The 4th chapter of Nidanasthana of Sushruta Samhita is named as Bhagandara Nidanam Adhyaya. This chapter deals with Fistula-in-Ano.

अथातो भगन्दराणां निदानं व्याख्यास्यामः ।।१ ।।
यथोवाच भगवान् धन्वन्तरिः ।।२ ।।

We will now expound Bhagandara nidanam – diagnosis of Fistula-in-ano; as revealed by the venerable Dhañvañtari .

Nirukti – Bheda: Definition and kinds

वातपित्तश्लेष्मसन्निपातागन्तुनिमित्ताः शतपोनकोष्ट्रग्रीवपरिस्राविशम्बूकावर्तोन्मार्गिणो यथासङ्ख्यं पञ्च भगन्दरा भवन्ति |
ते तु भगगुदबस्तिप्रदेशदारणाच्च ‘भगन्दरा’ इत्युच्यन्ते |
अभिन्नाः पिडकाः, भिन्नास्तु भगन्दराः ||३||
There are five kinds of Bhagandara. They are –
Bhagandara Type Other name
Vataja Sataponaka
Pittaja Ustragriva
Kaphaja Parisravi
Sannipataja – caused due to simultaneous aggravation of all the three doshas Sambukavarta
Agantuja – caused by external causes Unmargi

Why is it called Bhagandara?
This disease is called as Bhagandara because it causes a tear in the region of pelvis, rectum and urinary bladder.
They are called Pidaka – eruption – when they are not open. On the other hand, when they are opened, they are called Bhagandara – fistula.

(Basically, this disease progresses through different stages. It starts with an eruption. Later this eruption bursts and later a sinus forms – fistula.)

Purvarupa: Premonitory symptoms

तेषां तु पूर्वरूपाणि – कटीकपालवेदना कण्डूर्दाहः शोफश्च गुदस्य भवति ।।४ ।।
Below mentioned are the premonitory symptoms of Bhagandara –

• Pain in the alae of the pelvic bones
• Itching
• Burning sensation
• Swelling / edema of the anus

Samprāpti – Rupa: Pathogenesis and clinical features

Sataponaka Bhagandara

तत्रापथ्यसेविनां वायुः प्रकुपितः सन्निवृत्त : स्थिरीभूतो गुदमभितोऽङ्गले व्यङ्गुले वा मांसशोणिते प्रदूष्यारुणवर्णं पिडकां जनयति , साऽस्य तोदादीन् वेदनाविशेषाञ्जनयति , अप्रति क्रियमाणा च पाकमुपैति , मूत्राशयाभ्यासगतत्वाच्च व्रण : प्रक्लिन्नः शतपोनकवदणुमुखैश्छि दैरापूर्यते , तानि च छिद्राण्यजस्रमच्छं फेनानुविद्धमधिकमास्राव स्रवन्ति , व्रणश ताडयते भिद्यते छिद्यते सूचीभिरिव निस्तुद्यते , गुदं चावदीर्यते , उपेक्षिते च वातमूत्रपुरीषरेतसामप्यागमश्च तैरेव छिट्टैर्भवति ; तं भगन्दरं शतपोनकमित्याचक्षते ।।५ ।।
Vata gets aggravated in persons who regularly indulged in unhealthy foods and activities.
This aggravated vata gets localized at a distance of about one or two angula (2-4 cm approximately) around the guda – anus.
The localized aggravated vata vitiates the muscles and blood around the anal region.
Later it gives rise to an eruption. The eruption is of light red in color and is associated with pricking pain and also other kinds of pain.
This eruption undergoes suppuration if not treated in proper time.
The eruption / ulcer becomes greatly moist through the minute pores in it which resemble a Shataponaka (sieve) because it is situated near the urinary bladder.
Discharges (exudes) occur continuously from these holes in great quantity. The fluid discharge is clear and frothy.
The person feels as if the ulcer therein is being hit, split, torn and pricked by needles. The rectum also gets torn.
Fart, urine, feces and semen are also eliminated from these pores / holes if this condition is neglected.
This kind of Bhagandara is called Sataponaka Bhagandara.

Uşțragriva Bhagañdara

पित्तं तु प्रकुपितमनिलेनाधः प्रेरितं पूर्ववदवस्थितं रक्तां तन्वीमुच्छ्रितामुष्टग्रीवाकारां पिडकां जनयति ; साऽस्य चोषादीन् वेदनाविशेषाञ्जनयति ; अप्रतिक्रियमाणा च पाकमुपैति ; व्रणश्चाग्निक्षाराभ्यामिव दह्यते , दुर्गन्धमुष्णमास्त्रावं स्रवति , उपेक्षितश्च वातमूत्रपुरीषरेतांसि विसृजति ; तं भगन्दरमुष्टग्रीवमित्याचक्षते ।।६ ।।
Pitta gets aggravated by its etiological factors.
This pitta is pushed down by vata.
This pitta gets localized in the same areas mentioned earlier.
Now, pitta gives rise to an eruption. This eruption is red in color, small, elevated and is of the shape of the neck of the camel. That is why it is called Ustragriva (Ushtra = camel, Griva = neck).
The symptoms manifest in the form of sucking and other kinds of pains of pitta origin, like burning sensation, increased heat etc.
This eruption would undergo suppuration and form ulcers if it is not treated at proper time. Burning sensation is manifested in the ulcer wherein the person experiences as if that region is burnt by fire or alkali. There is also exudation which is warm and smells bad.
Flatus, urine, feces and semen come out through the ulcers if this condition is neglected.
This Bhagandara of Pitta origin is called Ustragriva Bhagandara.

Parisrāvī Bhagañdara

श्लेष्मा तु प्रकुपितः समीरणेनाधः प्रेरितः पूर्ववदवस्थितः शुक्लावभासां स्थिरां कण्डूमती पिडकां जनयति , साऽस्य कण्ड्वादीन् वेदनाविशेषाञ्जनयति , अप्रतिक्रियमाणा च पाकमुपैति , व्रणश्च कठिनः संरम्भी कण्डूप्रायः पिच्छिलमजस्रमास्त्रावं स्रवति , उपेक्षितश्च वात मूत्रपुरीषरेतांसि विसृजति ; तं भगन्दरं परिस्राविणमित्याचक्षते ।।७ ।।
Sleshma / kapha gets aggravated by its factors.
This kapha is pushed down by Vata.
The aggravated kapha gets lodged, as already described earlier.
This leads to the manifestation of an eruption.
The eruption is white in color, is fixed and associated with itching.
As a result, itching and other kinds of pains of kapha origin are manifested.
The eruption undergoes suppuration if it is not properly treated.
When suppuration occurs, an ulcer which is hard, swollen and associated with itching is formed.
Exudations which are slimy fluids can be seen discharging continuously.
Flatus, feces, urine and semen come out of the ulcer when it is neglected and not treated promptly.
This Bhagandara caused due to predominant aggravation of kapha is called Parisravi Bhagandara.

Sambükāvarta bhagañdaram

वायुः प्रकुपितः प्रकुपितौ पित्तश्लेष्माणौ परिगृह्याधो गत्वा पूर्ववदवस्थितः पादा पृष्ठाग्रप्रमाणाः सर्वलिङ्गा पिडकां जनयति , साऽस्य तोददाहकण्ड्वादीन् वेदनाविशेषाञ्जनयति , अप्रतिक्रियमाणा च पाकमुपैति , व्रणश्च नानाविधवर्णमास्रावं स्रवति , पूर्णनदीशम्बूकावर्तवच्चात्र समुत्तिष्ठन्ति वेदनाविशेषाः ; तं भगन्दरं शम्बूकावर्तमित्याचक्षते ।।८ ।।
Sambukavarta Bhagandara is caused due to the combination of aggravated vata with aggravated pitta and kapha.
These doshas move downward and get localized in the areas described earlier.
These doshas now give rise to an eruption.
The eruption is the size of the big toe. It presents features (symptoms) of all the three doshas. Pricking pain, burning sensation, itching and other symptoms are also present.
The eruption undergoes suppuration if not treated at proper time and forms an ulcer.
The ulcer exudes fluids of different colors and also produces pain.
The ulcer resembles Sambukavarta i.e. spirals of the conch shell. (Sambukavarta also explains the nature of pain i.e. pain seated deep and moves circularly, as spirals found in the conch shell).
This Bhagandara manifested due to aggravation of all the three doshas is called Sambukavarta Bhagandara.

Unmārgi Bhagañdara

मूढेन मांसलुब्धेन यदस्थिशल्यमन्नेन सहाभ्यवहृतं यदाऽवगाढपुरीषोन्मिश्रमपाने नाध : प्रेरितमसम्यगागतं गुदमपक्षिणोति तदा क्षतनिमित्तः कोथ उपजायते , तस्मिंश्च क्षते पूय रुधिरावकीर्णमांसकोथे भूमाविव जलप्रक्लिन्नायं क्रिमय : संजायन्ते , ते भक्षयन्तो गुदमनेकधा पार्श्वतो दारयन्ति , तस्य तैर्मार्गः कृमिकृतैर्वातमूत्रपुरीषरेतांस्यभिनिःसरन्तिः ; तं भगन्दर मुन्मार्गिणमित्याचक्षते ।।९ ।।
Causes –

• Consumption of meat along with bone pieces and other foreign bodies by a foolish person who is greedy of eating meat.
• Feces becoming hard
  Pathogenesis – the meat with bones and hard feces, as the case may be, is pushed down by Apana Vata and moves in an improper manner. They reach the rectum / anus, get lodged therein and produce a wound.
  Further events – Sloughing (putrefaction) of the muscles takes place due to the wound. Pus and blood flows out. Later, there is manifestation of worms / bacteria in that place, just like the worms develop in the land wherein there is waterlogging.
  Symptoms – These worms eat away the anus / rectum at many places. They also produce tears in the walls of anus. Air (flatus), urine, feces and semen get discharged from the tears created by worms.
  This Bhagandara is called Unmargagami Bhagandara.

Anya vidha pidaka: Other kinds of eruptions

भवन्ति चात्र-
उत्पद्यतेऽल्परुक् शोफात् [१] क्षिप्रं चाप्युपशाम्यति |
पाय्वन्तदेशे पिडका सा ज्ञेयाऽन्या भगन्दरात् ||१०||
पायोः स्याद् द्व्यङ्गुले देशे गूढमूला सरुग्ज्वरा |
भागन्दरीति विज्ञेया पिडकाऽतो विपर्ययात् ||११||
Some verses here –
There may be some other eruptions which develop in the anal region which are associated with less pain and swelling which also disappear quickly. These eruptions may not be Bhagandara and shall be understood as different from them.
On the other hand, those eruptions which develop at a rough distance of about 2 angulas i.e. 4 cm approximately around the anal region should be considered as pidaka or bhagandara, especially so when they are deep seated and accompanied with pain and fever.

Bhagandara Purvarupa: Premonitory symptoms of bhagandara

यानयानान्मलोत्सर्गात् कण्डूरुग्दाहशोफवान् ।।
पायुवेगुजः कटयां पूर्वरूपं भगन्दरे ।।१२ ।।

Below mentioned are the premonitory symptoms of Bhagandara –

• Itching
• Pain
• Burning sensation
• Swelling in anal region and waist
  These symptoms are manifested while the person having Bhagandara rides vehicles or animals or during defecation.

घोरा : साधयितुं दुःखा : सर्व एव भगन्दराः ।।
तेष्वसाध्यस्त्रिदोषोत्थः क्षतजश भगन्दरः ।।१३ ।।
All types of Bhagandara are dreadful and are difficult to cure. Bhagandara caused by all three doshas is considered to be incurable and so is that which is caused by injury.

इति श्रीसुश्रुतसंहितायां निदानस्थाने भगन्दरनिदानं नाम चतुर्थोऽध्यायः ।।४ ।।
Thus ends the fourth chapter by name Bhagandara nidāna – in Nidäna Sthana of Sushruta samhita.