Passmed Endocrinology Mushkies Flashcards
What is the pathophysiology of DKA?
DKA is causes by uncontrolled lipolysis which results in an excess of free fatty acids that are ultimately converted into ketone bodies
What are the 3 most common precipitating factors of DKA?
- Infection
- Missed insulin doses
- MI
What are some features of DKA?
- Abdo pain
- Polyuria, polydipsia, dehydration
- Kussmaul respiration (deep hyperventilation)
- Acetone-smelling breath (pear-drops smell)
What are the diagnostic criteria for DKA?
- Glucose >11mmol/l or known DM
- Ketones > 3mmol/l or ++ on dipstick
- pH < 7.3
4, Bicarb < 15mmol/l
What is the management of DKA?
- 0.9% saline
- Insulin = 0.1 unit/kg/hour
- 5% dextrose once blood glucose < 15mmol/l
- Correction of hypokalaemia
- Long acting insulin continued, short acting insulin stopped
How fluid depleted are most pts with DKA?
5-8 litres
What is the JBDS fluid replacement regime for pts with DKA with SBP>90mmHg?
- 0.9% NaCL = 1000ml over 1st hour
- 0.9% NaCL + KCl = 1000ml over next 2hrs
- 0.9% NaCL = 1000ml over next 2hrs
- 0.9% NaCL = 1000ml over next 4hrs
- 0.9% NaCL = 1000ml over next 4hrs
- 0.9% NaCL = 1000ml over next 6 hours
What is the JBDS potassium replacement guideline for pts in DKA?
Potassium level in 1st 24 hours
- > 5.5 = No K
- 3.5-5.5 = 40 mmol/L
- <3.5 = senior review as additional K needs to be given
What are some complications of DKA and its management?
GVAAAI
- Gastric stasis
- VTE
- Arrhythmias secondary to hyperkalaemia/iatrogenic hypokalaemia
- ARDS
- AKI
- Iatrogenic due to incorrect fluid therapy = cerebral oedema, hypokalaemia, hypoglycaemia
What are children/young adults particularly susceptible during fluid resus for DKA?
- Cerebral oedema, usually 4-12 hours after commencement of tx
- 1:1 nursing ut monitor neuro obs, headache, irritability, visual disturbance, focal neurology etc.
- Any suspicion of oedema –> CT head and senior review
What does an ‘unrecordable’ blood glucose mean?
It is rather high
For group 1 vehicles, when are diabetic pts on insulin allowed to drive?
- If they have hypoglycaemic awareness
- Not more than one episode of hypoglycaemia requiring the assistance of another person within the preceding 12 months
- No relevant visual impairment
What overdose could cause metabolic acidosis with a raised anion gap?
Aspirin
What is the eponymous triad for an insulinoma?
Whipple’s triad
What is Whipple’s triad of symptoms for an insulinoma?
- Hypoglycaemia with fasting or exercise
- Reversal of symptoms with glucose
- Recorded low BMs at the time of symptoms
What is an insulinoma?
A neuroendocrine tumour deriving mainly from the pancreatic Islets of Langerhans cells
What are some stats about insulinomas?
- Most common pancreatic endocrine tumour
- 10% malignant
- 10% multiple
- Of pts with multiple tumours, 50% have MEN1
What are the features of MEN1?
3 Ps
- Pituitary adenoma
- Parathyroid hyperplasia
- Pancreatic tumour e.g. insulinoma, gastrinoma (recurrent peptic ulceration)
How is an insulinoma diagnosed?
- Supervised, prolonged fasting (up to 72 hours)
2. CT pancreas
What is the management for an insulinoma?
- Surgery
2. Diazoxide and somatostatin if pts are not candidates for surgery
What are features of MEN2A?
- Parathyroid hyperplasia
- Medullary Thyroid Carcinoma
- Phaeochromocytoma
What are features of MEN2B?
- Mucosal neuromas
- Marfanoid body habitus
- Medullary Thyroid Carcinoma
- Phaeochromocytoma
What is the management of subclinical hypothyroidism in the elderly?
Watch and wait
What are the TFT features of subclinical hypothyroidism?
- Raised TSH
- Normal T3 and T4
- No symptoms
What is the risk of progression to overt hypothyroidism from subclinical hypothyroidism?
2-5% per year
Pt <65 y/o with symptoms of hypothyroidism, high TSH, normal T3 and T4?
Trial of levothyroxine, if there is no sx improvement, stop
Mx of asymptomatic subclinical hypothyroidism <65 y/o?
Observe are repeat TFTs in 6m
TSH > 10 and normal T3 and T4 management?
Start tx even if asymptomatic
What is the management of myxoedema coma?
Levothyroxine and hydrocortisone
Why is hydrocotisone given for myxoedema coma?
To treat adrenal insufficiency, pts w/ myxoedema due to secondary hypothyroidism are at risk of hypopituitarism due to location of lesion, thus are treated as presumed adrenal insufficiency until it has been ruled out
How can you classify the features of hypothyroidism?
- General = weight gain, lethargy, cold intolerance
- Skin = dry, cold, non-pitting oedema, coarse hair, loss of lateral 1/3rd of eyebrow
- GI = constipation
- Gynae = HMB
- Neuro = dereased deep tenon reflexes, carpa tunnel syndrome
- Hoarse voice
What mutation accounts for 70% of MODY cases?
Hepatic Nuclear Factor 1 Alpha (HNF1A) mutation (MODY 3)
What is the optimal treatment for HNF1A-MODY?
Sulfonylureas
What is MODY?
The development of T2DM in pts <25y/o, typically inherited in an autosomal dominant fashion
How many different mutations are documented to cause MODY?
6
What malignancy is MODY 3 associated with?
HCC
How do you diagnose T2DM in a symptomatic pt?
- Fasting glucose ≥ 7.0 mmol/l OR
- Random glucose ≥ 11.1 mmol/l OR
- Post OGTT glucose ≥ 11.1mmol/l
How do you diagnose T2DM in an asymptomatic pt?
Same as symptomatic, but must be demonstrated on 2 separate occasions
What is the HbA1c T2DM diagnostic threshold?
> 48mmol/mol (6.5%)
What is pre-diabetes, in terms of both HbA1c and fasting glucose?
- HbA1c 42-47 mmol/l (6.0-6.4%)
2. Fasting glucose 6.1-6.9 mmol/l
What is normal fasting glucose in terms of both HbA1c and fasting glucose?
- HbA1c < 41mmol/mol (5.9%)
2. Fasting glucoe <6.0mmol/l
What is 48mmol/mol HbA1c in %?
6.5%
What is 41mmol/mol HbA1c in %?
5.9%
Does a HbAlc value of less than 48 mmol/mol (6.5%) exclude diabetes?
No, fasting samples are more sensitive
What can cause misleading HbA1c results?
Conditions that cause increased red cell turnover
- Haemoglobinopathies
- Haemolytic anaemia
- Untreated IDA
- Children
- HIV
- CKD
- Steroids
What defines impaired fasting glucose?
6.1-6/9 mmol/l
What defines impaired glucose tolerance?
- Fasting plasma glucose <7.0mmol/l
2. OGTT > 7.8 but less than 11.1 mmol/l
What should pts with IFG be offered?
An OGTT to rule out a diagnosis of diabetes
What is the first line investigation for Conn’s syndrome?
Renin:aldosterone ratio
What are 3 causes of primary hyperaldosteronism?
- Bilateral idiopathic adrenal hyperplasia (70%)
- Conn’s syndrome (adrenal adenoma)
- Adrenal carcinoma
What are 4 features of primary hyperaldosteronism?
- Hypertension
- Hypokalaemia
- Hypernatraemia
- Alkalosis
What is the management of bilateral idiopathic adrenal hyperplasia?
Aldosterone antagonist e.g. spironolactone
What is the management of Conn’s syndrome?
Surgery
What are the different types of thyroid cancers?
- Papillary (65%)
- Follicular (20%)
- Medulllary (5%)
- Anaplastic (1%)
- Lymphoma
Where does papillary thyroid cancer commonly metastasise to?
Cervical lymph nodes
What is a tumour marker for papillary and follicular thyroid carcinoma?
Thyroglobulin
What do you see on light microscopy of papillar thyroid carcinoma?
Orphan Annie eyes
Where does follicular thyroid carcinoma commonly metastasise to?
Lung and bones
Where do MTCs originate from and as such what is the tumour marker?
Parafollicular Cells, that produce Calcitonin
What demographic does papillary thyroid cancer usually affect, and what is its prognosis?
Young females, excellent prognosis
What condition is thyroid lymphoma associated with?
Hashimoto’s thyroiditis
What is the management of papillary and follicular thyroid cancer?
- Total thyroidectomy
- Followed by radioiodine (I-131) to kill residual cells
- Yearly thyroglobulin levels to detect early recurrent disease
In what demographic is anaplastic thyroid carcinoma most common?
Elderly females
What steroid has minimal glucocorticoid activity, and very high mineralocorticoid activity?
Fludrocortisone
What steroid has high glucocorticoid activity, and high mineralocorticoid activity?
Hydrocortisone
What steroid has high glucocorticoid activity, and low mineralocorticoid activity?
Prednisolone
What steroids have very high glucocorticoid activity, and minimal mineralocorticoid activity?
- Dexamethasone
2. Betamethasone
What are the s/es of
mineralocorticoids?
Fluid retention and hypertension
What are the s/es glucocorticoids?
- Endocrine = Cushings
- MSK = osteoporosis, proximal myopathy, AVN femoral head
- Immune = suppression
- Psych = Insomnia, mania, depression, psychosis
5.
How does Kartagener’s syndrome present?
Dextrocardia and a history of recurrent sinusitis/bronchitis
What is the karyotype of Klinefelters?
47XXY
What are some features of klinefelter’s?
- Taller than average
2, Lack of secondary sexual characteristics - Small, firm testes
- Infertile
- Gynaecomastia
- Elevated gonadotrophin levels but low testosterone
What diabetes drug is c/i in HF?
Thiazolidinediones e.g. pioglitazone, as they cause fluid retention
What is the MOA of thiazolidinediones?
- PPAR-y agonists in adipocytes to promote adipogenesis and fatty acid uptake
- Reduce peripheral insulin resistance
What are some features of Hashimoto’s thyroiditis?
1, Hypothyroidism
- Firm, non-tender goitre
- Anti-TPO Abs (also anti-Tg Abs)
How much more common is hashimoto’s thyroiditis in women?
10x
High TSH, normal T4, on levothyroxine, whats going on?
Poor compliance with medication - started taking thyroxine properly just before test. This will correct the thyroxine level but the TSH takes longer to normalise
What is Nelson’s syndrome?
Rapid enlargement of an ACTH producing adenoma that occurs after bilateral adrenelectomy for Cushings syndrome
What is the prevalence of pituitary adenomas?
10% all people
How can pituitary adenomas be classified?
- Size (microadenoma <1cm, macroadenoma >1cm)
2. Hormonal status (functioning vs. non-functioning)
What is the most common pituitary adenoma?
Prolactinoma
How do pituitary adenomas cause symptoms?
- Excess hormone production
- Depletion of hormone due to compression of normal functioning gland
- Headache due to stretching of dura within/around pituitary fossa
- Bitemporal hemianopia due to compression of optic chiasm
What are the components of a pituitary blood profile?
- GH
- Prolactin
- ACTH
- LH
- FSH
- TFTs
What are some differentials of a pituitary adenoma?
- Pituitary hyperplasia
- Craniopharyngioma
- Meningioma
- Brain mets
- Lymphoma
- Hypophysitis
- Vascular malformation e.g. aneurysm
What are the general management strategies for pituitary adenomas?
- Hormonal therapy
- Surgery (e.g. transsphenoidal transnasal hypophysectomy)
- Radiotherapy
What are the TFT findings of sick euthyroid syndrome?
Everything is low (sometimes TSH is normal)
What 2 conditions account for 90% of cases of hypercalcaemia?
- Primary hyperparathyroidism (commonest in non-hospitalised pts)
- Malignancy (commonest in hospitalised pts)
What are some malignancies that cause hypercalcaemia?
- Bone mets
- Myeloma
- PTHrP from squamous cell lung cancer
What are some ‘other’ causes of hypercalcaemia
- Endo = Acromegaly, Thyrotoxicosis, Addison’s, Vit D intoxication
- Inflammation = sarcoidosis
- Drugs = thiazides
- Dehydration
- Milk-alkali syndrome
How many phases are there in subacute thyroditis?
4 phases following viral infection
What are the phases of subacute thyroiditis?
- 3-6 weeks = hyperthyoidism, painful goitre, raised ESR
- 1-2 weeks = euthyroid
- Wks-ms = hypothyroidism
4 . Thyroid structure and function returns to normal
What investigation can you do for subacute thyroiditis?
Thyroid scintigraphy –> globally reduced uptake of Iodine-131
What is the management of subacute thyroiditis?
- Usually self limiting, no tx
- Thyroid pain may respond to aspirin or NSAIDs
- If hypothyroidism develops –> steroids
What are the causes of primary hypothyroidism?
- AI (Hashimoto’s, atrophic)
- Iodine deficiency
- Thyroiditis (post-viral, post-partum, Riedel’s)
- Iatrogenic (thyroidectomy, radioiodine, drugs)
What is the triad of presentation of phaeos?
- Sweating
- Headaches
- Palpitations
What is the first line investigation for phaeos?
24hr Urinary metanephrines (97% sensitivity)
What are the 3 genetic associations of phaeos?
- MEN II
- vHL
- NF
What is the rule of 10%s for phaeos?
- 10% extra-adrenal
- 10% bilateral
- 10% familial
- 10% children
- 10% malignant
- Discussed 10x more than it is actually seen
What is the most common extra-adrenal site for phaeos?
The organ of Zuckerkandl, adjacent to the bifurcation of the aorta
What is the management of phaeos?
- Alpha blocker (e.g. phenoxybenzamine) THEN
- Beta blocker (e.g. propranolol) THEN
- Surgery
What are the causes of primary hyperparathyroidism?
- Solitary adenoma (80%)
- Hyperplasia (15%)
- Multiple adenomas (4%)
- Carcinoma (1%)
What are the features of primary hyperparathyroism
‘Bones, stones, abdominal groans and psychic moans’
1. Bone pain/fracture
2. Renal stones, polydipsia, polyuria
3. Peptic ulceration/constipation/pancreatitis
4. Depression
5, HTN
What is a characteristic X ray finding of primary HPT?
Pepperpot skull
What scan can be done for primary HPT?
Technetium-MIBI subtraction scan
What is the management of primary HPT
- Definitive = total parathyroidectomy
- Conservative management if there is no evidence of end organ damage and and calcium levels arent too high
- Calcimimetic agents e.g. cinacalcet in pts unsuitable for surgery
What are some causes of an Addisonian crisis?
1, Sepsis or surgery causing acute exacerbation of chronic insufficiency
- Adrenal haemorrhage (Waterhouse-Friderichsen syndrome due to fulminant meningococcaemia)
- Steroid withdrawal
What is the management of an Addisonian crisis?
- Hydrocortisone 100mg IM/IV
- 1L normal saline infused over 30-60mins or with dextrose if hypoglycaemic
- Continue hydrocortisone 6 hrly until pt is stable (no fludrocortisone required as hydrocortisone exerts weak mineralocorticoid action)
What is the tx for painful diabetic neuropathy to relieve pain?
- First line = Duloxetine, Amitryptiline, Gabapentin, Pregabalin
- If 1st drug doesnt work try one of the others
- Tramadol may be used as rescue therapy for acut exacerbations
- Topical capsaicin for localised neuropathic pain e.g. post-herpetic neuralgia
- Pain clinics
How can diabetes cause GI symptoms?
GI autonomic neuropathy
What are 3 forms of GI autonomic neuropathy?
- Gastroparesis
- Chronic diarrhoea (often at night)
- GORD (caused by decreased lower oesophageal pressure)
What are the symptoms and management for gastroparesis due to GI autonomic neuropathy?
- Sx = erratic blood glucose control, bloating and vomiting
2. Mx = metoclopramide, domperionde, erythromycin (prokinetic agents)
Thyrotoxicosis with tender goitre?
Subacute (De Quervain’s) thyroiditis
What is the infusion rate of insulin during DKA?
0.1 unit/kg/hr
What is the most common cause of thyrotoxicosis?
Graves’ disease
What are features seen in Graves that arent seen in other causes of thyrotoxicosis
- Eye signs (30%) pts = exophthalmos, ophthalmoplegia
- Pretibial myoxoedema
- Thyroid acropachy
What Abs are seen in Graves disease?
- TSH receptor stimulating Abs (90%)
2. Anti-thyroid peroxidase Abs (75%)
In whom does a hyperosmolar hyperglycaemic state commonly present?
In the elderly with T2DM
What has higher mortality, HHS or DKA?
HHS
What are some salient vascular complications of HHS?
- MI
- Stroke
- Peripheral arterial thrombosis
How long does it take for DKA and HHS to onset?
- DKA = hours
2. HHS = days
What is the pathophysiology of HHS?
- Hyperglycaemia –> osmotic diuresis w/ associated loss of sodium and potassium
- Severe volume depletion –> very high serum osmolality (typically >320 mosmol/kg) –> hyperviscosity of blood
What are some clinical features of HHS?
- General - fatigue, lethargy, N&V
- Neuro = altered consciousness, headaches, papilloedema, weakness
- Haem = hyperviscosity –> MI, stroke, peripheral arterial thrombosis
- CVS = dehydration, hypotension, tachycardia
How is HHS diagnosed?
- Hypovolaemia
- Marked hyperglycaemia (>30mmol/l) WITHOUT significant ketonaemia or acidosis
- Markedly raised serum osmolality (>320 mosmol/kg)
What are the goals of management of HHS?
- Normalise osmolality (gradually)
- Replace fluid and e- loss
- Normal blood glucose (gradually)
What are fluid losses in HHS estimated to be?
100-220ml/kg
What is the fluid replacement for HHS?
- 0.9% Nal, rate of rehydration determined by clinical picture
- 0.45% NaCl if serum osmolality is not declining with normal saline
What is the goal of fluid replacement in initial management of HHS?
Replace 50% loss in first 12 hours, remainder in next 12 hours, but use your clinical judgement
What should be carefully monitored during tx of HHS?
Serum osmolality, glucose and sodium. Should be plotted on a graph initially.
What are the ideal rates of fall of sodium and glucose during management of HHS?
- Na = Should not exceed 10mmol/l in 24hrs
2. Glucose = 4-6mmol/hr, targeting a blood glucose b/w 10-15mmol/l
Should insulin usually be used for management of HHS, and explain?
- NO
- Fluid replacement alone with 0.9% sodium chloride solution will result in a gradual decline of blood glucose and osmolarity
- Because most patients with HHS are insulin sensitive (e.g. it usually occurs in T2DM), administration of insulin can result in a rapid decline of serum glucose and thus osmolarity, and may precipitate CPM
Why are potassium levels not as concerning in HHS?
Pts with HHS are potassium deplete but less acidotic than those with DKA so potassium shifts are less pronounced. K should be replaced or omitted as required during management
How many units of insulin are in 1ml of standard insulin?
100 units
How can you classify insulin?
- By manufacturing process
2. By duration of action
What are the different manufactured forms of insulin
- Porcine = from pig pancreas
- Human sequence = enzyme modification of porcine or from recombinant DNA or yeast
- Analogues
What are the different subtypes of insulin based on duration of action?
- Rapid acting analogues
- Short acting
- Intermediate acting
- Long acting analogues
- Premixed preparations
What is the onset, peak and duration of rapid acting insulin?
O = 5 mins P = 1 hour D = 3-5 hours
What is the onset, peak and duration of short acting insulin?
O = 30 mins P = 3 hours D = 6-8 hours
What is the onset, peak and duration of intermediate acting insulin?
O = 2 hours P = 5-8 hours D = 12-18 hours
What is the onset, peak and duration of long acting insulin?
O = 1-2 hours P = flat profile D = up to 24 hours
What are some rapid acting insulin analogues?
- Insulin aspart = NovoRapid
2. Insulin lispro = Humalog
What are some short acting insulins?
- Actrapid (soluble)
2. Humulin (soluble)
What are some intermediate acting insulins?
Isophane insulin, often used in premixed formulation with long acting insulin
What are some long acting insulins?
- Insulin detemir = Levemir = Od or BD
2. Insulin glargine = Lantus = OD
What is a premixed insulin preparation?
- Combine intermediate acting insulin with with either:
- Rapid acting insulin analogue OR
- Soluble insulin
Why is it important to rotate insulin injection sites?
To prevent lipdystrophy
What menstrual problem is hyperthyrodism associated with?
Oligomenorrhoea or amenorrhoea