Diabetes Mellitus Dr Kuma Gbanan
Diabetes mellitus (DM) comprises a group of metabolic disorders that share the common phenotype of hyperglycemia (high glucose level). It could be classified as type 1 DM which is characterized by insulin deficiency and a tendency to develop ketosis, whereas type 2 DM is a heterogeneous group of disorders characterized by variable degrees of insulin resistance, impaired insulin secretion, and excessive hepatic glucose production. This implies that not every case of DM is resulting from insulin deficiency, some have the insulin but the tissues are not just sensitive to the insulin. Other specific types include DM caused by genetic defects ( maturity- onset diabetes of the young MODY) and other rare monogenic disorders, diseases of the exocrine pancreas (chronic pancreatitis, cystic fibrosis, hemochromatosis), endocrinopathies (acromegaly, Cushing’s syndrome, glucagonoma, pheochromocytoma, hyperthyroidism), drugs (nicotinic acid, glucocorticoids, thiazides, protease inhibitors) , and pregnancy (gestational DM). Type 1 DM usually results from autoimmune destruction of the pancreatic beta cells; it is also known as juvenile- onset diabetes because its peak incidence is in children and adolescents. Type 2 DM is associated with obesity. A significant portion of persons with DM are undiagnosed.
DM is associated with huge morbidity (burden) and significant mortality (death); it is the fifth leading cause of death worldwide.
The diagnosis of DM include one of the following:
•Fasting plasma glucose greater than or equal to 7.0mmol/L ( greater than or equal to 126 mg/dL)
•Symptoms of diabetes plus a random blood glucose concentration greater than or equal to 11.1 mmol/L ( greater than or equal to 200mg/dL)
•2 hour plasma glucose greater than or equal to 11.1mmol/L (greater than or equal to 200mg/dL) during a 75 g oral glucose tolerance test.
•Haemoglobin A1c greater than 6.5%
These criteria should be confirmed by repeat testing on a different day, unless unequivocal hyperglycemia is present.
It is important to mention two intermediate categories which include:
•Impaired fasting glucose in which the value of the fasting plasma glucose level is 5.6-6.9mmol/L (100-125 mg/dL)
•Impaired glucose tolerance for plasma glucose levels of 7.8-11.1 mmol/L (140-199 mg/dL) 2 hours after a 75g oral glucose load.
Individuals with impaired fasting glucose or impaired glucose tolerance do not have DM but are at substantial risk for developing type 2 DM and cardiovascular disease in the future.
Screening with a fasting plasma glucose is recommended every 3 years for individuals over the age of 45, as well as for younger individuals who are overweight (body mass index greater than or equal to 25 kg per metre square). Body mass index is one of the major objective indices for ascertaining whether one is underweight, normal weight, overweight or obese.
The clinical features of DM include polyuria (the person passes large volumes of urine frequently), polydipsia (excessive thirst), weight loss, fatigue, weakness, blurred vision, frequent superficial infections, and poor wound healing. In early type 2 DM, symptoms may be subtle and consist of fatigue, poor wound healing, and paresthesia (abnormal tingling sensation). The lack of symptoms is responsible for the delayed diagnosis of type 2 DM.
DM has acute and then chronic complications. The acute complications include diabetic ketoacidosis (DKA) , hyperglycemic hyperosmolar state (HHS) formerly known as hyperosmolar non-ketotic coma, hypoglycemia (low glucose levels), and lactic acidosis. DKA, HHS, and hypoglycemia can easily tilt the patient into unconsciousness and in a number of cases death. Lactic acidosis can also make someone go into unconsciousness. It is pertinent to state here that both elevation in plasma glucose levels and very low glucose levels can make someone go into unconsciousness. The onus is on the attending clinician to determine whether the cause of unconsciousness is due to high glucose levels or low glucose levels and then to manage approximately.
Chronic complications of DM include retinopathy refers to disease of the retina of the eye which could affect vision and might lead to blindness. Other chronic complications include chronic kidney disease, neuropathy (involvement of the nerves), erectile dysfunction, female sexual dysfunction, cardiovascular diseases, ulcers, constipation, diarrhoea.
A number of drugs are used for treating diabetes mellitus like oral glucose-lowering agents, insulin might also be used in some cases. Once the diagnosis is made, it is important that the individual adheres to the treatment outlined by their doctor.
Screening is very important because so many people have presented as cases of complications with the attendant effect.
Reference: Harrison’s Manual of Medicine, Essentials of Medicine by Davidson.