Hyperammonemia syndrome in lung transplant recipients: A survey on current clinical practice

PurposeHS is a rare but potentially fatal complication of LT. Etiology, risk factors as well as screening and treatment are not clearly established, no clinical guidelines exist.MethodsWe conducted an international cross-sectional pilot survey within the ISHLT network, distributed using an online questionnaire (Redcap database) collecting information on HS awareness in transplant health care providers (HCP), used HS prevention and treatment.Results49 HCP answered the survey: 61% (30/49) respirologist, 18%; (9/49) infectious diseases specialists, 10% (5/49) transplant surgeons, 4% (2/49) intensivist. 47% (23/49) reported to work in a center with 20-50 LT/y. HS was perceived as severe (85%; 41/48), and felt to be of infectious (60%; 30/48) and of donor and /or recipient (45%; 21/47) origin. 16% (8/48) felt it not to be effectively preventable, 23% (11/48) reported lack of knowledge about prevention. 45% (22/49) reported the use of any screening/primary prophylaxis: screening with serum ammonium (29%; 14/49), Mollicute PCR (16%; 8/49) and primary antimicrobial prophylaxis (10%: 5/49). Moreover, prevention procedures were not uniform Figure A. Hyperammonemia (100%; 39/39) and neurological symptoms (85%; 33/39) were the most frequent HS features. Reported treatment included antimicrobial therapy (100%; 39/39), measures to decrease blood ammonia levels (92%; 37/39: lactulose (78%; 29/37), bowel decontamination (51%; 19/37), nitro scavengers (38%; 14/37), renal replacement therapy (62%; 23/37)) and change of immunosuppression (21%; 8/39). Antimicrobial mono therapy was reported for prophylaxis (80%; 4/5), and combination for HS treatment (65%; 25/38).ConclusionHS was perceived as a severe but potentially preventable problem; however, preventive measures were reported by less than half of HCP. Moreover screening, diagnostic approaches and medical management varied widely. There is an unmet need to devise a uniform strategy of screening and treatment across lung transplant programs. HS is a rare but potentially fatal complication of LT. Etiology, risk factors as well as screening and treatment are not clearly established, no clinical guidelines exist. We conducted an international cross-sectional pilot survey within the ISHLT network, distributed using an online questionnaire (Redcap database) collecting information on HS awareness in transplant health care providers (HCP), used HS prevention and treatment. 49 HCP answered the survey: 61% (30/49) respirologist, 18%; (9/49) infectious diseases specialists, 10% (5/49) transplant surgeons, 4% (2/49) intensivist. 47% (23/49) reported to work in a center with 20-50 LT/y. HS was perceived as severe (85%; 41/48), and felt to be of infectious (60%; 30/48) and of donor and /or recipient (45%; 21/47) origin. 16% (8/48) felt it not to be effectively preventable, 23% (11/48) reported lack of knowledge about prevention. 45% (22/49) reported the use of any screening/primary prophylaxis: screening with serum ammonium (29%; 14/49), Mollicute PCR (16%; 8/49) and primary antimicrobial prophylaxis (10%: 5/49). Moreover, prevention procedures were not uniform Figure A. Hyperammonemia (100%; 39/39) and neurological symptoms (85%; 33/39) were the most frequent HS features. Reported treatment included antimicrobial therapy (100%; 39/39), measures to decrease blood ammonia levels (92%; 37/39: lactulose (78%; 29/37), bowel decontamination (51%; 19/37), nitro scavengers (38%; 14/37), renal replacement therapy (62%; 23/37)) and change of immunosuppression (21%; 8/39). Antimicrobial mono therapy was reported for prophylaxis (80%; 4/5), and combination for HS treatment (65%; 25/38). HS was perceived as a severe but potentially preventable problem; however, preventive measures were reported by less than half of HCP. Moreover screening, diagnostic approaches and medical management varied widely. There is an unmet need to devise a uniform strategy of screening and treatment across lung transplant programs.