Fistula

Definition of Fistula:

Fistula is defined as an abnormal tract lined by epithelium,endothelium,granulation tissue or fibrous tissue connecting two epithelial surfaces either in between the exterior and an internal viscus(External fistula) or in between two internal viscera(Internal fistula).

Classification:

A.Congenital:

• Bronchial fistula(neck,lower 1/3rd)
• Tracheo-oesophageal fistula

B.Acquired:

1. Fistula-in-ano
2. Arteriovenous fistula-Hemodialysis,Trauma
3. Neoplastic

• Rectovaginal fistula
• Gastrocolic fistula

Anorectal fistulas

Clinical features of Sinus/Fistula: 

1.Persistent or intermittent discharge from an abnormal opening.
2.intermittent swelling and pain of the local site followed by discharge and relief of pain.
3.Symptoms of underlying pathology,e.g.,
     a)TB

• Low grade fever
• Cough
• Haemoptysis
• Chest pain
• Dyspnoea

     b)Congenital sinus/fistula:
From birth,e.g.,Preauricular sinus
     c)Osteomyelitis(OM)

• High fever
• Pain
• Swelling of the bone concerned

     d)Perianal sinus/fistula:
History of ischiorectal abscess

Causes of persistence of a sinus:

1.Presence of FB or necrotic tissue

• Suture material
• Sequestrum(Necrotic tissue and foreign body)
• Bullet
• Pellet
• Worms

2.Non-dependent drainage or inadequate drainage
3.Abscess of rest for

• Fistula in ano(Proximal colostomy is done)

4.Distal obstruction
5.When the tract is lined by epithelium or endothelium
6.When the tract contains excessive fibrous tissue(prevents collapsing) around the tract(e.g.,Chronic empyema chest)
7.Naturre of infection

• TB
• Actinomycosis

8.Underlying malignancy
9.Persistent discharge(VVF-urine)
10.Chronic illness or systemic illness

• DM

11.Immunosuppression
12.Nutritional deficiency
13.Drugs

• Steroid

14.Irradication:

• RVF in treating carcinoma of cervix

15.Ischaemia

Principle of Treatment of Sinus/Fistula:

1.Excision followed by biopsy
2.Treatment of the underlying cause(e.g., TB,DM,Carcinoma,Malnutrition)