A novel cause of emergent hyperammonemia: Cryptococcal fungemia and meningitis

Abstract

Among etiologies of hyperammonemic emergencies, infection must be considered in certain clinical contexts, particularly among immunocompromised individuals. Although Cryptococcus neoformans is known to be urease-producing, to our knowledge it has not previously been described as a cause of hyperammonemia in patients. We report an immunocompromised man with acute on chronic kidney disease with hyperammonemic crisis due to Cryptococcal meningitis and fungemia. It is important to be aware of C. neoformans as a possible cause of hyperammonemia.

A Case of “Cryptammonia”: Disseminated Cryptococcal Infection Generating Profound Hyperammonemia in a Liver Transplant Recipient

“…While urease production in C neoformans is well recognized, to our knowledge, the association of hyperammonemia in the setting of clinical cryptococcal infection had not been recognized until 2021 when it was described in 2 case reports (see Table 1). [15][16][17] Our case adds to this growing body of knowledge with the addition of excluding the possibility of Ureaplasma as a confounding cause. It is interesting to note, patients in both reports presented with altered mental status implying a possible contribution from hyperammonemia.…”

Extrahepatic portosystemic shunts as an unusual but treatable cause of hyperammonemic encephalopathy in a noncirrhotic patient – a case report

“… 7 , 8 In addition, a recent case report highlighted cryptococcal infection as a rare cause of hyperammonemia in an immunosuppressed patient, which underlines the need for a broad microbiological workup, especially when patients are at particular risk for infection. 9 Hyperammonemic encephalopathy has also been described as a complication of bariatric surgery. 10 , 11 Furthermore, exposure to various substances has been associated with hyperammonemia, including carbamazepine, ribavirin, methamphetamine and chemotherapeutic agents, such as 5-FU.…”

A glance at transient hyperammonemia of the newborn: Pathophysiology, diagnosis, and treatment: A review

“…Portosystemic shunt Carbamoylphosphate synthetase 1 deficiency Infection Ornithine transcarbamylase deficiency Coronavirus disease [16] Argininosuccinate synthetase deficiency Urease-positive bacteria (C. neoformans, Mycoplasma hominis) overgrowth [26,27] Inhibitors of carbonic anhydrases (like topiramate) [28] Carnitine palmitoyltransferase II deficiency Asparaginase Carnitine-acylcarnitine translocase Sunitinib [29] Mitochondrial energy production disorder Methamphetamine [30] Mitochondrial complex V deficiency Nutrition Mitochondrial complex III deficiency Imbalanced total parenteral nutrition Combined oxidative phosphorylation deficiency 5…”

“…As shown in Table 1, THAN is an exclusive diagnosis that can only be made when other known causes of hyperammonemia are excluded. [16,[24][25][26][27][28][29][30] The mechanisms involved in THAN development are controversial. Fortunately, some clues have been derived from well-documented reports.…”

“…[36] When severe systemic infection occurs, platelets adherent to the liver vasculature actively migrate to scan Table 1 The causes of hypermmonemia. [16,[24][25][26][27][28][29][30]…”