Endo Flashcards
Causes of diabetes insipidus
Cranial (no ADH secretion) - pituitary tumour - infection (meningitis) - sarcoidosis Nephrogenic (insensitive to ADH) - increased Ca2+ - decreased K+ - lithium - inherited AVPV2 gene - idiopathic
Sx of DI
Polyuria (UO > 3L), nocturia, polydipsia, sx of hypernatraemia (lethargy, irritability, confusion)
Ix for DI
U&Es, HbA1c (exclude DM), water deprivation test (diagnostic)
Water deprivation test results for
a) normal
b) cranial
c) nephrogenic
a) ADH secretion occurs so increased plasma osmolality urine concentration
b) decreased urine osmolality [dilute]
c) decreased urine osmolality [dilute]
=> desmopression administered
b) urine osmolality increase >50%
c) urine osmolality increase <45%
Mx for DI
TREAT CAUSE
Cranial => intranasal desmopressin
Nephrogenic => thiazide diuretic or NSAIDs (inhibit prostalgandin synthase as prostaglandin inhibits ADH)
TIDM summary card
Hyperglycaemia due to deficiency of insulin production as a result of AI destruction of beta cells (90% cases)
PC: polyuria + polydipsia, tired, wt loss, DKA (N&V, abdo pain, Kussmaul breathing)
Associated w/ HLADR3/4 + other AI conditions
Tx: insulin, pt education, DKA (1st line - fluids)
TIIDM summary card
Hyperglycaemia due to increased peripheral resistance to insulin action
PC: polyuria and polydipsia
RFs: obesity, FHx, ethnicity, drugs
Tx: 1st - diet and lifestyle, 2nd - metformin => sulphonylurea => insulin
Which blood glucose measurements are diagnostic of diabetes mellitus?
Fasting blood glucose >/= 7mmol/L
Random blood glucose >/= 11.1mmol/L
How may hypernatraemia present and how is it treated?
Rarer sodium imbalance
- lethargy, signs of dehydration, irritability, fits, confusion, coma
Replace water + treat cause
What causes hypernatraemia?
D&V
Diabetes insipidus
Primary hyperaldosteronism
What leads to hyponatraemia?
SIADH
What causes hyponatraemia?
Causes can be split based on water status of the pt
1) Dry (hypovolaemic)
- D&V, diuretics
2) Normal (euvolaemic)
- hypothyroidism, hypoadrenalism, SIADH causes
3) Wet (hypervolaemic)
- HF, cirrhosis, nephrotic syndrome
How may hyponatraemia present?
Presentations suggest water status of pt:
1) Dry => dry mucous membranes, tachycardia
2) Normal => other sx of endo cause
3) Wet => increased JVP
Potential ix after bloods show hyponatraemia
TFTs, short synACHTen test
CXR, breast exam, brain MRI (SIADH malignancies)
Possible causes of SIADHq
CNS pathology
Lung pathology
Drugs: SSRI, TCA, opiates, PPIs, carbamazepine
Tumours (don’t forget breast!)
Mx of SIADH
Treat underlying cause
Fluid restriction 0.5-1L
If above ineffective: demeclocycline/vasopressin receptor antagonist (tolvaptan)
How may a prolactinoma present?
Headache, loss of visual fields
Women:
- galactorrhoea, amenorrhoea, infertility, loss of libido
Men:
- loss of libido, infertility, galactorrhoea common
*result of secondary hypogonadism
Causes of prolactinoma
Pituitary prolactionoma
Physiological (pregnancy, breastfeeding)
Hypothyroidism
Drugs (metocloporamide, antipsychotics; DA antagonists)
Ix and mx for prolactinomas
Ix => prolactin, TFTs, pituitary MRI
Mx
=> 1st line: DA agonist - bromocriptine, cabergoline
=> 2nd line: transphenoidal surgery
Compare hyper- and hypothroid presentations
Hyperthyroidism
- sweating, heat intolerance
- palpitations, irregular pulse
- irritable
- wt loss but good appetite
- tremor, diarrhoea
- menstrual irregularities/impotence
Hypothyroidism
- cold intolerance
- bradycardia, lethargy
- wt gain but appetite loss
- constipation
- dry skin, cold hands
- menstrual irregularities
Causes of hyperthyroidism and what they would show in a radioisotope scan
Grave's - diffuse increased uptake; smooth goitre Adenoma - single area of uptake Toxic multinodular goitre - multiple places of increased uptake De Quervain's thyroiditis - no uptake
How may sx/examination/ix differentiate between the different causes of hyperthyroidism?
Grave’s
- exopthalmos, pretibial myoxedema, thyroid acropachy
Adenoma
- solitary nodule on palpation
Toxic multinodular goiter
- elderly + iodine deficient areas
De Quervain’s thyroiditis (self-limiting, treat w/ NSAIDs)
- post-viral, fever, painful goitre, increased ESR
Causes of hypothyroidism
Hashimoto's disease (autoimmune) - no.1 cause in West Iodine deficiency - no.1 cause in world Iatrogenic - post-surgery, radioiodine, amiodarone De Quervain's thyroiditis - after hyper => hypo (self-resolving but may need thyroxine replacement for a few weeks)
Mx of hypothyroidism
Levothyroxine 25-200mg/day
- monitor TFTs at 6 weeks and adjust dose accordingly
Thyroid cancer summary card
Papillary (most common)
- radiation exposure, psammomna bodies, Orphan Anne nuclei, younger pts
Follicular
- Hurthle cells, middle-aged women
Medullary
- MEN2, ?FHx
Lymphoma
- female > male, occurs after pre-existing Hashiomoto’s
Anaplastic
- giant cells, pleomorphic hyperchromatic nuclei, elderly females
Presentation of acromegaly
Rings and shoes become tight Increased sweating Coarse facial features Sleep apnoea Weight gain Headaches/visual disturbance Carpal tunnel syndrome Hypertension Insulin resistance
Ix for acromegaly
Screen => IGF-1 serum levels
DIagnostic => OGTT (result: fails to suppress GH)
MRI => visualise pituitary tumour
Mx for acromegaly
1st line => transphenoidal hypophysectomy
2nd line => somatostatin analouge; octeotride
Types of tumours/sx that occur in the different MENs
MEN1 (menin gene, chr 11) - parathyoid (adenoma/hyperplasia) - pancreas (gastrinoma/insulinoma) - pituitary (prolactin, acromegaly, adrenal) MEN2 (RET gene, chr 10) - thyroid (medullary) - adrenal (pheochromocytoma, 50%) - parathyroid hyperplasia MEN2b/3 - medullary thyroid cancer (MEN2) - mucoual neurones (bumps on lips/cheeks/tongue/eyelids) - Marfanoid appearance
What are common sites and humoral factors of carcinoid tumours?
Rectum and appendix
- serotonin, histamine, tachykinins, prostaglandin
Presentation of carcinoid syndrome
Paroysmal flushing Diarrhoea Crampy abdo pain Wheeze Sweating Palpitations
Ix for suspected carcinoid syndrome
24hr urine collection (increased 5-H1AA levels; serotonin metabolite)
CT/MRI (localise tumour)
Consider looking for underlying MEN1
A 49 year old woman presents with 4kg weight loss over 2 months. She complains of feeling hot all the time and her partner mentions that she’s been more irritable recently. On examination she has a smooth goitre, and you also notice proptosis and a rash on her shins. What is the most likely diagnosis?
a) De Quervain’s thyroiditis
b) Toxic multinodular goitre
c) Grave’s disease
d) Menopause
e) Medullary thyroid cancer
c) Grave’s disease
A 16 year old boy presents to the GP with polyuria and polydipsia. He is diagnosed with diabetes insipidus. This condition is characterized by overproduction of which of the following?
a) Antibodies against insulin-producing beta cells of the pancreas
b) Anti-diuretic hormone
c) Brain natriuretic peptide
d) Oxytocin
e) Aldosterone
b) Anti-diuretic hormone
A 35 year old female presents with 4 month history of amenorrhoea. On examination, she is noted to have loss of peripheral vision. What is the most likely underlying problem?
a) Second cranial nerve palsy
b) Stroke
c) Hyperparathyroidism
d) Prolactinoma
e) Pregnancy
d) Prolactinoma
A 49 year-old man presents with a history of difficulty sleeping. He reports feeling increasingly tired and general weakness which he attributes to his poor sleep pattern. Additionally, the patient has noticed he has gained weight and sweats more easily. On examination, the patient has coarse facial features. What is the most likely diagnosis?
a) Hyperthyroidism
b) Cushing’s disease
c) Acromegaly
d) Hypothyroidism
e) Diabetes
c) Acromegaly
A 50 year old Asian man is referred to diabetes clinic after presenting with polyuria and polydipsia. He has a BMI of 30, a blood pressure measurement of 137/88 and a fasting plasma glucose of 7.7mmol/L. The most appropriate first-line treatment is:
a) Dietary advice and exercise
b) Sulphonylurea
c) Exenatide
d) Thiazolidinediones
e) Metformin
a) Dietary advice and exercise
A 15 year old girl complains of headaches which started 6 weeks ago. The headaches initially occurred 1-2 times a week but now occur up to five times a week, they are not associated with any neurological problems, visual disturbances, nausea or vomiting. The girl also reports a white discharge from both of her nipples. She has not started menstruating. The most appropriate investigation is:
a) Lateral skull X ray
b) CT scan
c) MRI scan
d) Thyroid function tests
e) Serum prolactin measurement
e) Serum prolactin measurement
A 58 year old woman presents with an acutely painful neck, the patient has a fever, blood pressure is 135/85, and heart rate is 102 bpm. The patient explains the pain started 2 weeks ago and has gradually become worse. She also experiences palpitations and believes she has lost weight. She presents one week later complaining of intolerance to cold temperatures. What would you see if you performed a radioisotope scan on her?
a) Single area of increased uptake
b) Multiple areas of increased uptake
c) Diffuse increased uptake
d) No uptake
e) She does not need a radioisotope scan
d) No uptake
