Endocrine Flashcards
What is the function of insulin?
- Suppress hepatic glucose output
- Increase glucose uptake into insulin sensitive tissues
- Suppress lipolysis and breakdown of muscle
What is the function of glucagon?
- Increase hepatic glucose output
- Reduce peripheral glucose uptake
- Stimulate peripheral release of gluconeogenic precursors
- Gluconeogenic precursors = glycerol and AA’s which cause lipolysis and muscle glyconeolysis and breakdown
Define Type I DM
Autoimmune destruction of pancreatic beta cells leading to complete insulin deficiency
Epidemiology of Type I DM
- Presents age 5-15
- Accounts for 10% of all diabetes
Risk factors of Type I DM
- HLA DR3-DQ2 or HLA DR4-DQ8
- Northern European
- Autoimmune disease - 90%
Pathophysiology of Type I DM
- Autoantibodies attack Beta cells in Islets of Langerhans
- Creates insulin deficiency
- Leads to hyperglycaemia
- Continuous breakdown of glycogen from liver (gluconeogenesis)
- Leads to glycosuria
Signs and symptoms of Type I DM
- Classic triad = polydipsia, polyuria, weight loss (BMI<25)
- Possible ketosis
Diagnosis of Type I DM
Random plasma glucose > 11mmol/L
Fasting plasma glucose > 7 mmol/L
Treatment of Type I DM
- Insulin
- Short acting insulin (4-6h)
- Longer acting insulin (12-24h)
Aetiology of Type II DM
- gradual insulin resistance/pancreatic beta cells fail to secrete enough insulin OR BOTH
- Cushing’s
- Chronic pancreatitis
Risk factors of Type II DM
- Lifestyle - obesity, exercise, excess calorie/alcohol
- Asian men
- > 40 yrs
- Hypertension
Signs and symptoms of Type II DM
- Polydipsia
- Polyuria
- Glycosuria
- Central obesity
- Slow onset
- Blurred vision
Diagnosis of Type II DM
- Fasting plasma glucose > 7 mmol/L
- Random plasma glucose > 11 mmol/L
- HbA1c > 48 mmol/L
Treatment of type II DM
1st line = lifestyle changes
2nd line = Medications
-Metformin
- If HbA1c remains high; dual therapy of Metformin AND:
-DPP4 inhibitor
-Sulphonylurea
-Pioglitiazone
-If still high triple therapy = above + insulin
Define Diabetic Ketoacidosis (DKA)
Complete lack of insulin -> high ketone production
Aetiology of DKA
- Untreated/undiagnosed T1DM
- Infection/illness
Pathophysiology of DKA
- Absence of insulin -> uncontrolled catabolism -> unrestrained gluconeogenesis and decreased peripheral glucose uptake -> hyperglycaemia
- Hyperglycaemia -> osmotic diuresis -> dehydration
- Peripheral lipolysis for energy -> FFAs in circulation increase -> FFAs turned to Acetyl CoA -> ketone bodies -> acidosis
Signs of DKA
- Kussmaul’s breathing
- Pear drop breath
- Hypotension
- Tachycardia
Symptoms of DKA
- N&V
- Weight loss
- Reduced mental state
- Lethargy
- Abdominal pain
Diagnosis of DKA
- Random plasma glucose > 11 mmol/L
- Plasma ketones > 3 mmol/L
- Blood pH < 7.35 / bicarb < 15 mmol/L
- Urine dipstick: glycosuria & ketonuria
- Serum U&E: Raised urea and creatinine
Treatment of DKA
- ABC management
- 0.9% saline IV
- IV insulin
- Restore electrolytes
Define Hyperosmolar hyperglycaemic state (HHS)
- Marked hyperglycaemia
- Hyperosmolality
- Mild/no ketosis
Aetiology of HHS
- Untreated/undiagnosed T2DM
- Infection/illness
Pathophysiology of HHS
- Low insulin -> increased gluconeogenesis -> hyperglycaemia but enough insulin to inhibit ketogenesis
- Hyperglycaemia -> osmotic diuresis -> dehydration
Signs and symptoms of HHS
- Reduced mental state
- Lethargy
- Severe dehydration
Diagnosis of HHS
- Random BLOOD glucose > 30 mmol/L
- Urine dipstick: glucosuria
- Plasma osmolality: high
- U+E: low total body K+, high serum K+
Treatment of HHS
- 0.9% saline IV
- Insulin at low rate of infusion
- Restore electrolytes
- Low Molecular Weight Heparin (LMWH)
Define hyperthyroidism
- Clinical effect of excess thyroid hormone
- Primary - abnormally high thyroid function
- Secondary - abnormally high Thyroid Stimulating Hormone (TSH) production
Aetiology of hyperthyroidism
- Graves Disease - 65-75%, autoimmune, F>M 9:1
- Toxic multinodular goitre
- Toxic adenoma
- Metastatic follicular thyroid cancer
Epidemiology of hyperthyroidism
- Young women 20-40 yrs
- Grave’s disease 0.5%
Risk factors of hyperthyroidism
- Smoking
- Stress
- HLA-DR3
- Other autoimmune disease
Pathophysiology of hyperthyroidism
Increase in T3 hormone leads to:
-> increased metabolic rate
-> cardiac output
-> bone resorption
-> activates sympathetic nervous system
Signs and symptoms of hyperthyroidism
- Hot & sweaty
- Diarrhoea
- Hyperphagia (excessive eating)
- Weight loss
- Palpitations
Diagnosis of hyperthyroidism
- Thyroid function test (TFT) - elevated T4/T3
- Primary hyperthyroidism = decreased TSH
- Secondary hyperthyroidism = increased TSH
- Thyroid autoantibodies (anti-TSHR)
- Ultrasound + CT head
Treatment of hyperthyroidism
- Drug management
a. Beta-blockers - rapid symptom relief
b. 1st line Carbimazole - blocks synthesis of T4
c. 2nd line Propylthiouracil - prevents T4->T3
conversion - Radioiodine
- Thyroidectomy
Pathophysiology of Grave’s Disease
- IgG autoantibodies bind to TSH receptors
- Increase T4/T3 production
- React with orbital autoantigens
What are some additional symptoms of Grave’s (except hyperthyroidism onoes)
- Thyroid eye disease
- Eyelid retraction
- Periorbital swelling
- Proptosis (bulging eyes)
- Pretibial myxoedema
- Thyroid acropachy (nail clubbing,digit swelling)
Epidemiology of hypothyroidism
- 4/1000 per year
- > 40yrs
- F>M 6:1
Pathophysiology of hypothyroidism
Inadequate T3 to increase metabolic rate for normal body functions
Aetiology of hypothyroidism
- Autoimmune causes
- Hashimotos (inflammation -> goitre)
- primary atrophic hypothyroidism
- Iodine deficiency
- Hypopituitarism
Signs and symptoms of hypothyroidism
- Fatigue + lethargy
- Weight gain + loss of appetite
- Cold
- Constipation
- Goitre
Diagnosis of hypothyroidism
- TFTs - decreased T4 and T3
- Primary hypo = increased TSH
- Secondary hypo = decreased TSH
- Autoantibodies