Abstract Introduction Caring for critically ill patients requires diagnostic vigilance, requiring clinicians to navigate between the parsimony of known diagnoses and the complex presentations our patients experience. Case Description A 40-year-old man with methamphetamine use disorder and housing instability presented with abdominal pain and weakness to an outside hospital. He was found to have severe liver injury, hypoglycemia, renal failure, and metabolic acidosis. His course was complicated by septic shock and cardiac arrest with successful resuscitation. Echocardiogram showed bulky aortic valve vegetations though blood cultures remained negative. After eight days, he was transferred to our hospital for consideration of valve surgery. Concurrently, he developed an enlarging left-sided perihilar infiltrate and evidence of embolic phenomena to both legs and a mycotic brain aneurysm. On hospital day 14, the results of a plasma cell-free DNA (cfDNA) metagenomic microbial sequencing assay performed at transfer returned and identified Bartonella quintana, Rhizopus arrhizus, and Aspergillus flavus. Bartonella quintana IgG titers were 1:1024. Treatment for Bartonella endocarditis was initiated but the fungi were not treated given no signs of overt fungal infection. Blood cultures drawn on the 18th day grew Cryptococcus neoformans with an antigen titer of 1:2560. He developed worsening liver injury and disseminated intravascular coagulation. On day 20, a small wound on his ear developed a foci of necrosis which rapidly extended to his jaw with biopsy showing mucormycosis. An MRI on the 21st day showed leptomeningeal enhancement and a right ganglia abscess. Basic hematology, HIV, quantitative immunoglobulins, lymphocyte enumeration panels, and vasculitis testing did not reveal immunodeficiency. Further immunodeficiency evaluation was deferred given clinical decline and the transition to comfort focused care. Discussion In addition to diagnostic vigilance, caring for critically ill patients requires curiosity about etiologies of disease and an open mind to atypical presentations. His initial presentation with culture-negative endocarditis, attributed to Bartonella, was rapidly diagnosed using a cfDNA microbial assay, though he also was eventually diagnosed with two severe opportunistic infections not detected after the initial cfDNA assay. A vast majority of patients with symptomatic disseminated cryptococcosis and mucormycosis have clearly identified immunocompromised status. Previous literature suggests that methamphetamines may increase the virulence of and susceptibility to Cryptococcus invasive infection, which is possibly contributing here. Mucormycosis may also have an association with substance use. Shotgun cfDNA metagenomic sequencing can be useful in identifying potentially pathogenic organisms, but how it fits into classical Bayesian clinical reasoning is poorly understood. This abstract is funded by: None
Baddour et al. (Fri,) studied this question.