Appendicular abscess differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]

Overview

Appendicular abscess must be differentiated from other causes of abdominal pain such as acute gastroenteritis and luminal obstruction. Age group and gender of the patient must be considered in differentiating an appendicular abscess from other intra-abdominal abscesses with similar complaints.

Differential diagnosis

Appendicular abscess should be diagnosed early and treat promptly not only to reduce morbidity and mortality, but it is also important to differentiate from other abdominal diseases presenting with RLQ pain, fever, nausea, and vomiting such as psoas abscess, cellulitis, torsion of testis and ovaries, and ectopic pregnancy as the undrained abscess carries high risk of mortality.

Diseases	Clinical features					Diagnosis		Associated findings
	Symptoms				Signs	Laboratory fingdings	Radiological findings
	Fever	Abdominal pain	Nausea vomiting	Diarrhea
Psoas abscess	+	Dull RLQ pain radiating to hip and thigh	+	-	Positive Psoas sign	↑ WBC ↑ ESR ↑ BUN	CT demostrates enhancing collection in the psoas muscle.	Associated with IV drug abuse and HIV Staphylococcus aureus is the most common pathogen involved
Cellulitis of right thigh	+	-	-	-	Involved site is red, hot, swollen, and tender	↑ WBC ↑ ESR ↑ BUN	Ultrasonographic-guided aspiration of pus is both gold standard for diagnostic and therapeutic In early cellulitis: Diffuse increase in the thickening and echogenicity of the subcutaneous tissue Late cellulitis: Accumulation of fluid in the subcutaneous tissue	Severe infection is indicated by Lymphangitic spread Circumferential cellulitis Pain out of proportion
Crohn's disease	+	RLQ continuous localized pain	+	Bloody	Fullness or a discrete mass in the RLQ of the abdomen	[ASCA]) are found in Crohn disease	Transmural ulcerations are seen on colonoscopy	H/O weight loss, Extra intestinal manifestaions Endoscopic biopsy for diagnosis
Gastroenteritis (Bacterial and viral)	+	Diffuse crampy intermittent abdominal pain	+	Bloody or watery	Rebound tenderness, rash	Fecal leukocytes Stool culture Stool toxin assay	No specific findings	H/O food poisoning, travel
Primary peritonitis	+	Abrupt diffuse abdominal pain	+	Bloody/watery	Abdominal distension, rebound tenderness	Peritoneal fluid shows >500/microliter count and >25% polymorphonuclear leukocytosis.	X-ray abdomen identifies free air under the diaphragm CT demonstrates abscess or fluid in abdomen	History of advanced cirrhosis or nephrosis Peritoneal fluid analysis confirms the diagnosis
Pyelonephritis	+	Flank pain radiating to inguinal region	+	-	Costovertebral angle (CVA) tenderness	Urine microscopy and culture confirm presence of bacteria.	CT demonstrates round swollen kidneys with hypo-dense appearance	H/o reccurent UTI
Ovarian torsion	-	Sudden sharp pain	+	-	Unilateral, tender adnexal mass		Ultrasonography shows ovarian cyst and decreased blood flow	Affects females of reproductive age group Ultrasound is gold standard in diagnosing Can be right or left sided
Testicular torsion	-	Sudden sharp pain	+	-	Swollen, tender, high-riding testis with abnormal transverse lie Loss of the cremasteric reflex	Normal blood test Normal urine analysis	Absent or decreased blood flow in the affected testicle Hypervascularity with a low resistance flow pattern (after partial torsion-detorsion)	Testicular Workup for Ischemia and Suspected Torsion (TWIST) is employed for determination of risk for torsion
Pelvic inflammatory disease	+	Bilateral lower quadrant pain	+	-	Purulent discharge from cervical os. Cervical motion tenderness	Abundant white blood cells (WBCs) on saline microscopy of vaginal secretions Laboratory evidence of cervical infection with N gonorrhoeae or C trachomatis(via culture or DNA probe)	Transvaginal ultrasonographic scanning or magnetic resonance imaging (MRI) shows thickened, fluid-filled tubes with or without free pelvic fluid or tubo-ovarian abscess (TOA).	Laparoscopy helps in confirmation of the diagnosis
Ruptured ectopic pregnancy	+	Diffuse abdominal pain	+	-	Unilateral or bilateral abdominal tenderness Abdominal rigidity, guarding On pelvic examination, the uterus may be slightly enlarged and soft, and cervicall motion tenderness	BHCG hormone level is high in serum and in urine	Ultrasound reveals presence of mass in fallopian tubes.	Triad of amenorrhea, abdominal pain and vaginal bleeding SIgns of hypotension Transvaginal ultrasound with BHCG levels are the gold standard for diagnosis