P1.001: Not Just a UTI: Complications of a Morganella morganii Urinary Tract Infection

Introduction: While urinary tract infections (UTIs) are fairly common in children, hyperammonemic encephalopathy caused by UTIs is not. However, patients with Eagle-Barrett Syndrome (Prune Belly Syndrome) and those with abnormal urologic collecting systems, are highly prone to UTIs and thus the consequence of hyperammonemia due to urease-splitting bacteria.

Case Description: A toddler male with Eagle-Barrett Syndrome, ACTA2 pathogenic variant, and vesicoureteral reflux presented to an outside hospital emergency department (ED) with cough and congestion, which progressed to lethargy on the day of presentation. Vital signs were initially normal for age in the ED, but on exam, the patient was noted to be toxic appearing with lethargy and intermittent agitation. Initial GCS was reported as 15. For lip-smacking with concern for seizure, he was given Ativan. Shortly after admission to the PICU, the patient became hemodynamically unstable, requiring vasoactive support. Ten hours after admission, the patient’s mental status worsened to a GCS of 3, and he was intubated for airway protection. Labwork on presentation was notable for acute uncompensated lactic acidosis (pH 7.21, CO2 35, HCO3 14, base deficit –14, lactate 9), hyperglycemia, uremia (33), hyperammonemia (185; reference: 0-40 µmol/L), and normal procalcitonin. Urinalysis revealed alkalotic pH 8.5, 2+ proteinuria, 1+ bilirubinuria, 1+ hematuria (3 RBC), 3+ leukocyte esterases with 5 WBC, moderate bacteriuria, calcium oxalate crystals, and granular casts. Toxicology testing was normal. Despite Ammonul (sodium benzoate/sodium phenylacetate), an ammonia scavenger, ammonia increased to a peak of 230. Continuous EEG was notable for multifocal epileptiform discharges from bilateral temporal and frontal regions with intermittent left temporal focal slowing, and he was begun on empiric Keppra. CT head revealed mild cerebral edema. Genetics and neurology were consulted, and an extensive workup proceeded, including evaluation for inborn errors of metabolism, meningitis/encephalitis, and accidental toxic ingestion.

Discussion: The patient was diagnosed with a Morganella morganii urinary tract infection (UTI), with the remainder of the workup unrevealing. The patient was given empiric broad-spectrum antibiotics – narrowed per urine culture results, and begun on stress-dose hydrocortisone, lactulose, and a lipid infusion with low-protein TPN. Hyperammonemia and acidosis resolved, and his mentation returned to normal.

Conclusion: M. morganii is a highly virulent, uncommon cause of complicated UTIs and one of several urease-splitting bacteria. Features common to urease-splitting bacterial UTIs are alkalotic urine, hyperammonemia, and acidosis. Hyperammonemia >200 carries a high risk of encephalopathy, seizures, and death. Ammonia should be checked in patients with Prune Belly syndrome and abnormal urinary collecting systems due to their higher risk of UTIs, which may be caused by urease-splitting bacteria.