripheral vascular disease. It is also a leading cause of kidney disease, blindness, and death in the United States.
What Causes Type 1 Diabetes?
Type 1 diabetes is caused by autoimmune destruction of the pancreatic islets cells resulting impaired insulin production. Insulin is an endocrine hormone responsible for glucose metabolism and homeostasis. Insulin helps drive glucose into cells for energy use and promotes the synthesis of glycogen in the liver – glycogen is a storage form of glucose. When insulin insufficiency produced, serum glucose levels remain elevated – long-term elevations in glucose are deleterious.
When glucose levels are significantly elevated, the kidneys’ capacity to reabsorb glucose gets overwhelmed– as a result, glucose gets spilled into the urine and water and sodium closely follow. The end-result of this process is severe dehydration as glucose, sodium, and water get dumped in the urinary tract and excreted out of the body through urine.
In type 1 diabetes, the body is in a state of starvation. Serum glucose levels are elevated, but glucose has trouble entering cells and cannot be metabolized. The body begins turning fat (triglycerides) into ketones in order to generate energy for metabolism. Ketones are acidic compounds that acidify the blood – severe acidosis may lead to respiratory failure and cardiovascular instability.
Glucose that is “lying around” and not being used is eventually converted to triglycerides (a type of fat). If fact, hyperlipidemia is a common comorbidity of diabetes mellitus – types 1 and 2. Fat enters the blood vessels leading to atherosclerosis, which further increases cardiovascular risk.
What Causes Type 2 Diabetes?
Type 2 diabetes is caused by insensitivity to insulin. In other words – there is no problem with insulin production, the problem is that tissues cannot properly handle insulin and use glucose. Diabetes is frequently associated with obesity, high cholesterol, elevated blood pressure (hypertension), kidney failure, heart disease, and stroke.
Long-term elevations in blood sugar lead to tissue injury and inflammation. This is especially problematic in the arteries, where it promotes the formation of fatty plaques. Arterial plaques lead to reduced blood supply to tissues and organs such as the heart, kidneys, eyes, and nervous system.
The most common risk factors for diabetes include:
- Family history
- Alcohol use
- Sedentary lifestyle
- Poor diet
Other conditions such as low thyroid function (hypothyroidism), Cushing syndrome, and certain medications (e.g. corticosteroids, beta blockers) can also cause diabetes.
How Common is Type 1 Diabetes?
Type 1 diabetes is exceedingly common in the United States and responsible for frequent primary care and emergency department visits. The condition often requires referral to an endocrinology specialist.
The disease most frequently affects children, but about 25% of cases occur in adults. About 2/3rds of new diagnoses of diabetes occur in Americans age <19.
How Common is Type 2 Diabetes?
Type 2 diabetes is an extremely common condition that is frequently evaluated in the primary care clinic. Advanced cases may require referral to an Endocrinology specialist. It is a leading cause of heart disease, stroke, kidney failure, blindness, and death in the United States.
It affects approximately 12% to 14% of Americans. The prevalence of diabetes is on the rise due to the Western diet and lifestyle.
Signs and Symptoms of Type 1 Diabetes
Symptoms of type 1 diabetes often include:
- Excessive thirst & drinking – polydipsia
- Frequent urination - polyuria
- Increased appetite & food intake - polyphagia
The excessive hunger and appetite are a consequence of the fact that the body is in a state of starvation – even though glucose levels are elevated, the body cannot use it for energy. Frequent urination occurs because of excessive spillage of glucose, sodium, and water into the urinary tract. This also is the cause of increased thirst and desire to drink. As opposed to type 2 diabetes, patients with type 1 diabetes are frequently thin or skinny – type 2 diabetics are generally overweight or obese.
Patients with diabetic ketoacidosis are typically very ill and often present acutely with:
- Respiratory distress
- Abdominal pain
- Nausea & vomiting
- Severe dehydration
Diabetic ketoacidosis can be provoked by insulin non-compliance, dietary non-compliance, infection, myocardial infarction (heart attack), or use of corticosteroids. If left untreated, diabetic ketoacidosis may lead to death.
Long-term complications of type 1 diabetes include:
- Cardiovascular disease – myocardial infarction (heart attack), coronary artery disease, heart failure, peripheral vascular disease
- Foot ulcers and infection
- Neurologic disease – stroke, peripheral neuropathy
- Renal disease – chronic kidney disease, diabetic nephropathy
- Gastrointestinal disease – gastroparesis, fatty liver disease
- Eye disease – retinopathy, glaucoma, blindness
Signs and Symptoms of Type 2 Diabetes
The classic symptoms of diabetes usually occur in type 1 diabetes and include:
- Eating excessively (polyphagia)
- Excessive thirst (polydipsia)
- Frequent urination (polyuria)
Patients with severe type 2 diabetes may also develop these symptoms and often require the use of insulin to control their blood sugar levels.
Other symptoms of diabetes that occur due to its complications include:
- Eye disease leading to blindness (retinopathy)
- Kidney failure – results in high blood pressure and swelling in the legs
- Heart attack – chest & difficulty breathing – although heart attacks in diabetes may be “silent”
- Nerve damage in the feet & hands (peripheral neuropathy) causes burning pain
You may also develop complete loss of sensation and ulcer formation in the feet, which is a very dangerous sign. Complete sensory loss can also result in problems with balance. The foot examination is a critical part of the physical examination in patients with diabetes.
Type 1 Diabetes Diagnosis
The diagnosis of type 1 diabetes is suggested based on symptoms and physical examination but typically confirmed with laboratory studies. The diagnostic guidelines for type 1 diabetes are similar to that of type 2 diabetes and based on fasting glucose, random glucose, and hemoglobin A1C levels:
- Fasting plasma glucose ≥126 mg/dL on 2 occasions
- Plasma glucose ≥200 mg/dL with hyperglycemia symptoms
- Positive oral glucose tolerance test - plasma glucose ≥200 mg/dL 2 hours after a standard glucose load
- Hemoglobin A1C ≥6.5%
Besides serum glucose and hemoglobin A1C levels, other commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), thyroid function (TSH, free T4), and cholesterol levels. Your doctor will also typically perform a urinalysis and check a urine microalbumin level. If you have hypertension or symptoms of heart disease, your doctor may obtain a chest x-ray, EKG (electrocardiogram), and ultrasound of the heart (echocardiogram).
Type 2 Diabetes Diagnosis
Diabetes is primarily diagnosed based on blood tests evaluating your glucose levels and hemoglobin A1C. Hemoglobin A1C gives your doctor an idea of how well your diabetes has been controlled in the past several months. The diagnosis of diabetes is made when your fasting glucose is >126 mg/dL, random blood glucose is >200, or if your hemoglobin A1C is >6.5%.
Your doctor will also likely order blood tests such as a CMP (comprehensive metabolic panel), CBC (complete blood cell count), cholesterol levels, urine microalbumin, and urine analysis.
If they suspect that you have heart disease they will likely obtain an EKG (electrocardiogram), and ultrasound of the heart (echocardiogram).
Type 1 Diabetes Medication
Type 1 diabetes is treated with insulin – this should typically be managed by an Endocrinology specialist. Meal and dietary activity should be ideally coordinated with physiologic insulin replacement – this involves frequent glucose monitoring.
For patients with type 1 diabetes, the goal of insulin therapy is to provide a physiologic amount of insulin by giving a basal level of insulin (daily or twice-daily injections of a long-acting insulin, or continuous insulin pump) and pre-meal bolus doses of a short-acting insulin. There are a variety of multiple daily injection regimens and the choice of basal and pre-meal bolus insulin depends upon patient preference, lifestyle, and cost. Continuous subcutaneous insulin infusion uses only short-acting insulins.
Examples of long-acting insulin include:
Examples of intermediate-acting insulin include:
- NPH (insulin isophane)
Examples of short and rapid-acting insulin include:
Blood glucose monitoring with a glucose meter is generally performed 4-7 times daily – usually before meals, mid-morning, mid-afternoon, and before bedtime. Continuous glucose monitoring devices monitor blood glucose levels in real time.
For adults with type 1 diabetes, the goal is typically to achieve an A1C value of <7%.
Type 2 Diabetes Medication
The treatment of type 2 diabetes is multifaceted and includes diet and exercise. Patients are encouraged to eat a low-carbohydrate diet. If you eat carbohydrates, they should be derived from fruits, whole wheat or whole grain products, or oatmeal. Your doctor will ask you to avoid sugar from sources such as high-fructose corn syrup, candy, pastries, or cakes. Patients with diabetes should also avoid alcohol use.
The most commonly prescribed drugs for type 2 diabetes include:
- Glucophage (metformin)
- Glucotrol (glipizide)
- Precose (acarbose)
- Glyset (miglitol)
- Byetta (exenatide)
- Prandin (repaglinide)
- Victoza (liraglutide)
- Januvia (sitagliptin)
- Jardiance (empagliflozin)
- Invokana (canaglifozin)
- Farxiga (dapagliflozin)
Patients with severe disease may also require the use of insulin.
- Levemir (insulin detemir)
- Lantus (insulin glargine)
- NovoLog Mix 70/30 (insulin aspart protamine-insulin aspart)
- Humalog Mix 75/25 (insulin lispro protamine-insulin lispro)
- Humalog Mix 50/50 (insulin lispro protamine-insulin lispro)
Your doctor may start you on low-dose aspirin depending on your age and presence of other cardiovascular risk factors. Patients with diabetes are also usually treated with cholesterol-lowering medications (eg, Lipitor - atorvastatin) and blood pressure reducing therapies (e.g., Zestril - lisinopril, Cozaar – losartan).
- Nathan DM, Cleary PA, Backlund JY, et al. Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes. N Engl J Med 2005; 353:2643. - https://www.nejm.org/doi/full/10.1056/NEJMoa052187
- Chiang JL, Kirkman MS, Laffel LM, et al. Type 1 diabetes through the life span: a position statement of the American Diabetes Association. Diabetes Care 2014; 37:2034. - https://www.ncbi.nlm.nih.gov/pubmed/24935775
- Fatourechi MM, Kudva YC, Murad MH, et al. Clinical review: Hypoglycemia with intensive insulin therapy: a systematic review and meta-analyses of randomized trials of continuous subcutaneous insulin infusion versus multiple daily injections. J Clin Endocrinol Metab 2009; 94:729. - https://www.ncbi.nlm.nih.gov/books/NBK76647/
- Pippitt K, Li M, Gurgle HE. Diabetes Mellitus: Screening and Diagnosis. Am Fam Physician. 2016 Jan 15;93(2):103-9. - https://www.ncbi.nlm.nih.gov/pubmed/20353144
- Screening for Abnormal Blood Glucose and Type 2 Diabetes Mellitus: Recommendation Statement. Am Fam Physician. 2016 Jan 15;93(2):Online. - https://www.aafp.org/afp/2016/0615/p1025.html
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.