Case Presentation: A 93-year-old female was brought by her daughter via EMS to the emergency department with complaints of vomiting and drowsiness. She was treated, 2 weeks prior, with Cefalexin for a presumed UTI. After antibiotics initiation, the patient developed multiple episodes of non-bloody, watery diarrhea, with subsequent drowsiness, confusion, and poor appetite. She denied abdominal pain, fever, or chills. On arrival, vitals showed severe bradycardia (HR 25) and labile soft BPs with systolic (90s-110s). On examination, she had agonal breathing prompting intubation for respiratory support. Physical examination including palpating the diffuse lower abdominal quadrants elicited facial grimace. Blood investigation revealed leukocytosis (23.3 x 109/L), hyperkalemia (8.5 mMol/L), lactate (5.7 mMol/L), metabolic acidosis (pH 7.25, bicarbonate 11 mMol/L), and creatinine (3.2 mg/dL). The patient was found to have AKI and a complete heart block secondary to hyperkalemia, which was corrected by medical management. CT abdomen and pelvis showed scattered small bowel diverticula with diverticulitis complicated by perforation with small scattered locules of intraperitoneal free air to the central lower abdomen, and pancolonic diverticulosis. The patient was started on broad-spectrum antibiotics (Zosyn), bowel rest, and obtained a surgical consult. The decision was made to manage the perforation conservatively as the patient showed no signs of clinical deterioration and serial CT abdomen showed stable diverticulitis with resolved residual free air. The patient progressively improved clinically with the resolution of abdominal tenderness, resumption of bowel movement, and improvement in her renal function. Her hospital course was further complicated by Extended-Spectrum Beta-Lactamase pneumonia (ESBL) for which antibiotics were switched to Meropenem. She was eventually liberated from the ventilator and was discharged home on Ertapenem with instructions to follow up with Infectious Disease and General Surgery.

Discussion: The incidence of non-Meckel small bowel diverticulosis is rare which occurs in < 1% of the general population. Small bowel diverticulosis is usually asymptomatic, but it can rarely present with nonspecific symptoms like diarrhea, malabsorption, chronic abdominal pain, and bloating. However small bowel diverticula rarely can have dramatic complications such as diverticulitis, perforation, abscess, generalized peritonitis, fistula, mechanical intestinal obstruction, and diverticular bleeding. It is unclear why diverticulosis occurs in the small bowel unlike the familiar pathophysiology of colonic diverticulosis. 60% of patients with small-bowel diverticulosis have coexisting colonic diverticulosis. Patients with localized and self-limited inflammation without free perforation on imaging can be treated conservatively with parenteral antibiotics and close monitoring. Surgical intervention is usually required for acute complicated presentations or cases with refractory symptoms.

Conclusions: Small bowel diverticulitis is a challenging disorder. Its rarity makes diagnosis difficult and thus delayed. Our main objective is to present this rare diagnosis as a potential cause in the differential diagnosis of acute abdomen, particularly among patients aged 60 or older, and to raise clinical suspicion to physicians.

IMAGE 1: CT abdomen showing perforation of the small bowel