Introduction to Diabetes Mellitus

By

Zeeshan Naseerznaseer34@yahoo.com

What is Diabetes Mellitus

•The American Diabetes Association defines DM as a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both.

• Symptoms of acute hyperglycemia include polyuria, polydipsia, polyphagia, weight loss, blurred vision, fatigue, headache, and poor wound healing. Chronic hyperglycemia can lead to damage and potentially failure of various organs, including the eyes, heart, kidneys, blood vessels, and nerves.

Classification

• There are four clinical classes of diabetes:

• type 1, type 2, gestational, and other specific types.

Type 1: Juvenile Youth Onset, Ketosis Prone, Insulin dependent diabetes mellitus

Type 1 diabetes mellitus (T1DM) is typically characterized by an absolute insulin deficiency attributed to an autoimmune destruction of the β-cells of the islets of Langerhans. Affected individuals will have autoantibodies to glutamic acid decarboxylase, pancreatic islet β-cells, and/ or insulin. T1DM may be diagnosed at any age, but is most likely to be diagnosed prior to the age of 30 years.

Type 1: Juvenile Youth Onset, Ketosis Prone, Insulin dependent diabetes mellitus

• The rate of destruction of β-cells is rapid in infants and children and slower in adults. Thus, the presentation in young people is often ketoacidosis, whereas older persons may have a longer symptomatic prodrome and may be diagnosed on the basis of hyperglycemia and positive autoantibodies.

• Exogenous insulin is required to control to control blood glucoses, prevent diabetic ketoacidosis and preserve life. When insulin is withheld from a person with T1DM, Ketosis will develop in 8 to 16 hours and ketoacidosis in 12 to 24 hours.

Type 2, Adult Onset, Maturity Onset, Ketosis Resistant, Non insulin dependent DM

• Type 2 diabetes mellitus (T2DM) is the most common form of DM and is typically identified in individuals over the age of 30 years; however, it has become a more prominent diagnosis in adolescents of certain ethnic origins (e.g., Hispanic, African American). Those diagnosed with T2DM are typically overweight or obese, have a positive family history of diabetes, and/or exhibit signs of insulin resistance (e.g., truncal obesity, high triglycerides, low high-density lipoprotein cholesterol [HDL-C], acanthosis nigricans is a brown to black,

poorly defined, velvety hyperpigmentation of the skin.); autoantibodies found in T1DM are absent in T2DM.

Gestational Diabetes Mellitus

• Gestational diabetes mellitus (GDM) is a condition in which women first exhibit levels of elevated plasma glucose during pregnancy. Women previously diagnosed with diabetes prior to pregnancy are excluded from this classification. After pregnancy, the diagnostic classification of GDM may be changed based on postpartum testing.

• About 60% of women with GDM will develop T2DM in the ensuing 5 to 10 years and all remain at an increased risk for the development of T2DM later in life.

Gestational Diabetes Mellitus

• Gestational diabetes is caused when insulin receptors do not function properly. This is likely due to pregnancy-related factors such as the presence of human placental lactogen that interferes with susceptible insulin receptors. This in turn causes inappropriately elevated blood sugar levels.

• Insulin resistance is a normal phenomenon emerging in the second trimester of pregnancy.

Other specific types

• Secondary diabetes: occurs when the diagnosis of diabetes is a result of other disorders (e.g., Cushing syndrome, acromegaly, cystic fibrosis, Down syndrome, pancreatic disorders) or treatments (e.g., glucocorticoids, antipsychotics).

Other specific types

• Monogenic DM: (formerly maturity-onset diabetes of the young) should be considered in children with an atypical presentation or response to therapy.

• Latent Autoimmune Diabetes of the Adult (LADA): which is a slow destruction of the pancreatic β-cells similar to T2DM, but autoantibodies are present as in T1DM.

Latent Onset Diabetes In Adult

• Latent Autoimmune Diabetes in Adults (LADA) is a form of autoimmune (type 1 diabetes) which is diagnosed in individuals who are older than the usual age of onset of type 1 diabetes. Often, patients with LADA are mistakenly thought to have type 2 diabetes, based on their age at the time of diagnosis.

• LADA often does not require insulin at the time of diagnosis and may be managed with diet and exercise, but tend to require insulin therapy sooner than patients with classic T2DM.

Maturity-Onset Diabetes of the Young (MODY)

• Onset of diabetes type 2 early in life: childhood, adolescence or young adulthood.

• Maturity-Onset Diabetes of the Young or MODY affects 1-2% of people with diabetes, although it often goes un recognised. The 3 main features of MODY are:

• Diabetes often develops before the age of 25.

• Diabetes runs in families from one generation to the next.

• Diabetes may be treated by diet or tablets and does not always need insulin treatment.

NEONATAL DIABETES

• Neonatal diabetes is a form of diabetes that is diagnosed under the age of nine months. It’s a different type of diabetes than the more common Type 1 diabetes as it’s not an autoimmune condition (where the body has destroyed its insulin producing cells).

• Neonatal diabetes is caused by a change in a gene which affects insulin production. This means that levels of blood glucose (sugar) in the body rise very high.

NEONATAL DIABETES

• The main feature of neonatal diabetes is being diagnosed with diabetes under the age of 6 months, and this is where it’s different from Type 1, as Type 1 doesn’t affect anyone under 6 months.

• There are two types of neonatal diabetes – transient and permanent. As the name suggests, transient neonatal diabetes doesn’t last forever and usually resolves before the age of 12 months. But it usually recurs later on in life, generally during the teenage years. It accounts for 50-60 per cent of all cases. Permanent neonatal diabetes as you might expect, lasts forever and accounts for 40-50 per cent of all cases.

Double Diabetes

• Double diabetes is when someone with type 1 diabetes develops insulin resistance, the key feature of type 2 diabetes.

• Someone with double diabetes will always have type 1 diabetes present but the effects of insulin resistance can be reduced somewhat.

• The most common reason for developing insulin resistance is obesity and whilst type 1 diabetes is not itself brought on by obesity.

• People with type 1 diabetes are able to become obese and suffer from insulin resistance as much as anyone else.

Type 3 Diabetes

• Type 3 diabetes is a title that has been proposed for Alzheimer's disease which results from resistance to insulin in the brain.

Type 3 Diabetes

• Studies carried out by the US Brown Medical School research team identified the possibility of a new form of diabetes after finding that insulin is produced by the brain as well as the pancreas.

• Whereas type 1 and type 2 diabetes are characterised by hyperglycemia (increased blood sugar), a separate study, carried out by the University of Pennsylvania and published in 2012, excluded people with a history of diabetes, indicating that Alzheimer’s can develop without the presence of significant hyperglycemia in the brain.

Steroid Induced Diabetes

• Corticosteroids are used to reduce harmful inflammation but can lead to diabetes - often referred to as steroid diabetes.

• People on steroids who are already at a higher risk of type 2 diabetes or those who need to take steroids for longer periods of time are the most susceptible to developing steroid induced diabetes.

Brittle Diabetes (Labile Diabetes)

• Brittle diabetes mellitus (or labile diabetes) is a term used to describe particularly hard to control type 1 diabetes.

• Those people who have brittle diabetes will experience frequent, extreme swings in blood glucose levels, causing hyperglycemia or hypoglycemia.

• It can be caused by absorption problems in the intestines. This includes delayed stomach emptying, drug interactions, insulin absorption issues and malfunctioning hormones.

• Gastroperesis, delayed stomach emptying, can affect the rate at which food, glucose and insulin is absorbed into the bloodstream.

Diabetes Insipidus

• Diabetes insipidus, often shortened to DI, is a rare form of diabetes that is not related to blood sugar-related diabetes mellitus, but does share some of its signs and symptoms.

• Diabetes insipidus is simply excessive urination (polyuria) and complications thereof, caused by an antidiuretice hormone called a vasopressin.

Diabetes Insipidus

Symptoms:

• Cracked skin

• Fatigue

• Confusion

• Dizziness and even

• Unconsciousness

References

• The Washington Manual of Medical Therapeutics

• Comprehensive Pharmacy Review.

• ADA

• Diabetes.co.uk

• Diabetes UK