Endocrine disorders Flashcards
Which drugs can be used to treat hyperthyroidism?
Carbimazole
Methimazole
Propylthiauracil
What risks should be explained to a patient starting on carbimazole?
Risks of haematological disturbances, especially neutropenia (low neutrophil count) which increases risk of infection.
Warning signs include:
- sore throat, mouth ulcers, bruising, fever
Describe the contraindications of carbimazole
Contraindication: Severe haematological disorders
Caution:
Pregnancy and breast feeding (Propylthiouracil is the firstline preference)
Hepatic impairment
Renal impairment (Propylthiouracil)
Describe the mechanism of carbimazole
Carbimazole is metabolised to methimazole. This acts by inhibiting thyroid peroxidise and thereby the production of thyroid hormones.
Describe the signs and symptoms of low growth hormone levels
Retarded growth, abnormal fat distrubution
Can potentially cause dwarfism
How is growth hormone deficiency treated?
Treat the underlying cause
Give an example of something that can cause a deficiency of growth hormone
Hypothyroidism
What condition is caused by congenital hypothyroidism?
Cretinism - impaired mental and physical development
What is the common name for autoimmune thyroiditis? What endocrine condition does this cause?
Hashimoto’s disease
Primary hypothyroidism
Describe the signs and symptoms of hypothyroidism
Low metabolic rate Low body temperature, cold intolerance Tiredness, lethargy Weight gain Dry skin, hair
What tests should be done if hypothyroidism is suspected?
TFTs - FT3, FT4, TSH
Serology for TPO autoantibodies
How is hypothyroidism treated?
Give oral Levothyroxine (T4)
Describe the signs and symptoms of hypocalcaemia
SPASMODIC: Spasms (e.g. Trousseau’s sign) Paraesthesiae / Prolonged QTc interval / Papilloedema Anxious, irritable, irrational Seizures Muscle tone increase in smooth muscle – colic, wheeze, dysphagia Orientation impaired, confusion Dermatitis Impetigo herpetiformis Cardiomyopathy / Cataract
What tests should be done in a patient with suspected hypocalcaemia?
Blood test for serum calcium level PTH level ECG FBC, U&E, albumin Vitamin D, magnesium, phosphate
How is hypocalcaemia managed?
Oral or IV calcium (depending on severity)
What disease causes low levels of aldosterone and cortisol?
Addison’s disease
Describe the symptoms of aldosterone deficiency
Polyuria Hypovolaemia High serum potassium Low serum sodium (Can lead to hypotension)
Describe the symptoms of cortisol deficiency
Fatigue, nausea, weight loss, irritability, depressions Hyperpigmentation Buccal pigmentation Hypotension Hypoglycaemia
What tests should be done in a patient with suspected adrenal insufficiency?
Routine bloods Random cortisol (<700 nmol/l) Short synacthen test ACTH levels Adrenal antibodies
How is Addison’s disease treated?
Give oral glucocorticoid (hydrocortisone) and oral mineralcorticoid (fludrocortisone) replacement
What is a life-threatening complication of Addison’s disease? Describe the clinical signs/symptoms.
Addisonian crisis
Hypotension, tachycardia
What causes Addisonian crisis?
Addisonian crisis happens in patients with chronic adrenal insufficiency when subject to an intercurrent illness or stress, e.g. burns, infection, pregnancy, allergy, MI.
Explain why patients in Addisonian crisis become hypotensive
Low aldosterone: Sodium (and therefore water) are not sufficiently reabsorbed by the kidney, so are excreted, which leads to hypovolaemia and therefore hypotension.
Low cortisol: cortisol has a permissive effect on catecholamine action, therefore low cortisol levels mea that catecholamines do not work as effectively. This prevents the blood vessels from constricting enough to raise the blood pressure, so exacerbate the hypotension.
Explain why patients in Addisonian crisis become tachycardic
Tachycardia is to compensate for the low blood pressure (caused by hypovolaemia) to maintiain sufficient cardiac output.
How is Addisonian crisis managed?
IV 0.9% saline
Oral hydrocortisone 20mg
Fludrocortisone
What conditions are caused by excess growth hormone?
Gigantism (before fusion of epiphyseal plate)
Acromegaly (after fusion of epiphyseal plate)
Describe the signs and symptoms of acromegaly
Enlarged hands, feet, jaw (causes spacing-out of teeth), tongue, thick/course facial features
Cardiac symptoms
Thick, oily skin
What is the most common cause of acromegaly? How is this treated?
Pituitary adenoma
Transphenoidal surgery to remove pituitary tumour
Radiotherapy of pituitary tumour
Somatostatin (GHIH) analogues, dopamine agonists
Give an example of a disease that causes hyperthyroidism
Grave’s disease
Describe the signs and symptoms of hyperthyroidism
High metabolic rate High body temperature, heat intolerance Anxiety, irritability Weight loss Sweaty palms Palpitations Exophthalamos/proptosis Eyelid retraction
What tests should be done in a patient with suspected hyperthyroidism?
TFTs - FT3, FT4, TSH
TSH-receptor antibodies (test for Grave’s)
How is Grave’s disease treated?
Antithyroid drugs - carbimazole - methimazole - propylthiouracil Radioiodine Surgery (thyroidectomy)
Describe the signs and symptoms of hypercalcaemia
stones, bones, (abdominal) moans, and psychic groans
Renal stones, gallstones
- renal dysfunction, polyuria
Bone pain, osteoporosis, arthritis, muscle weakness
Nausea, vomiting, anorexia, constipation, pancreatitis
Confusion, depression, fatigue
What tests should be done in a patient with suspected hypercalcaemia?
Bloods - serum calcium, PTH,
FBC, U&E, albumin, vitamin D, magnesium
How is hypercalcaemia treated?
Rehydration (fluids)
IV bisphosphonates
Surgery
What disease is associated with high aldosterone levels?
Conn’s syndrome
What are the signs and symptoms of Conn’s syndrome?
Water retention (and sodium retention)
Increased body weight
Low blood potassium level
Describe the signs and symptoms of Cushing’s syndrome
Tissue breakdown - weakness of skin, bone and muscle
Sodium retention - can lead to hypertension and heart failure
Insulin antagonism - causes glucose intolerance, hyperglycaemia
Hyperlipidaemia
Weight gain, acne, bruising, moon face, purple striae, hirsutism
Suppressed immunity
What tests should be done in a patient with suspected Cushing’s syndrome?
24-hour urinary free cortisol
Dexamethasone suppression test
Explain the principle of the dexamethasone suppression test
Used to test for cushing’s syndrome
In normal subjects, dexamethasone suppresses ACTH and therefore cortisol secretion. In Cushing’s syndrome, there is incomplete suppression.
How is Cushing’s syndrome treated?
Treat the underlying cause, e.g. surgical removal of tumour
Medical therapy: metyrapone or ketoconazole
What can cause excess catecholamines in the blood?
Phaeochromocytoma: a catecholamine-secreting tumor of chromaffin cells typically located in the adrenals.
Describe the symptoms/signs caused by a phaeochromocytoma
Hypertension
High blood glucose level
Postural hypotension
Paroxysmal attacks; sweating, headache, palpitations, tremor, pallor, anxiety/fear
What tests should be done in a patient with a suspected phaeochromocytoma?
24 hour urine (metanephrines - metabolites of adrenaline)
Plasma free metanephrine
Imaging to locate tumour
Genetic testing
How is a phaeochromocytoma treated?
Surgery to resect the tumour
Antihypertensive medication
What is precocious puberty?
Onset of sexual maturation before age 8 in girls or age 9 in boys. Two types:
- Gonadotropin-releasing hormone (GnRH)–dependent (central precocious puberty)
- GnRH-independent (peripheral sex hormone effects)
