Pott's spine leading to pelvic abscess is an uncommon presentation of tuberculosis. We recently cared for a young male who presented with a pelvic abscess without evidence of any primary genitourinary or bowel pathology. On computed tomography (CT), patient was found to have Pott's spine as the primary pathology. The pelvic abscess was drained by high transrectal drainage and its tubercular nature was confirmed by microbiological tests. Patient was subsequently stated on antitubercular drugs. Our patient is a rare and the first reported case of a young immunocompetent male who presented with a pelvic abscess as the sole manifestation of Pott's spine without coexisting psoas involvement or any neurological deficit. To conclude, any patient presenting with pelvic abscess, Pott's spine should be considered amongst the differential diagnosis especially in endemic regions.
Keywords: Antitubercular drugs, pelvic abscess, Pott′s spine
Tuberculosis is a pandemic and is amongst the top ten killer infectious diseases, second only to HIV, with 9.4 million cases reported worldwide. , Only 1-2% cases have involvement of the skeletal system, in which tubercular spine (Pott's spine) constitutes almost half of the cases. Pott's spine is a dangerous form of skeletal tuberculosis and is most frequent in lower thoracic and lumbar spine, with thoracolumbar junction being the commonest. 
Patients present commonly with local pain, constitutional symptoms, or paraplegia due to cord compression.  It may be complicated by development of psoas and/or retroperitoneal abscess with or without neurological sequale.  However, pelvic abscess as the sole manifestation and initial presentation of Pott's spine without neurological complications or psoas involvement has not been reported in the literature so far.
We report a rare case of a pelvic abscess in a young male resulting from a Pott's spine.
A 32-year-male presented with complaints of dull aching pain in lower abdomen, burning micturition and increased urinary frequency for 1 month, constipation for 15 days, and anorexia and weight loss. He had no history of back pain, hematuria, or previous episodes of acute abdominal pain. There was no history of any abdominal surgery in recent past.
General physical examination was unremarkable except for pallor. Per abdominal examination revealed a firm, tender, intra-abdominal lump present in the hypogastrium and extending into the pelvis. There was no other lump or hepatosplenomegaly. Per rectal examination revealed a firm boggy mass bulging from posterior rectal wall with mobile rectal mucosa over it. The lump was bimanually palpable. A provisional diagnosis of pelvic abscess was made.
On investigations, hemogram revealed anemia (haemoglobin of 8.1 gram/dl) with lymphocytosis and an elevated erythrocyte sedimentation rate (100 mm/hour). Liver and kidney function tests, coagulation profile, chest and abdominal X-rays, urine routine microscopy, and culture were within normal limits. HIV serology was nonreactive, whereas Mantoux test was strongly positive (20 mm).
Ultrasonographic evaluation of the abdomen and pelvis revealed a retrovesical heterogenous hypoechoic mass of 15 ×16 × 9.3 (450 cm 3 ) with thick septations, suggestive of pelvic abscess. There were calicified mesenteric and iliac lymph nodes suggesting a tubercular etiology. Contrast-enhanced computed tomography (CECT) of the abdomen showed geographic destruction of L5 vertebra with L5/S1 disc space involvement and focal destruction of right sacral ala [Figure 1]. There was a large enhancing walled collection with internal septae (9.16 × 7.5 × 9 cm) in the pelvis tracking down from the anterior prevertebral aspect of L5 spine, displacing the bladder and rectum anteriorly [Figure 2]. Multiple enlarged centrally necrotic and peripherally enhancing nodes were also noted. A final diagnosis of L5/S1 tubercul spondylodiscitis with pelvic abscess was made.
In view of a symptomatic large pelvic abscess, high transrectal needle aspiration was done under anesthesia wherein 250 ml pus was aspirated and examined for acid fast bacilli, BACTEC, and polymerase chain reaction (PCR) for tuberculosis; of which BACTEC and PCR were positive for TB. The patient was started on four drug based antitubercular chemotherapy, and advised bed rest for 4 weeks in view of the vertebral involvement. During follow-up, patient had relief of symptoms without appearance of any neurological deficit. Review ultrasound abdomen and pelvis after 6 weeks revealed resolution of pelvic abscess, and patient completed 9 months of antitubercular treatment without development of any neurological symptoms or recurrence of pelvic abscess during his follow-up.
Percival Pott, after whom Pott's disease is named, presented the classic description of spinal tuberculosis in 1779. Pott's disease is usually secondary to an extraspinal source of infection. 
The basic lesion involved in Pott's disease is a combination of osteomyelitis and arthritis that usually involves more than one vertebra. Lower thoracic vertebrae are the most common area of involvement (40-50%), followed by the lumbar spine (35-45%). Approximately 10% of Pott's disease cases involve the cervical spine. ,
Patients present with local pain, constitutional symptoms, spinal deformity, or paraplegia. Neurologic abnormalities occur in 50% of cases and may include spinal cord compression leading to paraplegia, paresis, impaired sensation, nerve root pain, and/or cauda equina syndrome.  Retroperitoneal, paraspinal, and psoas abscess secondary to Pott's spine can develop and extend to adjacent structures or skin.  Treatment options include antitubercular medication, drainage of abscess (surgical, percutaneous, or trans ependymal), and spinal cord decompression/immobilization when indicated. Spinal surgery is indicated in patients with neurological symptoms when they are not cured by antitubercular therapy or when they are extensive. Classical approaches of radical debridement have been gradually replaced by minimally invasive surgical procedure.  Effective chemotherapy for Pott's disease is the gold standard and must be started at the early stages of the disease.  Pelvic abscess as the sole manifestation of Pott's spine without neurological complications or psoas involvement has not been noted so far.
Pelvic abscess can be divided into primary or secondary on the basis of underlying etiology. Primary pelvic abscesses are those occurring de novo without any antecedent local pelvic pathology, while secondary abscess occur due to coexisting or underlying local pelvic inflammatory or infectious etiology. Appendicitis in males and pelvic inflammatory disease in females are the most common causes of secondary pelvic abscess, while genitourinary infections and tubo-ovarian pathologies, diverticulitis, Crohn's disease, and anastomotic leaks are among other common ones.  Primary pelvic abscess is more common in females due to pneumococcal or tubercular pelvic peritonitis. However, it is a rare entity in males and as a complication of Pott's spine, it is unreported so far. Theoretically, pus from Pott's spine can track beneath the prevertebral fascia and reach the presacral space where it can rupture into the pelvis because of closed space created by attachment of presacral fascia to spine.
Our patient is a rare and the first reported case of a young immunocompetent male who presented with a pelvic abscess as the sole manifestation of Pott's spine without coexisting psoas involvement or any neurological deficit. Transrectal drainage was attempted in our case as transependymal drainage was not possible and to avoid contamination of peritoneal cavity, had open drainage been contemplated.
Spinal surgery was not indicated in this patient as there was no neurological deficit. 
In a patient presenting with pelvic abscess, Pott's spine should be considered amongst the differential diagnoses especially in endemic country like India.
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]