Differentials
Endometriosis
SIGNS / SYMPTOMS
Deep, chronic pelvic pain; pain after sexual intercourse; painful periods significantly affecting quality of life; cyclical altered bowel habits during periods; infertility.
INVESTIGATIONS
Transvaginal ultrasound scan, transabdominal ultrasound, or MRI pelvis.
Diagnostic laparoscopy may be required in suspected cases when other tests return normal.
Colorectal cancer
SIGNS / SYMPTOMS
History of altered bowel habits, anemia, colonic polyps, and positive family history are suggestive of colorectal cancer.
INVESTIGATIONS
CT scan features of carcinoma include mass, stricture, and obstruction.
Anemia is frequent in colon cancer, whereas polymorphonuclear leukocytosis is a feature of acute diverticulitis.[51]
Appendicitis
SIGNS / SYMPTOMS
Patients with acute appendicitis are usually younger than those with acute diverticulitis. Presence of prodromal symptoms.
Pain localizes to the right lower quadrant in appendicitis and to the left lower quadrant in diverticulitis, with the exception of less common right-sided diverticulitis.
INVESTIGATIONS
CT scan may reveal characteristic changes of acute appendicitis; for example, appendix diameter >6 mm with associated periappendiceal inflammation.
Ulcerative colitis
SIGNS / SYMPTOMS
Usually presents at a younger age, but incidence increases again at about 70 years of age.[54]
Ulcerative colitis is more common in people with a family history and white ethnicity.[54][55]
INVESTIGATIONS
Limited flexible sigmoidoscopy in early stages reveals diffuse inflammation and ulceration in cases of acute ulcerative colitis.[56] Colonoscopy and biopsy are performed subsequently. Antineutrophil cytoplasmic antibodies in antibody test are present in >65% of cases of ulcerative colitis.
Crohn disease
SIGNS / SYMPTOMS
Usually presents at a younger age, but incidence increases again at about 70 years of age.[54]
Crohn disease is more common in people with a family history and white ethnicity.[54][55]
INVESTIGATIONS
Anti-Saccharomyces cerevisiae in antibody blood test may indicate Crohn disease; present in >65% of patients. Colonoscopy and biopsy are performed subsequently.
Urinary tract infection (UTI)
SIGNS / SYMPTOMS
Increased frequency and urgency of urination. Accompanied with burning pain, dysuria, and lower abdominal pain.
INVESTIGATIONS
Urinalysis with UTI will show increased leukocyte count, bacteria, and presence of nitrites.
Pyelonephritis
SIGNS / SYMPTOMS
Fever, chills, leukocytosis, flank pain, and renal tenderness.
INVESTIGATIONS
Urinalysis with pyelonephritis will show increased leukocyte count, bacteria, and presence of nitrites.
Ischemic colitis
SIGNS / SYMPTOMS
Usually occurs in older people with evidence of generalized atherosclerosis, and presents with abdominal pain and rectal bleeding.
INVESTIGATIONS
Abdominal radiographs may show edema of the bowel wall and minute ulcers thumb printing in the right colon with ischemic colitis.
CT scan with ischemic colitis shows similar changes in a more precise fashion and angiography confirms the diagnosis.
Limited flexible sigmoidoscopy without air insufflation may be helpful in identifying ischemic mucosa.
Pelvic inflammatory disease
SIGNS / SYMPTOMS
Urethral/vaginal discharge evidence of STI; cervical motion tenderness.
INVESTIGATIONS
Isolation of organisms in urethral/vaginal swabs by direct microscopy, culture, or other available tests.
Irritable bowel syndrome
SIGNS / SYMPTOMS
Usually occurs in younger patients with presence of Rome IV criteria and absence of evidence of systemic illness.[57]
INVESTIGATIONS
Normal laboratory tests and imaging studies.
Infectious colitis
SIGNS / SYMPTOMS
Acute-onset diarrhea, fever, tenesmus, and abdominal pain. Possible history of recent travel.
INVESTIGATIONS
Isolation of organisms in stool samples by direct microscopy, culture, or other available tests.
Ovarian cysts
SIGNS / SYMPTOMS
Female patient, often premenopausal.[58]
INVESTIGATIONS
Normal laboratory tests, presence of ovarian cyst confirmed on imaging (ultrasound or CT).
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