Deruxtecan-Induced Reversible Fanconi Syndrome.

Increasingly complex and constantly emerging cancer treatment protocols are associated with kidney toxicities. Data clearly demonstrate that when patients with cancer develop acute or chronic kidney disease, severe fluid and electrolyte abnormalities, outcomes are inferior, and the promise of curative therapeutic regimens is lessened. We present a case of a 74-year-old woman with metastatic, recurrent ER+/PR-/HER2+ invasive ductal carcinoma of the right breast, status post bilateral mastectomies, chemotherapy, radiation therapy, and hormonal therapies, who were clinically stable on Trastuzumab/Pertuzumab maintenance for about a year. She then experienced disease progression. She was started on Trastuzumab+Deruxtecan (T-Dxt). However, due to worsening diarrhea of more than 12 episodes per day, decreased oral intake, weakness and weight loss, she got admitted to the hospital. Laboratory data showed hyponatremia, hypokalemia, non-anion gap metabolic acidosis, hypomagnesemia, and hypophosphatemia. These laboratory abnormalities were initially attributed to diarrhea. Renal losses were suspected when the electrolyte abnormalities did not correct despite improving diarrhea. Urine electrolytes were hence tested. There was evidence of Fanconi syndrome with glucosuria, proteinuria, and renal potassium and phosphorus wasting. Fanconi syndrome was attributed to the Deruxtecan component of the combination chemotherapy, as she was previously on Trastuzumab with no such abnormalities. The electrolyte abnormalities resolved over the course of a few months. To our knowledge, this is the first case of Fanconi syndrome due to T-Dxt.

A Case Report on Metformin-Associated Lactic Acidosis and Transient Blindness.

Metformin is the first-line treatment for any patient with type 2 diabetes. Metformin-associated lactic acidosis and transient blindness have only been reported in some case series and case reports. It is rare and presents especially in patients with underlying chronic kidney disease (CKD) Stage III and above and on high doses of metformin or with a normal dose of metformin and an associated renal injury. We present here a rare and interesting case of something similar. A 77-year-old woman with a past medical history of type 2 diabetes on metformin, obesity status post gastric bypass, CKD Stage III, presented with complaints of nausea, vomiting, confusion, abdominal pain, diarrhea, decreased urine output, sudden visual loss, and a hypoglycemic episode at home. She was hemodynamically stable. Lab work was suggestive of leukocytosis, hyperkalemia, severe high anion gap metabolic and lactic acidosis, acute-on-chronic kidney injury. Findings on the computed tomography (CT) brain, chest radiograph, and CT abdomen and pelvis could not explain the current scenario. She received Ringer's lactate, a bicarbonate push, and an infusion. Acidosis continued to worsen, she became hypotensive requiring pressor support, and she was immediately taken for hemodialysis. All her symptoms, including vision loss, had improved with a single session of hemodialysis, even before the acidosis had corrected. Work-up for other causes of renal dysfunction came back negative. Metformin was discontinued. She was placed on insulin for her diabetes control.

Hidden Tunnel: A Case of Duodenal-Colonic Fistula Caused by Cytomegalovirus.

We present the case of an 86-year-old African American gentleman who presented with fatigue, diarrhea, and weight loss. He had elevated liver enzymes in an obstructive pattern. A magnetic resonance cholangiopancreatography scan showed edema around the stomach and duodenum, which prompted evaluation with an esophagogastroduodenoscopy. A large enteric fistula between the duodenum and colon was visible, and biopsies returned positive for cytomegalovirus (CMV). The patient did not have any known risk factors for immunodeficiency and was successfully treated with medical therapy. Our case is unique in the severity of CMV infection in an otherwise healthy individual.

Strongyloides stercoralis Hyperinfection Syndrome: A Neglected Cause of Abdominal Pain.

Strongyloides stercoralis infection is usually acquired from tropics or subtropics, often causes asymptomatic chronic infection, but in immunosuppressed, it can lead to hyperinfection syndrome. We report a case of chronic abdominal pain resulting from Strongyloides infection in a 55-year-old male with a history of partial small bowel resection for small intestinal lymphoma and a recent diagnosis of chronic kidney disease with proteinuria on steroid therapy. He presented with chronic abdominal pain, nausea, loss of appetite, and weight loss. Initial laboratory workup and imaging including retroperitoneal ultrasound and CT of the abdomen/pelvis were within normal limits, and he was discharged on acid suppression therapy. He was readmitted with worsening symptoms and underwent esophagogastroduodenoscopy (EGD) and duodenal biopsy, which revealed Strongyloides infection. We later discovered a travel history to Cambodia. His symptoms resolved with ivermectin therapy. This case highlights the importance of travel history, which can prevent unnecessary investigations and delay in the diagnosis.