|tuberculosis of the abdomen|
While it is well known that tuberculosis (TB) is a disease of the lungs, it is not appreciated that tuberculosis can affect several other organs in the body. There are over 5 million cases of TB in the world, and about 10% of these are patients with abdominal TB.
While virtually any organ can be affected by TB, the abdominal organs most often involved are the peritoneum, the abdominal lymph nodes, and the intestines. The kidney also commonly develops TB. The stomach and liver are less often affected, and TB of the spleen and gall bladder is very rare.
TB is caused by a bacterium, Mycobacterium tuberculosis. The disease usually starts in the lung, where the focus of infection is sometimes so small that it cannot be detected. It then spreads to other parts of the body, usually by the blood stream. Swallowing of infected saliva can cause intestinal lesions. The TB lesions in hollow organs such as intestine later heal with narrowing ("stricture" or "stenosis") of the intestine, leading to intestinal obstruction. The urinary bladder also can shrink with TB infection: this may markedly decrease the amount of urine that the patient can hold. The peritoneum is a membrane, and can become studded with hundreds of fine, 2 mm nodules, which represent tissue reactions to the TB bacillus. The solid organs such as lymph nodes initially swell with infection. Later the inner tissue breaks down to form pus. This is also called a TB abscess, and can also develop in the kidneys. TB of the testes can cause infertility.
Most patients are young adults. The peak incidence is between the ages of 20 and 40. Females are somewhat more commonly affected than males. Diagnosis may be very difficult, and less than 50% of cases are correctly diagnosed. The disease may present as an acute illness, or with gradually worsening, chronic symptoms. Many persons have no symptoms at all.
Pain is the commonest symptom. There is no classical pattern, and it may vary markedly in quality and intensity. Usually the pain is mild to moderate, and perceived as a diffuse, dull ache in the abdomen. Other features are weight loss and fever (Table)
The illness may present with intestinal obstruction, peritonitis or as gastrointestinal bleeding. TB of the kidney may present with pain in the flanks or as a painless hematuria (blood in the urine). Many clinical features are similar to those seen in various cancers, which should be carefully ruled out by investigations.
features in gastrointestinal TB
In urinary TB, the symptoms are haematuria, increased frequency of urination, often with burning. There may be a nodular swelling in the testis.
Diagnosis of abdominal TB is difficult. Most of the tests are nonspecific and are associated with high false positive and false negative values. Depending upon the clinical findings, one or more of the following tests are done:
Microbiological tests include demonstration of AFB* and the polymerase chain reaction (PCR). Because of certain laboratory staining properties TB bacteria are often called "acid fast bacilli", or AFB. There are very few other bacteria which have similar properties, therefore the demonstration of AFB on examination of tissue is virtually diagnostic of TB infection. Unfortunately demonstration of AFB either on smear, culture or animal inoculation is often unsussessful since tissues do not usually contain large quantities of bacteria. Sometimes urine examination and culture may demonstrate AFB in patients with urinary TB. The PCR is the test of the future. Presently it is not standardized, therefore interpretation is difficult. Moreover it is available in very few places.
Radiological tests. Radiology is the single most important investigative modality for abdominal TB. A chest X-ray should be obtained in all patients. Evidence of TB can be seen in a third of patients. Plain X-ray of the abdomen can be done, but is rarely informative in TB, and its main value is to rule out other diseases. Barium studies such as barium follow-through and barium enema are diagnostic in about two thirds of patients with abdominal TB. There are changes in speed of movement of barium, and in appearance of the intestines, that can lead to a reasonably certain diagnosis of abdominal TB. Intravenous pyelography can pick up lesions of renal TB. Ultrasound and computerized tomography of the abdomen are good in evaluating peritoneal, lymph nodal and urinary TB. Ultrasound can pick up increased peritoneal fluid as well as enlarged lymph nodes. The same features are also picked up well on CT scan, which should be used if quality ultrasound is not available or inconclusive. In urinary TB, ultrasonography and CT can both help in diagnosis.
Endoscopy. Endoscopy such as colonoscopy and biopsy may be of great value in the diagnosis of colonic and ileocecal TB. The lesions of TB, such as ulcers and strictures can be easily seen. The ulcers can also be biopsied during endoscopy, and the biopsy may establish the diagnosis. Cystoscopy (urinary endoscopy) is occasionally needed, if there are bladder symptoms in urinary TB.
Pathology. Pathology provides the final, clinching diagnosis. If an abdominal mass is present, a fine needle aspiration cytology of the masses can be used to make a diagnosis, and this is the test of choice. The results are improved by guiding the sampling with ultrasound or CT. In some patients tissue will be obtained from a surgical excision. Histopathology of this tissue will provide a proof of TB.
Surgery for diagnosis. If the suspicion of abdominal TB is high, and if all other tests are inconclusive, a diagnostic laparoscopy may be performed. The accuracy in peritoneal TB may be as high as 75%-100%, and this may be the most accurate method of diagnosis. The disadvantage of laparoscopy is that general anesthesia is usually needed, and occasional complications have been reported. Open surgery may be used instead of laparoscopy, and is not significantly more traumatic. In some cases gastrointestinal lesions open surgery may be diagnostic as well as therapeutic.
Search for TB elsewhere. As a policy, when TB is suspected a search should be made for TB elsewhere in the body. In particular chest TB (by a chest X-ray) and lymph node TB (by examination, cytology or biopsy of lymph nodes if enlarged) should be ruled out.
"Therapeutic trial". Since TB is very common, many doctors advise antitubercular drugs in patients even if the usual tests have not proved TB. This is n emperical method, with all the disadvantages of hit and trial treatment, but often is better than doing nothing. While no doctor immediately recommends this "therapeutic trial", all doctors are forced to resort to it now and then. In countries with a high incidence of TB a therapeutic trial has a definite role. In most cases a response is seen in two weeks or less. The patient feels much better, fever comes down, and the ESR in the blood begins to fall. Intestinal symptoms may take longer to respond. If response is not seen in 3-4 weeks, the trial should be abandoned.
The treatment for all forms of TB, including abdominal TB, is antitubercular therapy ("ATT"). ATT is the treatment for the infection, and is needed in all patients with TB. If the patient has to be operated, ATT may be started before surgery, although this is not mandatory. ATT will be required for 6 months, whether or not surgery has been performed.
may be required for diagnosis, as described above.
Prognosis. Most patients have an excellent outcome from abdominal TB, if treated in time.
Patients with abdominal TB ordinarily may take a normal diet. Patients who have recurrent obstruction may need to avoid high residue food (vegetables, fruits etc) until the obstruction is relieved.
Antitubercular therapy, ATT, consists of administration of a combination of drugs. The usual drugs are:
(or INH) 300 mg once daily: occasional liver
Four drugs are given for 2 months, then the first two for another four months. Other regimes are also used.
Severe abdominal pain, or persistent abdominal pain should prompt a thorough medical check up. Unexplained weight loss is always an indication for consultation. Blood in the urine and in the stools also makes a medical visit mandatory.
Regional enteritis, as the name suggests, is a disease in which there is inflammation of parts of the intestines. Portions of the intestine become thick walled, with marked narrowing of the lumen. When seen under the microscope, there is inflammation characterized by the presence of clusters of cells called granulomas. These granulomas are somewhat similar to those seen in tuberculosis. Along with cells of inflammation these granulomas contain cells "giant cells", which are large cells with several nuclei. Regional enteritis was first described by Crohn in 1932, and is also therefore called Crohn's disease.
Crohn's disease usually affects the small intestine, but may cause disease in the colon, and less often in other parts of the alimentary canal.
Chrohn's disease is a chronic disease that usually affects young caucasian adults. It is common among Jews, and rare in non-white Asians. There is a tendency to occur in families. The most frequent symptoms are unexplained fatigue, weight loss, abdominal discomfort or pain, fever, loss of appetite and vomiting. During an acute exacerbation of the disease the pain may occur in the right lower abdomen, and often strongly mimics the features of appendicitis. The diagnosis is often made during surgery for an appendectomy! Patients often develop the symptoms of intestinal obstruction: pain, vomiting, cessation of stools and abdominal distension. At other times diarrhea may be present, and treatment for worms or amebic infestation is often given. In fact the clinical picture is so variable that it is difficult to diagnose, and some patients are inevitably diagnosed as having a psychiatric illness. Some patients have extra-abdominal features, such as ankylosing spondylitis. The risks of gallstones, urinary stones and of amyloidosis is increased.
The diagnosis is made by barium X-rays of the small intestine and colon. CT scan and endoscopy may help in a few cases. Acute illness may be confused with appendicitis, and chronic involvement of the colon may be difficult to distinguish from ulcerative colitis. Crohn's disease may resemble abdominal tuberculosis, and in developing countries where tuberculosis is common a diagnosis is not easy to make.
In a few patients, especially those who present with an acute episode, the illness is not progressive. In the majority however the disease advances to involve more and more of the intestine, with episodes of obstruction and formation of internal fistulas. There is no specific therapy, and most treatment is symptomatic. Antidiarrheals are used for episodes of diarrhea. Sulfasalazine, used for ulcerative colitis, is also used in Crohn's disease, but has less efficacy. Persistent active disease may require steroids, usually in the form of oral prednisolone. Intra-abdominal complications such as obstruction, fistula formation or perforation with abscesses may need surgery. Crohn's disease patients may need an operation many times.
Sood, MBBS (AIIMS), MS (AIIMS), MAMS, is a
practising surgeon attached to Dharamshila Cancer
Hospital, Sir Ganga Ram Hospital and to Noida Medicare
Center. Formerly Professor of Surgery, Himalayan
Institute of Medical Sciences, Dehradun, Dr Sood has a
special interest in gastrointestinal surgery. He has had
an active academic career, has published several papers
in national and international journals, and is the Editor
(with Dr Anurag Krishna) of a widely acclaimed book
titled Surgical Diseases in Tropical Countries.
Last revised: May 19, 2000