Article Type : Case Report
Authors : Choayb S, El Harras Y, Allali N, Chat L, and El Haddad S
Keywords : Tuberculosis; Abdominal tuberculosis; Pediatric abdominal tuberculosis; Lymphadenopathy
Tuberculosis (TB) is a major public health
problem in the world. Abdominal tuberculosis is a rare manifestation in
children with chronic and not particularly specific symptoms. We discuss the
case of a 3-year-old child whose diagnosis of abdominal tuberculosis was
established on the basis of clinical findings, laboratory tests, and
radiological elements.
Pediatric abdominal tuberculosis is not very common,
and its symptoms are long-lasting and not very specific. The diagnosis is hard
to make and is based on a positive culture, but imaging is essential to get
proof of a long-term infection [1].
A 3-year-old girl with no known comorbidities came to
the children's emergency department with a 2-month history of prolonged fever,
abdominal distension, loss of appetite, and weight loss. During the clinical
examination, the patient was found to have hyperthermia (38;5°), tympanitic
abdominal distension, and several swollen lymph nodes in the cervical and
axillary regions. No respiratory discomfort was noted. A blood test showed anemia
(the hemoglobin level was at 10 g/dL) as well as an elevated CRP of 88 mg/L.
Her chest radiography was normal (not shown). Abdominal ultrasound revealed
free peritoneal fluid at the right paracolic gutter, ileocecal wall thickening,
and multiple enlarged lymph nodes (Figures 1,2). A CT scan confirmed the bowel
wall thickening of the ascendant colon, terminal ileum, and cecum and showed
multiple retroperitoneal enlarged lymph nodes with central necrosis and ascites
of the right paracolic gutter (Figure 3). No splenic or hepatic lesions were
observed. Imaging suggested abdominal TB, which a positive gastric aspirate and
geneXpert test later confirmed. Caseous necrosis was also found in the cervical
lymph nodes. The patient received quadruple anti-TB therapy (rifampicin,
isoniazid, pyrazinamide, and ethambutol) for 2 months and was maintained on
double anti-TB therapy for 4 more months with a favourable outcome.
Tuberculosis is a serious public health problem in both developing and developed countries [2]. However, while pulmonary TB is the most prevalent form, TB can occur in other systems such as the intestines, lymph nodes, bones, meninges, and so on [1]. About 11% of individuals with extra pulmonary TB develop abdominal tuberculosis, the sixth most common form. It can affect the peritoneum, gastrointestinal tract, mesentery, lymph nodes, hepatobiliary tract, or solid viscera like the spleen and liver [1-3]. Children have the greatest risk of developing extra-pulmonary TB and tend to progress more severely [4]. Abdominal TB may develop after the ingestion of sputum infected by Mycobacterium tuberculosis or milk infected by Mycobacterium bovis. It may also develop following hematogenous or lymphatic dissemination from an active site of TB or by direct extension from adjacent infected tissues. It is also possible for an earlier primary infection in older children and teenagers to result in the subsequent reactivation of a latent abdominal infection [2]. Clinical manifestations are not specific, and the progression of the disease is slow and insidious. The most frequent signs are abdominal pain, vomiting, constipation, weight loss, anorexia, fever, night sweats, abdominal distension, and bleeding from the rectum. Acute presentations are not very common; nevertheless, they are more frequent in immunocompromised patients with severe forms [1,2].
Figure
1: A and
B; para umbilical abdominal ultrasound revealing multiple enlarged and
hypoechoic lymph nodes.
Figure
2: A: longitudinal ultrasound image showing irregular thickening and
decrease of echogenicity of the bowel wall. B: cross-sectional abdominal
ultrasound showing eccentric thickening of the bowel wall.
Figure 3: A and B axial enhanced computed tomography of the abdomen show multiple enlarged and low-density lymph nodes with peripheral enhancement (blue arrows), thickening of the ascending colon wall and cecum (red arrows), and ascites of the right paraglottic gutter (white arrows).
Tuberculosis peritonitis is rare and almost always
affects young individuals. Besides the clinical symptoms, blood tests
frequently reveal anemia and elevated infection indicators [1]. Imaging plays
an essential role in the diagnosis and can detect potential complications such
as perforation, fistula, and abscess. Further, it can assist in guiding an
appropriate biopsy and evaluating the efficacy of treatment [2,3].
Lymphadenopathy is the most classic sign of TB, and in some cases, it is the
only marker. Typically, they are located in the paraaortic and mesenteric
areas. Their appearance ranges from a simple increase in the number of
normal-sized nodes to clusters or mass-forming nodes. They tend to lose their
elliptical shape and become ovoid or circular. On ultrasound and CT, caseous
necrosis appears as a central hypoechoic or hypodense area. A different pattern
of enhancement can be displayed, including homogenous, peripheral, or mixed.
Additionally, they could be multiloculated or non-enhancing. The presence of
calcifications is not necessarily indicative of inactivity. Caseous necrosis is
not specific, as it can also be caused by metastases, lymphoma, and pyogenic
infection in addition to tuberculosis [2-6]. Hepatic or splenic tuberculosis
can cause hepatosplenomegaly, micro nodular multiple small lesions (0.5 to
1cm), and single or multiple macro nodular lesions. The most prevalent
presentation is hepatosplenomegaly accompanied by several micro abscesses.
Ultrasound and CT show hypoechoic or hypodense lesions with or without
peripheral enhancement. They may heal with calcification. The differential
diagnosis should include fungal or pyogenic infections, metastases, and
sarcoidosis, although the latter is less common [2-6]. Gastrointestinal TB
mainly affects the ileocecal region, terminal ileum, and colon. Thickening of
the bowel wall, tangled masses resulting from thicker loops, lymphadenopathy, and
ascites suggest it. The principal differential diagnosis is Crohn's disease.
Left colonic involvement, a long segment, the existence of skip lesions, and
the comb sign favor Crohn's disease. On the other hand, intestinal tuberculosis
is more frequently associated with the involvement of the ileocecal area, a
small segment, as well as the presence of lymph nodes greater than 1 cm.
Differentiating these two entities is mandatory, as steroid therapy can have
devastating consequences for patients who have underlying abdominal TB [2-6].
The presence of ascites is indicative but not pathognomonic. Fine septations,
mobile strands, or particles can be detected on ultrasound. On CT, it tends to
have a high density (high protein content) and can be associated with omental
thickening as well as regular or nodular thickening of the peritoneal layers.
Additionally, the mesentery can become thicker with a stellate appearance due
to lymphadenopathy lining the vessels [2-6]. TB skin tests are considered
diagnostic of recent infection with Mycobacterium tuberculosis in children
under the age of 5 years. However, its reliability in older patients is
significantly lower [2]. The interferon-gamma release has higher sensitivity
and specificity in individuals with latent TB, particularly in children under
the age of 5 [2,3]. Analysis of ascites fluid will reveal an exudative
character with a lymphatic predominance. High levels of adenosine deaminase
possess high sensitivity (100%) and specificity (97%) [7]. However,
histological confirmation is necessary before initiating long-term treatment.
It could be done by culture of ascites fluid, peritoneal biopsy, or detection
of Mycobacterium tuberculosis in the sputum [4-6]. In regions where the disease
is prevalent and confirmation tests are unavailable, treatment may be initiated
based on a strong clinical diagnosis and suggestive imaging. In these cases,
the patient’s response to treatment is a kind of indirect confirmation of the
diagnosis [7]. Treatment is based on anti-tuberculous medications that are
administered for a period of 6-9 months and proven to be effective. Surgery is
performed in cases of complications such as bowel obstruction, fistula,
bleeding, or perforation. Continued follow-up is required until disease
resolution [3].
Abdominal tuberculosis is a serious public health
problem and is rarely found in children. Clinical symptoms are not specific.
Early diagnosis is necessary because abdominal TB is associated with high
mortality and morbidity. CT and ultrasound play an important role in the
diagnosis, which needs to be confirmed by histology or biology before starting
a long-term treatment.