Endo general Flashcards
What are the symptoms of hyperthyroidism?
Cardio- palpitations, SOB
Metabolic- weight loss
Psychiatric- anxiety, agitation
Neuro- tremors, shakes
GI- diarrhoea, increased appetite
Skin- sweating, heat intolerance
What are the signs of hyperthyroidism?
Cardio- tachycardia, flow murmur, AF, hypertension
Psychiatric- anxiety, agitation
Neuro- hyperreflexia, tremor
Skin- Pre-tibial myxedema, onycholysis
Ocular- exophthalmous, stare
Neck- goitre, tender, nodules
What distinguishes Graves disease from other causes of hyperthyroidism?
- Ocular involvement only present in graves disease (except the stare/lid retraction from sympathetic activation)
- Pre-tibial myxedema specific to graves disease
What is the enzyme deficiency in typical congenital adrenal hyperplasia? What is tested for at birth
21 hydroxylase deficiency
17 hydroxyprogesterone (OHP) is tested for at birth as will be a very high levels in the blood
What are the classes of hyponatraemia and how are they differentiated?
What is psuedohyponatraemia? How is hyponatraemia investigated?
What are the different classes of hypernatraemia?
What is the alternate calculation for the Delta Gap?
Na - Cl - 36
What is an alternate method of determining if there is an A-a gradient without performing the calculation?
PaO2 should be at least 4x the Fi02
ie 0.21 x 4 = 88 (lower limit of normal Pa02 at sea level)
When calculating the anion gap should the measured or corrected Na+ be used?
The measured Na+ is used for the anion gap calculation
The corrected Na+ is only used in determining the presence of dehydration and pseudohyponatraemia
How is water deficit estimated using Na+ value?
Fluid deficit = (Weight x 0.6) x ([measured Na+/140] - 1)
ie for a 100kg male with Na+ 170
100 x 0.6 = 60
170/140 = 1.2
60 x (1.2-1) = 12L deficit
What is an alternate method for determining the PA02 other than Fi02 x 713?
%Fi02 x 7
ie 0.21 = 21%
21x 7 = 147, 0.21 x 713 = 149
50 x 7 = 350, 0.50 x 713 = 356
A good rough approximation, add slightly more if want complete accuracy but not needed for determing if A-a gradient present
What is the maximum rate of correction for hypernatraemia?
Usually use 5% dextrose to correct hypernatraemia, unless severe intercurrent hypovolaemia/shock
Aim to correct Na+ no more than 10-12mmol/L per 24hr period
Most cases are presumed to be chronic (>48hrs), acute usually in context of salt poisoning or diabetes insipidus with exacerbation (ie surgery) and should be screened for
What does an elevated anion gap in the absence of acidosis suggest?
A raised anion gap >20, and especially >30 suggests a high change of a masked HAGMA being present
If a metabolic alkalosis is found suggest looking at the anion gap and delta gap to see if concurrent HAGMA
What are the main differentials for a triple base disturbance
Salicylate toxicity
CNS infections (ie causing SIADH)
Pneumonia/Lung tumour with hyponatraemia
What is the morbidity and mortality of DKA?
- Cerebral oedema has a 70% mortality rate
- DKA is responsible for 70% of diabetes deaths in kids <10
- Overall mortality for DKA is 5-15%
- DKA during pregnancy has a foetal death rate of 50%
Risk factors for cerebral odema
- <5yo
- First presentation
- Long history poor control
- Corrected sodium >160
What are the endpoints of hypertonic saline?
- When the patient is asymptomatic (ie no seizures)
- When the Na+ has risen by 20mmol
- When the serum Na+ is >125
Serum sodium shouldn’t rise more than 10mmol/24hrs and 25mmols/48hrs
What are the diagnostic criteria for SIADH?
- Urine osmolality >100mmol/Kg and Urine sodium >20mmol/ml
- Normal or unchanged cardiac, hepatic, renal, thyroid and adrenal function
- Absence of extracellular volume depletetion
- Hypotonic hyponatraemia
What are the risk factors for hypernatraemia?
- Extremes of age
- Diabetes
- Hypertonic infusions
- Tube feeding
- Osmotic diuretics
- Lactulose
- Polyuria disorders
- Altered mental status
- Mechanical ventilation
What are the causes of hypocalcaemia and issues around treatment?
- Hypoparathyroidism (1)
- Factitious (hypoalbuminaemia, EDTA tube malfunction)
- Hypomagnesaemia
- Pseudohypoparahyroidism
- Low Vit D
- Acute pancreatitis
- Hyperphosphataemia
- Hungry bone syndrome (post thyroid and parathyroidectomy)
- Drugs ie furosemide
Treatment issues
- Alkalosis exacerbates hypocalcaemia so any metabolic acidosis must be corrected after calcium is replaced
- Sodibic and phosphate both cause calcium crystal formation and shouldn’t be used concurrently
What are the symptoms and signs of hypercalcaemia? What is the treatment?
Clinical
- Short QT interval
- Prolonged PR and QRS
- Altered conscious state
- GI upset/abdominal pain
- Thirst
Treatment
- Pamidronate 60mg IV
- Frusemide IV
- IV rehydration
- RRT
- Definitive surgery
What are the causes of hypercalcaemia?
- Malignancy (breast, lung and cervix most common)
- Hydrochlorothiazide use
- Vitamin A + D toxicity
- Sarcoidosis
- Adrenal insufficiency
- Phaeochromocytoma
- High albumin/spurious
- Hyperparathyroidism
- Rhabdo
- Lithium toxicity
What are the main causes of adrenal insufficiency?
- Addisons disease
- Bilateral adrenal haemorrhage (Waterhouse Friedrichsen syndrome ie from meningococcal sepsis)
- Infections ie Tuberculosis, HIV
- Ketoconazole
- Malignancies
- Iron toxicity
- Autoimmune (ie sarcoidosis)
What are the causes of and clinical effects seen in Addisonian crisis?
Clinical
- NAGMA
- Hyponatraemia hyperkalaemia
- Skin pigmentation
- Hypotension
- GI upset/pain
Causes
- Major surgery/anaesthesia
- AMI
- Hypoglycaemia
- Major trauma
- Drugs (morphine, chlorpromazine)
- Pscyhiatric illness
What are the features of pheochromocytoma?
Tests
- Urine metanephrines and catecholamine
- MRI/PET (octreotide scintigraphy)
- Clonidine suppression test
Clinical
- PAROXYSMAL catecholamine surges
- Panic attacks
- Hypertensive/vasoconstrictive crises ie APO, ICH, AMI
- Strong association with thyroid carcinoma
Treatment
- Alpha = Phentolamine
- Beta = b-blocker of choice, but give this after controlling the alpha (unopposed alpha syndrome)
- IV fluids
What are the symptoms and causes of Wernicke’s Encephalopathy?
Pathology
- Thiamine is co-factor in synthesis of ATP from glucose, lack of thiamine leads to cell starvation
Causes
- Malnutrition (reduced uptake) ie anorexia, weird diets, starvation, hyperemesis gravidarum
- Liver disease (reduced storage)
- Alcoholism (impaired uptake(
- Hypercatabolic states (ie extensive malignancy, terminal HIV)
- Dialysis (increased clearance)
- Often brought on by sudden increase in glucose intake when thiamine depleted (ie refeeding)
Clinical
- Ophthalmoplegia particularly CN VI
- nystagmus
- Altered mental status
- Ataxia
- Polyneuropathy worse in legs
- Heart failure (wet beri beri)
- Hypothermia from hypothalamus damage
What are the electrolyte abnormalities associated with hyperventilation?
Hypocalcaemia
Hypokalaemia
Hypophosphataemia
all lower in the setting of hypocarbic respiratory alkalosis
What is the Strong Ion difference and how is it calculated?
The difference between the number of cations and anions in the plasma
- Na/K/Ca/Mg - Cl/lactate/Urate
Simplified SID
- Na - Cl
- Should equal 42
If >42 then there is a chloride deficit and metabolic alkalosis
If <42 then there is a chloride excess and a hyperchloraemic acidosis (ie NAGMA)
What are the differentials for elevated ketones?
- DKA
- Alcoholic ketoacidosis
- Starvation ketosis
- Pregnancy
- Metabolic deficiencies (usually children/neonates)
What are the causes of hypokalaemia?
Drugs
- Insulin
- Beta adrenergics
- Diuretics (frusemide)
- Potassium binders
Endocrine
- Period hypokalaemia paralysis
- Alkalosis
- Hyperaldosteronism (Conns)
- Hyperthyroidism
- Cushings, DKA
GI
- Upper and lower GI losses
- Vomiting and diarrhoea
- Mucous secreting tumours
- Zollinger-Ellison syndrome
Renal
- RTA 1 and 2
- Barters
- Over dialysis
What are the typical doses of different replacement therapies for potassiun?
- Slow/Span K = 8mmol
- Chlorvescent = 14mmol
- 10mmol IV in 100mls of 0.29% Saline
- 30mmols IV in 1000mls of 0.9% Saline
