Introduction
A lower abdominal swelling can signal a broad range of causes—from gastrointestinal pathologies to urological, gynecological, and even vascular conditions. This guide walks through the key regional swellings, diagnostic signs, and investigations to identify the underlying problem.
Overview of Abdominal Regions
- Right Iliac Fossa (RIF)
- Left Iliac Fossa (LIF)
- Suprapubic Area
- Structures: terminal ileum, caecum, sigmoid colon, ovaries, bladder, uterus, rectum
Right Iliac Fossa Swelling
1. Caecum / Ascending Colon
- Appendix mass or abscess: Acute tenderness, possible fever
- Carcinoma: Hard, non-tender, anemia, weight loss
2. Terminal Ileum
- Crohn’s mass: Rubbery hard, non-mobile, often with diarrhea or weight loss
- Tuberculous mass: Similar to Crohn’s but slower in onset, systemic signs
3. Ovarian/Tubal
- Ovarian cyst: Large, mobile, bimanually palpable
- Ectopic pregnancy: Sudden, very tender, pregnancy signs
- Pyosalpinx: Very tender, fluctuant, infection features
4. Pelvic Kidney
- Smooth, non-tender, regular; anatomical variant
Left Iliac Fossa Swelling
1. Sigmoid Colon
- Diverticular mass: Tender, rubbery, fixed
- Diverticular abscess: Tender, febrile, fluctuant
- Carcinoma: Hard, craggy, immobile
- Faeces: Soft, indentable, mobile with colon
2. Ovarian/Tubal
- Similar pathology as RIF (cyst, ectopic, pyosalpinx)
- Consider gynae malignancies in older women
3. Pelvic Kidney
- Smooth, non-tender, anatomical variant
Suprapubic Swelling
1. Bladder
- Urinary retention: Stony dull mass, disappears after voiding
- Transitional cell carcinoma: Irregular, fixed, ±hematuria
2. Uterus
- Pregnancy: Smooth, central, moves with fetal movements
- Fibroid: Smooth, may be irregular if multiple
- Carcinoma: Firm, irregular, postmenopausal bleeding
3. Ovary / Tube
- Ovarian tumor or cyst
- Pyosalpinx / Ectopic pregnancy: Emergency scenarios
4. Rectum
- Carcinoma: Irregular, immobile, PR bleeding, change in bowel habit
5. Urachus (rare)
- Cystic swelling below umbilicus, possible discharge
Clinical Features to Distinguish Masses
| Feature | Appendix Mass | Faecal Lump | Ovarian Cyst | Bladder Distension | Fibroid |
|---|---|---|---|---|---|
| Tenderness | Yes | No | ± | No | No |
| Mobility | Fixed | Mobile | Mobile | Immobile | Mobile |
| Consistency | Firm | Soft | Cystic | Stony dull | Firm |
| Special sign | Fever, sepsis | Indents | Bimanual exam | Voiding urgency | Irregular menstrual hx |
| Investigations | USG, CT | X-ray | USG pelvis | USG bladder, MSU | USG abdomen/pelvis |
Red Flags to Consider
- Postmenopausal bleeding + suprapubic mass
- Rapidly enlarging firm mass in RIF or LIF
- PR bleeding + firm immobile rectal mass
- Pregnancy signs + acute RIF/LIF pain = suspect ectopic
- Urinary retention with suprapubic swelling = urgent relief required
Key Investigations
| Test | Utility |
|---|---|
| FBC | Anemia, infection |
| WCC | Infection, inflammation |
| LFTs | Associated liver metastasis |
| USG abdomen/pelvis | Ovarian, bladder, fibroid, appendix, kidneys |
| CT scan | Abscess, malignancy, Crohn’s, omentum |
| Colonoscopy | Sigmoid and rectal mass evaluation |
| Small bowel enema | Crohn’s disease |
| Barium enema | Diverticular disease |
| MSU | UTI, retention |
| β-hCG | Rule out pregnancy |
Differential Diagnosis Summary Table
| Region | Common Masses | Key Differentiating Feature |
|---|---|---|
| RIF | Appendix mass, Crohn’s, ovarian cyst | Fever vs diarrhea vs cyclical pain |
| LIF | Diverticular mass, carcinoma, ovarian pathology | Fixed tender mass vs bleeding vs mobile cyst |
| Suprapubic | Bladder, fibroid, pregnancy | Voiding issue vs uterine size vs fetal signs |
Management Overview
Appendix Abscess
- Antibiotics
- Percutaneous drainage or delayed surgery
Crohn’s / TB Mass
- Medical therapy (steroids, anti-TB)
- Surgery if complications arise
Ovarian Cyst / Tumor
- Monitoring if benign
- Surgery if large or suspicious
Ectopic Pregnancy
- Medical (methotrexate) or surgical emergency
Diverticulitis / Carcinoma
- Antibiotics for abscess
- Resection if carcinoma or complication
Fibroids
- Medical management, embolization, or myomectomy/hysterectomy
Bladder Mass
- TURBT or cystectomy
- Investigate hematuria urgently
FAQs
How can I tell if my lower abdominal swelling is dangerous?
Hard, fixed, painful, and growing swellings, or those with bleeding or systemic symptoms, require urgent evaluation.
Does bladder swelling always mean urinary retention?
Not always—but retention is the most common cause of midline, dull-to-percussion swelling.
Can a fibroid be felt through the abdomen?
Yes—large fibroids can cause firm, smooth suprapubic swellings.
Which scan is best for diagnosing pelvic swellings?
Ultrasound is first-line; CT or MRI may be needed for complex or large lesions.
What is the best test for ectopic pregnancy?
Serum β-hCG + pelvic ultrasound is diagnostic.
Conclusion
Lower abdominal swellings span across gynecologic, GI, urinary, and lymphatic systems. Regional assessment, clinical palpation, and focused imaging lead to prompt diagnosis and better outcomes—especially in emergency situations like appendicitis or ectopic pregnancy.
