Necrosis and Gangrene – Ulcers, Fistulas
NECROSIS
Definition:
Necrosis is localized pathologic death of cells or tissue in a living organism, affecting a part of an organ due to irreversible injury. Unlike apoptosis, it is uncontrolled and often associated with inflammation.
Types of Necrosis
Clinical Signs of Necrosis
Pain (early stage, before nerve death)
Loss of function
Signs of causative factor:
- Trauma (bruising, swelling)
- Ischemia (pale, pulseless, paresthesia )
- Infection (fever, purulence)
GANGRENE
Definition:
Gangrene is extensive necrosis affecting a large portion of tissue c aused by a lack of blood supply, most often limbs or viscera (e.g. bowel, gallbladder, appendix).
Types of Gangrene
Wet can develop secondarily from dry if infected
ULCERS
Definition:
An ulcer is a break in the epithelium with loss of surface tissue caused by loss of tissue with inflammation, often chronic and non-healing. (Can be acute or chronic).
Etiology (6 main causes)
- Vascular insufficiency – arterial, venous, or lymphatic
- Neuropathy – diabetic ulcers
- Radiation – radiation- induced ulcers
- Chronic inflammation – pressure ulcers, infections
- Digestive secretions – peptic ulcers
- Tumors – ulcerated malignant growths
Clinical Features
Depends on location:
- Skin: non- healing wound, may be painless
- GI tract (e.g. peptic ulcer): epigastric pain, bleeding
Pain – usually chronic
Complications:
- Bleeding → hematemesis or melena
- Perforation → peritonitis (emergency)
- Penetration into adjacent organs
Diagnosis: Clinical exam, endoscopy, biopsy, imaging
H. pylori testing in peptic ulcers (biopsy, urease test)
Treatment
Conservative:
- Treat underlying cause (e.g. H. pylori eradication)
- PPIs (e.g. omeprazole)
- Wound care (pressure relief, debridement)
Surgical:
- For complications (e.g. perforation, malignancy)
- Ulcer excision, vagotomy, resection
FISTULAS
Definition:
A fistula is an abnormal epithelial-lined connection between two hollow structures (e.g., organs, vessels, or skin). It can result from disease, surgery, trauma, or congenital defects.
Types (by anatomical pattern)
Classification
- By etiology:
- Congenital (branchial, thyroglossal)
- Acquired:
Inflammatory (Crohn's, infections)
Neoplastic
Post- surgical/anastomotic leak
Therapeutic (e.g. tracheostomy)
- By completeness:
- Complete fistula: Internal + external openings
- Blind/incomplete:
Only one opening (internal or external)
Specific Example: Anal Fistula
Common surgical condition
Classified by Parks System:
- Intersphincteric (70%)
- Transsphincteric (23%)
- Extrasphincteric (5%)
- Suprasphincteric (2%)
- Diagnosis
Clinical exam + imaging:
- Fistulography, MRI, CT scan, endoscopy
Anal endosonography = accurate for anal fistula anatomy
- Treatment
Goal: Remove the tract while preserving continence and preventing recurrence
- Postoperative Complications
Recurrence
Fecal incontinence
Anal stenosis
Delayed healing (especially in Crohn’s disease)