Bacterial infections can cause back pain, though this is less common than mechanical issues like muscle strains or disc problems. Unlike typical back discomfort that resolves with conservative measures, pain from an infection requires prompt medical attention. These infections affect structures within or near the spine, leading to inflammation and damage. Understanding this potential cause is important for proper diagnosis and effective treatment.
Types of Bacterial Infections Causing Back Pain
Bacterial infections can target different parts of the spinal column and surrounding tissues, each causing back pain.
Vertebral osteomyelitis is a bacterial infection of the vertebrae, the bones of the spine. This infection can destroy bone tissue, causing severe pain and potential spinal instability. It often spreads to the vertebral body through the bloodstream from a distant site.
Discitis is an infection affecting the intervertebral disc space, located between the vertebrae. Infected discs become inflamed and painful, which can be debilitating due to nerve irritation. Both osteomyelitis and discitis often occur together, sometimes called spondylodiscitis.
A spinal epidural abscess is a collection of pus in the epidural space surrounding the spinal cord. This abscess can compress the spinal cord or nerve roots, leading to severe pain and neurological deficits. Rapid diagnosis and treatment are crucial to prevent permanent damage, including paralysis. This condition typically arises from bacterial spread through the bloodstream or direct inoculation.
Psoas abscess, while not a direct spinal infection, can also cause back pain. This involves a pus collection within the psoas muscle, a large abdominal muscle along the lower spine. The inflamed psoas muscle can cause referred pain to the lower back or groin, making differentiation from spinal issues challenging without imaging. These abscesses can result from infection spread from nearby structures or through the bloodstream.
Kidney infections (pyelonephritis) can cause flank pain that radiates to the back. Although a urinary tract infection, the pain can be intense and localized to the lower back or side, mimicking musculoskeletal back pain. Differentiating pyelonephritis from true spinal infections relies on identifying associated urinary symptoms and specific diagnostic tests.
Recognizing Symptoms of Infectious Back Pain
Distinguishing infectious back pain from common mechanical back pain involves recognizing key accompanying symptoms. Unlike typical muscle strains, infectious back pain often presents with systemic symptoms, indicating the body’s response to an invading pathogen. These include unexplained fever, chills, fatigue, night sweats, and unintentional weight loss.
The pain itself differs from mechanical causes. Infectious back pain is persistent and unremitting, meaning it does not improve with rest or positional changes. It can be worse at night, disrupting sleep, and may not respond to typical pain relievers. The pain is usually localized over the affected spinal segment but can radiate if nerves are involved.
Neurological symptoms are warning signs, especially if the infection compresses the spinal cord or nerve roots. These include new or worsening leg weakness, numbness or tingling, and changes in bowel or bladder function. Any sudden onset of these symptoms with back pain warrants immediate medical evaluation.
A patient’s recent medical history also provides clues. Back pain developing after a recent surgery, injury, or infection elsewhere in the body (e.g., skin or urinary tract infection) raises suspicion. Infectious back pain often begins without a clear mechanism of injury or specific event, pointing towards an underlying infectious process.
Who Is at Higher Risk?
Certain individuals are more susceptible to bacterial infections causing back pain due to compromised immune defenses or bacterial entry pathways. Those with weakened immune systems are vulnerable, including people with chronic conditions like diabetes, HIV/AIDS, or cancer. Patients undergoing organ transplantation or receiving immunosuppressant medications also face elevated risk.
Intravenous drug use is a significant risk factor, as it introduces bacteria directly into the bloodstream, which can then travel to the spine. Individuals who have recently undergone surgeries or medical procedures, especially spinal surgeries, are also at increased risk due to potential bacterial contamination or spread. Chronic infections elsewhere in the body, such as urinary tract infections or endocarditis, can allow bacteria to spread to the spinal column.
Elderly individuals are generally at higher risk due to often weakened immune systems and a greater prevalence of other medical conditions. Malnutrition or other debilitating illnesses can also compromise the body’s defenses, increasing susceptibility to widespread bacterial infections affecting the spine.
Medical Diagnosis and Treatment
Accurate diagnosis of infectious back pain begins with a comprehensive medical history and physical examination. Healthcare providers inquire about pain, systemic symptoms, risk factors, or recent medical procedures. The physical exam assesses for spinal tenderness, neurological deficits, and signs of systemic infection. These steps guide further diagnostic investigations.
Blood tests are typically among the first laboratory investigations. Elevated white blood cell counts, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) indicate inflammation and infection. While these markers suggest an infection, they do not pinpoint its location or specific type, necessitating more targeted tests.
Imaging studies are crucial for visualizing affected spinal structures. Magnetic Resonance Imaging (MRI) is the most sensitive modality for detecting infections of spinal soft tissues and bones, such as discitis, osteomyelitis, and epidural abscesses. MRI has a reported sensitivity of 96% and specificity of 94% for evaluating spinal infections. X-rays and CT scans are less sensitive in early infection stages.
To identify the specific bacteria and guide antibiotic therapy, a biopsy and culture of the infected tissue are often necessary. This involves taking a tissue sample from the affected disc, vertebra, or abscess, usually guided by imaging. Growing the bacteria in a laboratory ensures the most effective antibiotics are chosen.
Antibiotics are the primary treatment for bacterial back pain. Once identified, targeted antibiotics are administered, often intravenously initially, for an extended period. For vertebral osteomyelitis, antibiotic therapy typically ranges from 6 to 12 weeks, with studies suggesting 6 weeks can be non-inferior to longer durations. The specific type and duration depend on the pathogen, infection severity, and patient response.
In some cases, surgical intervention is necessary. Surgery may drain an abscess, decompress the spinal cord or nerve roots, or remove infected and damaged tissue. Spinal stabilization might also be required if the infection has compromised vertebral integrity. Following acute treatment, pain management and supportive care, including rest and physical therapy, aid recovery. Early diagnosis and appropriate treatment are important for preventing severe complications and achieving a positive outcome.