A spinal infection occurs when microorganisms, such as bacteria or fungi, invade spinal structures like the vertebrae, intervertebral discs, or surrounding soft tissues. Though uncommon, these infections can lead to severe complications if not promptly identified and treated. Understanding the specific signs helps distinguish infectious symptoms from common back discomfort.
Localized Pain and Tenderness
The most frequent symptom of a spinal infection is pain localized to the infected area. This discomfort differs significantly from typical mechanical back pain, which often improves with rest. Infection-related pain is generally described as severe, deep, and persistent.
This pain frequently worsens when resting, particularly at night, often disrupting sleep. Movement of the spine, such as turning or getting up from a chair, sharply increases the intensity. The pain is often felt directly over the affected vertebral segment, and pressing on the area can elicit tenderness.
This inflammatory pain occurs as the infectious agent causes destruction and inflammation within the bony vertebrae or the intervertebral disc space. Stiffness and a decreased range of motion in the neck or back are also common as the body attempts to guard the painful area.
Systemic Signs of Infection
Beyond localized pain, a spinal infection triggers systemic signs reflecting the immune system’s attempt to fight the invading microorganisms. Fever and chills are common indicators, though fever may be low-grade, intermittent, or absent in about half of all cases, complicating early diagnosis.
Patients often report profound fatigue and malaise, which is disproportionate to activity. The body’s increased metabolic demands can also lead to unintentional weight loss and loss of appetite. Night sweats are another constitutional symptom frequently associated with spinal infections.
These non-specific symptoms, combined with persistent back pain, suggest a deep-seated infection. Laboratory tests often confirm this systemic response by showing elevated levels of inflammatory markers, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).
Neurological Deficits and Urgent Symptoms
As the infection progresses, it can extend into the spinal canal, leading to the formation of an abscess that places mechanical pressure on the spinal cord or nerve roots. This compression results in neurological deficits, which demand immediate medical attention. Radiculopathy, or nerve root pain, is a common finding, presenting as shooting pain, numbness, tingling, or weakness that radiates into the limbs.
Difficulty walking, an unsteady gait, or muscle weakness in the arms or legs can develop due to pressure on the motor nerves. The most urgent complication is Cauda Equina Syndrome, which occurs when the bundle of nerves at the lower end of the spinal cord is compressed. Symptoms include new-onset loss of sensation in the “saddle area,” covering the groin, buttocks, and inner thighs.
Acute onset of bowel or bladder dysfunction is also concerning, involving difficulty urinating, urinary retention, or incontinence. The appearance of any of these signs—especially new weakness, numbness, or problems with bladder or bowel function—constitutes a medical emergency. Delays in treatment can lead to permanent paralysis or sexual dysfunction.
Timeline and Progression of Symptoms
The rate at which a spinal infection develops varies widely. Some patients experience an acute onset, where severe pain, high fever, and systemic symptoms appear rapidly over a few days. This presentation is often more noticeable and prompts quicker medical evaluation.
More commonly, the onset is insidious or subacute, meaning symptoms develop slowly over several weeks to months. Localized back pain may gradually worsen, accompanied by low-grade systemic signs like chronic fatigue or minor weight loss. This slow progression can cause symptoms to be initially overlooked or misdiagnosed.
The pain may initially be mild, but as the infection destroys bone and disc tissue, the pain intensifies. The appearance of neurological deficits often signals a later stage in the disease, occurring after weeks or months of progressing back pain. Persistent, worsening back pain combined with systemic symptoms or new neurological signs warrants an urgent medical evaluation to prevent irreversible damage.