: A 12 year old female presented with two months of right hip pain. She was diagnosed with right trochanteric bursitis and treated with triamcinolone injection, but hip pain continued to worsen. Hip MRI was significant for sacroiliitis, explaining the source of hip pain, but it also had incidental finding of fluid in the pelvis. Abdominal CT revealed ascites with soft tissue thickening of omentum (omental caking). The patient was admitted for further evaluation of suspected peritoneal carcinomatosis.
Peritoneal fluid analysis showed: glucose 29, protein 7.2, WBC 4493. It was negative for malignant cells, bacteria, fungus, and AFB.
On laparoscopy, granulomas were seen over omentum, ovaries, and diaphragm. Omental biopsy revealed confluent granulomas but was negative for AFB and fungal stains. PPD was initially negative.
Hip pain and presence of sacroiliitis on MRI prompted rheumatologic workup, but it was negative and she failed to respond to NSAID.
Five weeks later, omental culture turned positive for Mycobacterium tuberculosis. She began anti-TB treatment, and over the next two months her hip pain resolved. At the end of 12 months of therapy, repeat abdominal CT and hip MRI revealed complete resolution. Repeat PPD had been positive; she was found to have had exposure to a grandmother with TB in Puerto Rico.
: Tuberculous peritonitis is very uncommon in children. Infection usually occurs after reactivation of latent tuberculous foci in the peritoneum that had initially spread hematogenously from a primary lung focus. With disease progression, tubercles form along the visceral and parietal peritoneum, and ascites develops from exudation of fluid from tubercles. More than 90% of patients with peritoneal TB have ascites at time of presentation.
Because of the insidious onset of the disease and because the diagnosis is often unsuspected, 70% of patients have symptoms for more than four months before the diagnosis is made. Patients most commonly present with several weeks of abdominal pain, fever, and weight loss. Exam usually reveals abdominal tenderness, hepatomegaly, and ascites. Many have a diffusely distended, tender abdomen.
In this patient, six months passed between the onset of symptoms and diagnosis. Her unusual presentation contributed to this delay in diagnosis. She had no fever or abdominal pain; exam revealed no abdominal distention or tenderness and no hepatomegaly. The ascites was an incidental finding upon radiological workup of hip pain.
Inflammation of the sacroiliac joint that caused the hip pain in this patient is most likely due to Poncet's disease, a reactive inflammatory process secondary to tuberculosis. As expected with Poncet's disease and with peritoneal tuberculosis, medical cure and symptom relief was achieved after initiation of anti-TB therapy.
Figures 1: Omental caking on CT of abdomen and pelvis
Figure 2: Sacroiliac joint enhancement on MRI