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32 Cards in this Set
- Front
- Back
Which is not a criteria for Dx of SIADH?
1. urine sodium > 20 mmol/L 2. hypotonic hyponatraemia 3. normal cardiac and renal function 4. presence of hypovolaemia/ hypotension 5. normal adrenal and thyroid function |
4. ABSENCE of hypotension, hypovolaemia
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Causes of hypervolaemic hyponatraemia {3} ?
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1. CCF
2. Renal Failure 3. Hepatic cirrhosis |
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Causes of Euvolaemic hyponatraemia {2} ?
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1. SIADH [ High urinary sodium]
2. Water intoxication [ normal urinary sodium] |
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Causes of Hypovolaemic hyponatraemia
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1. Adrenocortical insufficiency [ High urine sodium / low aldosterone]
2. Diuretics [ High urine sodium / normal aldosterone] 3. GIT Losses a. Upper GIT losses [ Alkalosis] b. Lower GIT losses [ Acidosis] |
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Causes of Hyponatraemia with High Urine sodium
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1. SIADH
2. Diuretics 3. Adrenocorticoid deficiency 4. Nephropathy |
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Causes of Hyponatraemia with Low / normal urine sodium
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1. CCF
2. hepatic cirrhosis 3. Renal Failure 4. GIT losses |
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Which is incorrect regarding hyponatraemia?
A. It is the most common electrolyte disorder B. Most cases of hyponatraemia are caused by drugs. C. It is defined as a serum sodium < 135 mmol/L D. Severe hyponatraemia is defined as a sodium < 120 mmol/L, and is a Medical Emergency. |
B. Not strictly correct. there are 3 main causes:
1. Drugs 2. SIADH 3. Fluid retaining conditions - eg. CCF |
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Which is not a well recognised association of hyponatraemia?
A. Increased morbidity and mortality in Hospitalised patents. B. Prolonged Hospitalisation C. Increased mortality in patients with Community acquired pneumonia (CAP). D. Cushing's Disease |
D. Addison's Disease, or adrenocortical insufficiency.
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True or false: By far the commonest cause of hyponatraemia in Clinical Practice is "dilutional hyponatraemia" due to the retention of water in excess of sodium ===> SIADH
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True
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In regards to Euvolaemic Hyponatraemia, which is incorrect?
A. It is the most common form of hyponatraemia B. SIADH has a higher urine osmolality than plasma osmolality. C. Pneumonia causes SIADH D. Exercise -associated hyponatraemia is a hypovolaemic condition-not euvolaemic. |
D. Exercise -associated hyponatraemia is Euvolaemic- due to excessive hypotonic fluid intake during extreme exercise.
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List the 4 broad categories of the causes of SIADH.
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1. Head -CNS
2. Chest- Respiratory 3. Occult Malignancy 4. Miscellaneous |
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What are the CNS causes / associations of SIADH?
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1. Stroke / CVA / ICB
2. CNS infection ( meningo-encephalitis ) 3. Hydrocephalus 4. Cerebral tumour 5. Neurosurgical procedures - pituitary |
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What are the Respiratory causes / associations with SIADH?
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1. Pneumonia
2. Asthma 3. Pneumothorax 4. Respiratory Failure +/- PPV 5. Pulmonary malignancies : mesothelioma / SCC lung 6. major thoracic surgery |
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What are the Malignancies associated / causative of SIADH?
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1. Pulmonary ( mesothelioma / SCC lung )
2. Head and neck malignancies 3. Lymphoma |
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List the miscellaneous conditions associated / causative of SIADH.
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1. Hereditary
2. HIV / AIDS 3. Guillain Barre Syndrome (GBS) 4. Multiple sclerosis (MS) |
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Which is not a cause / association of hypovolaemic hyponatraemia.
A. Thiazide diuretics B. Cerebral salt wasting C. Liver failure D. Nephropathy |
C.
A: Thiazides can cause hypovolaemic or euvolaemic-the latter being more common B: Occasional cause in Neurosurgical patients / patients with SAH |
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List the main drugs associated with hyponatraemia.
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1. Diuretics
2. Antiepileptics ( carbamazepines ; valproate ) 3. Antidepressants ( SSRI ; TCA ; Venlafaxine ) 4. Antipsychotics ( phenothiazines ; haloperidol ) 5. Recreational drugs ( MDMA -ecstasy ) 6. NSAIDS |
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What type of hyponatraemia would be expected with a low sodium and impaired renal function: hypervolaemia, euvolaemic or hypovolaemic ?
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Hypovolaemic hyponatraemia.
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What types(s) of hyponatraemia wold be expected with a low sodium and normal renal function ( normal creatinine and urea)?
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Likely a "dilutional hyponatraemia" :
1. Euvolaemic 2. Hypervolaemic |
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A maximally dilute urine has an osmalality of how many mmol/L
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< 100 mmol/L
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A urine osmolality of > 200 mmol/L indicates what 2 potential abnormal processes in euvolaemic hyponatraemia?
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1. Lack of appropriate SUPPRESSION of antidiuretic hormone (ADH) [ ie. ADH should normally be suppressed- leading to less water retention and a more dilute urine ]
= SIADH 2. Inability to maximally dilute the urine = Diuretics |
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A urine sodium < 20mmol/L indicates which hyponatraemia category?
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HYPOvolaemic hyponatraemia
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A urine sodium of > 20mmol/L indicates which category of hyponatraemia?
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EUVOlaemic Hyponatraemia.
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Which Causes of hyponatraemia would be associated with a urinary sodium > 20mmol/L ?
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1. Euvolaemic hyponatraemia
- SIADH 2. Hypovolaemic hyponatraemia - Diuretics - adrenocortical insufficiency |
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What Endocrine diseases are associated with hyponatraemia?
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1. Hypothyroidism
2. Hypopituitarism 3. Addison's Disease |
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What are the min treatments for each group of hyponatraemia ( Euvolaemic ; Hypovolaemic ; Hypervolaemic )?
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Euvolaemic:
1. Fluid restriction 2. +/- Withdraw causative drug 3. +/- Treat identifiable cause of SIADH 4. Hypertonic saline for severe < 120 mmol/L Hypovolaemic 1. Volume expansion with Isotonic saline 2. treat underlying process Hypervolaemic 1. Fluid restriction 2. Diuretics 3. Treat underlying process |
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In regards to serum osmolarity, which of the following levels and expected symptoms / signs is incorrect?
A. > 350 = excessive thirst B. > 400 = ataxia / tremor C. > 430 = hyperreflexia / focal Neurological deficit D. > 430 = seizures / coma |
C : > 420 = hyperreflexia / focal Neurological deficit
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In regards to serum osmolarity, which of the following levels is likely to be associated with seizures ?
A. > 350 mOsm/kg B. > 400 mOsm / kg C. > 430 mOsm/kg D. > 450 mOsm/kg |
C.
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In regards to serums osmolarity, which of the following levels is likely to be associated with ataxia?
A. > 430 mOsm/kg B. > 400 mOsm/kg C. > 350 mOsm/kg D. > 320 mOsm/kg |
B.
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What is the normal measured serum osmolarity ?
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285 - 295 mOsm/kg
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What situations / patients are at an increased risk of developing Central Pontine Myelinosis with correction of hyponatraemia >
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1. Hyponatraemia present for > 48 hours
2. Alcoholics 3. Malnourished 4. Elderly ** |
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What Clinical findings occur with Central Pontine Myelinosis ?
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( aka : osmotic demyelination syndrome )
Progressively Develops over 3-5 days after correction of the sodium : 1. Fluctuating conscious state 2. Seizures 3. Quadriparesis 4. Dysphagia + dysarthria 5. Mutism |