Ultrasound Diagnosis of Subhepatic Appendicitis

Acute subhepatic appendicitis is an exceptionally rare anatomical variant (accounting for 0.01-0.09% of all appendicitis cases) that arises from embryological intestinal malrotation or incomplete cecal descent. A 39-year-old male presented to the emergency department with a 48-h history of progressive right upper quadrant pain, anorexia, mild nausea, low-grade fever (37.8 °C), marked leukocytosis (19 × 10⁹/L with a left shift), and elevated C-reactive protein (5.2 mg/L). Physical examination demonstrated localized tenderness and guarding in the right hypochondrium, with a negative clinical Murphy's sign. Bedside abdominal ultrasonography was performed utilizing a dedicated dual-probe strategy: a low-frequency convex transducer (1-5 MHz) for anatomical orientation and a high-frequency linear transducer (6-12 MHz) for targeted near-field interrogation. Graded compression identified a non-compressible, aperistaltic, blind-ending tubular structure in the hepatorenal recess (Morison's pouch) measuring 9 mm in outer diameter with a thickened wall (3.2 mm), an appendicolith at the base, mural hyperemia on color Doppler, and surrounding hyperechoic fat stranding with localized free fluid. Real-time sonography systematically excluded acute cholecystitis, hepatic lesions, and perforated peptic ulcer. Preoperative CT was omitted, and the patient proceeded directly to emergent diagnostic laparoscopy, which confirmed an inflamed, non-perforated appendix in the right subhepatic space adjacent to the liver margin. A laparoscopic appendectomy was successfully performed. Histopathology confirmed uncomplicated suppurative appendicitis, and the patient was discharged uneventfully on postoperative day three. Emergency high-resolution ultrasonography using a targeted dual-probe technique can conclusively diagnose subhepatic appendicitis, challenging the paradigm that CT is strictly mandatory. In patients presenting with atypical right upper quadrant pain, dedicated sonographic interrogation of the hepatorenal space facilitates prompt surgical management while eliminating ionizing radiation and diagnostic delays.