A female in her 50s with no relevant past medical history, aside from a previous inguinal hernia repair, presented to the emergency department with chief complaint of abdominal pain in the right lower quadrant ongoing for about 1 day before presentation. The pain was constant, sharp, and nonradiating. The patient denied nausea or vomiting.

At the initial evaluation, the patient was awake and alert with a Glasgow Coma Scale (GCS) of 15 and the vital signs were as follows: blood pressure of 114/74 mmHg, heart rate of 75 beats per minute, an oxygen saturation of 98% on room air and a subfebrile temperature of 37.6°C.

On physical examination, the patient was found to have abdominal tenderness on the right lower quadrant, without signs of peritonitis.

Laboratory studies showed increased inflammatory markers, including a white blood cell count of 14.2×10³ /μL and a C-reactive protein (CRP) of 115.3 mg/L.

Computed tomography (CT) scan of the abdomen and pelvis without contrast revealed a situs inversus totalis with a wall thickening of the right-sided sigmoid colon and the presence of fat stranding (Figure 1). It was also possible to identify a confined pericolic abscess with 22×11 mm, suggesting an acute colonic diverticulitis Hinchey modified classification stage Ib (Figure 2).

The patient was admitted for medical management and started on intravenous antibiotics: 500 mg of Metronidazole every 8 hours and 400 mg of Ciprofloxacin every 12 hours. She was put on complete bowel rest with intravenous hydration and pain was controlled by administering parenteral analgesics. After a clinical improvement within two days, patient’s diet was further advanced.

The patient responded well to this conservative therapy and was discharged in a stable condition after five days of hospitalization. She completed the remaining course of 14 days with oral antibiotics in an outpatient regime.

Six weeks after the acute diverticulitis attack, the patient performed a complete colonoscopy that was able to exclude a concomitant colonic cancer.

Colonic diverticula are one of the most common structural abnormalities of the bowel [1]. Being an acquired condition, diverticula usually affect the sigmoid colon in Western societies and about 4% of patients will develop acute diverticulitis [2].

Diverticulitis always starts with a micro- or macroscopic perforation of a diverticulum. This is caused by either a rise in intraluminal pressure and/or erosion by inspissated feces. If the initial injury does not resolve, it might cause a localized abscess or, if adjacent organs are implicated, an obstruction or a fistula [3].

An acute attack of diverticulitis typically begins with lower abdominal pain that then localizes to the left iliac fossa due to the sigmoid colon involvement [4].

Diverticulitis with a localized abscess (stages Ib–II) is generally resolved with conservative treatment. Situs inversus totalis (SIT) is a rare congenital abnormality where the abdominal and thoracic cavity structures are opposite of their usual position. Being aware of its existence is especially important in emergency situations. Clinically, situs inversus by itself is asymptomatic. Although careful physical examination can raise its suspicion, advanced imaging modalities like computer tomography (CT) or magnetic resonance imaging (MRI) make it possible to confirm the findings.