Need to know Flashcards
What fluids will you give patients with acute, severe, symptomatic hyponatraemia (< 120 mmol/L)?
Hypertonic saline (typically 3% NaCl) is usually indicated
This patient is in severe acute hyponatremia, and thus would need sodium correction which is generally done with hypertonic saline, which is saline with a sodium chloride (NaCl) concentration higher than the physiological concentration of 0.9%. This generally a concentration of 3% NaCl.
What are the principles for management of hyponatraemia?
Management of hyponatremia is complicated and primarily based on the following parameters:
duration of hyponatremia: is it acute or chronic?
acute: develops over a period of < 48 hours
chronic: develops over a period > 48 hours
the severity of hyponatremia: what is the sodium level?
mild: 130-134 mmol/L
moderate: 120-129 mmol/L
severe: < 120 mmol/L
symptoms: is the patient symptomatic?
patients with mild hyponatraemia may be symptomatic
early symptoms may include: headache, lethargy, nausea, vomiting, dizziness, confusion, and muscle cramps
late symptoms may include: seizures, coma, and respiratory arrest
the suspected aetiology of the hyponatraemia:
hypovolemic hyponatraemia/clinically dehydrated: diuretic stage of renal failure, diuretics, Addisonian crisis
euvolemic hyponatraemia: SIADH
hypervolaemic hyponatraemia: heart failure, liver failure, nephrotic syndrome
What is the management of Chronic hyponatreamia without severe symptoms?
Initial steps in all patients
exclude a spurious result (e.g. blood taken from a drip arm)
review medications that may cause hyponatraemia
Chronic hyponatreamia without severe symptoms
If a hypovolemic cause is suspected
normal, i.e. isotonic, saline (0.9% NaCl)
this may sometimes be given as a trial
if the serum sodium rises this supports a diagnosis of hypovolemic hyponatraemia
if the serum sodium falls an alternative diagnosis such as SIADH is likely
If a euvolemic cause is suspected
fluid restrict to 500-1000 mL/day
consider medications:
demeclocycline
vaptans (see below)
If a hypervolemic cause is suspected
fluid restrict to 500-1000 mL/day
consider loop diuretics
consider vaptans
What is the management of Acute hyponatreamia with severe symptoms?
Patients with acute, severe (<120 mmol/L) or symptomatic hyponatraemia require close monitoring, preferably in an HDU or above setting.
Hypertonic saline (typically 3% NaCl) is used to correct the sodium level more quickly than would be done in patients with chronic hyponatraemia.
What medications should be avoided in patients with hypovolemic hyponatremia?
Vasopressin/ADH receptor antagonists (vaptans):
these act primarily on V2 receptors - antagonism of V2 receptors results in selective water diuresis, sparing the electrolytes
They should be avoided in patients who have hypovolemic hyponatremia
Vasopression/ADH receptor antagonists can stimulate the thirst receptors leading to the desire to drink free water. They can be hepatotoxic in patients with underlying liver disease.
What are complications of treatment of hyponatremia?
Osmotic demyelination syndrome (central pontine myelinolysis)
can occur due to over-correction of severe hyponatremia
pathophysiology:
thought to develop secondary to astrocyte (and possibly oligodendrocyte) apoptosis
astrocytes and oligodendrocytes (cells of the glial syncytium) are crucial for normal myelination
chronic hyponatraemia → loss of osmotically active organic osmolytes (such as myoinositol, glutamate, glutamine) from astrocytes. These provide protection against cerebral oedema
organic osmolytes cannot be replaced quickly enough when the brain volume begins to shrink in response to the correction of hyponatraemia
the dehydrated astrocytes and oligodendrocytes undergo apoptosis or other forms of injury → demyelination
to avoid this, Na+ levels are only raised by 4 to 6 mmol/l in a 24-hour period
symptoms usually occur after 2 days and are usually irreversible: dysarthria, dysphagia, paraparesis or quadriparesis, seizures, confusion, and coma
patients are awake but are unable to move or verbally communicate, also called ‘Locked-in syndrome’
What is the warfarin management in INR 5.0-8.0
No bleeding
Withhold 1 or 2 doses of warfarin
Reduce subsequent maintenance dose
What is the warfarin management in INR 5.0-8.0
Minor bleeding
Stop warfarin
Give intravenous vitamin K 1-3mg
Restart when INR < 5.0
What is the warfarin management in INR > 8.0
No bleeding
Stop warfarin
Give vitamin K 1-5mg by mouth, using the intravenous preparation orally
Repeat dose of vitamin K if INR still too high after 24 hours
Restart when INR < 5.0
What is the warfarin management in INR > 8.0
Minor bleeding
Stop warfarin
Give intravenous vitamin K 1-3mg
Repeat dose of vitamin K if INR still too high after 24 hours
Restart warfarin when INR < 5.0
What is the warfarin management in Major bleeding (e.g. variceal haemorrhage, intracranial haemorrhage)
Stop warfarin
Give intravenous vitamin K 5mg
Prothrombin complex concentrate - if not available then FFP*
What are the steps for asthma diagnosis in adults?
First-line investigations NICE
1.measure the eosinophil count OR fractional nitric oxide (FeNO)
diagnose asthma, without further investigations, if:
eosinophil is above the reference range
FeNO is ≥ 50 ppb
If asthma is not confirmed by the eosinophil count or FeNO
2. measure bronchodilator reversibility (BDR) with spirometry
diagnose asthma if:
the FEV1 increase is ≥ 12% and 200 ml or more from the pre-bronchodilator measurement, or
the FEV1 increase is ≥ 10% of the predicted normal FEV1
if spirometry is not available or it is delayed, measure peak expiratory flow (PEF) twice daily for 2 weeks
diagnose asthma if:
PEF variability (expressed as amplitude percentage mean) is ≥ 20%
If asthma is not confirmed by eosinophil count, FeNO, BDR or PEF variability but still suspected on clinical grounds:
3.refer for consideration of a bronchial challenge test
diagnose asthma if bronchial hyper-responsiveness is present
What are the steps for diagnosing/Investigating suspected asthma in children aged 5 to 16?
First-line investigation NICE
measure the fractional nitric oxide (FeNO)
diagnose asthma if:
FeNO is ≥ 35 ppb
If the FeNO level is not raised, or if FeNO testing is not available:
measure bronchodilator reversibility (BDR) with spirometry
diagnose asthma if:
the FEV1 increase is ≥ 12% from the pre-bronchodilator measurement, or
the FEV1 increase is ≥ 10% of the predicted normal FEV1
if spirometry is not available or it is delayed, measure peak expiratory flow (PEF) twice daily for 2 weeks
diagnose asthma if:
PEF variability (expressed as amplitude percentage mean) is ≥ 20%
If asthma is not confirmed by FeNO, BDR or PEF variability but still suspected on clinical grounds:
perform skin prick testing to house dust mite OR measure total IgE level and blood eosinophil count
exclude asthma if there is no evidence of sensitisation to house dust mite on skin prick testing OR if the total serum IgE is not raised
diagnose asthma if there is evidence of sensitisation OR a raised total IgE level and the eosinophil count is > 0.5 x 109/L
If there is still doubt about the diagnosis
refer to a paediatric specialist for a second opinion, including consideration of a bronchial challenge test
What are the steps to investogate/diagnose suspected asthma in children under 5?
The guidelines acknowledge the difficulty of performing tests in such young children. They suggest: NICE
treating with inhaled corticosteroids as per the management guidelines with regular review
if they still have symptoms at age 5 then attempt objective tests
refer to a specialist respiratory paediatrician any preschool child with an admission to hospital, or 2 or more admissions to an emergency department, with wheeze in a 12-month period.
Elevations of CK that are ‘only’ 2-4 times that of normal are not supportive of what diagnosis
rhabdomyolysis
elevated creatine kinase (CK)
the CK is significantly elevated, at least 5 times the upper limit of normal in rhabdomylolysis
elevations of CK that are ‘only’ 2-4 times that of normal are not supportive of a diagnosis and suggest another underlying pathophysiology
What is the firstline and second line treatment for Helicobacter pylori ?
PPI+Amoxicillin++ (clarithromycin OR metronidazole)
if ongoing symptoms after first line treatment: PPI + amoxicillin+ (clarithromycin OR metronidazole, whichever was not used first line)
if penicillin-allergic: a proton pump inhibitor + metronidazole + clarithromycin
What are clinical features of achalasia?
dysphagia of BOTH liquids and solids
typically variation in severity of symptoms
heartburn
regurgitation of food- including nasal regurgitation
may lead to cough, reccurent aspiration pneumonia etc
malignant change in small number of patients
chest pain, weight loss due to difficulty eating
What are the investigations for achalasia?
oesophageal manometry
excessive LOS tone which doesn’t relax on swallowing
considered the most important diagnostic test
barium swallow
shows grossly expanded oesophagus, fluid level
‘bird’s beak’ appearance
chest x-ray
wide mediastinum
fluid level
