What is Pott's Disease?
Pott's disease, also known as spinal tuberculosis or tuberculous spondylitis, is an extrapulmonary form of tuberculosis caused by Mycobacterium tuberculosis that affects the vertebral column through hematogenous spread from a primary focus, most commonly the lungs. 1, 2, 3
Pathophysiology and Epidemiology
Pott's disease represents approximately 50% of all skeletal tuberculosis cases and constitutes the most common cause of spinal infections worldwide, particularly in tuberculosis-endemic regions. 3, 4
The infection typically spreads hematogenously from a central focus (often pulmonary) to the highly vascular cancellous bone of the vertebral bodies. 3
The thoracolumbar spine is the most frequently affected site, though any spinal region can be involved. 5
The paradiscal type (involving intervertebral discs) is the most common presentation, occurring due to the shared segmental arterial supply between adjacent vertebral bodies. 3, 4
Clinical Presentation
Back pain is the predominant and most consistent presenting symptom in Pott's disease. 5
Systemic symptoms such as fever, weight loss, and anorexia may occur but are more commonly observed in patients with disseminated disease or concurrent extra-spinal tuberculosis. 5
Progressive vertebral body destruction can lead to severe complications including neurological impairments (Pott's paraplegia), spinal deformities (kyphosis), and cold abscess formation. 3, 6
The indolent nature and subacute course of the disease frequently result in delayed diagnosis, often not occurring until complications such as large abscesses, neurological deficits, or vertebral fractures develop. 6, 7
Diagnostic Approach
Image-guided aspiration biopsy should be performed to confirm the diagnosis and determine drug susceptibility in all suspected cases. 1, 2
Hold antibiotics for 1-2 weeks prior to biopsy when feasible to maximize microbiological yield, except in cases with neurological compromise, impending sepsis, or hemodynamic instability. 2
Request mycobacterial cultures and nucleic acid amplification testing (PCR) on all specimens, as these provide faster diagnosis than traditional culture methods. 2, 7
MRI with gadolinium represents the gold standard imaging modality for diagnosis, revealing characteristic findings of vertebral involvement, disc destruction, and associated soft tissue abscesses. 6, 7
Treatment Strategy
Medical Management
The standard treatment consists of a 6-month rifampin-containing regimen: 2 months of isoniazid, rifampicin, pyrazinamide, and ethambutol (2HRZE), followed by 4 months of isoniazid and rifampicin (4HR). 1, 2
Daily dosing is strongly recommended over intermittent regimens, and fixed-dose combinations may provide more convenient drug administration. 1
If pyrazinamide cannot be tolerated, extend treatment duration to 9 months. 1
For multidrug-resistant tuberculosis (MDR-TB), treatment should be guided by drug susceptibility testing and managed by or in close consultation with tuberculosis experts. 1, 4
Never add a single new drug to a failing regimen, as this promotes further acquired resistance. 1
Surgical Indications
Immediate surgical intervention is mandatory for patients with neurological compromise, spinal instability from bony destruction, spinal cord or nerve root compression, or significant sequestered paraspinal/epidural abscesses. 1, 2, 6
Medical treatment alone is ineffective when large abscesses are present, as antibiotics cannot adequately penetrate the abscess capsule to achieve therapeutic concentrations. 6
Surgical approaches include debridement of infected tissue, abscess drainage, fusion stabilization, and correction of spinal deformity. 1, 3
Monitoring and Prognosis
Monitor treatment response clinically and radiographically rather than bacteriologically, as the paucibacillary nature of spinal tuberculosis makes microbiological monitoring unreliable. 2, 4
Long-term follow-up is essential, particularly for children, as spinal growth can exaggerate deformities over time. 1
Neurological recovery can be expected in most cases if treatment is initiated before irreversible spinal cord damage occurs. 1
Affected vertebrae may continue to show radiographic changes during treatment without indicating treatment failure. 1
Critical Pitfalls to Avoid
In developed countries, maintain high clinical suspicion for tuberculosis in immigrants from endemic areas, as it remains the most common cause of spinal infections globally despite being less common domestically. 1, 2
Treatment failure most commonly results from poor adherence, drug resistance, or inadequate treatment duration—directly observed therapy (DOT) is recommended to ensure adherence. 1
The emergence of multidrug-resistant (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), combined with HIV co-infection, presents significant management challenges requiring expert consultation. 1, 3, 4