Abstract Background Hyperammonemia is defined by elevated serum ammonia (NH3) levels, caused by either decreased clearance or increased production. Common etiologies include hepatic dysfunction (most common), bowel obstruction, enzyme deficiencies, and presence of urea splitting organisms, among others. While patients may present asymptomatically or with mild symptoms like lethargy and confusion - conversion of NH3 to glutamine in astrocytes causes cellular swelling and rupture, leading to severe symptoms like cerebral edema, seizures, brain herniation and death. Fortunately, most patients respond well to treatment which involves correcting the underlying cause and increasing NH3 clearance via medications, dialysis, or both. However, treatment failure does rarely occur - for which advanced options like double dialysis and molecular adsorbent recirculating system (MARS) have shown to be effective in certain situations. Case Report A 56 year old male with history of alcoholic cirrhosis presented via EMS after being found unresponsive at home. He was intubated and hyperammonemic on arrival with NH3 431, treated with rectal and oral lactulose, and rifaximin. CT abdomen revealed dilated small bowel loops with transition point at an incarcerated ventral hernia consistent with SBO. He then developed status epilepticus requiring versed, propofol, keppra and fosphenytoin. CT head revealed cerebral edema and obscured grey-white junction for which he received IV decadron and hypertonic saline. A dialysis catheter was placed for emergent HD. Post-HD labs revealed NH3 481 and CTH with worsening cerebral edema. He was started on CVVHD and levophed for hypotension, and transferred for neurocritical care services. Following transfer, patient developed dilated pupils and lost brainstem reflexes. CTA revealed cerebellar tonsillar herniation and absence of cerebral intravascular enhancement. Diagnosis of brain death was subsequently made. He was transitioned to comfort care and expired shortly after. Discussion The reason why this patient’s hyperammonemia was refractory to standard therapies is uncertain. Possible explanations include synergy of impaired metabolism due to cirrhosis and decreased excretion due to SBO, undiagnosed urea cycle enzyme deficiency, infection or SIBO with urease + organisms, rifaximin resistance, or a combination of these. In this circumstance, more advanced methods like double dialysis or MARS may have been more effective at lowering serum NH3 levels. This case highlights why severe hyperammonemia warrants extreme caution - given risk of rapid deterioration, potential for failure of standard therapies, and the lethal consequences of cerebral edema. For these reasons, transfer to a facility with the capability of advanced therapies should at least be considered on initial evaluation. This abstract is funded by: None
Gewirtz et al. (Fri,) studied this question.