Endocrinology Flashcards
What are the symptoms of acromegaly?
- Growth of bones of the hands, feet and lower jaw
- Protrusion of the forehead
- Soft tissue swelling in hands, feet, face and tongue
- Increased size of organs
- Excessive sweating
This can lead to additional health probelms:
- Carpal tunnel syndrome (soft tissue swelling)
- Diabetes Mellitus (Diabetogenic effects of GH)
- Congestive cardiac failure (cardiomyopathy)
- Gastrointestinal Cancers (colon polyps)
Describe the diagnosis of acromegaly.
IGF-1 testing:
- Elevated in acromegaly
- First-line
- Should then be followed up by the tests below
OGTT:
- Usually a high dose of glucose would decrease the levels of GH in the blood.
- In acromegaly, there is a paradoxical rise in GH after glucose administration
MRI pituitary:
- Would show the pituitary adenoma (responsible for 95% of cases)
Summarise the treamtent of acromegaly.
Surgery (transphenoidal adenectomy) is the mainstay of treatment. In those that are not suitable for surgery, or whilst waiting for surgery:
- Somatostatin analogues e.g. ocreotide
- GH receptor antagonist eg. pegsivomant
- Radiotherapy
What are the cardivascular complications of acromegaly?
- Congestive cardiac failure
- Hypertension
- Arrhythmia
- Valvular disease
- Hypertrophy
What is the HbA1c range for prediabetes and diabetes?
Prediabetes: 42-47 mmol/mol (6.0-6.4%)
Diabetes: ≥48 mmol/mol (>6.5%)
How do you handle the hydrocortisone and fludrocortisone replacements in a patient with Addison’s during acute illness?
Double hydrocortisone, keep fludrocortisone the same dose.
What are the neoplasm part of MEN-1?
The 3 P’s:
- Parathyroid
- Pituitary
- Pancreatic: insulinomas and gastrinomas
What are the neoplasm part of MEN-2a?
Medullary Thyroid Cancer
2P’s:
- Parathyroid
- Phaeochromocytoma
What are the neoplasm part of MEN-2b?
Medullary Thyroid Cancer
1 P:
- Phaeochromocytoma
Also: Marfanoid body habitus + Neuromas
At what time of the day should the urine sample for the albumin:creatinine ratio be collected as part of the annual diabetic screen?
Early mornign.
This is so as to reduce the impact of factors such as hydration status and physical activity on the results.
What are drugs that can be used to treat hyperthyroidism?
Carbimazole and propylthiouracil can be used to treat hyperthyroidism.
Radioactive iodine is a more permanent option, and also first-line for toxic nodular goitre.
Name some causes for SIADH.
In SIADH there is increased water retention due to increase in AQP-2 channels by ADH secretion. Causes for increased ADH secretionare:
Malignant:
- Small cell lung cancer
- (Pancreas, prostate)
Neurological:
- Stroke
- Subarachnoid haemorrhage, subdural haemorrhage
- Meningitis, encephalitis, abscess
Infections:
- Pneumonia
Drugs:
- Psychiatric: SSRIs, tricyclics
- Carbamezapine
Other:
- PEEP
- Porphyrias
What electrolyte abnormality is seen with SIADH?
Hyponatraemia
Describe the Corticosteroids in terms of their glucocorticoid and mineralocorticoid effects.
What is the management of subclinical hypothyroidism?
subclinical hypothyroidism is when the TSH is raised but T3 and T4 are normal.
The managment if symptomatic and TSH 4-10 is:
- < 65 years: trial for levothyroxine. If no improvement of symptoms, stop.
- >80 years: watch and wait
If asymptomatic, observe and repeat TFT in 6 months.
If TSH >10 regardless of symptoms:
- < 70 years: levothyroxine.
- >80 years: watch and wait
What is the main element of treatment for rhabdomyolysis?
- IV fluids (normal saline) to encourage good renal output
- Urinary alkalinisation is sometimes used
Which medications can cause hyperkalaemia?
- Potassium sparing diuretics (Sporinolactone)
- ACE inhibitors
- ARBs
- Ciclosporing
- Heparin (via inhibition of aldosterone)
What are drug causes of gynaecomastia?
- Spironolactone
- Digoxin
- Finasteride
- Oestrogens
- Cannabis
What are causes of gynaecomastia?
- Phyiological: normal in puberty
- Syndromes with androgen deficiency (Kallman’s, Klinfelter’s)
- Testicular failure (e.g. mumps)
- Liver disease
- Ectopic tumour secretion
- Haemodialysis
- Drugs
What is sick euthyroid?
In sick euthyroid syndrome (now referred to as non-thyroidal illness) it is often said that everything (TSH, thyroxine and T3) is low. In the majority of cases however the TSH level is within the >normal range (inappropriately normal given the low thyroxine and T3).
Changes are reversible upon recovery from the systemic illness and hence no treatment is usually needed.
What are the blood sugar target levels in T1DM before meals?
In type 1 diabetics, blood glucose targets:
- 5-7 mmol/l on waking
- 4-7 mmol/l before meals at other times of the day
What is Kallman’s syndrome?
Kallman’s Syndrome is a cause of secondary hypogonadism. It is a inability fo the hypothalamus to release GnRH and therefore no production of LH/FSH by the anterior pituitary
What is Klinefelter’s Syndrome?
This is a cause primary hypogonadism in males. It si when there are one or more additional X chromosomes in a man (e.g. XXY or (+)XXY)
What are the causes of primary hyperparathyroidism, in order of preference?
- Solitary adenoma (80%)
- Hyperplasia (15%)
- Multiple adenoma (4%)
- Carcinoma (1%)
What factors can lead to falsely high or low HbA1c values?
Falsely low:
- Diseases that decrease RBC lifespan (e.g. sickle cell, G6PD, hereditary spherocytosis)
Falsely high:
- States that increase RBC lifespan (B12/folate deficiency, IDA, splenectomy)
What is cerebral salt wasting syndrome?
This is a rare endocrine condition seen after head trauma.
It leads to excessive salt excretion by the kidneys.
This leads to hyponatraemia, which can be distinguished from SIADH by fluid status: SIADH is normal/overloaded, whereas the patient is dehydrated in CSWS.
What are common primaries that metastasise to the bone?
Which sites in the bone are monst commonly affected?
- Prostate
- Breast
- Bronchus
Sites:
- Spine
- Pelvis
- Ribs
- Skull
- Long Bones
What is the Wolff-Chaikoff effect?
This describes the effect that large amounts of iodine can lead to suppression of thyroid function.
This usually passess after ~10 days in patients with normal thyroids.
What are the features of an Addisonian Crisis?
How is this treated?
This is a potentially life-threatening condition where there is a lack of cortisol.
It presents with confusion, severe lethargy, convulsions and aelectrolyte disturbances:
- Hyperkalaemia
- Hyponatremia
And hypoglycaemia.
Management:
- IV or IM hydrocortisone 100mg
- Continue hydrocortisone 6 hourly until the patient is stable. (fludrocortisone is not required)
- Oral replacement may begin after 24 hours and be reduced to maintenance after 3-4 days.
What test is used to confirm the diagnosis of Addison’s disease?
The short snyACTHen test. It can confirm primary adrenal insufficiency.
- Cortisol and alosterone are measured (low makes you suspect Addison’s disease).
- ACTH is given to a patient. (in a healthy patient cortisol levels would rise)
- If it the cortisol doesn’t rise appropriately, secondary adrenal insufficiency is likely
What are the target HbA1c values for patients with T2DM?
Diagnosis if HcA1c 48mmol/l.
Targets:
- Lifestyle: < 48 mmol/L
- Lifestyle + metformin < 48 mmol/L
- Add a second drug only if >53 mmol/L (or >7%)
- Add a third drug if >58 mmol/L (7.5%)
What are the clinical signs you might expect to see in someone with hypocalcaemia?
- Chvostek’s sign = hypocalcaemia, tapping over parotid (CN7) causes facial muscles to twitch
- Trousseau’s sign = hypocalcaemia, often occurs after 2 minutes of cuff inflation above systolic pressure
Which anti-diabetic medication is associated with an increased irks of bladder cancer
The thiazoledinediones such as pioglitazone are associated with an increased risk of bladder cancer.
Other side-effects include:
- Fluid retention (hence not used in cardiac failure)
- Weight gain
- Liver impairment
- Increased risk of fractures
What is the risk of giving 0.9% NaCl to patients requiring large volimes of fluid replacement?
Hyperchloraemic metabolic acidosis.
What is the management of malignancy-related (i.e. 2° to bone mets) hypercalcaemia?
Acutely, treat with IV fluids (as for normal hypercalcaemia) + bisphosphonates.
Chronically:
- Advice about good hydration (3-4 L a day)
- Normal diet (don’t need to avoid calcium)
- Encourage mobilisation
- Teach about symptoms of hypercalcaemia
What is the screening test performed for microalbuminuria in diabetics?
The albumin:creatinine ratio.
This is from an early morning urine sample.
Dipstick cannot be used.
What medications are used to treat in renal disease hyperphosphataemia?
Calcium acetate is a calcium-based binder used to treat hypophosphataemia (can cause hypercalcaemia).
Sevelamer is a non-calcium based phosphate binder.
What are the most common casues causes for hyperaldosteronism?
Hyperaldosteronism can be caused by:
- Bilateral hyperplasia (most common): treat with spironolactone
- Unilateral adenoma (second most common): treat with surgery
What ECG abnormality may occur in hypocalcaemia?
- Corrected QT interval prolongation
- Rare: AF or TdP
What is MODY?
A group of inherited genetic disorders affecting the production of insulin. Results in younger patients developing symptoms similar to those with T2DM, i.e. asymptomatic hyperglycaemia with progression to more severe complications such as diabetic ketoacidosis.
Talk about thyroid eye disease.
This is seen in 25-50% of patients with Grave’s disease, thought to be due to retro-orbital inflammation.
When there are vision changes with thyroid eye disease, urgent referral is warranted.
Complications:
- Exophthalmus -> inability to close lids can lead to exposure keratopathy
- Optic disc swelling -> vision changes
- Ophthalmoplegia
Which durgs are associated with SIADH?
- Carbamezapine
- Sulfonylureas
- SSRIs
- tricyclics
Describe the link between calcium and magensium in physiology.
Mg is required for both PTH secretion and its action on target tissues.
Hypomagnesaemia may therefore both cause hypocalcaemia, and render patients unresponsive to treatment with calcium and witamin D supplementation.
How do you treat a phaeo whilst awaiting definitive tumour management?
First, alpha blockade is required (to prevent unopposed alpha blocade casing hypertension).
This can be achieved by labetalol (very selective for slpha receptors) or phenoxybenzamine
What haematological abnormality may be observed in adrenal insufficiency?
A normocytic anaemic can be seen in up to 15% of patients.
What is the first line investigation for acromegaly?
IGF-1 in serum. This has overtaken the OGTT (which is still used to confirm once IGF-1 test comes back positive.
What are the different types of thyroid cancer? Comment on prevalence and differentiating features.
- Papillary: 70%. Often young females; excellent prognosis
- Follicular: 20%
- Medullary: 5%. Cancer of parafollicular cells, secrete calcitonin. Part of MEN-2a and 2b
- Anaplastic: 1%. Elderly patients. Poor prognosis as not responsive to treatment
What test do you do for a phaeochormocytoma initially?
24 hours urinary metanephrines (not urinary catecholamines).
What is the mechanism of action of orlistat?
It works by inhibtigin pancreatic lipase to reduce the digestion of fat.
What do you give in myxoedema coma?
Levothyroxine and hydrocortisone.
You give the hydrocortisone to cover for panhypopituitarism, until it has been ruled out.
What would the Ix for Wilson’s Disease show?
Reduced caeruloplasmin, reduced serum copper.
Increased 24h urinary copper excretion.
Treated with penicillamine
What is tumour lysis syndrome?
This syndrome describes the complications seen with rapid tumour cell death after administration of chemotherapy, e.g. in Burkitt’s Lymphoma:
- Hyperkalaemia
- Hyperphosphataemia
- Hypocalcaemia
- Hyperuricaemia
- Acute renal failure
What can be given preventatively for tumour lysis syndrome?
Allopurinol or rasburicase.
What are the causes of primary hyperparathyroidism?
- 80% adenoma
- 15% hyperplasia (associated with MEN-1 and MEN-2a)
- 4% multiple adenoma
- 1% carcinoma
What is the definition of malnutrition?
There are three possible criteria for a diagnosis of malnutrition:
- A body mass index of less than 18.5kg/m²
- A body mass index of less than 20kg/m² and unintentional weight loss greater than 5% within the last 3-6 months
- Unintentional weight loss greater than 10% within the last 3-6 months with any BMI
What is sublinical hypothyroidism?
And subclinical hyperthyroidism?
Subclinical hypothyroidism is where there is elevated TSH iwth a normal T4 and symptoms of hypothyroidism.
Subclinical hyperthyroidism is where there is low TSH but a normal T4 and symptoms of hyperthyroidism.
What is the management of cord compression?
- High-dose oral dexamethasone
- Urgent oncological assessment for consideration of radiotherapy or surgery
List the causes of carnial and nephrogenic DI.
Cranial:
- Idiopathic
- Post head injury
- Pituitary surgeries
- Craniopharyngiomas
- Haemochromatosis
Nephrogenic:
- Genetic (mutations of channel or ADH receptor)
- Electrolytes: hypercalcaemia, hypokalaemia
- Drugs: demeclocycline, lithium
- Tubulo-interstitial disease: obstruction, sickle-cell, pyelonephtirits
