Posteriores reversibles enzephalopathisches Syndrom und Hyperammonämie: zwei Entitäten für Hirnödem und Status epilepticus bei einer Patientin nach Lungentransplantation

Hyperammonemia syndrome in immunosuppressed individuals

PURPOSE OF REVIEW

Hyperammonemia syndrome is an increasingly recognized and often fatal condition that occurs in immunosuppressed individuals, most commonly lung transplant recipients. Growing evidence suggests hyperammonemia syndrome is associated with systemic infections caused by urease-producing organisms, namely Ureaplasma spp., an organism unable to grow with routine culturing techniques. This review will summarize the epidemiology and clinical manifestations of hyperammonemia syndrome, as well as diagnostic and management strategies once hyperammonemia syndrome is suspected.

RECENT FINDINGS

Hyperammonemia syndrome is being described in increasing frequency in the solid organ transplant population. Morbidity and mortality, even with treatment, is high once hyperammonemia syndrome occurs. Surveillance studies indicate the prevalence of lung donor colonization with Ureaplasma spp. is high, suggesting screening and treatment may be of benefit. Antibiotic resistance is common, and rapid diagnostics can facilitate appropriate antimicrobial therapy in the peri-transplant period.

SUMMARY

Hyperammonemia syndrome is most commonly seen in lung transplant recipients and has a high mortality rate once it occurs. Screening for Ureaplasma spp. should be considered in all lung transplant donors.

Impact of Screening and Treatment of Ureaplasma spp on Hyperammonemia Syndrome in Lung Transplant Recipients: A Single Center Experience

BACKGROUND

Infection with Ureaplasma species (spp) has been linked to fatal hyperammonemia syndrome (HS) in lung transplant recipients. We sought to characterize the epidemiology of Ureaplasma spp in candidates and donors and describe outcomes of antimicrobial therapy in preventing and treating HS.

METHODS

Candidate testing for Ureaplasma spp was performed with urine culture and PCR pre-transplant. Positive candidates were treated with levofloxacin. Donor testing was performed with bronchoalveolar lavage culture and PCR intraoperatively. From 7/2014-2/2017 patients were treated according to results; from 2/2017-10/2018 recipients received empiric levofloxacin and azithromycin at transplant until testing returned negative. HS was defined as new onset altered mental status after transplant with ammonia > 200 µmol/L.

RESULTS

60 patients who underwent lung transplant were included. 80% (n = 48) of patients had negative screening tests in donor and candidate pre-lung transplant, 8.3% (n = 5) of recipients had positive Ureaplasma spp testing in urine pre-transplant, and 13.3% (n = 8) had positive donor BAL testing at the time of lung transplant. 3 patients developed HS a median of 7 days post-transplant; 2 died of HS. Recipients of organs with Ureaplasma spp who received empiric therapy did not develop HS. Donors with Ureaplasma spp were younger and more sexually active.

CONCLUSION

Donor-derived Ureaplasma spp in lung transplant was associated with HS. Screening lung donors for Ureaplasma spp might allow for targeted therapy to reduce risk for development of HS, but future confirmatory studies are needed.