Diabetes & Obesity Flashcards
(24 cards)
Healthy blood glucose range
3.9 - 6.1 mmol/L
Hormones that Decrease Blood Glucose
in response to high BG
Insulin secreted from B-cells in the Islets of Langerhans in the pancreas, converts excess glucose to tissue stores - muscle / liver glycogen
Hormones that Increase Blood Glucose
in response to low BG / Stress
Glucagon (secreted from a-cells in the Islets of Langerhans in the pancreas) converts glycogen tissue stores to restore normal blood glucose.
Growth Hormone (secreted from anterior pituitary)
Cortisol (from Adrenal Cortex)
Adrenaline (from Adrenal Medulla)
Stress Response
Cortisol and Adrenaline work to convert tissue stores to mobilise glucose into the blood stream.
Diabetes Mellitus =
Diabetes Mellitus = group of disorders with many different causes, all are characterised by a persistently raised blood glucose level.
What is:
TYPE 1 Diabetes Mellitus
- Diminished insulin production
- Destruction of B-islet cells in pancreas
- Usually auto-immune process; infiltration of lymphocytes - T-lymphocytes infiltrate B -islet cells -> inflammatory destruction. Auto-antibodies present in most.
- Disease typically manifests once approx. 90% of B-islet cells destroyed
What is:
TYPE 2 Diabetes mellitus
Complex metabolic disorder characterised by varying degrees of insulin resistance - insulin present but cells are resistant to its actions:
o Insulin resistance = the central metabolic abnormality in most cases of type 2 diabetes mellitus
o Failure of the intracellular signalling pathways that normally operate once insulin has bound to the cell surface. Results in reduced ability:
- Of Muscle and fat cells to take up glucose
- To suppress liver glucose production after eating
The net consequence is raised circulating blood glucose levels.
- Dysfunction of -islet cells in pancreas
o Deregulation of normal homeostatic mechanisms that control insulin production
o Deregulation results in failure to produce appropriate insulin levels when eating or fasting
o Initial hyperinsulinaemia - insulin levels increased to counteract the insulin resistance
As the disease progresses over many years there is late hypoinsulinaemia as the -cells fail.
Gestational Diabetes Mellitus
- Occurring or first recognised in pregnancy
1-2% of Caucasian pregnancies
Higher risk in Asians. - Incidence increasing - obesity, pregnancy later in life
- Insulin resistance develops in second half of pregnancy
- Gestational diabetes or glucose intolerance? - Mostly resolves once the baby has been born. 60% will go on to develop diabetes later in life.
TYPE 1 Diabetes mellitus
Epidemiology
< 10%
Peak incidence approx 14 years old
TYPE 2 Diabetes mellitus
Epidemiology
> 90%
Many undiagnosed - presentation more chronic (T1 more acute)
Primarily an illness of middle-age and older - onset typically much later than type 1 DM
Highest risk group = Certain ethnic groups who adopt western lifestyle e.g. immigrants from south-east Asia to UK have a 4-6 fold increased risk of diabetes mellitus compared to Caucasians.
TYPE 1 Diabetes mellitus
Clinical presentation
Rapid clinical onset; pt becomes progressively unwell over a period of week or a matter of days = ‘classic presentation’
- Polyuria - excess urine
- Polydipsia - excessive thirst
- Polyphagia - increased appetite
- Weight loss
- Fatigue
- Blurred vision
- Diabetic Ketoacidosis = classic presentation of T1 DM, most typical in very young
TYPE 2 Diabetes mellitus
Clinical presentation
- No dramatic onset, evolves over long time frame (unlike type 1). Symptoms development and evolution not always noticed by patient (mostly obese - but not all).
Symptoms usually develop without weight loss and are typically (but not always) associated with:
- Weight gain
- Dehydration - polydipsia & polyuria
- Fatigue
TYPE 1 Diabetes mellitus
Diagnosis
Blood Glucose
- Typically very high at first presentation
Ketones in Urine
- POSITIVE if D.K.A.
TYPE 2 Diabetes mellitus
Diagnosis
Fasting blood glucose
- Pt fasts overnight
- Diabetes diagnosed if ≥7.0mmol/L fasting venous plasma glucose on more than one occasion (unless very high)
Ketones in urine
- NEGATIVE
DM - Associated Chronic Illnesses
(-> damage to blood vessels and nerves)
Small vessel disease - capillary endothelial damage and basement membrane thickening
Large artery disease -
**Accelerated atherosclerosis
Neuropathy - somatic and autonomic nerves
Metabolic Syndrome =
Descriptive term for the co-existence of several major risk factors for cardiovascular disease. Tightly linked to obesity - weight reduction significantly reduces adverse outcomes.
Metabolic Syndrome Abnormalities
MS Abnormalities: Glucose intolerance Hyperinsulinaemia Insulin resistance Hypercortisolism Dyslipidaemia
Metabolic Syndrome Overt Disease
MS Overt Disease: Type 2 diabtes mellitus Coronary heart disease Polycystic ovary disease Central fat distribution Morbid obesity Hypertension Stress & depression
Possible Consequences of DM
Diabetic retinopathy -> blindness
Renal failure - Leading cause of renal impairment and failure - accounts for 1in5 people starting renal dialysis
Diabetic Foot - most common in Caucasians and men>60yrs old
Impaired wound healing
Sexual dysfunction - Male erectile dysfunction common (55-59yr olds 52.4%)
High glucose ideal for secondary bacterial or fungal infections e.g. candidiasis
Increased risks to foetus and mother during pregnancy
Exacerbated periodontal disease
Altered saliva quality and quantity - Xerostomia
Sialosis (enlargement of the major salivary glands)
Oral dysaesthesia = painful, burning sensation in the mouth
DM + Illness or trauma
Insulin requirements increase
Beware painful dental infection
Decrease diet and increase insulin needs, especially if patient decreasing insulin as eating less
Diabetes Mellitus & HbA1C
Haemoglobin becomes glycosylated in presence of glucose
HbA1C gives a measure of glycosylated haemoglobin = good indicator of glycaemic control over last 8-12 weeks
Health = 20-41 mmol/mol
Diabetes good control = <59 mmol/mol
T1 DM Management
Insulin
Smoking cessation
T2 DM Management
Diet & exercise
Weight loss
Oral Hypoglycaemic Agents - e.g. Metformin
Consequences of Long-standing Obesity
- Metabolic Syndrome closely linked to obesity
- Reduced life expectancy
- T2 DM
- Hypertension, Heart Failure, Stroke
- Coronary Heart Disease
- Dyspnoea - Breathlessness
- Obstructive Sleep Apnoea
- Asthma
- Osteoarthritis
- Menstrual disturbances and reduced fertility in women
- Excessive sweating
- Depression & low self-esteem
