Endocrinology Flashcards
What is the name of the dopamine agonist used in acromegaly and prolactinoma?
Cabergoline
What is the pathophysiology of acromegaly?
Increased secretions of GH from pituitary tumour or hyperplasia. GH stimulates soft tissue growth through increased secretion of insulin like growth factor 1.
What two hormones does the posterior pituitary secrete?
Vasopressin (supraoptic nucleus) and Oxytocin (paraventricular nucleus)
What is the action of oxytocin?
Smooth muscle contraction in uterus, and lactation in the breast
What is the action of vasopressin?
ADH - acting on collecting ducts - reabsorption of water so decrease urine output
Also causes arteriolar constriction which leads to peripheral vascular resistance and increase BP
Name 5 hormones secreted in hypothalamus that cause secretions in anterior pituitary?
Thyrotropin releasing hormone (TRH) Corticotropin releasing hormone (CRH) Gonadotropin releasing hormone (GnRH) Growth hormone releasing hormone (GHRH) Dopamine
Which 6 hormones are secreted in the anterior pituitary?
- FSH
- LH
- GH
- Prolactin
- ACTH
- TSH
What is the action of prolactin?
Stimulates lactation in the breasts
Which hormone from hypothalamus stimulates prolactin release and which hormone inhibits it?
TRH - stimulates prolactin release
Dopamine- inhibits it (overrides TRH)
What negative feedback loop is caused by increased prolactin?
Causes decreased of GnRH release from hypothalamus
Which nucleus in the hypothalamus controls the circadian rhythm?
Suprachiasmatic nucleus
Name the two most common causes of primary adrenal insufficiency?
Addisons disease and CAH (congenital adrenal hyperplasia)
Name 5 signs and symptoms of adrenal crisis?
Hypotension, hypoglycaemia, hyponatraemia and hyperkalaemia, fatigue and fever
Why do you get hypoglycaemia, hyponatraemia, hyperkaelamia in adrenal crisis?
Lack of production of aldosterone, causes hyponatraemia and hypoerkalemia because aldosterone is not reabsorbing Na in kidneys, hypoglycaemia because cortisol isn’t producing
What is the immediate management of adrenal crisis?
Hydrocortisone
In acromegaly why is GH plasma levels non-diagnostic?
GH is pulsatile- increases in stress, sleep, pregnancy and puberty
What are the 3 stages of diagnosis in acromegaly?
- Plasma GH levels
- Glucose tolerance test (should be no suppression of glucose)
- IGF-1 levels
Give 4 signs of acromegaly?
Acral enlargement, maxiofacial changes, scalp folds, curly hair
What are the 3 stages of treatment for acromegaly?
- Transphenoidal surgery
- Medical therapy
- Radiotherapy
Give two disadvantages to using radiotherapy in acromegaly?
Delayed response
Can cause hypogondism
Which are the 3 medications used in acromegaly treatment in order of effectiveness?
- Somatostatin analogue - eg IM octreoride
- GH receptor antagonist eg Pegvisomant
- Dopamine antagonist eg oral cabergolin
Give 4 symptoms of acromegaly?
Amenorrhoea, loss of libido, headache, sweating, snoring, skin darkening, weight gain and low voice
Give 3 causes hyperprolactinaemia?
- Prolcatinoma
- Compression of pituitary stalk –> decreased dopamine
- Drugs eg dopamine antagonists
What medication would you use to treat prolcatinoma?
Dopamine agonist eg Oral Cabergoline
Give 3 common presentations of prolactinomas?
- Amenorrhoea
- Infertility
- Decreased libido and increased weight
What 3 signs would you expect to see in Conn’s syndrome?
Hypernatraemia, hypokalaemia and hypertension
What would you see on an ECG in a patient with Conns?
Hypokalaemia = flat T waves, ST depression and long QT
What is a) initial screening and b) diagnostic investigation in Conns?
a) Plasma aldosterone: renin ratio
b) aldosterone antagonist ef oral spironalactone
Name 2 treatment methods for Conns?
- Laproscopic aldrenalectomy
2. Oral spironolactone
How do you diagnosis secondary adrenal insufficiency?
Low ACTH and normal mineralocorticoid
What is the pathophysiology behind secondary adrenal insufficiency?
Lack of ACTH due to problems with the HPA axis - most common cause is iatrogenic
What are the two causes of primary adrenal insufficiency?
- CAH - congenital adrenal hyperplasia
2. Addisons
Give 3 causes of Addisons disease?
Adrenalitis, infections eg TB, adrenal infarction, metastases from lungs and stomach
Name 3 symptoms you can get due to cortisol deficiency in addison’s?
Fatigue, muscle weakness, hyper pigmentation, abdominal pain
Name a symptom you can get due to a) aldosterone deficiency and b) androgen deficiency in addison’s?
a) Postural hypotension
b) Loss of libido and menstrual irregularities
Name 4 things you would see on a blood test for a patient with Addisons?
- Hypnatraemia, hyperkalaemia, hypoaldoesteronism, eosinophils and anaemia
Which adrenal antibody may be present in Addison’s disease?
21 hydoxylase antibody
Name 2 diagnostic tests you would perform in addison’s?
- Short ACTH stimulation test using tetracosaride
2. 9am ACTH levels
Give 2 treatment methods for addison’s disease?
- Replace cortisol with hydrocortisone
2. Replace mineralcorticoaids with fludrocortisone
What is diabetes insidipidus?
Passage of large volumes of dilute urine due to impaired water reabsorption in kidney - passage of urine >3L
Give 3 cranial causes of diabetes insipidus?
Idiopathic, congenital defect in ADH gene, tumour eg posterior pituitary and trauma
Give 3 nephrogenic (resistant to ADH) causes of diabetes insipidus?
Metabolic (hypercalacermia, hypokalaemia)
Drugs (Lithium)
Osmotic diuresis (diabetes mellitus)
Inherited
What is the clinical presentation of diabetes insipidus?
Polyuria, compensatory polydipsia, hypernatraemia (lethargy, weakness), dehydration
How do you differentiate cranial and nephrogenic causes of DI?
Water deprivation test then
Desmopressin stimulation - urine not concentrated in nephrogenic
Give a treatment method for a) nephrogenic and b) cranial causes of diabetes insidipidus?
a) Thiazide diuretics eg oral bendrofluromethiazide
b) Give oral desmopressin
What should the normal blood glucose be between?
3.5-8mmol/L
Give 4 causes of secondary Diabetes?
a) Pancreatic pathology eg Haemochromatosis
2. Endocrine disease eg acromegaly
3. Drug induced eg thiazide diuretics
4. Maturity onset diabetes of youth (MODY)
Which tissue type is type 1 diabetes associated with?
HLA DR3 and HLA DR4
Which other autoimmune diseases are associated with type 1 diabetes?
Autoimmune thyroiditis, coeliac disease, addison’s disease, perncious anaemia
Name 5 of the presenting features of type 1 diabetes?
- Polyuria
- Polydipsia
- Muscle and weight loss
- Blurred vision
- Pruritus valence and balantis
- Hunger due to decrease useable energy source
Which 3 factors would lead to an immediate diagnosis of type 1 diabetes if 2/3 were present?
Weight loss, short history of severe symptoms and moderate/large urinary ketones
What are the 3 main types of insulin given in type 1?
- Short acting soluble insulin
- Short acing insulin analogue
- Long acting insulin
Give 4 complications of insulin treatment?
- Hypoglycaemia
- Injection site - lipohypertrophy
- Insulin resistance
- Weight gain
Give 3 biochemical factors you need to make a DKA diagnosis?
- Hyperglycaemia >11mmol/l
- Raised plasma Ketones (>2 on urinary dipstick)
- Metabolic Acidosis, plasma Hco3 <15mmol
Give 4 complications of DKA?
Hypotension
Cerebral oedema
Adult Respiratory Distress syndrome
Arrhythmia (if K+ unmanaged)
Give 3 signs of DKA?
Hyperventilation (Kussmal breathing) , hypotension, tacycardia, ketonic breath, coma
Give 3 symptoms of DKA?
Polyuria, polydipsia, cause, vomitting, drowsiness, confusion
Give 4 symptoms of hypoglycaemia?
Sweating, tremor, drippiness, confusion, sweating, hungry, personality change
What does EXPLAIN stand for in non-diabetic causes of hypoglycaemia?
Exogenous drugs, pituitary insuffieicny, liver failure, addison’s, islet cell tumour,non-pancreatic neoplasm
Name 4 factors for diabetes diagnosis?
- Random plasma glucose >11mmol/L
- Fasting plasma glucose >7mmol/l
- Oral glucose tolerance test]
a) fasting >7mmol
b) after 2 hours >11 mol - HbA1c >6,5% normal
Give 3 risk factors of type 2 diabetes?
- Overweight/obese
- Family history
- Hypertension, increased triglycerides/cholesterol
- South Asia
What is the first line treatment of T2 diabetes?
Lifestyle changes: Dietary factors, weight loss and exercise, ACE inhibitors and statins
Which 3 medications are used to treat diabetes mellitus?
- Metformin - increase insulin sensitivity and reduce rate of gluconeogenesis in liver
- Sulfonyura (gliceride) - increases insulin
3.
Name 5 complications associated with poor glycemic control?
- Diabetic neuropathy
- Diabetic nephropathy
- Peripheral vascular disease
- Diabetic retionopathy
- Stroke / MI
What is the function of the parathyroid?
Releases PTH in response to decreased calcium levels - increases calcium reabsorption in kidneys and decreases calcium excretion - stimulates hydrolysis of 25-hydroxyvitamin D to caclitriol
Give 5 symptoms/ signs of hypercalcaemia as a result of primary hyperparathyroidism?
Renal stones. painful bones, abdominal groans (Gi upset, nausea) psychiatric moans (lethargy, fatigue and memory loss)
What would the lab results show in primary hyperparathyroidism?
Increase PTH, Increase Ca, decrease phosphate,
What would the lab results show in primary hyperparathyroidism?
Increase PTH, Decrease Ca, increase phosphate, increase alkaline phosphate
What are the causes of secondary hyperparathyroidism?
Chronic kidney disease and vitamin D deficiency
Which lab result excludes hyperparathryoidism (primary, secondary and tertiary)?
Low PTH
Which 4 tumours can cause hypercalcaemia of malignancy ?
Squamous cell lung tumour, renal and breast (secrete parathryoid like protein)
Bone infiltration due to multiple myeloma and secondary metastatses
Lymphoma
What would the lab results show in hypercalcaemia of malignancy?
Low PTH as tumour produces parathyroid like protein, high calcium, low albumin
In acute severe hypercalcaemia what would be your management steps?
Saline - increase fluid
Bisphosphonates
Steroids eg prednisolone
Why is the phosphate high in primary hypoparathyroidism?
Phosphate reabsorption from the kidney is reduced by PTH. Thus if PTH levels are low, serum phosphate will rise (more will be reabsorbed).
What is the most common cause of hypocalcaemia and what is the mechanism behind this?
Secondary to increased phosphate levels in CKD. Decrease calcitriol production and phosphate rentention
Give 3 causes of vitamin D deficiency?
Reduced UV exposure,
Malabsorption
Anti-epilieptic drugs
How do you treat acute hypocalcaemia?
IV calcium gluconate
How do you treat vitamin D deficiency?
Oral colecalciferol
How do you treat hypoparathyroidism?
Calcium supplements + calcitriol
Name 2 signs you would see in hypocalcaemia?
Trousseau’s sign- carpopedal spasm (hand spasm)
Chvostek’s sign - twitching of ipsilateral facial muscles on facial nerve
What is the clinical presentation of hypocalcaemia?
SPASMODIC (Spasms, personal parasthesia, anxious, seizures muscle tone increase, orientation impaired, dermatitis, impetigo hepetiformis, Choveks sign
What would the lab results be in hypoparathyroidism?
Low serum calcium, low PTH, high phosphate
Name 4 investigations you could perform in hypercalcaemia?
X-Ray eg pepper pot skull DXA bone density scan High resolution CT Radioisotope scanning Parathyroid ultrasound
What is the definition of osmolality?
The concentration of a solution expressed as the total number of solute particles per kilogram
What is the definition of hyponatraemia?
Serum sodium <135mmol/L
Severe <125mmol/l
Give the 4 main causes of hyponatraemia?
SIADH, blood sample from drip arm, renal failure, malignancy, iatrogenic
Give 4 symptoms of hyponatraemia? (quicker the onset the worse the symptoms)
Headache, lethargy, anorexia and abdominal pain, weakness, confusion, agitation, coma (severe cases)
Name 3 drugs which causes SIADH?
Carbamazepine, thiazides, MAO inhibitors
What is the clinical presentation of hyperkalaemia?
Fast, irregular rapid pulse, chest pain, weakness, muscle pain, fatigue, kaussmaul respiration if metabolic acidosis
Give the 2 main causes of hyperkalaemia?
AKI
Drugs eg Spironalactone, ACE, NSAIDS
(accosted with Addisons)
Name 3 characteristics of an ECG in a patient with hyperkalaemia?
Tall tented T waves, small P waves and a wide QRS
Name 3 characteristics of an ECG in a patient with hypokalaemia?
Small inverted T waves, prominent U waves, long PR interval and depressed ST segments
Give a cause of a false hypocalcaemia?
Low serum albumin
If serum calcium is low, what changes to QT interval?
It gets longer
Give 3 causes of hypocalcaemia?
Vitamin D deficiency leading to osteomalacia
Give 4 causes of hypoparathyroidism?
Syndromes, genetic, surgical, radiation, autoimmune, infiltration, magnesium deficiency
What is pseudohypoparathyroidism?
Resistance to parathyroid hormone
What hand abnormality would you see in pseudohypoparathyroidism?
short fourth metacarpal
What are the two most common causes of hypercalcaemia?
Malignancy
Primary hyperparathyroidism
How does lymphoma cause hypercalcaemia?
Lymphoma has macrophages, macrophages express 1 alpa hydroxyylase which converts 25-hydroxyvitamin D to 1,25 hydroxyvtaiman D
What is the major a) extracellular and b) intracellular cation?
Extracellular = Sodium Intracellular = Potassium
How is osmolality measured?
Measured by an osmometer by freezing point
Name two methods to diagnose diabetes insidious?
Water deprivation test
Hypertonic saline infusion and measurement of AVP (vasopressin)
Name 3 tests you would do in a patient with hyponatraemia?
- Plasma osmolality
- Urine osmolality
- Plasma glucose
- Urine sodium
What is a craniophayngioma?
Squamous epithelial remnants of Rathke’s pouch
What do patients with meningioma usually present with?
Loss of visual acuity
Endocrine dysfunction and visual field defects
Give 4 consequences of large masses in the pituitary?
- Visual field defects
- CSF rhinorrhoea
- Headaches
- Cranial nerve palsy
What is first line imaging in pituitary dysfunction?
MRI
Why does a patient need a long acting insulin?
Gluconeogenesis, glycogenloysis
What are the non-pharmacological management of diabetes?
Education - self - management
DAFNE - type 2 diabetes
Exercise - HbA1c <48
In pregnancy what are risks for someone with type 1 diabetes?
Pre-eclampsia, miscarriage
What level is hypoglycaemia?
<3mmol, symptoms <4mmol
What are the symptoms of hyperthyroid?
Tachycardia, sweating, palpitations, hungry, weight loss
What is the main causesof hyperthyroid?
Graves disease (40-60%)
Toxic multi nodular goitre
Toxic adenoma - bright red hot spot
What are triggers of hyperthyroid?
Addisons, Type 1 DM, Pregnancy, Stress, Infection
What is one of the methods in administrating carbimazole?
Block and replace (higher dose carbimzaole) and T4
What are the functions of PTH?
Increase calcium reabsorption in kidney, increase osteoclast activity (increase calcium), activate vitamin D
What is the difference between gigantism and acromegaly?
Gigagantism when your growth plates haven’t fused
What is the role of Incretins?
Released after eating , increase pancreatic B cells to produce insulin to decrease blood glucose and promote satiety
Which patients are most at risk of diabetic retinopathy?
Long term diabetes, insulin treatment, poor glycemic control and pregnancy
In diabetic retinopathy what would you see on fundoscopy?
Cotton wool spots, haemorrhage, microanuerisms, macular thickening
Give 4 signs of vascular disease in a patient with diabetes?
Diminished pedal pulse, cold feet, weak skin and nails, absence of hair on legs
Give two educational programmes provided for patients with type 2 diabetes?
Desmond, DAFNE
Give 5 components of the diabetic review?
Take BP, review blood glucose control, review HbA1c and cholesterol levels, advise change in regimen, eye and foot examination, take height and weight
What are the triggers for diabetic ketoacidosis?
Infection, surgery, MI, pancreatitis, chemotherapy, antipsychotics, non-compliance
Give some treatments you would use in diabetic ketoacidosis?
Saline bolus (if BP low), IV rapid acting insulin, K+ replacement
What are you worries about in a patient with hyperglycaemia?
DVT - give prophylaxis
What is Phaeochromoctoma?
Catecholamine producing tumour arising from chromatin cells - usually found in adrenal medulla
What is the triad of presentation in Phaeochromoctoma?
Episodic headache, sweating, tacycardia - hypertension