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Dr Harsh Shah
MS, MCh (Surgical Gastroenterology), DrNB (Surgical Gastroenterology)
Registered with Gujarat Medical Council, Reg. No. G-38738
Gastro & Cancer Surgeon
Dr. Jivraj Mehta Hospital, Vasna, Ahmedabad · 18 years of experience
In short
The TB germ slips through the bowel lining, is swallowed by defence cells, and is walled off in tiny knots called granulomas. These knots break down into ulcers.
The lower small bowel is hit most because it is rich in defence tissue and food moves slowly there. Healing of the ulcers leaves scars that can narrow the bowel.
Most people need tablets only. A surgeon is needed when a narrowing blocks the bowel, a hole forms or the diagnosis stays unclear.
This post explains what bowel TB does to the gut wall. For the full pathway, from tests and tablets to surgery, see our intestinal tuberculosis treatment page.
The germ crosses the bowel lining, defence cells swallow it, and the body builds a small wall of cells around it. That wall is the start of the damage.
The TB germ has a thick, waxy coat. This coat helps it survive stomach acid, so it can pass into the small bowel after it is swallowed. There it reaches patches of defence tissue under the lining. Special cells over these patches pick up whatever passes by and hand it to the defence cells beneath.
The defence cells engulf the germ, but they cannot kill it easily. The germ lives on inside them. The body then gathers more cells around the spot and tries to seal it off. In many people the germ stays sealed for years and causes no illness. If the defence weakens, the germ breaks out and the disease begins.
The lower small bowel and the start of the large bowel hold the most defence tissue, and food moves slowly there. The germ gets both time and a place to stay.
The last stretch of the small bowel, called the ileum, is packed with patches of defence tissue. The valve where it joins the large bowel slows the flow. Fluid is absorbed in this region, so the contents become thick. A germ that lands here stays in contact with the wall for longer than it would higher up.
This is why the lower right belly is the usual site of pain in bowel TB, and why the region is called the ileocaecal region. It is also where appendicitis hurts, and one reason the two are sometimes confused at first. Our post on who gets bowel TB in India and why it is missed explains how the germ reaches the belly in the first place.
A granuloma is the small knot of defence cells the body builds around the germ. In TB its centre often turns cheesy and dies, and that is what breaks the lining.
Under the microscope, a TB granuloma has a typical look. Round pale cells and a few giant cells sit around a centre of dead, cheesy tissue. Doctors call this caseation. When a tissue sample shows it, TB becomes much more likely.
The granuloma matters for three reasons. It is how the germ is held back, so it shows the body is fighting. It is what damages the wall when the centre breaks down. And it is what a pathologist looks for in a biopsy, so it helps tell TB from Crohn disease, where the knots are usually smaller and tidier. A sample can miss it, and a normal sample does not rule TB out.
Bowel TB is ulcerative, hypertrophic or a mix of both. The form decides whether you have mostly pain and loose motions or a lump and a blockage.
| Form | What happens in the wall | What you may notice |
|---|---|---|
| Ulcerative | Ulcers form where the knots break down, often in rings around the bowel | Cramps, loose motions, weight loss, low fever |
| Hypertrophic | The wall thickens and scars, and a firm lump may form near the caecum | A lump in the lower right belly, slow blockage, bloating |
| Mixed (ulcero-hypertrophic) | Ulcers and thickening occur together | Pain, a lump and signs of narrowing |
The ulcerative form is more often found in the small bowel, and the hypertrophic form near the caecum. A scan or colonoscopy shows which pattern you have, and the pattern guides what your doctors watch for.
TB ulcers tend to run in rings around the bowel. When a ring heals, the scar pulls tight like a band, and the passage becomes narrow.
The defence tissue and its small lymph channels run around the bowel rather than along it. TB ulcers follow them, so they lie across the bowel in rings. A ring-shaped ulcer cannot heal without shortening the wall at that level. The scar draws the sides together, and a tight band forms.
This is different from Crohn disease, where ulcers more often run along the length of the bowel. The difference is one of the clues doctors use, though it is never the only clue.
Tablets stop the germ and the ulcers heal. Even so, a ring that has already scarred may stay narrow, and that is when a surgeon is needed. Our post on what happens next when TB blocks the bowel covers this stage.
Besides the bowel wall, TB can involve the glands, the lining of the belly and sometimes the liver. These sites often occur together.
| Site | What happens there | Why it matters |
|---|---|---|
| Lower small bowel and caecum | Ulcers, thickening, scarring | Pain, lump, narrowing |
| Glands next to the bowel | Swollen glands with a dead centre | Can press on the bowel or form an abscess |
| Lining of the belly (peritoneum) | Fluid, thickening, stuck loops | A swollen belly and a matted bowel |
| Liver and spleen | Small knots in the organ | Often silent, found on scans |
Because these sites occur together, a scan of the whole belly is more useful than a test of the bowel alone.
Ulcers cause cramps, loose motions and blood loss. Scars cause blockage. A thick, scarred wall and swollen glands are what a scan picks up.
Each change in the wall has a matching complaint. Ulcers irritate the lining, so food moves through quickly and the motion is loose. Scarring narrows the bowel, so cramps follow meals and the belly swells. Swollen glands and thickened lining explain the lump and the fever. Poor absorption and a poor appetite explain the weight loss.
On a scan or colonoscopy, doctors see a thickened wall near the valve, a valve that sits open, ulcers across the bowel, narrow segments and glands with a dark centre. No one sign settles the diagnosis. They are read together with the story and the reports. For the signs themselves, see our post on bowel TB symptoms and warning signs, and for the comparison with Crohn disease, our post on how doctors tell bowel TB from Crohn disease.
See a doctor if belly pain, low fever or weight loss lasts more than two to three weeks. Go to hospital the same day for repeated vomiting, a hard swollen belly or no motion or wind.
Bring every earlier scan, report and the list of tablets you have taken. Dr Harsh Shah works with your physician and TB doctor, who manage the tablets, and he is there when the bowel needs a surgeon.
The germ is swallowed and survives stomach acid. In the small bowel it crosses the lining over patches of defence tissue and is taken up by defence cells.
It holds the most defence tissue, and food moves slowly there. The germ gets time and a place to stay. This is why pain is often felt in the lower right belly.
A granuloma is a small knot of defence cells built around the germ. In TB its centre often turns cheesy and dies, which breaks the lining and forms an ulcer.
TB ulcers lie in rings around the bowel. When a ring heals, the scar tightens like a band and narrows the passage.
No. It can be ulcerative, hypertrophic with a thick wall and a lump, or a mix of both. The pattern is seen on a scan or colonoscopy.
Yes. It can involve the glands, the lining of the belly and sometimes the liver, often together with the bowel.
Yes, in most people. Tablets stop the germ and the ulcers heal. A ring that has already scarred may stay narrow, and surgery is then considered.
When the bowel is blocked, a hole forms, bleeding does not stop, a lump stays unexplained or the diagnosis remains unclear after tests.
For questions before you travel, call +91-63555-64601. The pages below cover the nearby topics.
Dr Harsh Shah — Dr. Jivraj Mehta Hospital, Vasna, Ahmedabad
Dr. Jivraj Mehta Hospital, Dr Jivraj Mehta Marg, Vasna, Ahmedabad 380007.
Consultations, review of reports and scans, operations and follow-up. OPD Monday to Saturday, 9 am to 5 pm.
Appointments: +91-63555-64601 · +91-63590-11009 · Hospital 079-2663 6363
Directions to the hospital · WhatsApp +91-63555-64601
Told you may have TB of the bowel and want to know what it is doing inside your belly? Understanding the disease makes the tests and the treatment easier to follow. Dr Harsh Shah is a surgeon who treats the bowel problems that TB leaves behind, and he works with your physician and TB doctor. Bring your scans and reports to the consultation. Call, or message us on WhatsApp. Call For Appointment Book on WhatsApp Tapping Book on WhatsApp will likely open the WhatsApp app on your phone.
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