Which ONE of the following conditions does NOT cause a wide anion gap (AG) metabolic acidosis?
Answer: B: Causes of high AG metabolic acidosis can be remembered by the following mnemonic.
CAT MUDPILES
The four major groups of conditions that can cause high AG metabolic acidosis are:
Frusemide is a diuretic and it causes urinary acid loss leading to metabolic alkalosis.
Reference:
Regarding an increased osmolar gap (OG) in a poisoned patient, which ONE of the following statements is TRUE?
Answer: A: In a patient with suspected poisoning, an increased OG is most likely to be due to the presence of unmeasured osmotically active molecules of a toxic alcohol such as acetone, methanol, ethylene glycol, isopropyl alcohol and propylene glycol. In a poisoned patient, concomitant alcohol ingestion can also cause such an increase. In addition, other non-toxicological medical conditions can cause an increased OG due to increased osmotically active molecules. The presence of a high AG metabolic acidosis and increased OG is highly suggestive of toxic alcohol ingestion in a suspected patient.
The osmolality can be calculated from routine biochemistry results:
calculated osmolality (mOsm/kg) = 2 x Na + urea + glucose + ethanol
(Na, urea, glucose and ethanol concentrations should be in SI units i.e. in mmol/L.) However, the measured osmolality should be specifically requested from the laboratory. This measures additional osmotically active molecules that are present.
osmolar gap = measured osmolality – calculated osmolality
Additionally, a normal OG does not exclude toxic alcohol poisoning.
Regarding torsades de pointes occurring in a poisoned patient, all of the following statements are true EXCEPT:
Answer: A: A number of drugs can cause QT prolongation in a poisoned patient. This list includes:
QT prolongation on the 12-lead ECG is associated with increased risk for development of torsades de pointes in these patients. This polymorphic ventricular tachycardia can degenerate rapidly into a ventricular fibrillation causing cardiac arrest. Bradycardic patients with QT prolongation are more at risk. Chan et al. described a QT nomogram where the QT interval can be plotted against the heart rate. If this point is located above the ‘at risk’ line the patient is more likely to develop torsades de pointes.
References:
All of the following medications have a narrow therapeutic to toxic ratio in the presence of diminished renal function EXCEPT:
Answer: D: The glomerular filtration rate (GFR) decreases by approximately 50% from age 30 to 80 years. Elderly patients may be on a variety of drugs that can potentially be toxic in the presence of poor renal function. Drugs with a narrow therapeutic window include:
These should be prescribed with caution in elderly and in patients with diminished renal function.
Which ONE of the following drugs or substances is LEAST likely to cause significant toxicity if a 10 kg toddler ingests a small amount?
Answer: A: Toddlers are more likely to accidentally ingest medications and other toxic and nontoxic substances that are easily accessible. Some of these medications and substances can produce significant toxicity in toddlers when ingested in small quantities such as 1–2 tablets or a mouthful, as the dose ingested per kilogram of body weight can be high. Furthermore, the onset of toxicity may be delayed for certain agents. It is therefore recommended that a toddler who ingested an unidentified tablet should be observed for at least a 12-hour observation period.
Mercury from a thermometer is unlikely to cause significant toxicity in a toddler. One tablet of a sulphonylurea can produce significant hypoglycaemia in a 10 kg toddler. Few tablets of tricyclic antidepressant can produce seizures, cardiac arrhythmias, hypotension and coma. A sip or mouthful of camphor can cause a reduced level of consciousness, hypotension and seizures.
Other drugs and substances that can potentially cause significant toxicity in small quantities in toddlers include:
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