Endocrinology Flashcards
Zollinger-Ellison syndrome
Gastrinomas mainly formed in duodenem
Features:
multiple gastroduodenal ulcers
diarrhoea
malabsorption
Hyperthyroidism in pregnancy mx
1st trimester Propylthiouracil
2nd trimester onwards carbimazole
Hypothyroidism in pregnancy mix
increase their thyroid hormone replacement dose by up to 50% as early as 4-6 weeks of pregnancy
The most appropriate treatment for this patient with excessive facial hair due to polycystic ovarian syndrome is
- combined oral contraceptive
- co-cyprindiol (anti-androgen)
- topical eflornithine.
blood glucose targets in gestational diabetes
The target for fasting blood glucose in gestational diabetes is <5.3 mmol/L.
The target for blood glucose two hours after an oral glucose tolerance test is <6.4 mmol/L.
Diabetes meliitus diagnosis:
fasting > 7.0, random > 11.1 - if asymptomatic need two readings
biochemical abnormality in Cushing’s Syndrome
hypokalaemic metabolic alkalosis (excess cortisol has mineralocorticoid action)
hyperglycaemia
Management of pre-existing diabetes in pregnancy
weight loss for women with BMI of > 27 kg/m^2
stop oral hypoglycaemic agents, apart from metformin, and commence insulin
diagnosing cushings syndrome vs disease
disease (pituitary tumour)
- (ACTH) production from the pituitaries can be inhibited by high doses of dexamethasone
syndrome (adrenal gland) however autonomous cortisol production from the adrenals will not be affected.
distinguishing Cushing’s syndrome due to other causes (e.g. adrenal adenomas) vs ectopic ACTH (eg. lung ca) – measure ACTH levels
First line treatment in diabetic neuropathy
amitriptyline, duloxetine, gabapentin or pregabalin
link between plasma glucose and HBA1c
average plasma glucose = (2 * HbA1c) - 4.5
SIADH - drug causes
carbamazepine, sulfonylureas, SSRIs, tricyclics
mx thyrotoxic storm
Thyrotoxic storm is treated with beta blockers, propylthiouracil and hydrocortisone
medical management of prolactinoma?
cabergoline (dopamine agonist)
medical management to control the growth of advanced neuroendocrine tumours for instances where surgery is not possible
Octreotide is a synthetic form of the natural hormone somatostatin
*side effect - biliary stasis and frequent gall stones
fasting glucose vs impaired glucose cut offs
a fasting glucose (hepatic insulin resistance) greater than or equal to 6.1 but less than 7.0 mmol/l implies impaired fasting glucose (IFG)
impaired glucose tolerance (IGT) (muscle insulin resistance) is defined as fasting plasma glucose less than 7.0 mmol/l and OGTT 2-hour value greater than or equal to 7.8 mmol/l but less than 11.1 mmol/l
Turner’s syndrome - most common cardiac defect ?
bicuspid aortic valve
where does mRNA splicing occur?
nucleus
features of DiGeorge Syndrome
CATCH22:
C - Cardiac abnormalities
A - Abnormal facies
T - Thymic aplasia –> T Cell disorder
C - Cleft palate
H - Hypocalcaemia/ hypoparathyroidism
22 - Caused by chromosome 22 deletion
Obesity hormones
Leptin Lowers appetite
Ghrelin Gains appetite
disorders associated with marfanoid appearances and their distinguishing features
multiple endorine neoplasia 2b (AD)
- phaechromocytoma
- neuromas
marfans (AD)
- UPWARD lens dislocation
Homocystinuria (AR)
- DOWNWARD lens dislocation
- intellectual disability
caused by a deficiency of cystathionine beta synthase. This results in severe elevations in plasma and urine homocysteine concentrations.
mx. Treatment is vitamin B6 (pyridoxine) supplements.
what is subclinical hypothyroidism?
high TSH
normal T3/4
usually asymptomatic
management of t2DM, on triple therapy
switch one drug for a GLP-1 mimetic (eg. exenatide)
which diabetic drug can cause weight gain
sulfonylureas eg. gliclazide
they stimulate insulin release resulting in increased glucose uptake
thyroid hormone changes in pregnancy that are normal
Raised total T3 and T4 but normal fT3 and fT4 suggest high concentrations of thyroid binding globulin, which can be seen during pregnancy due to increased oestrogen
Klinnefelter vs kallman
Klinefelter XXY: testosterone low, syndrome the LH and FSH levels are raised
Kallman: X linked recessive. neurons don’t migrate in hypothalmus. anosmia.
The LH and FSH levels are inappropriately low-normal given the low testosterone concentration,
Metabolic ketoacidosis with normal or low glucose
alcoholic ketoacidosis
X ray findings primary hyperparathyroidism
pepperpot skull
osteitis fibrosa cystica
how to distinguish gout and pseudogout from x ray
Chondrocalcinosis = pseudogout
osteopetrosis vs paget’s disease of the bone
paget’s disease - abnormal bone formation, raised ALP, older
osteopetrosis - AD inheritance, younger patients, thick bone forms within bone making it more brittle, normal calcium, phosphate, ALP and PTH levels –> bone pain and neuropathies
management of Thyrotoxicosis with tender goitre and recent viral infection
= subacute (De Quervain’s) thyroiditis
conservative mx
naproxen
what drugs can cause false negatives results in investigations for primary hyperaldosteronism?
RAAS inhibitors
Thyrotoxic storm treatment and explanation
beta blockers, propylthiouracil and hydrocortisone
Hydrocortisone acts to prevent the peripheral conversion of T4 to T3 and is particularly effective in Graves’ disease. Propranolol blocks the effects of thyroid hormones and reduces the heart rate. Propylthiouracil stops the release and production of thyroid hormones and reduces the peripheral conversion of T4 to T3.
which dibaetic drugs cause weight gain?
sulfonylureas
thiazolidinediones (glitazones)
where do sulphonylureas bind to exert their effects?
bind to an ATP-dependent K+(KATP) channel on the cell membrane of pancreatic beta cells.
how do thiazolidinediones (glitazones) exert their effects?
Activation of peroxisome proliferator-activated receptor-gamma (PPAR gamma) –> increased insulin sensitivity
where does metformin bind?
activating the AMP-activated protein kinase (AMPK), helping cells to respond more effectively to insulin and take in glucose from the blood.
PHaeochromocytoma mx
- give PHenoxybenzamine (alpha blocker) before beta-blockers (propranolol)
Rick factor for malt lymphoma
Hashinotis thyroditis
Which type two diabetes drug increases risk of developing dka?
SGLT - 2 inhibitors ie. Flozins
what can cause the development / worsening of thyroid eye disease in Grave’s disease
Radioiodine treatment
Impaired fasting glycaemia (IFG) cut offs
is defined as a fasting plasma glucose level between 6.1 mmol/l and 6.9 mmol/l,
blood glucose cut offs to diagnose T2DM
if the patient is symptomatic:
fasting glucose greater than or equal to 7.0 mmol/l
random glucose greater than or equal to 11.1 mmol/l (or after 75g oral glucose tolerance test)
if asymptomatic, then patient needs the above results on 2 separate occasions
mx. intrahepatic cholestasis of pregnancy
features: itchy, raised bili,
mx:
ursodeoxycholic acid is used for symptomatic relief
weekly liver function tests
women are typically induced at 37 weeks
features + mx. Acute fatty liver of pregnancy
occurs in 3rd trimester/ post partum
features: severe abdominal pain, jaundice
nausea & vomiting
headache
hypoglycaemia
severe disease may result in pre-eclampsia
HELLP
Haemolysis, Elevated Liver enzymes, Low Platelets
mx. supportive
Marfan’s syndrome is caused by a mutation in ?
in a protein called fibrillin-1
when to use hypertonic saline
Patients with acute, severe (<120 mmol/L) or symptomatic hyponatraemia require close monitoring, preferably in an HDU or above setting.
BOLUS Hypertonic saline (typically 3% NaCl) is used to correct the sodium level more quickly than would be done in patients with chronic hyponatraemia.
how can carcinoid syndrome affect BP?
hypotension
ramadan and T2DM management
metformin dose should be split one-third before sunrise and two-thirds after sunset (Iftar)
recommends switching once-daily sulfonylureas to after sunset. For patients taking twice-daily preparations such as gliclazide it is recommended that a larger proportion of the dose is taken after after sunset
no adjustment is needed for patients taking pioglitazone
sarcoidosis management
majority = conservative
major organ failure = immunosuppressants
splenic/hepatic/renal/cardiac involvement, lupus pernio, hypercalcemia, eye/CNS involvement or deteriorating pulmonary function tests or deteriorating chest x-ray changes.
Subclinical hyperthyroidism is defined as:
normal serum free thyroxine and triiodothyronine levels
with a thyroid stimulating hormone (TSH) below normal range (usually < 0.1 mu/l)
first-line test for acromegaly
Serum IGF-1 levels
The OGTT test is recommended to confirm the diagnosis if IGF-1 levels are raised.
best test to diagnose Addison’s disease
The short synacthen test
Lithium Toxicity may be precipitated by:
dehydration
renal failure
drugs: diuretics (especially thiazides), ACE inhibitors/angiotensin II receptor blockers, NSAIDs and metronidazole.
drugs that may exacerbate myasthenia:
beta-blockers
lithium
phenytoin
antibiotics: gentamicin, macrolides, quinolones, tetracyclines
penicillamine
quinidine, procainamide
monitoring after starting ACEi
acceptable changes are an increase in serum creatinine, up to 30% from baseline and an increase in potassium up to 5.5 mmol/l.
otherwise stop
distinguishing Primary hyperaldosteronism, bilateral renal artery stenosis and Bartter syndrome
Primary hyperaldosteronism, bilateral renal artery stenosis and Bartter syndrome are associated with hypokalaemia due raised serum aldosterone.
Aldosterone is elevated in bilateral renal artery stenosis and Bartter syndrome due to reduced renal perfusion. Aldosterone is high in primary hyperaldosteronism due to (most commonly) an aldosterone producing adenoma.
However, serum renin is usually low in primary hyperaldosteronism due to the resulting hypertension causing excessive renal perfusion, which results in decreased renin production (negative feedback mechanism). High renin levels are seen in renal artery stenosis and Bartter syndrome as a mechanism to improve renal perfusion.
the single most useful test in determining the cause of hypocalcaemia
Parathyroid hormone
diagnostic for obstructive sleep apnoea
Polysomnography
increased serum and urine levels of hydroxyproline
Paget’s disease - (collagen marker)
Anorexia biochemical features
G’s and C’s raised: growth hormone, glucose, salivary glands, cortisol, cholesterol, carotinaemia
Insulinoma is diagnosed with
supervised prolonged fasting
Maturity-Onset Diabetes of the Young (MODY) is a form of monogenic diabetes, inheritance pattern?
autosomal dominant
treatment with low-dose sulfonylureas
ccording to NICE guidelines which type of insulin should be tried initially?
NPH insulin
[also known as isophane insulin] (injected once or twice daily according to need) should be offered.
Nephrogenic diabetes insipidus may be caused by which genetic mutations?
the more common form affects the vasopression 2 (ADH) receptor
the less common form results from a mutation in the gene that encodes the aquaporin 2 channel
dermatomyositosis antibodies
ANA positive
SLE antibodies
SLE is the underlying disease, for which the most sensitive test is an antinuclear antibody (ANA) with 100% sensitivity. However, there are other tests for SLE with better specificity. The most specific tests are anti-double-stranded DNA (dsDNA) antibody and an anti-Smith (Sm) antibody with 99% specificity.
mechanism of digoxin toxicity in hypoklaemia
Digoxin normally binds to the ATPase pump on the same site as potassium. Hypokalaemia results in digoxin more easily binding to the ATPase pump and increased inhibitory effects,
diagnostic for phaecromocytoma
24 hr urinary collection of metanephrines (sensitivity 97%*)
this has replaced a 24 hr urinary collection of catecholamines (sensitivity 86%)
what hyperthyroid feature is very specific for Graves
pretibial myxoedema
Stages of sleep
N1 (jerks) → N2 → N3 (sleep working, nightmares) → REM (dreaming, loss of muscle tone, erections)
Theta → Sleep spindles/K-complexes → Delta → Beta
The Sleep Doctor’s Brain
most common cause of primary hyperaldosteronism
1) Bilateral idiopathic adrenal hyperplasia
2) adrenal adenoma (Conn’s)
is Azathioprine considered safe to use in pregnancy?
yes
atorvastatin 20 mg should be offered if type 1 diabetics who are:
older than 40 years, or
have had diabetes for more than 10 years or
have established nephropathy or
have other CVD risk factors
collagen disorders by type
Type 1: of osteogenesis imperfecta
- fractures following minor trauma
- blue sclera
- deafness secondary to otosclerosis
- dental imperfections
Type 2 collagen is the main component of cartilage. Chondrodysplasias
Type 3 collagen is the main component of reticular fibres. Ehlers-Danlos syndrome.
Type 4 collagen forms the basal lamina.
Alport’s syndrome and Goodpasture’s syndrome.
Type 5 collagen is found in cell surfaces, hair and placentas. Disorders include the classical variant of Ehlers-Danlos syndrome.
Grave’s eye disease complications
Exposure keratopathy
this is the most common complication of thyroid eye disease
- exposed and irritated eye. Pain, dryness, corneal ulceration
Optic neuropathy - inflamed eye muscles compress optic nerve, reducing visual acuity and visual field defects
Strabismus and diplopia - inflamed eye muscles
most common Grave’s eye disease complications
Exposure keratopathy
Mycophenolate mofetil (MMF) mechanism of action
reduces lymphocyte production through inhibition of iosine-5’-monophosphate dehydrogenase.
rickets X ray findings and blood work
raised ALP, low Ca, low vit D
Swollen metaphyseal region on X-ray.
Calcium is required for the mineralisation and formation of mature bone tissue. If this cannot occur, a build up of this non-mineralised osteoid bone results in rickets disease.
aka. osteomalacia in adults
rickets in children
Sarcoidosis CXR
1 = BHL
2 = BHL + infiltrates
3 = infiltrates
4 = fibrosis
Ocular manifestations of rheumatoid arthritis
keratoconjunctivitis sicca (most common, dry eyes )
episcleritis (erythema)
scleritis (erythema and pain)
corneal ulceration
keratitis (moderate to intense pain and usually involves impaired eyesight, photophobia, redness of the eye with a gritty sensation)
which disease-modifying anti-rheumatic drug which is safe in both pregnancy and breastfeeding
Sulfasalazine
Causes of raised prolactin - the p’s
pregnancy
prolactinoma
physiological
polycystic ovarian syndrome
primary hypothyroidism
phenothiazines, metoclopramide, domperidone
stopping anti depressants
Antidepressants should be continued for at least 6 months after remission of symptoms to decrease risk of relapse
arthralgia, myositis and Raynaud’s
what is the disease? what is the diagnosis?
Anti-ribonuclear protein (anti-RNP) = mixed connective tissue disease
HLA associated with coeliac disease.
HLA-DQ2
first hormone secreted in response to hypoglycaemia
Glucagon
Homocystinuria
- what is the inheritance pattern?
- what enzyme is deficient?
- what is the treatment?
Homocystinuria is a rare autosomal recessive disease caused by a deficiency of cystathionine beta synthase.
Treatment is vitamin B6 (pyridoxine) supplements.
best sign of active SLE
complement levels (C3, C4)
Looser’s zones x-ray are most characteristically associated with which condition?
osteomalacia
also known as pseudofractures or Milkman’s fractures
occur due to insufficient mineralisation of osteoid produced by osteoblasts.
due to low vit D resulting in low ca absorption from intestine
polyarteritis nodosum diagnosis
clinical diagnosis: unexplained fever, arthralgia, subcutaneous nodules, skin ulcers, pain in the abdomen or extremities, new foot drop or wrist drop, or rapidly developing hypertension.
The diagnosis when other causes are excluded.
pANCA and hep B serology MAY be positive
bone pain
bone/muscle tenderness
fractures: especially femoral neck
proximal myopathy: may lead to a waddling gait
Osteomalacia
the first-line investigation in suspected primary hyperaldosteronism
A plasma aldosterone/renin ratio
Indications for corticosteroid treatment for sarcoidosis are:
parenchymal lung disease (not just hilar lymphadenopathy), uveitis, hypercalcaemia and neurological or cardiac involvement
In toxic multinodular goitre, nuclear scintigraphy reveals ?
graves?
patchy uptake = toxic multinodular goitre
diffuse increased uptake = graves
most common non-iatrogenic cause of Cushing’s syndrome?
Pituitary tumour. This condition, also known as Cushing’s disease,
how can carcinoid syndrome affect the heart?
right side of the heart.
The valvular effects are tricuspid insufficiency and pulmonary stenosis (TIPS)
Peptic ulceration, galactorrhoea, hypercalcaemia -
multiple endocrine neoplasia type I
which patients should be on metformin?
diabetics BMI >25
On examination a hard, fixed, painless goitre is noted. It is usually seen in middle-aged women.
Riedel’s thyroiditis is a rare cause of hypothyroidism characterised by dense fibrous tissue replacing the normal thyroid parenchyma.
It is associated with retroperitoneal fibrosis.
Diabetic ketoacidosis: the IV insulin infusion dose
should be started at 0.1 unit/kg/hour
Poor compliance with thyroxine blood test results
high TSH
normal T4 (starts taking meds before blood test)
recent steroids, thyroxine blood test result
low TSH
normal T4
subclinical hypothyroidism result
high TSH
normal T4
euthyroid sick syndrome, which is commonly seen in critically ill patients.
In this condition, there is a decrease in serum triiodothyronine (T3) and thyroxine (T4) levels, with a normal or slightly decreased thyroid-stimulating hormone (TSH).
link between CKD and vit D
advanced chronic kidney disease there is impaired 1-alpha hydroxylation of 25-hydroxycholecalciferol by the kidney to 1,25-dihydroxycholecalciferol.
1,25-dihydroxycholecalciferol is the active form of vitamin D. In health, 1,25-dihydroxycholecalciferol promotes calcium and phosphate absorption from the gut and kidney,
