Endocrine Flashcards
Diabetes Inspidius
Central DI results from impaired production, transport or release of ADH.
Nephrogenic DI results from inability of the renal collecting ducts to respond to ADH.
Both cause defective water reabsorption in kidneys = excessive production of dilute, hypotonic urine.
S: Polydypsia, Polyuria, Dehydration, Hyponatraemia
D: Water deprivation test, Desmopressin stimulation test
T: CDI requires desmopressin and oral/IV fluids, NDI requires low Na diet, thiazide and NSAIDs
Hyperthyroidism
Overproduction of T3 and T4
Caused by Graves’ disease or Toxic multinodular Goitre.
S: Sweating, weight loss, increased bowel movements, anxiety, irritability, palpitations, oligomenorrhea, lid lag.
D: TFTs (low TSH, high T3)
T: Carbimazole (decreases T hormone synthesis), Radioiodine (kills thyroid cells), Thyroidectomy
Hypothyroidism
Underactivity of the thyroid gland
Caused by Hashimoto’s thyroiditis, thyroid atrophy, Post-partum thyroiditis, Iatrogenic, Drug-induced, Congenital hypothyroidism.
S: lethagry, low mood, cold-disliking, weight gain, constipation, menorrhagia, decreased memory/cognition, weakness, bradycardia, dry skin, cold peripheries, puffy face, ascites.
D: TFTs (high TSH, low free T4), anaemia, hyperlipidaemia, hyponatraemia
T: Levothyroxine at a daily dose of 1.6 μg/kg body weight
Growth hormone deficiency
Pituitary gland fails to release enough growth hormone (somatotropin).
Can be idiopathic, or caused by Prader-Willi syndrome, Turner’s syndrome, trauma, infection, radiation therapy damaging the hypothalamus or pituitary gland, pituitary tumour.
S in children: hypoglycaemia, short stature, delayed bone age, decreased muscle development.
S in adults: weakened muscles, low bone density, depression, poor memory, social withdrawal.
D: Measure GH, IGF, X-ray
T: Growth hormone therapy
Hyperparathyroidism
Overproduction of the parathyroid hormone
Primary - parathyroid adenoma due to genetic mutation, hyperplasia, carcinoma
S: kidney stones or gallstones, polyuria, chronic bone pain, constipation, depression
Secondary: excess parathyroid hormone in response to chronic hypocalcaemia
S: CKD (usually the cause), renal osteodystrophy, calcification in blood vessels
Tertiary: Develop primary from secondary
S: Same as primary, elevated phosphate
D: Measure parathyroid hormone, phosphate, calcium, vit D.
T: Remove the parathyroid glands or calcimimetics if primary or tertiary, phosphate binders, supplements and calcitriol analogues if secondary.
Hypoparathyroidism
Underproduction of parathyroid hormone.
C: thyroid/parathyroid surgery, Autoimmune polyendocrine syndrome type 1, DiGeorge syndrome, genetics (auto dom), Pseudohypoparathyroidism type 1a.
S: hypocalcaemia and hyperphosphatemia, tetany, paraesthesia, changes in cardiac output, calcification in the basal ganglia and the lens of the eye, Chvotek’s sign, Trousseau’s sign.
D: parathyroid hormone, calcium, vitamin D, albumin, phosphorus, magnesium, Prolonged QT, prolonged ST segment or arrhythmias on ECG.
T: Calcium and Vitamin D supplements
Recombinant human parathyroid hormone
Hyperaldosteronism
Adrenal gland produces too much aldosterone.
1 causes: Idiopathic, Conn syndrome, Familial
2 causes: High levels of renin, chronic low blood pressure e.g. congestive heart failure or cirrhosis
Hyperaldosteronism leads to hypokalaemia and hypernatremia and high blood vol and high blood pressure.
S: hypertension-related symptoms like headaches and flushing and hypokalaemia-related symptoms like constipation, weakness and heart changes in rhythm.
D: Measuring levels of renin and aldosterone
T: Potassium-sparing diuretics, Treating underlying cause e.g. removing tumour in Conn syndrome, managing heart failure and cirrhosis
Addison’s disease
Adrenal gland is unable to produce enough aldosterone or cortisol due to the adrenal gland itself.
Causes: damage to adrenal cortex due to autoimmune destruction, TB, metastatic carcinoma.
S: Depends on the area damaged
ZG: aldosterone falls, hyperkalaemia and hyponatremia, hypovolaemia, metabolic acidosis, cravings for salty foods, nausea and vomiting, fatigue, dizziness.
ZF: weak, tired, disorientated, overactive pituitary gland leading to hyperpigmentation
ZR: women can experience a loss of pubic and armpit hair and a decreased sex drive
Addisonian crisis: sudden pain in the lower back, abdomen or legs with severe vomiting and diarrhoea, followed by hypotension, dehydration and loss of consciousness.
D: ACTH stimulation test
T: Hormones - aldosterone, cortisol, androgens taken for life
Cushing’s syndrome
Elevated cortisol levels in the blood.
Causes: Steroid medications that mimic the action of cortisol (endogenous), excess ACTH caused by a pituitary adenoma (Cushing disease), small cell lung cancer, adrenal adenomas and carcinomas.
S: Muscle wasting, thin extremities, skin thinning and easy bruising, abdominal striae, fractures due to osteoporosis, ‘full moon’ face, ‘buffalo hump’ back, truncal obesity, hyperglycaemia.
D: Measuring free unbound cortisol in the urine over 24 hours, Dexamethasone suppression test, ACTH plasma levels, MRI of the pituitary gland, CT of the adrenals, CT of the chest, abdomen or pelvis.
T: Exogenous medications, surgical excision of the adrenals, adrenal steroid inhibitors
Pituitary adenoma
A tumour that develops in the hormone-producing cells of the pituitary gland. Sits just behind the eyes.
Can be a Microadenoma (<1cm) or a Macroadenoma (>1cm).
Most common is a prolactinoma - causes amenorrhoea and galactorrhoea in women and low libido and gynecomastia in men.
Pituitary adenoma in the somatotrophs causes gigantism in children and acromegaly in adults.
A ACTH-secreting tumour leads to Cushing’s disease.
D: Measuring pituitary hormone levels, MRI
T: Prolactinomas are usually treated with medication, Somatotropic and corticotropic - usually require transsphenoidal surgical resection, non-functional tumours compressing other structures may require surgery.
Acromegaly
Hormonal disorder in adults where there is excess growth hormone (somatotropin) which causes the continued growth of the extremities (large face, hands and feet).
C: Pituitary adenoma, Hypothalamic tumours, multiple endocrine neoplasia type 1.
S: Growth of the bones of the hands, feet and lower jaw, Protrusion of the forehead, Soft tissue swelling in the hands, feet, face and tongue, Increased size of the organs, Excess sweating
D: Increased levels of insulin-like growth factor 1 and GH in spite of receiving a large dose of glucose, MRI
T: Pituitary adenoma - surgery/radiation therapy
Somatostatin analogues or GH receptor antagonists
Prolactinoma
Benign tumour of the pituitary gland that secretes excess prolactin.
<10mm = Microprolactinomas - asymptomatic
>10mm = Macroprolactinomas - headaches, bitemporal hemiopia
In women, galactorrhoea, amenorrhea, vaginal dryness, brittle bones
In men, gynecomastia, erectile dysfunction
Both sexes can experience decreased libido and infertility
D: elevated levels of prolactin in the blood, MRI
T: Dopamine agonists - Bromocriptine and Cabergoline, Surgery, Radiation therapy
Diabetes mellitus
A metabolic disorder characterised by chronic hyperglycaemia due to the lack of insulin.
C: T1 due to autoimmune destruction of insulin producing beta cells, T2 due to ‘secretory exhaustion’ of beta cells caused by obesity.
S: Polyuria, polydypsia, recurrent UTIs and skin infections, T1 can present as diabetic ketoacidosis, nephropathy, neuropathy, retinopathy, vascular disease, foot ulcers.
D: Fasting plasma glucose of more than 7 mmol/L or a random plasma glucose more than 11.1 mmol/L. In borderline patients, do a oral glucose tolerance test.
T: T1 (daily injection basal bolus insulin regime, dietary control), T2 (lifestyle changes, metformin, can add sulfonylureas, meglitinide, thiazolidinedione, gliptin, SGLT-2 inhibitor, or GLP-1 receptor agonist)
Hypocalcaemia
Normal blood calcium levels: 8.6-10.3mg/dL (2-2.5mmol/L) in Hypocalcaemia: <8.5mg/dL, (<2mmol/L)
C: Hypoparathyroidism (post-surgery, idiopathic, congenital, HIV), Pseudohypoparathyroidism (PTH resistance), decreased vit D or Mg, CKD, acute pancreatitis, acute rhabdomyolysis, bisphosphonates, chemo.
S: Spasms, Perioral paraesthesiae, Anxiety, Seizures, Muscle tone increased, Orientation impaired, Dermatitis, Impetigo herpetiformis, Chvostek’s sign and cardiomyopathy
D: serum phosphate, magnesium, calcium, PTH, vitamin D levels, corrected calcium, ECG (prolonged QT interva, arrhythmias)
T: give calcium 5mmol/6hr PO, with daily plasma Ca2+ levels, alfacalcidol in CKD, if severe 10mL 10% calcium gluconate IV over 30mins.
Hypercalcaemia
Serum calcium concentration of 2.6mmol/L or higher on 2 occasions (following correction for serum albumi).
C: Hyperparathyroidism (osteoclast breakdown), malignant tumours release PTHrP (mimics PTH), excess vitamin D, thiazides
S: Stones (renal), Bones (pain, fractures, osteoporosis), Moans (confusion, fatigue, depression), Groans (abdo pain, pancreatitis, peptic ulcer disease)
D: serum phosphate, magnesium, calcium, PTH, vitamin D levels, corrected calcium, ECG (short QT interval, bradycardia, AV block), bone scan, 24hr urinary Ca2+ excretion
T: Required if >15mg/dL. Treat underlying cause. Rehydrate to encourage Ca excretion, loop diuretics e.g. furosemide and bisphosphonates to prevent bone resorption.
Hypoglycaemia
Defined by Whipple’s triad plasma hypoglacaemia (<3.0 mmol/L), symptoms of low glucose, resolution of symptoms with correction.
C: Alcohol, poor glycaemic control, drugs and toxins, pancreatic insulin tumours, extra pancreatic IGF-II-secreting neoplasms, autoimmune, reactive, starvation, hormone-deficiencies, self-induced.
S: Shaking, sweating, pins and needles in mouth, palpitations, headache, double vision, slurring of speech, confusion, change of behaviour, coma.
D: HbA1c, LFTs and TFTs, 72-hour fast and prolactin levels if insulioma is suspected, CT scan, endocrine investigations.
T: Glucose 10-20g (liquid, sugar, glucogel) or IV glucose, or SC/IM 1mg glucagon. Once more alert, give a meal or infusion of 10% glucose with regular insulin dose. In coma, IV mannitol and dexamethasone with constant glucose monitoring and IV glucose. Treatment of underlying cause - alcohol abuse, medication review, diet review, removal of insulin-secreting tumour.
Hypercholesterolaemia
Elevated levels of low-density lipoprotein cholesterol or non-high-density lipoprotein cholesterol.
C: Diet, stress, T2 diabetes, obesity, alcohol use, dialysis therapy, nephrotic syndrome, hypothyroidism, cushing’s syndrome, anorexia, medications, genetics (familial)
S: Asymptomatic, ischaemia causing loss of vision, dizziness and impairment of balance, difficulty speaking, weakness or numbness or tingling, calf pain, chest pain, abdominal pain after a meal, xanthelasma, xanthomata
D: Cholesterol levels, routine screening
T: Lifestyle changes, for familial restrict intakes of total fat to 25–35% of energy intake, saturated fat to less than 7% of energy intake, and cholesterol to less than 200 mg per day, statins.
Hypernatraemia
Serum sodium concentration exceeding 145 mmol/L.
C: dehydration (DI, lack of water, dementia, hypothalamic lesions), hypovolaemia (burns, excessive sweating, GI loss, urinary loss), hypertonic sodium gain (IV antibiotics, excessive Na intake, hyperaldosteronism)
S: DI (polydipsia, polyuria) CNS (lethargy, weakness, confusion, irritability, myoclonic jerks and seizures), hypovolaemia (dry mouth, abnormal skin turgor, oliguria, tachycardia, orthostatic hypotension).
D: serum sodium, potassium, urea, creatinine, calcium and plasma glucose, lithium levels, urine and serum osmolality, neuroimaging.
T: Address the underlying cause - stop gastrointestinal fluid losses, control pyrexia, correct hyperglycaemia, withhold lactulose and diuretics.
Active correction - fluids should be administered orally or enterally and intravenous therapy used only as a last resort.
Hyponatraemia
A relative excess of water in relation to sodium and is defined as a serum sodium <136 mmol/L. <120 is severe.
C: Isotonic (hyperproteinemia, hyperlipidaemia), hypotonic hypovolamic (extrarenal and renal salt loss), hypotonic euvolaemic (SIADH, hypothyroidism, post-op, endurance exercise, drug reaction), hypotonic hypervolaemic (HF, liver or kidney diseasse) hypertonic (hyperglycaemia, mannitol, sorbitol, glycerol, maltose, radiocontrast agents).
S: Asymptomatic, anorexia, headache, nausea, vomiting, lethargy, personality change, cramps, weakness, confusion, drowsiness, seizures.
D: Fluids status, BP, HR, cardio exam, serum Na and K, TFTs, urine Na level, random serum cortisol levels or ACTH stimulation test.
T: Hypovolaemic - IV saline replacement. Normovolaemic - fluid restrict, use of vaptans
Hypervolaemic - treat the underlying cause (usually heart failure, AKI, liver cirrhosis), loop diuretics.
Hypokalaemia
Serum potassium concentration of <3.5 mmol/L.
C: Increased renal excretion (diuretics, hypomagnesaemia, renal disease), GI losses, alkalosis, B-agonists, insulin (redistribution to the cells), reduced intake.
S: Asymptomatic, muscle weakness, heart arrythmias.
D: U&Es, serum Mg, Cl, bicarb, glucose, ECG (flat T waves, ST depression, prominent U waves), urinary K, Na, osmolarity
T: Treat underlying cause, review diuretics, replacement with oral potassium chloride supplements, Mg should be normalised. IV potassium chloride (in NaCl) for patients with hypokalaemia and DKA or severe hypokalaemia with cardiac arrythmias or muscle weakness.
Hyperkalaemia
Serum potassium of concentration >5.5 mmol/L.
C: Decreased excretion (AKI, drugs, Addison’s disease), redistribution (DKA, metabolic acidosis, tissue necrosis or lysis), extraneous blood load (potassium chloride, salt substitutes, transfusion of stored blood)
S: Very few until cardiac arrest, muscle weakness and paralysis, metabolic acidosis.
D: Serum potassium, 24-hour urine volume and electrolytes, FBC, plasma glucose, Digoxin level, ABG, ECG (peaked T waves, prolongation of PR interval, widening of QRS).
T: Mild (dietary potassium restriction, restriction of drugs causing hyperkalaemia and a loop diuretic to increase urinary potassium excretion).
Emergency - IV calcium gluconate bolus (to protect heart), soluble insulin 10 units+50 mL 50% dextrose intravenously, sodium bicarbonate.
LT - Polystyrene sulphonate resin orally or rectally. Treat underlying cause. Review medication. Haemodialysis or peritoneal dialysis if conservative measures fail.
Volume depletion
Loss of total body sodium causes loss of water across plasma membranes. Serum sodium concentration can be high, low, or normal.
C: Extrarenal (bleeding, dialysis, D&V, burns, excessive sweating, intestinal lumen, intraperitoneal, retroperitoneal losses)
Renal, adrenal and pituitary (AKI, adrenal disorders, genetic disorders, diuretics, salt-wasting disease)
S: Diminished skin turgor, oliguria, thirstiness, dry mucus membranes, orthostatic tachycardia, hypotension, shock.
D: Clinical findings, serum electrolytes, BUN (blood urea nitrogen), and creatinine
T: Replacement of sodium and water - orally if possible, tube feeding, IV fluids.
Hypertriglyceridaemia
High blood levels of triglycerides. Increased risk of cardiovascular disease.
C: Obesity, diabets mellitus, excessive alcohol, kidney failure, lipoprotein lipase deficiency, lysosomal acid lipase deficiency, hypothyroidism, SLE, medications.
S: Asymptomatic, eruptive xanthoma, eye abnormalities (lipemia retinalis), hepatosplenomegaly (enlargement of the liver and spleen), and neurological symptoms.
D: Triglyceride levels - normal level is less than 150 mg/dL (1.7 mmol/L), identify underlying cause.
T: Lifestyle changes, drugs: Niacin, omega-3 fatty acids (epanova), statins, fibrates.
Thyroid cancer
Uncommon but most common endocrine cancer.
Types: Papillary, follicular, (more common and treatable) Hürthle cell carcinoma, medullary, anaplastic (less common, aggressive), thyroid lymphomas.
C: Ionising radiation, history of goitre, thyroid nodule or thyroiditis, fhx of thyroid disease, Cowden’s syndrome, obesity, Familial adenomatous polyposis.
S: Hard and fixed thyroid nodule, non-tender, firm cervical masses (lymph node metastasis), vocal cord paralysis.
D: TFTs, serum calcitonin, ultrasound, fine-needle aspiration cytology, CT/MRI
T: Total thyroidectomy for tumours greater than 4cm, DTC - near-total thyroidectomy, followed by administration of iodine-131, thyroid suppression therapy.
MTC - total thyroidectomy and prophylactic central lymph node dissection, radiotherapy and chemo-embolisation for metastasis.
No effective treatment for ATC.
