Endocrine Diseases Flashcards
What is the aetiology of SIADH?
- Tumours: Prostate, thymus, pancreas, small cell carcinoma of lung
- Pulmonary lesions: pneumonia, TB
- Metabolic causes: Alcohol withdrawal
- CNS: Meningitis, tumours, head injury, subdural haematoma
- Drugs: Chlorpromide, carbamezapine etc
Briefly explain the pathophysiology of SIADH?
- Excess ADH release causes excess insertion of aquaporin 2 channels in apical membrane of collecting duct
- Therefore excess water retention and hyponatraemia
How is SIADH diagnosed?
- Low serum Na+, high urine Na+
- Euvolaemia: normal blood vol
- Low plasma osmolality, high urine osmolality
- Test with saline - sodium depletion will respond but SIADH won’t
What are the clinical features of SIADH?
- Symptoms due to hyponatraemia
- Varied and genetic
- Anorexia, nausea and malaise
- Weakness and aches
- Reduction in GCS and confusion with drowsiness
- Fits and coma if severe
How is SIADH treated?
- Treat underlying cause
- Restrict fluids to 500-1000ml daily
- Hypertonic saline if really symptomatic to prevent brain swelling
- Oral demeclocycline daily (Inhibits ADH)
- Vasopressin antagonist e.g. oral tovaptan daily
- Salt and loop diuretic
What is Conn’s syndrome?
Primary hyperaldosteronism= Excess production of aldosterone, independent of the renin-angiotensin system. Resulting in increased sodium, and thus water retention (and increased blood pressure), and decreased renin release
What is the epidemiology of Conn’s syndrome?
Rare condition accounting for less than 1% of hypertension
What is the aetiology of Conn’s syndrome?
- 2/3rds= Adrenal adenoma that secretes aldosterone
- 1/3rd= Bilateral adeno-cortical hyperplasia
What are the risk factors for Conn’s syndrome?
- Hypertension under 35, with no family history
- Hypokalaemia before diuretics
- Conventional antihypertensives don’t work
- Unusual symptoms e.g. sweating
Briefly explain the pathophysiology of Conn’s syndrome
- Excess aldosterone production due to aldosterone producing carcinoma
- Na+ and water retention, thus K+ loss (to balance charge
- Thus hypokalemia and hypertension
What is the clinical presentation of Conn’s syndrome?
- Often asymptomatic
- Hypertension due to increased blood vol, associated with renal, cardiac and retinal damage
- Hypokalaemia: Weakness, cramps, paraesthesia, polyuria
How is Conn’s syndrome diagnosed?
- Hypokalaemic ECG= Flat T wave, ST depression, Long QT
- Serum hypokalaemia
- Plasma aldosterone:Renin (ARR)= If increased aldosterone levels that are not suppressed w 0.9% saline infusion= Diagnostic
- CT or MRI on adrenal
How is Conn’s syndrome treated?
- Laproscopic adrenalectomy
- Aldosterone antagonist e.g. oral sprinolactone for 4 weeks pre-op to control BP and K+
What is giantism?
Excessive GH production in children before fusion of epiphyses of long bones
What is acromegaly?
Excessive GH in adults
What is the aetiology of acromegaly?
- Most cases are due to benign GH producing pituitary tumour, but can be due to hyperplasia
What is the epidemiology of acromegaly?
Rare, increased incidence in middle age
What are the risk factors for acromegaly?
5% associated with MEN-1
Briefly explain the pathophysiology of acromegaly
- Increased GH due to pituitary tumour or ectopic carcinoid tumour
- Binds to receptors, resulting in increased IGF-1
- This stimulates skeletal muscle and soft tissue growth
- Local tumour expansion can also cause compression of tissue and thus symptoms
List some symptoms of acromegaly
- Headaches
- Excessive sweating
- Bitemporal hemianopia
- Snoring
- Wonky bite
- Low weight
- Low libido
- Amenorrhea
- Backache
- Increased size of hands and feet
List some signs of acromegaly
Skin darkening Fatigue Deep voice Carpal tunnel syndrome Macroglossia Coarsening face with wide nose Prognanthism and big supraorbital ridge
List some common co-morbidities with acromegaly
- Low glucose tolerance
- Diabetes
- Sleep apnoea
- CVS Problems
How is acromegaly diagnosed?
- High glucose, Calcium, and phosphate
- IGF1= Raised = Diagnostic
- Plasma GH levels= Can rule out acromegaly if random GH is undetectable or is low
- Pituitary function test
- Glucose tolerance test= No suppression of glucose= Diagnostic
- MRI of pituitary fossa
- Old photos= See changes
How is acromegaly treated?
- 1st line treatment= Trans-sphenoidal surgery to remove tumour and fix compression. If this fails, try somatostatin analogues e.g. IM octreotide
- GH receptor antagonists if intolerant to SSA= Supresses IGF-1
- Dopamine agonist e.g. Oral cabergoline
- Stereotactic radiotherapy
What is the epidemiology of diabetes mellitus type 1?
Typically occurs in childhood
Increasing incidence
Common in Northern Europe
Briefly explain the pathophysiology of DMT1
Autoimmune destruction of auto anti-bodies of the pancreatic insulin secreting beta-cells in the islets of langerhans causing insulin deficiency and thus continued breakdown of liver glycogen leading to glycosuria and ketonuria as more glucose is in the blood.
What is the aetiology of DMT1?
Autoimmune against Beta cells
Idiopathic
Genetic susceptibility
What are the risk factors for DMT1?
- Northern European
- Family history
- Associated with autoimmune disease: thyroidisms, coeliacs, Addison’s, perncious anaemia
- Environment: Diet, Vit D deficiency, cleaner environment, enteroviruses
How is DMT1 treated?
- Self adjusted doses using finger pricking glucose
- Synthetic human insulin via a subcut injection into abdomen, thighs or upper arm (change site to avoid lipohypertrophy)
- Can use short acting insulin, short acting insulin analogues or longer acting insulins
What are the complications of DMT1 treatments?
Hypoglycaemia
Lipohypertrophy
Insulin resistance
Weight gain
What is the aim of DMT1 treatment?
Aims to restore the physiology of the beta cell
What is the acute presentation of diabetes mellitus?
Young people (usually DMT1) often present in first 2-6 weeks with polyuria and nocturia, polydipsia and weight loss Patients may have ketonuria and breath smelling of ketones (Pear drops)
What is the subacute presentation of diabetes mellitus?
Occurs during first months-years
Typical triad of polyuria, polydipsia and weight loss but all are less marked
Also lack of energy, visual blurring, infections
What are the complications that can be the presenting features for diabetes mellitus?
- Staph. skin infection
- Retinopathy
- Polyneuropathy causing tingling and numbness in the feet
- Erectile dysfunction
- Arterial disease
What would be the only clinical feature of asymptomatic diabetes mellitus?
Glycosuria/hyperglycaemia
What is the plasma glucose concentration that is diagnostic for diabetes mellitus (DMT1 usually)?
- Random plasma glucose >11.1 mmol/L
- Fasting plasma glucose >7 mmol/L
In symptomatic individuals, one result is diagnostic. If there is only one positive, perform a oral glucose tolerance test (again >7 for fasting, and >11.1 for random)
What test can be performed for diabetes mellitus risk?
IGT (Impaired glucose tolerance)
What is the main test for DMT2?
HbA1c > 48
What is the epidemiology of hyperosmolar, hyperglycaemic state?
Patients present in middle/later life often with previously undiagnosed diabetes
What are the risk factors for hyperosmolar, hyperglycaemic state?
Infection= Most common cause
Consumption of glucose rich food
Concurrent medications such as thiazide diuretics or steroids
Briefly explain the pathophysiology of hyperosmolar, hyperglycaemic state?
Endogenous insulin levels are reduced but are still sufficient to inhibit hepatic ketogenesis but insufficient to inhibit hepatic glucose production
What is the clinical presentation of hyperosmolar, hyperglycaemic state?
- Severe dehydration
- Decreased consciousness
- Hyperglycaemia
- Hyperosmolality
- No ketones in blood/urine
- Stupor or coma
- Bicarbonate isn’t lowered
How is hyperosmolar, hyperglycaemic state diagnosed?
- Hyperglycaemia= blood glocse >11mmol/L
- Urine dipstick shows heavy glycosuria
- Plasma osmolality is extremely high
- Total body K+ is low, but serum K+ is often raised
How is hyperosmolar, hyperglycaemic state treated?
Lower rate of insulin infusion
Fluid replacement with 0.9% saline
Restore electrolyte loss
Low molecular weight heparin (SC Enoxaparin) to reduce risk of thromboembolism, MI, stroke, and arterial thrombosis
What are the types of hypoglycamia?
- Plasma glucose <4 mmol/L
- Serious= plasma glucose <3mmol/L
- Severe= Impaired cognitive incidence
What is the aetiology of hypoglycamia?
- In diabetes= due to insulin or sulphonylurea treatment
- In non diabetes= Exogenous drugs, pituitary insufficiency, liver failure, Addison’s disease, Islet’s cell tumour, Non pancreatic neoplasm
What is the clinical presentation of hypoglycamia?
- Autonomic= Sweating, anxiety, hunger, tremor, palpitations, dizziness
- Neuroglycopenic= Confusion, drowsiness, visual trouble, seizures, coma
- Rarely, focal symptoms= Personality change, transient hemiplegia, mutism etc
How is hypoglycamia diagnosed?
Fingerprick blood glucose= Shows hypoglycaemia, C peptide and ketones
Take drug history and exclude liver failure
How is hypoglycamia treated?
Oral sugar and long acting starch
If cannot swallow, give 50% glucose IV or IM
In diabetics, re-educate
What is the epidemiology of diabetic nephropathy?
Clinical nephropathy secondary to glomerular disease usually manifests 15-25yrs after diagnosis and affects 25-35% of patients diagnosed under age 30
What is the pathophysiology of diabetic nephropathy?
Thickening of the basement membrane in glomerulus due to poor glycaemic control, which leads to micro-albuminuria
What are the risk factors for diabetic nephropathy?
Poor blood pressure and blood glucose control
How is diabetic nephropathy diagnosed?
- Urine albumin:creatinine ratio >3 will indicate micro albuminuria
- This may progress to intermittent albuminuria followed by persistent proteinuria
- Normochromic normocytic anaemia and raised ESR
How is diabetic nephropathy treated?
- Aggressive treatment of BP
- Reductions in insulin dosage as insulin sensitivities is increased
- Avoid drugs excreted via kidney
What is the epidemiology of diabetic neuropathy?
Affects 30-35% of patients with diabetes
What is the aetiology of diabetic neuropathy?
Isolated mononeuropathies are thought to be as a result of occlusion of the vasa nervorum. More diffuse neuropathies may arise from the accumulation of the fructose and sorbitol which disrupts the structure and function of the nerve
What are the risk factors of diabetic neuropathy?
Hypertension, Smoking, HbA1c, BMI
What are the clinical features of diabetic neuropathy?
- Pain: allodynia, burning etc
- Autonomic: Postural hypotension, gastroparesis, diarrhoea, constipation
- Insensitivities: Glove and stocking sensory loss
- Mononeuritis multiplex
- Diabetic amyotrophy
How is diabetic neuropathy treated?
- Good glycaemic control
- Treated with paracetamol
- Tricyclic antidepressants
- Anticonvulsants
- Opiates
- Transcutaneous nerve stimulation
- Avoidance of weight bearing
What are the most common complications of diabetes?
- Atherosclerosis= Stroke, MI, peripheral vascular disease
- Microvascular complications= Diabetic retinopathy, nephropathy, neuropathy
- Diabetic foot ulceration
- Infection
What is the epidemiology of diabetic foot ulceration?
Foot ulceration occurs in 15% of people with DM
What is the pathophysiology of diabetic foot ulceration?
Neuropathy results in increased risk of silent trauma of the foot. Furthermore, neuropathy results in autonomic features that results in increased skin dryness of foot, which is thus more susceptible to cracking and ulceration.