Low back pain (LBP) refers to pain, muscle tension, or stiffness localized below the costal margin and above the inferior gluteal folds, with or without leg pain (sciatica). It is one of the leading causes of disability worldwide and a frequent reason for outpatient visits, especially among middle-aged and elderly populations.

Low back pain may be:

• Acute (< 6 weeks)

• Subacute (6–12 weeks)

• Chronic (> 12 weeks)

In many patients, no specific structural pathology is identified; this is termed nonspecific low back pain. Acute ligamentous sprain and muscular strain are the most common and are usually self-limiting.

Epidemiology

• Lifetime prevalence: up to 70–85% of adults

• Peak incidence: 30–60 years

• More common in sedentary occupations

• Major cause of work absenteeism and disability

Etiology

Low back pain may be categorized as mechanical, inflammatory, infectious, neoplastic, congenital, metabolic, or psychogenic.

1. Mechanical Causes (Most Common)

• Lumbar muscle strain

• Ligament sprain

• Degenerative disc disease

• Herniated disc

• Osteoarthritis (lumbar spondylosis)

• Spinal stenosis

• Spondylolisthesis

• Poor posture

• Obesity

• Pregnancy

• Repetitive overuse injuries

2. Disc Pathology

• Protruding or ruptured intervertebral disc

• Nerve root compression causing radiculopathy

3. Traumatic Causes

• Vertebral fracture

• Ligament rupture

• Muscle tear

4. Infectious Causes

• Tuberculosis (Pott’s disease)

• Septic discitis

• Epidural abscess

5. Malignancy

• Metastatic disease (especially prostate, breast, lung)

• Multiple myeloma

• Primary spinal tumors

• Prostatic carcinoma metastasis

6. Congenital Abnormalities

• Sacralization of L5 transverse process

• Abnormal intervertebral facets

7. Spondylolisthesis

Forward slipping of one vertebra over another, often L5 over S1.

8. Spinal Canal Narrowing

• Lumbar spinal stenosis

• Neurogenic claudication

9. Psychogenic Pain

The back is a common site for somatization disorders. Inconsistent historical and physical findings across examinations may suggest psychogenic etiology.

10. Systemic and Rheumatologic Causes

• Fibromyalgia

• Polymyalgia rheumatica

• Connective tissue diseases

In selected inflammatory conditions, corticosteroids (e.g., dexamethasone 0.1 mg/kg once daily) may be considered under specialist supervision.

Pathophysiology

Low back pain arises from:

• Mechanical stress on muscles and ligaments

• Annular tear or disc degeneration

• Inflammatory cytokine release

• Nerve root compression

• Vertebral instability

• Bone destruction (infection or tumor)

• Central sensitization (chronic pain states)

Distinction Between Inflammatory and Mechanical Back Pain

Red Flag Symptoms

Urgent evaluation is required if the patient presents with:

• History of cancer

• Unexplained weight loss

• Fever

• Night pain

• Severe trauma

• Progressive neurological deficit

• Saddle anesthesia

• Urinary retention or incontinence (suspect cauda equina syndrome)

• Age > 50 with new onset pain

Signs and Symptoms

• Localized lower back pain

• Muscle spasm

• Stiffness

• Reduced range of motion

• Radicular leg pain (sciatica)

• Numbness or tingling

• Weakness in lower limbs

• Gait disturbance

• Bowel or bladder dysfunction (emergency)

Diagnostic Criteria

Diagnosis is primarily clinical and includes:

1. Detailed History

• Onset and duration

• Radiation of pain

• Aggravating/relieving factors

• Trauma history

• Constitutional symptoms

2. Physical Examination

• Inspection and palpation

• Range of motion testing

• Straight Leg Raise test

• Neurological examination (motor, sensory, reflexes)

3. Common Diagnoses

• Acute muscular strain

• Ligament sprain

• Chronic osteoarthritis

Investigations

Investigations depend on clinical suspicion:

Imaging

• X-ray: fractures, spondylolisthesis, degenerative changes

• CT scan: bony detail

• MRI: disc prolapse, nerve compression, spinal stenosis, infection, malignancy

MRI is the investigation of choice for neurological symptoms.

Laboratory Tests

• FBC (infection, anemia)

• ESR/CRP (inflammation, infection, malignancy)

• Serum protein electrophoresis (suspected myeloma)

• PSA in elderly males

Treatment

Management depends on cause, severity, and duration.

1. Pharmacological Management

Mild to Moderate Pain

• Ibuprofen 400 mg orally every 8 hours for 5 days

Severe Pain

• Diclofenac 75 mg IM every 12 hoursOR

• Diclofenac 50 mg rectal every 8 hours for 3 days

• Diclofenac gel every 12 hoursOR

• Tramadol 50 mg orally every 8 hours for 3 days

Radicular Pain (Chronic)

• Gabapentin 300 mg nocte for 4 weeks

• Pregabalin 75 mg nocte for 4 weeks

• Vitamin B1 + B6 + B12 once daily for 4 weeks

Use NSAIDs cautiously in elderly, renal disease, peptic ulcer, or cardiovascular risk.

2. Non-Pharmacological Management

Acute Phase

• Short period of bed rest (not > 48 hours)

• Comfortable position (hips and knees semiflexed)

• Heat therapy

• Gradual mobilization

Chronic Phase

• Weight reduction

• Core muscle strengthening

• Physiotherapy

• Postural correction

• Ergonomic modifications

• Cognitive behavioral therapy if indicated

3. Surgical Management

Indications:

• Cauda equina syndrome

• Progressive neurological deficit

• Severe spinal stenosis

• Refractory disc herniation

• Unstable vertebral fracture

• Tumor

Procedures may include:

• Discectomy

• Laminectomy

• Spinal fusion

Complications

• Chronic disability

• Depression

• Opioid dependence

• Permanent neurological deficit

Prognosis

• 80–90% recover within 6 weeks

• 10% progress to chronic pain

• Early mobilization improves outcomes

Prevention

• Maintain healthy weight

• Regular core strengthening exercises

• Proper lifting techniques

• Avoid prolonged sitting

• Ergonomic workplace adjustments

• Smoking cessation

• Early treatment of minor episodes

Patient Education

• Remain active

• Avoid prolonged bed rest

• Follow physiotherapy program

• Recognize warning signs

• Maintain good posture