intestinal tuberculosis

Intestinal Tuberculosis: A Rare but Serious Condition

Intestinal tuberculosis (TB) is a type of tuberculosis that affects the intestines, which are the long, tube-like structures in the digestive system where food is broken down and absorbed. This condition is caused by the bacterium Mycobacterium tuberculosis or Mycobacterium bovis, which can infect any part of the gastrointestinal tract (GIT), including the ileocecal region, small intestine, large intestine, rectum, and peritoneum.

Symptoms of Intestinal TB

The symptoms of intestinal TB can be non-specific and mimic those of many other gastrointestinal conditions. Some common symptoms include:

• Abdominal pain
• Diarrhea or constipation
• Bloating
• Appetite loss
• Unexplained weight loss
• Fever
• Enlarged lymph nodes

Causes and Risk Factors

Intestinal TB can occur in the context of active pulmonary disease or as a primary infection without pulmonary involvement. The exact cause is not always clear, but it's believed to be related to:

• Infection through contaminated food or water
• Direct spread from an infected organ or lymph node
• Hematogenous (blood-borne) spread

Diagnosis and Treatment

Diagnosing intestinal TB can be challenging due to its non-specific symptoms. A high degree of clinical suspicion is required, along with a combination of:

• Clinical evaluation
• Imaging studies (e.g., X-rays, CT scans)
• Endoscopy or colonoscopy
• Biopsy or tissue sampling

Treatment for abdominal TB typically lasts 6-9 months but can extend to 9-12 months or longer, depending on the infection severity. The treatment involves a combination of antibiotics and other medications.

Prevalence and Impact

Intestinal TB accounts for around 5% of all TB cases worldwide. It's a serious condition that requires prompt attention and treatment to prevent complications and improve outcomes.

References:

• [3] Ileocecal region is the most commonly affected site; however, it can involve any part of the gastrointestinal tract (GIT).
• [11] Clinical features of intestinal tuberculosis include: weight loss, fever, abdominal pain, diarrhea, and palpable abdominal mass.
• [12] Intestinal tuberculosis is the commonest form of abdominal tuberculosis which has a non-specific clinical presentation and mimics other infectious and non-infectious disorders affecting the intestine.

Intestinal tuberculosis (TB) can present with a range of symptoms, which may vary depending on the severity and location of the infection.

Common signs and symptoms include:

• Abdominal pain [1, 4, 5]
• Weight loss [2, 4, 11]
• Fever [2, 4, 11]
• Diarrhea or constipation [8, 11]
• Bloating and abdominal distension [10]
• Loss of appetite [6, 11]
• Nausea and vomiting [5, 11]

Other possible symptoms:

• Ascites (fluid accumulation in the abdomen) [8, 11]
• Intestinal obstruction or blockage [11]
• Blood in stool [11]
• Dysphagia (difficulty swallowing) [6]
• Retrosternal pain (pain behind the sternum) [6]

It's worth noting that:

• The symptoms of intestinal TB can be similar to those of other gastrointestinal conditions, making diagnosis challenging.
• Intestinal TB is a less common form of tuberculosis, accounting for only 1-3% of all TB cases worldwide [9].
• Early detection and treatment are crucial in preventing complications and improving outcomes.

References:

[1] Context result 1 [2] Context result 2 [3] Context result 4 [4] Context result 5 [5] Context result 6 [6] Context result 11 [7] Context result 8 [8] Context result 9 [9] Context result 10

Diagnostic Modalities for Intestinal Tuberculosis

Intestinal tuberculosis (TB) diagnosis can be challenging due to its diverse clinical manifestations and low positivity rates using current diagnostic tests. Various modalities have been employed to aid in the diagnosis, including:

• Histopathological evaluation: Histopathological examination with positive acid-fast bacilli (AFB) staining remains the gold standard for diagnosing abdominal TB [1].
• Imaging studies: Multiple radiographic tests, such as barium enema, CT, and magnetic resonance imaging of the abdomen, have been shown to be helpful in aiding diagnosis [7].
• Ascitic fluid analysis: Ascitic fluid analysis can also aid in the diagnosis, particularly when combined with other diagnostic modalities [8].
• Obtaining biopsy specimens: Obtaining biopsy specimens through laparoscopy or intestinal biopsy can provide a definitive diagnosis [8].
• Ultrasonography and computed tomography (CT) scan: Ultrasonography and CT scans may show generalized or localized ascites, thickened omentum and peritoneum, which can aid in the diagnosis [9].

New Diagnostic Tests

Recent studies have also explored new diagnostic tests for intestinal TB, including:

• Xpert MTB/RIF assay: The Xpert MTB/RIF assay has been shown to be a useful tool in detecting tuberculosis, including intestinal TB [3].
• Multiplex-PCR: Multiplex-PCR has also been used to detect M. tuberculosis DNA in intestinal tissue samples [3].

Clinical Algorithm

A clinical algorithm has been proposed to support the diagnosis of gastrointestinal TB, which takes into account various variables such as age, symptomatology, duration of symptoms, liver function tests, blood chemistry, and blood count [14].

It is essential to note that a critical review of the diagnostic modality is needed before it is applied to patients suspected of intestinal tuberculosis, as each test has its advantages and disadvantages [1].

References:

[1] S Rana (2015) - Histopathological evaluation with positive AFB staining remains the gold standard for diagnosing abdominal TB. [3] P Mor (2022) - Various modalities employed for abdominal TB diagnosis include clinical features, imaging, bacteriological tests (smear/culture), histopathological/cytological examination, and molecular tests like Xpert MTB/RIF assay and multiplex-PCR. [7] For example, multiple radiographic tests, including barium enema, CT, and magnetic resonance imaging of the abdomen, have been shown to be helpful in aiding in diagnosis. [8] Nov 2, 2022 - Outline · - Radiographic imaging · - Ascitic fluid analysis · - Obtaining biopsy specimens · Peritoneal biopsy – Laparoscopy · Intestinal biopsy – ... [9] by FM Abu-Zidan (2019) - Ultrasonography and computed tomography CT scan may show generalized or localized ascites with thin mobile septa, thick omentum and peritoneum, which can aid in the diagnosis. [14] To develop a clinical algorithm to support diagnosis of gastrointestinal TB, we calculated the odds ratios and log odds of relevant variables (age, symptomatology, duration of symptoms, liver function tests, blood chemistry and blood count), comparing probable and confirmed TB cases to confirmed non-TB cases.

Treatment of Intestinal Tuberculosis

The treatment of intestinal tuberculosis typically involves a combination of antituberculous drugs, which are administered for a specific period to effectively combat the infection.

• The standard regimen for treating drug-susceptible tuberculosis includes isoniazid, rifampicin, pyrazinamide, and ethambutol. This 4-drug regimen is usually administered daily or thrice weekly under direct observation.
• For children of any age, a 6- or 9-month regimen of rifapentine, isoniazid, pyrazinamide, and ethambutol (RIPE) is recommended.
• In some cases, empirical antituberculous drug treatment for 2–3 months may be considered appropriate in countries with a high prevalence of abdominal TB.

Key Drugs Used

• Isoniazid: An essential component of the standard regimen, isoniazid is used to prevent or delay the emergence of resistant strains.
• Rifampicin: This drug is crucial for treating tuberculosis and is often used in combination with other antituberculous medications.
• Pyrazinamide: Used in conjunction with rifampicin and isoniazid, pyrazinamide helps to shorten the treatment duration.
• Ethambutol: This medication is active against M. tuberculosis and is used in combination with other anti-TB drugs.

Treatment Duration

The treatment duration for intestinal tuberculosis can vary depending on several factors, including the severity of the infection and the patient's overall health. In general, a 6-month regimen is considered adequate for patients with peritoneal or intestinal tuberculosis.

Important Considerations

• Incomplete treatment can lead to treatment ineffectiveness, the development of drug-resistant TB strains, and disease relapse.
• It is essential to complete the full course of treatment as prescribed by a healthcare professional to ensure effective recovery from intestinal tuberculosis.

The differential diagnosis of intestinal tuberculosis (ITB) can be quite challenging due to its overlapping clinical features with other conditions, such as Crohn’s disease (CD). Here are some key points to consider:

• Clinical manifestations: ITB and CD share many symptoms, including abdominal pain, diarrhea, weight loss, and fever. However, certain signs may suggest one condition over the other:
  • Ascites, ileocecal valve involvement leading to incompetence, and submucosal large caseation granuloma are more commonly associated with ITB [10].
  • Diarrhea, hematochezia, and extraintestinal symptoms are more typical of CD [3].
• Radiological features: Imaging studies can also be helpful in differentiating between ITB and CD:
  • The radiologic differential for the appearance of colorectal TB includes amebic colitis, Crohn's disease, pseudomembranous and ischemic colitis, and malignancy [9].
  • Intestinal TB may present with features such as ileocecal valve involvement, mesenteric lymphadenopathy, and ascites on imaging studies [12].
• Histological features: A definitive diagnosis of ITB often requires histopathological examination:
  • Histological features necessary for differential diagnosis between ITB and CD include the presence of caseating granulomas, which are more typical of TB [13].

It's essential to note that differentiating between ITB and CD can be challenging, especially in areas where both conditions have a high prevalence. A combination of clinical, radiological, and histopathological features should be considered when making a differential diagnosis.

References:

[3] S Ahmed · 2023 · Cited by 3 [9] by H Ladumor · 2021 · Cited by 48 [10] [12] [13]