Imported bugs, not beasts: extensively drug-resistant tuberculosis and acute kidney injury

The latest UK annual tuberculosis (TB) report shows that the rates of TB have remained at a more consistent level in the UK over recent years; however, the incidence of TB in the UK remains high (13.9 per 100 000 population) in comparison to most other Western European Countries. The proportion of multi-drug-resistant (MDR-TB) cases is stable at 1.6% with two cases of extensively drugresistant tuberculosis (XDR-TB) reported in 2012 [1]. However, worldwide, 10% of MDR-TB cases are XDR-TB [2]. XDR-TB is defined as resistance in vitro to isoniazid, rifampicin, any fluoroquinolone and at least one of three injectable second-line drugs (amikacin, kanamycin or capreomycin) used to treat TB. Treatment with at least five drugs to which the organism is susceptible is recommended [3, 4]. Treatment of XDR-TB is only successful in 40% [5]. The incidence of drug-resistant TB is higher in patients who have had previous TB treatment and in individuals born outside of the UK [1]. The treatment for TB continues to be a balance of benefit and risk to the patient and the wider population and is outlined in Table 1. Inadequate treatment leads to an increased risk of further resistance and increases morbidity and mortality. XDR-TB is best treated with six agents in the intensive phase (6–9 months) and then four agents during the continuation phase (21–25 months) [5]. Regimes for anti-TB therapies are guided by local microbiology advice, based on sensitivities and there is still considerable toxicity from current TB therapy, especially agents used to treat XDR-TB. We present a case of acute kidney injury (AKI) secondary to capreomycin toxicity in a young female receiving treatment for XDR-TB.