Diabetes Mellitus and long term impact on overall health - Comprehensive overview of complications of Diabetes Mellitus

The silent killer - Diabetes Mellitus

Reality check:

Statistics published by WHO in November 2021 are as follows:

  • Diabetes is a major cause of blindness, kidney failure, heart attacks, stroke and lower limb amputation.
  • Between 2000 and 2016, there was a 5% increase in premature mortality from diabetes.
  • In 2019, diabetes was the ninth leading cause of death with an estimated 1.5 million deaths directly caused by diabetes.

Unfortunately, even those patients who otherwise seem well aware, fail to comprehend the enormity of the medical condition “Diabetes Mellitus”. For the majority, diabetes is a “disease of excessive blood sugar” to be controlled by restricting sugar intake. And the complications arising out of diabetes are considered a “natural progression” of the disease.

                                    Reality couldn’t be farther from the truth.

Diabetes is defined as “a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long-term damage, dysfunction, and failure of different organs, especially the eyes, kidneys, nerves, heart, and blood vessels.
Body response to increase in blood glucose levels.
Body response to presence of glucose in blood. 

The distinction between the sugar consumed in our food and the blood glucose (which is the product of metabolism post digestion of food) is lost on most patients. As a consequence, during the early stages of the disease adequate precautions or control of blood glucose levels is not exercised leading to complications of Diabetes Mellitus.

Complications due to diabetes mellitus can be divided into 2 groups:

Acute complications

  1. Hypoglycaemia :

The Diabetes Control and Complications Trial (DCCT) defines diabetes as. : Low blood glucose (RBS <50 mg/dl) along with symptoms such as profuse sweating, palpitations, blurred vision, irrational speech, confusion, seizures, coma

Hypoglycaemia is more commonly seen in patients with type 1 Diabetes Mellitus. It is also seen frequently in type 2 Diabetes Mellitus on insulin therapy.

Hypoglycemia unawareness is a life threatening condition where a patient does not have initial symptoms of low blood glucose and can present with severe symptoms such as convulsions and coma. It’s commonly seen in elderly patients and those on sulphonylurea group of anti diabetic drugs.

2. Diabetic Ketoacidosis (DKA) :

Diabetic Ketoacidosis (DKA) is a potentially life-threatening complication, more commonly seen in patients with DM-1, who are insulin dependent. The condition develops when your body cant produce enough insulin. This leads to breakdown of fats for fuel by the body leading to excessive production of acids called ketones.

Typically respiratory or urinary infections act as a trigger for development of DKA.

Symptoms develop within 24 hours and include -

  1. excessive thirst
  2. frequent urination
  3. stomach pain of unknown cause
  4. fruity scented breath
  5. confusion.
  6. Lab findings of high blood glucose and high urinary ketones clinch the diagnosis.
Summary of DKA

3.Hyperosmolar hyperglycemic state (HHS) :

This is another life threatening complication in chronic diabetics, where a person’s blood glucose levels are too high for long period of time leading to dehydration and increase in blood osmolarity. Though the symptoms are similar to DKA, there are key differences such as:

  • Mainly seen in type 2 DM
  • Develops over a period of time
  • Patients are obese (in DKA, patients are thin built)
  • Absence of ketone bodies in urine
  • Lack of fruity smell to breath

Factors predisposing to HHS are :

  • History of stopping medications of DM
  • Preceding serious health condition such as heart attack or stroke
  • Medications such as diuretics

As the symptoms develop over days or weeks, it can get difficult to diagnose early. Symptoms include:

  1. Increased Blood glucose levels > 600mg/dl
  2. CNS symptoms - confusion, drowsiness, stupor, hallucinations, coma
  3. Extreme thirst and dry mouth
  4. Increased urination
  5. Blurred vision
  6. Hemiparesis/hemiplegia (weakness or paralysis of one side of body)

Both DKA and HHS are medical emergencies and need hospital admission for prompt diagnosis and treatment.

Chronic complications

Chronic complications develop insidiously and many times are the presenting symptoms of the patients. The risk of developing the complications is a direct function of duration of the disease and degree of hyperglycaemia i.e. high blood glucose levels.  A poorly controlled diabetic patient has much higher risk of developing complications as compared to a patient who has well controlled diabetes.

Generally the injurious effects of high blood glucose are divided into:

Macro vascular complications

Pathogenesis of macro vascular disease is accelerated atherosclerosis. Deposition of fats in the inner lining of arteries is a consequence of ageing as well as function of lifestyle. This is called atherosclerosis. Hyperglycaemia is an independent risk factor for atherosclerosis thus leading to premature onset heart diseases in diabetes.

American Diabetes Association (ADA) and American Heart Association(AHA) have declared Diabetes as a coronary disease equivalent.

Clinical outcome of macro vascular complications are thus:

  1. Coronary Artery Disease (CAD): angina, acute myocardial infarction (heart attack), sudden cardiac arrest, heart failure, arrhythmias and Ischaemic Heart Disease (IHD)

In the majority of diabetic patients, mild cardiac events go unnoticed as prolonged hyperglycemia blunts the autonomic nervous system leading to lack of pain perception. In fact the same leads to painless injuries and ulcers of lower limbs, but that will be addressed further.

2. Cerebrovascular Disease: Diabetic patients are more susceptible to Transient Ischemic Attacks (TIAs) and Strokes as compared to non diabetic patients especially those patients who have coexisting CAD. Also the recurrence of stroke and the complications arising out the same are common in diabetic patients.

3. Peripheral Arterial Disease (PAD): The statistics suggest that prevalence of PAD in non diabetic population < diabetic male (2-3 times) < diabetic female (5-6 times).

Along with diabetes, concomitant presence of the following factors increases the risk of developing PAD:

  • Hypertension
  • Dyslipidemia
  • Smoking
  • Poor glycemic control
  • Peripheral neuropathy
Diabetes mellitus remains the commonest cause of non traumatic limb amputations.

Micro vascular complications

Chronic hyperglycemia is the causative factor in developing micro vascular complications in both type 1 and type 2 Diabetes Mellitus. 4 theories have been proposed to explain the biochemistry of cellular damage occurring as a consequence of chronic hyperglycemia. Each theory is plausible and probably it is the combinations of various cellular level mechanisms that lead to irreversible damage to each organ system.

The Diabetes Control and Complications Trial (DCCT) provided definitive proof that reduction in chronic hyperglycemia can prevent many early complications of type1 DM.

Let’s discuss the important microvascular complications that affect the quality of life in diabetic patients.

  1. Diabetic nephropathy

Diabetic Kidney Disease (DKD) along with Hypertension remain the primary health conditions leading to Chronic Kidney Disease (CKD) and End Stage Renal failure.

Proteinuria (detection of proteins in urine) is a telltale sign of Diabetic Nephropathy.
DKD is clinically defined by presence of proteinuria ≥ 0.5gm/24 hours or persistent albuminuria ≥ 300mg/24 hour or ≥ 200mcg/min + presence of diabetic retinopathy and absence of other causes of renal system disorder.
Microalbuminuria is defined as persistent albuminuria in the range of 30 - 299 mg/24hours and is considered to be the earliest manifestation of diabetic nephropathy.

2. Diabetic neuropathy

Diabetic neuropathy (DN) is defined as the presence of symptoms and/or signs of peripheral nerve dysfunction in people with diabetes after the exclusion of other causes. - API textbook of Medicine.

In layman terms, nerve damage seen in diabetic patients due to prolonged hyperglycemia.
The incidence of DN in India is not well known but in a study from South India 19.1% type 2 diabetic patients had peripheral neuropathy.

Diabetic Neuropathy (DN) most often damages the nerves of legs and feet, but it can also affect the digestive system, urinary tract and heart.

Some of the common symptoms of DN are:

  1. Numbness or pain in limbs (feet more common than hands)
  2. Slippers slipping out of legs while walking
  3. Loss of touch sensitivity - causes small cuts on feet which can fester leading foot ulcers.
  4. Burning sensation in feet, more common at night.
  5. Abdominal bloating
  6. Bowel dysfunction - diarrhoea/constipation
  7. Postural hypotension
  8. Incomplete bladder emptying
  9. Arrhythmias - can lead to sudden cardiac arrest.

Diabetic Foot Ulcers are late sequelae of DN which may result in amputation and Charcot (neuropathic) arthropathy.

3. Diabetic retinopathy (DR)

Prolonged hyperglycemia induced damage to blood vessels of the light sensitive part of the eye i.e. retina leads to complications in eyesight. This is called as Diabetic Retinopathy. The risk of developing DR is rectory proportional to the duration of diabetes mellitus.

DR is asymptomatic to begin with, hence patients with Type 1 DM need to undergo dilated fundus examination (diabetic eye check up) annually.

Patients diagnosed with Type 2 DM need to get the fundus examined at the time of the diagnosis as the time of onset and duration of DM is difficult to predict.

Symptoms include: Floaters in eyes, blurred vision, fluctuating vision eventually leading to blindness if not treated in a timely fashion.

Other eye complications commonly seen in diabetes are cataracts and glaucoma.

4. Sexual dysfunction

Both men and women are equally affected by abnormalities in sexual function due to diabetes.

Erectile Dysfunction(ED) is commonly seen in diabetics and affects quality of sexual experience for both men and their partners. ED can be a presenting symptom of previously undiagnosed diabetes. Onset of ED in diabetics is associated with increasing age, duration of diabetes, damage to small blood vessels, neuropathy, alcohol consumption and anti hypertensive medications.

Common symptoms in women include lack of arousal and vaginal lubrication.

5. Infections

Diabetes is considered as a secondary immune deficiency disorder by the World Health Organization (WHO).

Chronic Hyperglycemia is the culprit again as it overwhelms the various components of the immune system leading to inadequate immune response. Increased predilection to infections affects the blood glucose control which in turn leads to delayed recovery from infections.

  • Fungal infections : very common, but often neglected. eg oropharyngeal candidiasis, vulvovaginal candidiasis, inter-trig Indus candidiasis (can lead to gangrene of foot)
  • Chronic cholecystitis
  • Chronic urinary tract infections and pyelonephritis (pus formation in kidneys)
  • Mucormycosis: typically starts in the sinuses of the nose, but rapidly spreads to the brain.
  • Infections of gums and teeth.
  • Tuberculosis: more common in diabetics and diagnosed late as typical symptoms are absent, more cavitary lesions in lungs, greater incidence of hemoptysis, lesser chance of spread outside lungs.
  • Hepatitis C infection.

Early diagnosis and adherence to treatment, which includes lifestyle modification, is essential to prevent or at least delay the onset of complications of diabetes.

A few habit hacks if implemented early in the disease ensures good diabetes control.

  • Regular exercise
  • Consuming low glycemic index foods. This is significant and is explained in the previous blog - good carbs, bad carbs
  • Managing stress
  • Good sleep hygiene
  • Regular health check ups which includes eye, feet and dental check ups.
  • Avoiding smoking.
  • Managing weight such that BMI is maintained in the healthy range of 18.5 - 24.9
  • Maintaining blood pressure within acceptable limits.

It’s important to maintain healthy blood glucose levels

  • FBS (Fasting Blood Glucose): between 70 - n130 mg/dl
  • PPBS 2 (blood glucose level 2 hours post meals): < 180 mg/dl
  • HbA1c around 7%

Parting Words

There is light at the end of the tunnel - it is not the end of the world, if you are diagnosed with the condition. Diabetes is a health condition, and like other health conditions, the key is proper medical care and management. Work to adopt healthy lifestyle choices, follow medical advice, and keep a watch for any signs that may indicate advancing disease to seek prompt advice.

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