Acute RIF pain is a common clinical presentation to the general practitioner. Diagnosis and management promptly required in order to limit morbidity and mortality. Clinical and laboratory findings are non specific and early recourse to imaging is being used more frequently in order aid diagnosis. Even after imaging, in approximately one third of patients the cause is not apparent.
By far the commonest cause of acute RIF pain is acute appendicitis. Other important conditions in the differential diagnosis are:
- Acute ileocolitis (inflammatory eg Crohns disease
- or infective)
- Mesenteric adenitis
- Acute endometriosis
- Ruptured ectopic pregnancy
- Pelvic inflammatory disease
- Meckels diverticulitis
- Epiploic appendagitis
- Perforated caecal tumour
- Right sided urinary tract calculous disease
- Acute cholecystitis
- Incarcerated inguinal hernia
Selecting the most appropriate imaging modality would depend on:
- Age and body Habitus
- <20: US initially then CT/MRI for clarification if additional info required
- >20: US initially in young slim adults especially women of reproductive age but if the patient habitus is such that US quality will be poor then low dose CT is warranted.
- Suspected pathology
- If a particular diagnosis is suspected based on clinical findings and laboratory studies then this should determine the imaging pathway followed eg. In a female with acute RIF pain with a positive beta HCG then transvaginal US is the most appropriate imaging modality but in a patient with RIF pain and haematuria, CT would be more appropriate.
- There are times that neither imaging modality will yield a diagnosis and in these cases diagnostic laparoscopy could be considered as a last resort.
Acute Appendicitis on US. Maximal Appendix diameter is 6mm
Distal right ureteric calculus
Hoeffel C, Crema MD, Belkacem A et al. Multi-detector row CT: spectrum of diseases involving the ileocecal area. RadioGraphics 2006; 26: 1373-1390.
Purysko AS, Remer EM, Leao Filho HM et al. Beyond appendicitis: common and uncommon gastrointestinal causes of right lower quadrant abdominal pain at multidetector CT. RadioGraphics 2011; 31: 927-947