Louisiana Via Research Day Book 2026

Case Studies: Section 2

Case Studies: Section 2

Binod Mehta, MD; Nisheem Pokharel, MD; Hamama Javaid, MD; Edward Cornell Pierce, MD Department of Internal Medicine, St. Francis Medical Center, Monroe, Louisiana 96 RARE BUT FATAL: HIV-ASSOCIATED HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS IN A PREVIOUSLY HEALTHY YOUNG ADULT

Kavita Shah, MD; Sarah Hemphill, DO; Navin Ramlal, MD; Pamraj Sharma, MD St. Francis, Monroe, Louisiana 97 RAOULTELLA PLANTICOLA AS AN EMERGING CAUSE OF URINARY TRACT INFECTION IN AN IMMUNOCOMPETENT ELDERLY PATIENT

Context: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening immune hyperactivation syndrome. While secondary HLH is usually triggered by infections or malignancies, HLH due to HIV infection is exceptionally rare, with only 13 cases reported in the literature to date. This rarity combined with overlapping clinical features of HIV and HLH creates substantial diagnostic challenges. Report of Case: A 19-year-old previously healthy man presented with two weeks of fatigue, weight loss, anorexia, and shortness of breath. On admission, he was hypothermic (90.7 °F), hypotensive (62/27 mmHg), and hypoxemic. Labs showed pancytopenia, hyperbilirubinemia, and transaminitis. He was initially treated for septic shock and multiorgan failure. Further evaluation revealed newly diagnosed advanced HIV infection (viral load 3.27 million copies/mL, CD4 count 23 cells/mm³). Extensive infectious workup including EBV, CMV, and tuberculosis was negative. Despite starting antiretroviral therapy and broad antimicrobials, he continued to worsen. Ferritin was markedly elevated (> 33,000 ng/mL), and the combination of fever, splenomegaly, and cytopenia raised suspicion

for HLH. Bone marrow biopsy did not show hemophagocytosis. However, soluble IL-2 receptor (sCD25 = 13,935 pg/mL) met diagnostic criteria, and his H-Score of 227 indicated a high likelihood of HLH. With no secondary trigger identified, HIV-associated immune dysregulation was considered the cause. The patient failed to improve on antiretroviral therapy alone but responded well to etoposide, high-dose dexamethasone, and cyclosporine. Conclusion: HLH caused solely by HIV infection is exceptionally rare and can be difficult to recognize due to overlapping features with advanced HIV. In immunocompromised patients, the mortality rate may reach up to 70%, underscoring the need for prompt evaluation when HLH is suspected. HIV treatment alone is often insufficient, and early initiation of HLH directed therapy can be lifesaving.

Background: Raoultella planticola is an uncommon gram-negative bacillus that is becoming increasingly recognized as a human pathogen. Although primarily found in the environment, it can lead to clinically significant infections particularly in older, immunocompromised or medically complex patients. Infections with R. planticola are otherwise uncommon in immunocompetent. In a 2015 five-year retrospective review 50% of all R. planticola infections were urinary tract infections (UTIs), underscoring its role as a potential emerging uropathogen. Report of Case: An 86-year-old female with known history of recurrent urinary tract infections who presented for evaluation of mild confusion, dysuria and urinary frequency. Her urinalysis on arrival revealed evidence for pyuria and bacteriuria. Subsequent urine culture grew >100,000 CFU/mL of Raoultella planticola, labeled as an abnormal species confirming true infection. Because R. planticola can demonstrate variable antimicrobial susceptibility, targeted therapy with TMP-SMX was initiated following results of culture sensitivities. Patient improved

rapidly thereafter, with complete resolution of symptoms within days.

Conclusion: This case highlights the importance of recognizing an underreported Raoultella planticola as a meaningful cause of UTI in immunocompetent healthy adults. High-count isolates in urine cultures should be regarded as clinically significant rather than contaminants. Incorporating epidemiologic awareness with accurate identification and susceptibility-guided therapy can lead to prompt clinical improvement and prevent complications.

111

110

2026 Research Recognition Day