Etomidate in the management of severe Cushing's disease and MRSA bacteraemia in a district general hospital in the United Kingdom

SUMMARY

We report our experience on managing a case of florid Cushing's disease with Methicillin-resistant Staphylococcus aureus (MRSA) sepsis using intravenous etomidate in the intensive care unit of a UK district general hospital.

LEARNING POINTS

Severe Cushing's syndrome is associated with high morbidity and mortality. Etomidate is a safe and effective medical therapy to rapidly lower cortisol levels even in the context of severe sepsis and immunosuppression. Etomidate should ideally be administered in an intensive care unit but is still feasible in a district general hospital. During treatment with etomidate, accumulation of serum 11β-deoxycortisol (11DOC) levels can cross-react with laboratory cortisol measurement leading to falsely elevated serum cortisol levels. For this reason, serum cortisol measurement using a mass spectrometry assay should ideally be used to guide etomidate prescription.

False acute kidney injury alert due to model car fuel ingestion

We report a case of accidental ingestion of model car fuel (Optifuel) resulting in an apparent elevation of serum creatinine of 274 µmol/L (3.1 mg/dL) as measured by the Jaffe (alkaline picrate) reaction, which resulted in an acute kidney injury (AKI) stage 3 alert being reported. Optifuel contains nitromethane, which has been reported to interfere in the Jaffe reaction causing falsely high creatinine measurements. The laboratory staff were vigilant about this potential interfering substance so repeated the analysis of the creatinine using an enzymatic method that showed a markedly lower result of 47 µmol/L (0.5 mg/dL). This report highlights the ability of nitromethane to potentially mimic AKI and the importance of being aware of the limitations of biochemical tests to avoid misinterpretation of results and instigating inappropriate treatment.

The relationship between estimated glomerular filtration rate and thyroid function: an observational study

Background

Estimated glomerular filtration rate (eGFR) is now routinely reported by most National Health Service laboratories. There are many limitations when interpreting eGFR: thyroid dysfunction is not widely recognized as being one of these.

Methods

We extracted from the pathology computer system results of all patients with hypothyroidism and hyperthyroidism who also had serum creatinine measured. We also extracted creatinine data on euthyroid patients. eGFR was calculated using the simplified Modification of Diet in Renal Disease Study equation.

Results

The median eGFRs of the hypothyroid, euthyroid and hyperthyroid patients were 64, 77 and 107 mL/min/1.73 m2, respectively; all groups were significantly different from each other ( P < 0.001).

Conclusion

Thyroid dysfunction is associated with significant alterations in eGFR and actual GFR.