Diabetes Mellitus - Type I Diabetes Mellitus Flashcards
What is Type I Diabetes Mellitus?
A disease where the pancreas stops being able to produce insulin.
Epidemiology of Type I Diabetes Mellitus.
Childhood/Early Adult Life.
Aetiology of Type I Diabetes Mellitus.
- Unclear Aetiology.
- Genetic Component.
- Triggers : Coxsackie B Virus and Enterovirus.
Pathophysiology of Type I Diabetes Mellitus.
Autoimmune disorder where the B-cells are destroyed by the immune system, resulting in an absolute deficiency of insulin.
Hormones Involved in Blood-Glucose Homeostasis (2).
- Insulin - B cells in Islets of Langerhans of Pancreas - anabolic hormone - reduces blood sugar.
- Glucagon - a cells in Islets of Langerhans of Pancreas - catabolic hormone - increases blood sugar.
Processes of Hormones in Blood-Glucose Homeostasis (3).
- Insulin - Glycogenesis (Uptake into Liver and Muscle Cells).
- Glucagon - Glycogenolysis (Liver Breakdown of Glycogen into Glucose).
- Glucagon - Gluconeogenesis ((Liver Conversion of Proteins and Fats into Glucose).
Ideal Blood Glucose Concentration.
Between 4.4 and 6.1 mmol/L.
What is Ketogenesis?
Hepatic conversion of fatty acids into ketones - water-soluble fatty acids when insufficient glucose supply and glycogen stores are exhausted.
Physiological Ketogenesis (2).
- Normal e.g. prolonged fasting or very low carbohydrate-high fat diets when buffered (using Bicarbonate) to prevent acidosis.
- Extreme Hyperglycaemic Ketosis - Metabolic Acidosis (Diabetic Ketoacidosis).
Important Aspects of Diabetic Ketoacidosis (3).
KDP :
- Ketoacidosis.
- Dehydration.
- Potassium Imbalance.
How is Dehydration caused by Diabetic Ketoacidosis? (5)
- Hyperglycaemia overwhelms kidneys.
- Glucose is filtered into the urine.
- Osmotic Diuresis.
- Polyuria - Severe Dehydration.
- Stimulation of Thirst Centre - Polydipsia.
How is Potassium Imbalance caused by Diabetic Ketoacidosis? (5)
- Insulin normally drives Potassium into cells.
- In DKA, serum Potassium is high/normal but total body Potassium is low.
- Treatment with Insulin means Potassium rapidly enters cells.
- Severe Hypokalaemia.
- Arrhythmias.
Clinical Features of Diabetic Ketoacidosis.
- Polyuria & Polydipsia.
- Nausea and Vomiting.
- Acetone ‘Pear-Drops’ Smell Breath.
- Dehydration & Hypotension.
- Altered Consciousness.
- Symptoms of Underlying Trigger e.g. Sepsis.
- Abdominal Pain.
- Kussmaul Respiration (Deep Hyperventilation).
Clinical Features of Type I Diabetes Mellitus (5).
- Weight Loss.
- Polydipsia.
- Polyuria.
- Secondary Enuresis (Bedwetting in a Previously Dry Child).
- Recurrent Infections.
Monitoring Blood Glucose (3).
- HbA1C - Glycated Haemoglobin (over last 3 months) : measure every 3-6 months in red-top EDTA bottle (target : 48 / 6.5%).
- Capillary Blood Glucose (target : 5-7 on waking and 4-7 before meals).
- Flash-Glucose Monitoring.
Diagnosis of Diabetic Ketoacidosis (3).
- Hyperglycaemia (Blood Glucose > 11).
- Ketosis (Blood Ketones > 3).
- Acidosis (pH < 7.35).
Management of Diabetic Ketoacidosis (7).
FIG-PICK :
- F - IV Fluid Resuscitation with Normal Saline e.g. 1L STAT then 4L with added Potassium over next 12 Hours.
- I - Insulin Infusion e.g. Actrapid at 0.1 unit/kg/hour.
- G - Glucose (Monitor and Dextrose Infusion if below 14).
- P - Potassium (Monitor and Correct).
- I - Infection (Treat Underlying Triggers).
- C - Chart (Fluid Balance).
- K - Ketones (Monitor Directly or Use Bicarbonate Monitoring).
* correct dehydration over 48 hours to reduce risk of cerebral oedema
Important Consideration Before Stopping FIG-PICK.
Establish the patient on their normal SC Insulin regime prior to stopping the insulin and fluid infusion. Continue Long-Acting Insulin and Stop Short-Acting Insulin.
Investigations in Type I Diabetes Mellitus (5).
- Urine Dipstick for Glucose and Ketones.
- Fasting and Random Glucose Levels.
- HbA1C NOT Accurate.
- C-Peptide : Low.
- Diabetes-Specific Antibodies.
Give 4 Diabetes-Specific Antobodies.
- Antibodies to Glutamic Acid Decarboxylase (Anti-GAD).
- Islet Cell Antibodies (ICA) against Cytoplasmic Proteins in B-Cells.
- Insulin Autoantibodies (IAA).
- Insulinoma-Associated-2-Autoantibodies (IA-2A).
Diagnostic Criteria for Type I Diabetes (2).
- Hyperglycaemia + 1 of : Ketosis, Rapid Weight Loss, Age < 50, BMI < 25 Personal/Family History of Autoimmune Disease.
- Consider C-Peptide and Diabetes-Specific Autoantibody Titres if Unsure Between Types.
Management of Type I Diabetes Mellitus (5).
- Patient Education.
- SC Insulin Regimes (Combination of Background Long-Acting Insulin OD AND Short-Acting Insulin 30 minutes at meals).
- Monitor Dietary Carbohydrate Intake.
- Monitor Blood-Glucose on Waking, at each Meal and Before Bed.
- Monitor for and Manage Complications.
Why should patients cycle their injection sites? (3)
- Injecting into the same spot can cause Lipodystrophy.
- Subcutaneous fat hardens.
- Patient does not absorb insulin properly from further injections into this spot.
When is Metformin indicated in Type I Diabetes Mellitus?
If BMI is above 25.
Sick-Day Rules of Diabetes Patients (4).
- Increase Frequency of Blood-Glucose Monitoring.
- Encourage Fluid Intake (3L in 24 hours).
- Sugary Drinks if struggling to eat.
- Continue Insulin (risk of DKA if stopping).
Short-Term Complications of Type I Diabetes Mellitus (2).
- Hypoglycaemia.
2. Hyperglycaemia and DKA.
Management of Hypoglycaemia (2).
- Combination of rapid-acting glucose (e.g. Lucozade) and slower-acting carbohydrates (e.g. biscuits and toast).
- Severe : IV Dextrose and IM Glucagon.
Management of Hyperglycaemia (2).
- No DKA : Increase Insulin Dose.
2. DKA : Admission.
Long-Term MACROVASCULAR Complications of Type I Diabetes Mellitus (4).
- Coronary Artery Disease.
- Peripheral Ischaemia - Poor Healing, Ulcers, Diabetic Foot.
- Stroke.
- Hypertension.
* chronic exposure to hyperglycaemia causes damage to endothelial cells of blood vessels.
Long-Term MICROVASCULAR Complications of Type I Diabetes Mellitus (3).
- Peripheral Neuropathy.
- Retinopathy.
- Nephropathy - especially Glomerulosclerosis.
* leaky malfunctioning vessels that are unable to regenerate.
Long-Term INFECTIOUS Complications of Type I Diabetes Mellitus (4).
- Urinary Tract Infections.
- Pneumonia.
- Skin/Soft Tissue Infections (e.g. Feet).
- Fungal Infections (e.g. Oral/Vaginal Candidiasis).
* suppression of immune system
Pathophysiology of Cerebral Oedema (4).
- Dehydration and Hyperglycaemia cause water to move from the intracellular space in the brain into the extracellular space.
- Shrinkage and Dehydration of Brain Cells.
- Rapid Correction of Dehydration and Hyperglycaemia causes a rapid shift into cells.
- Cerebral Oedema - Brain Cell Destruction and Death.
Management of Cerebral Oedema (4).
- Monitor neurology e.g. GCS every hour and check for headaches, altered behaviour, bradycardia or changes to consciousness.
- Slow IV Fluids.
- IV Mannitol.
- IV Hypertonic Saline.
Insulin Regimes in Type I Diabetes Mellitus.
BASAL - BOLUS REGIME :
- Basal - Injection of Long-Acting Insulin = Lantus in the evening.
- Bolus - Injection of Short-Acting Insulin = Actrapid TDS before meals.
Complications of DKA (6).
- Ketonaemia and Acidosis should resolve within 24 hours.
1. Gastric Stasis.
2. Thromboembolism.
3. Arrhythmias.
4. Cerebral Oedema, Hypokalaemia, Hypoglycaemia.
5. ARDS.
6. AKI.