Polymicrobial infections in hemodialysis contribute to increased morbidity and mortality. We report a patient who was readmitted due to infection with multiple pathogens and was treated with favorable outcomes. A 51-year-old male with diabetes mellitus, hypertension, and end-stage renal disease was evaluated in the emergency room following fever and chills observed during hemodialysis via a right chest tunneled catheter 2 days before admission. Two months prior, a left forearm arteriovenous graft had been placed. Initial blood cultures at his dialysis center grew Gram-negative bacilli. Empiric vancomycin and gentamicin were initiated to cover both Gram-positive and Gram-negative pathogens commonly associated with catheter-related infections. When contacted, the dialysis center reported cultures had revealed Klebsiella pneumoniae and Enterobacter cloacae complex. Chest imaging suggested pneumonia, and antibiotics were changed to vancomycin and piperacillin-tazobactam. Blood cultures obtained at admission subsequently identified ESBL-producing Klebsiella pneumoniae, prompting escalation to meropenem. Following tunneled dialysis catheter removal and placement of a right femoral central venous catheter, subsequent cultures identified Achromobacter xylosoxidans sensitive to meropenem. He was discharged 3 weeks after negative cultures. One month later, he was readmitted with fever and worsening hypoxemia requiring oxygen supplementation. Hospital course was complicated by diarrhea, with stool analysis confirming Clostridioides difficile infection. Symptoms resolved with oral vancomycin. Blood cultures identified A. xylosoxidans, leading to meropenem treatment. The left internal jugular tunneled dialysis catheter was removed. He experienced spontaneous bleeding at the graft site. Angiography showed no pseudoaneurysm. An urgent graft excision revealed A. xylosoxidans in the resected arteriovenous graft, along with A. denitrificans in blood cultures. Antibiotics were switched to ceftazidime due to suspected meropenem-induced transaminitis and confirmed susceptibility of the organism. Following negative cultures, a left chest tunneled dialysis catheter was placed, and he was discharged. Infections with multiple microorganisms in hemodialysis require prompt and targeted antimicrobial therapy for favorable outcomes.

Acute infectious diarrhea remains a leading cause of morbidity and mortality worldwide. Similar to pediatric populations, geriatric patients represent a highly vulnerable group with increased hospitalization rates, prolonged length of stay, heightened dehydration susceptibility, diminished physiological reserve, and elevated mortality risk. While pediatric populations benefit from well-established clinical severity scores such as Vesikari and Clark scales, analogous prognostic tools specifically validated for geriatric patients with acute infectious diarrhea remain lacking. Specific inflammatory markers such as procalcitonin and C-reactive protein require additional testing and increase costs. Complete blood count (CBC)-derived inflammatory indices offer a practical alternative as they are inexpensive, universally available, and calculated from routine tests. This retrospective study utilized the MIMIC-IV database (2008-2019) to assess diagnostic accuracy of nine CBC-derived inflammatory indices (AISI, NPAR, HALP, NLR, SII, PLR, MLR, SIRI, PNI) for predicting adverse outcomes in geriatric patients (≥ 65 years) with acute infectious diarrhea. Patients were identified through two independent database queries using ICD-9 codes (008-009 infectious diarrhea, 003-005 bacterial/foodborne; n = 2,208 raw records) and ICD-10 codes (A02-A05 bacterial/foodborne, A08 viral enteritis, A09 infectious gastroenteritis unspecified; n = 1,868 raw records), which yielded overlapping results due to MIMIC-IV spanning both coding eras (2008-2012 ICD-9; 2012-2019 ICD-10); after cross-encounter deduplication retaining one index admission per patient, the non-redundant cohort comprised 3,934 patients. Exclusions (n = 1,087) comprised non-infectious gastroenteritis, inflammatory bowel disease, radiation enteritis, ischemic colitis, drug-induced diarrhea, immunosuppressed patients, missing laboratory data, and C. difficile recurrence. Among 2,847 immunocompetent geriatric patients, comorbidities included hypertension (32.8%), diabetes mellitus (18.6%), and chronic kidney disease (10.4%). Bacterial pathogens were identified in 276 (9.7%) and viral in 151 (5.3%; norovirus 64.1%, rotavirus 23.4%, adenovirus 12.5%). Hospital admission occurred in 668 (23.5%), ICU admission in 34 (1.2%), in-hospital mortality in 14 (0.5%), and AKI in 421 (14.8%). Thirty-day mortality, ascertained via Social Security Death Index linkage, occurred in 31 patients (1.1%). Bacterial infections demonstrated significantly elevated indices versus viral: AISI (9,845 vs. 920, more than tenfold higher), NLR (14.8 vs. 1.82, more than eightfold higher; all p < 0.001). For bacterial-viral differentiation, NLR achieved AUC 0.892. In bacterial infections (n = 276), AISI demonstrated highest accuracy for AKI (AUC 0.896), ICU (0.882), and mortality (0.868); NPAR showed comparable results (AKI 0.854, ICU 0.872, mortality 0.848). In viral infections (n = 151), indices showed moderate performance: AISI for AKI (AUC 0.782), ICU (0.768), mortality (0.754); NPAR for AKI (0.764), ICU (0.756), mortality (0.742). HALP achieved strong mortality prediction in both groups (bacterial 0.874, viral 0.768). In diabetic patients (n = 530), AISI achieved strong discriminatory performance (AUC 0.908 for AKI) with higher complications (AKI 26.8% vs. 12.1%; p < 0.001). CKD patients (n = 296) showed highest complications (AKI 38.6%, mortality 2.1%). Multivariable analysis confirmed AISI (aOR 1.052), NPAR (aOR 1.046), and HALP (aOR 0.91) as independent predictors (all p < 0.001). Among nine CBC-derived indices evaluated in geriatric patients with acute infectious diarrhea, AISI, NPAR, and HALP demonstrate superior diagnostic value for predicting AKI, ICU admission, and mortality, with higher accuracy in bacterial compared to viral infections. These cost-effective biomarkers may address the current gap in geriatric-specific prognostic tools; however, pathogen-stratified AUC values pertain exclusively to microbiologically confirmed cases and represent upper-bound estimates requiring prospective validation with multiplex PCR-based pathogen ascertainment.

Metformin-associated gastrointestinal (GI) intolerance is a frequent clinical problem that can limit treatment initiation, delay dose escalation, and reduce long-term adherence in patients with type 2 diabetes mellitus. Common symptoms include nausea, diarrhea, abdominal discomfort, and bloating, although symptom pattern and severity vary substantially between individuals. This narrative review summarizes current evidence on the determinants, mechanisms, and clinical evaluation of metformin-associated GI intolerance. In routine practice, assessment should begin with potentially modifiable exposure-related factors, including dose, single-dose burden, titration pace, formulation, administration with meals, kidney function, and concomitant medications. If symptoms persist or appear disproportionate to treatment exposure, clinicians should then consider broader host susceptibility, including baseline GI vulnerability, microbiome-related influences, altered bile acid handling, mucosal and neuroregulatory responses, comorbidity burden, and polypharmacy. This exposure-susceptibility framework provides a practical way to interpret metformin-related GI symptoms in routine care. It supports a stepwise clinical approach in which modifiable contributors are addressed first, broader context is reviewed when needed, and premature discontinuation is avoided whenever possible. Despite limitations in the current evidence base, available data support a structured and clinically useful approach to metformin intolerance.

Metformin-associated lactic acidosis (MALA) is a rare phenomenon mostly described in the setting of impaired renal elimination or following an acute overdose. While metformin is first-line treatment for type 2 diabetes mellitus, glucagon-like peptide-1 (GLP-1) receptor agonists and glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 dual receptor agonists are frequent add-on agents. Both classes of medications share common gastrointestinal adverse reactions, including decreased appetite, nausea, vomiting, and abdominal pain. We present a series of four critically ill patients with type 2 diabetes mellitus on high-dose metformin who presented with severe MALA following the introduction or dose escalation of a GLP-1 or GIP/GLP-1 dual receptor agonist, or during an acute gastrointestinal illness while also on a maintenance dose of a GLP-1 receptor agonist, requiring acute renal replacement therapy. Prudence must be exercised when co-prescribing these 2 classes of medications with close monitoring of kidney function, possible reduction in metformin dose, and emphasis on sick day rule teaching.

Immunosuppression from human immunodeficiency virus (HIV) or other comorbidities increases susceptibility to gastrointestinal infections such as Entamoeba histolytica and cytomegalovirus (CMV). Although each pathogen can independently cause severe colitis, co-infection is rare and may lead to rapid clinical deterioration if not recognized early. We report two cases of concurrent amebic and CMV colitis in immunocompromised patients. The first patient, a 56-year-old man with HIV, Kaposi sarcoma, and hepatitis C, presented with bloody diarrhea and hypotension. Colonoscopy revealed pancolitis with ulcerations, and biopsy initially confirmed E. histolytica. Despite an initial response to anti-amebic therapy, he later developed recurrent bleeding and sepsis and died on hospital day 24. Postmortem pathological examination subsequently identified CMV co-infection. The second patient, a 48-year-old HIV-negative man with diabetes, chronic hepatitis B and C, and prior colorectal cancer, presented with 1 month of bloody diarrhea. Colonoscopy and histopathology confirmed dual infection, which was successfully treated with metronidazole and ganciclovir. A follow-up colonoscopy later demonstrated complete resolution. These cases highlight the importance of early endoscopic evaluation and tissue diagnosis in immunocompromised patients with persistent bloody diarrhea, as prompt recognition of co-infection allows timely, targeted therapy and may prevent fatal outcomes.