A 42 years old male teacher referred to our hospital complaining of the 15-day history of progressive back pain radiating to both thighs. He subsequently developed weakness affecting both lower limbs, but mainly on the left side, with urinary incontinence and constipation. It was associated with low-grade fever, loss of appetite and ended with the inability to walk.
On examination, he looked pale and uncomfortable. He had a pulse rate of 95 beats per minute, blood pressure 110/70, temperature 38.3  C, and a respiratory rate of 19 cycles per minute.
Inability to walk, severe tenderness in the back around the midline and paraspinal region, and severe limitation of spinal motion.    
Sensation:  paresthesia below the inguinal ligaments in both lower limbs.
grade 2 knee extension;
grade 1 knee flexion;
grade 1 ankle dorsiflexion;
grade 1 ankle plantar flexion.
Left side: 
grade 3 knee extension and flexion;
grade 2 ankle plantar flexion and dorsiflexion.
Right side: 
diminished knee and ankle jerk;
equivocal Babiniski sign.
urinary incontinence;
constipation.
Hemoglobin 11.1 g/dL, white blood cell count 11 x 109 with lymphocytosis (60%), essential sedimentation rate 95 mm/hour, C-reactive protein 90, random blood sugar 114 g/dL, blood urea 78 mg/dL, and serum creatinine 1.3.
Plain X-ray of the lumbosacral spine in both Antero-posterior and lateral view revealed no abnormality. MRI of lumbosacral spine in both T1, T2, and STIR showed a localized collection of pus in the canal compressing the dural sac at L3, L4 and L5 levels with a small collection of pus at L2-L3 level. Also, there were multiple pockets of pus in the paraspinal muscles (Figures 1-3).  
After discussing the treatment options with the patients, we decided to proceed with surgery. Using a posterior midline approach, in a prone position and under general anesthesia, the paraspinal muscles were dissected. We noticed multiple pockets of pus imbedded in the paraspinal muscles, mainly on the left side, which were evacuated. Then a laminectomy of L3-L4 was done with hemilaminectomy at L2-L3 and L4-L5. Pus was draining from these levels through the spinal canal. Samples were taken from pus, laminae bone, and soft tissue and sent for histopathological and microbiological studies.
Thorough irrigation and debridement were done, a drain was applied, and the wound was closed in layers.
The patient was kept on broad-spectrum antibiotics for 14 days pending microbiological laboratory results.
Microbiological results showed no growth of bacteria, Acid Fast Bacilli was negative, but Polymerase chain reaction (PCR) was positive.
Histopathological study: sections showing calcified mature bony trabeculae and degenerative cartilaginous tissues component in between marked hematopoietic depletion, dense chronically inflamed fibrous replacement including heavy mixed chronic inflammatory cells which include foamy histiocytic and mature lymphocytic cells infiltrate. Multiple ill-defined granulomas were seen with obvious extra bony inflammatory extension to the surrounding soft tissue and skeletal, muscular tissues. The final impression was a chronic specific tuberculous granulomatous spinal cold abscess.
Anti TB antibiotics were started after the above results became available.
Postoperatively, gradual neurological recovery occurred in both lower limbs. At one month follow up, the right lower limb had full motor recovery (grade 5), while the left lower limb was weaker on knee flexion and ankle dorsiflexion (grade 4). The patient was still incontinent to urine and constipated.
At two months after surgery, the left lower limb showed further neurological improvement (grade 4+), and though the patient reported some improvement of his sphincter control, he was still complaining of nocturnal incontinence and constipation. A follow-up MRI at two months of index surgery showed complete abscess resolution with good decompression of the cauda equina region (Figure 4). Surprisingly, The images also showed signs of spondylitis of L5. Because the clinical condition of the patient was improving, there were no signs of discitis nor vertebral collapse, the patient was further treated conservatively.
Five months later, he recovered both lower limbs motor strength and full control of his sphincters.