34 Questions
What is the primary cause of water retention at the renal distal tubules in F.SIADH?
Increased secretion of ADH (or vasopressin)
Which of the following is NOT a symptom of severe hyponatremia (serum [Na+] < 120 mEq/L)?
Polyuria
What is the typical serum sodium level range for asymptomatic hyponatremia?
130-135 mEq/L
Which of the following is a symptom of mild hyponatremia (serum [Na+] 130-135 mEq/L)?
Headache
What is the most severe consequence of severe hyponatremia?
Respiratory arrest
Which of the following is a symptom of moderate hyponatremia (serum [Na+] 120-130 mEq/L)?
Unsteadiness
What is the recommended rate of increase in serum sodium concentration for correcting hyponatremia?
0.5 mEq/L/hour or less
What is the consideration for correcting hyponatremia in patients with chronic hyponatremia?
Correct slowly due to equilibration of brain electrolytes
What is the purpose of using the equation for sodium requirement in hyponatremia?
To calculate the sodium requirement for correction
What is the recommended infusion rate calculation in hyponatremia?
Infusion rate = (Na requirement × 1000)/(infusion Na concentration × time)
What is the indication for using fludrocortisone in hyponatremia?
To reduce sodium loss in CSWS
What is the recommendation for patients with severe neurologic symptoms due to hyponatremia?
Correct rapidly up to 4-6 mEq/L
How often should serum sodium be monitored during rapid correction of hyponatremia?
Every 4 hours
What is the consideration for patients with acute hyponatremia?
Correct rapidly as they may tolerate quicker correction
What is the primary indication for case selection?
Adult patients with CSF shunt or ventriculostomy infections for difficult-to-eradicate pathogens
When may case selection be considered reasonable in patients receiving systemic therapy?
When CSF cultures have not cleared after 3-4 days
What is the recommended approach for dosing in case selection?
Intravenous plus intraventricular
What should be avoided when using dextrose in case selection?
Using diluents containing dextrose
What should be considered when adjusting daily dosing in case selection?
The amount of CSF drainage from external ventricular drain
What type of medications should be avoided in case selection?
Medications that lower the seizure threshold
What is the maximum dose of alteplase in mg for thrombolysis in patients with acute ischemic stroke?
90 mg
What is the recommended time frame for administration of alteplase in patients with acute ischemic stroke?
Within 4.5 hours of symptom onset
What percentage of the total dose of alteplase is administered as an intravenous bolus?
10%
In patients with acute ischemic stroke who awake with stroke symptoms or have unclear time of onset, what imaging modality can be used to help select those who can benefit from intravenous alteplase administration?
MRI
What is the dose of tenecteplase in mg/kg for thrombolysis in patients with acute ischemic stroke?
0.25 mg/kg
What is the recommended duration of the intravenous infusion of alteplase in patients with acute ischemic stroke?
60 minutes
What is the approximate osmolality of the Vancomycin antimicrobial solution for intraventricular administration?
291 mOsm/kg
Which antimicrobial solution has the highest osmolality for intraventricular administration?
Amikacin
What is the daily dose of Amphotericin B deoxycholate for intraventricular administration?
0.5 mg/3 mL of SWI
Which of the following antimicrobial solutions is prepared in sterile water for injection (SWI) for intraventricular administration?
Amphotericin B deoxycholate
What is the common adverse effect of Gentamicin, Tobramycin, and Amikacin for intraventricular administration?
Seizures
Which antimicrobial solution has an unknown adverse effect for intraventricular administration?
Daptomycin
What is the volume of the Gentamicin antimicrobial solution for intraventricular administration?
4–8 mg/1 mL of NS
Which of the following antimicrobial solutions has a daily dose of 10–20 mg for intraventricular administration?
Vancomycin
Study Notes
Neurocritical Care
- Hyponatremia can cause neurologic symptoms such as delirium, agitation, tremor, seizure, or coma.
Clinical Symptoms of Hyponatremia
- Asymptomatic:
- Headache
- Nausea
- Vomiting
- Fatigue
- Confusion
- Anorexia
- Muscle cramps
- Depressed reflexes
- Mild hyponatremia (serum [Na+] 120-130 mEq/L):
- Malaise
- Unsteadiness
- Headache
- Nausea
- Vomiting
- Fatigue
- Confusion
- Anorexia
- Muscle cramps
- Severe hyponatremia (serum [Na+] < 120 mEq/L):
- Headache
- Restlessness
- Lethargy
- Seizures
- Brain stem herniation
- Respiratory arrest
- Death
Treatment of Hyponatremia
- Fludrocortisone 0.1-0.4 mg/day may help reduce sodium loss in cerebral salt-wasting syndrome (CSWS).
- Consider potassium supplementation for hypokalemia.
Rapid Correction of Hyponatremia
- Recommended increase in serum sodium concentration is 0.5 mEq/L/hour or less.
- Patients with chronic hyponatremia may need to be corrected more slowly.
- Patients with acute hyponatremia may tolerate quicker correction.
- Patients with severe neurologic symptoms may tolerate rapid correction of 4-6 mEq/L.
Sodium Correction Equations
- Na requirement (mmol) = total body water (0.6 × kg) × (desired Na - current Na)
- Infusion rate (mL/hr) = (Na requirement × 1000)/(infusion Na concentration × time)
Intraventricular Administration of Antimicrobials
- Vancomycin: 10-20 mg/1 mL of NS, osmolality 291 mOsm/kg
- Gentamicin: 4-8 mg/1 mL of NS, osmolality 293 mOsm/kg
- Tobramycin: 4-8 mg/1 mL of NS, osmolality 283 mOsm/kg
- Amikacin: 30 mg/1 mL of NS, osmolality 383 mOsm/kg
- Polymyxin B: 5 mg/1 mL of NS, osmolality 10 mOsm/kg
- Colistimethate: 10 mg/3 mL of NS, osmolality 367 mOsm/kg
- Amphotericin B deoxycholate: 0.5 mg/3 mL of SWI, osmolality 256 mOsm/kg (in dextrose 5%)
- Daptomycin: 5 mg/2 mL of NS, osmolality 364 mOsm/kg
Thrombolysis for Ischemic Stroke
- Alteplase 0.9 mg/kg (maximum 90 mg) within 4.5 hours of symptom onset.
- Tenecteplase 0.25 mg/kg intravenous bolus (maximum 25 mg) within 4.5 hours of symptom onset may also be considered for off-label use.
This quiz covers the clinical symptoms of hyponatremia in neurocritical care, including serum sodium levels and their corresponding symptoms. It is part of the ACCP Updates in Therapeutics Critical Care Pharmacy Preparatory Review and Recertification Course.
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