Acute Lower Back Pain: 4 Possible Causes

What is acute lower back pain?

A common reason to see the doctor is for lower back pain. According to the Australian Institute for Health and Welfare (AIHW), low back pain affects 70-90% of the population at some point in their lives. [1],[2]

The spine has a column of bones (vertebrae) and joints (such as the intervertebral joint and facet joints) that help protect and create pathways that nerves travel through. There are many supporting muscles, ligaments, and soft tissue that help the strength and movement of the spinal column.

‘Acute’ lower back pain refers to the sudden onset of pain in the lumbar (lower) region of the spine (below the ribs, above the buttocks) that can last from a few hours to a few weeks. In contrast, ‘chronic’ lower back pain refers to persistent pain that has lasted for three months or more. A large proportion of individuals can progress from ‘acute’ to ‘chronic’ lower back pain.[3]

The most common cause of acute back problems is injury to the muscles or joints in the back. This can include muscle spasms or a strain. However, lower back pain can also be caused by underlying medical issues such as fractures, disc herniation, and more. There are various different treatment options, depending on the cause and severity of the pain.

What are the symptoms of acute lower back pain?

The symptoms of acute low back pain can include:

• Sharp, shooting, or dull pain in the lower back

• Radiating pain into the legs or feet

• Reduced movement of the spine

• Pain worsened with everyday activities, such as sitting or standing

• Muscle spasms

• Sharp lower back pain

• Muscle tightness

It is important to seek medical attention for any ‘red flags’, which are signs and symptoms that can indicate there is a serious underlying medical issue or emergency.

Red flags include:

• Sudden bladder or bowel incontinence

• Leg weakness

• Tingling, weakness, or numbness in the legs

• Severe, unrelenting pain

• Fever

• Shortness of breath

• Nausea or vomiting

• Night pain

• Any other unexplained symptoms.

What causes acute lower back pain?

There are many different causes of low back pain.

Common causes include:

1. Muscle spasms or strains

There are many muscles and joints in the spine. Acute lower back pain can be caused by an injury to these structures, particularly after lifting something heavy with poor technique, moving awkwardly, or even sitting with poor posture for prolonged periods of time.

This can cause an overload or overstretching of the spine. The pain often comes on suddenly, and it may become difficult to walk or sit. Other symptoms may include stiffness and reduced range of motion in the lumbar region and legs. Often, lower back pain from a muscle spasm or sprain resolves with time or simple treatment remedies.

2. Disc herniation

A disc herniation, sometimes called a slipped disc, occurs when the disc between the vertebrae extrudes into the spinal canal. When this fibrocartilaginous tissue compresses on nerves, it can cause pain. Often, the symptoms will include a sharp, shooting, sometimes burning pain in the back or legs.

A common scenario where a disc herniation may occur is when lifting something heavy, particularly in a flexed and twisted position. It can also occur in high intensity sports, such as weightlifting or rowing. The pain is called discogenic pain, and can be sharp, or even radiating.

Disc herniation can become a medical concern if there is any sensory loss or weakness.

3. Spinal stenosis

Spinal stenosis is a degenerative condition where there is a narrowing in the joints, such as the facet joints. This reduces the space for nerves to travel through, which can cause nerve compression. Whilst it is an underlying condition, it can cause acute pain if the spine is overloaded or twisted awkwardly. If there is nerve compression, the pain can be sharp and radiating.

Spinal stenosis can be caused by underlying conditions, such as osteoarthritis or rheumatoid arthritis, which cause inflammatory degenerative changes in the bone and spinal structures.

4. Fractures

Acute lower back pain can be caused by spinal fractures (breaks). This may occur in the event of an accident, such as a car crash or a fall. The pain is usually sudden and sharp.

Spinal fractures require immediate medical input. Surgery may be necessary to stabilise the fracture as there can be significant risks if the fracture is left untreated, such as paralysis.

Other causes of acute lower back pain

Acute low back pain can also be caused by:

• Sciatica

• Scoliosis or kyphosis

• Spinal infection, such as meningitis

• Spinal tumours

• Organ problems, such as kidney stones

• Intestinal issues, such as gallstones.

Diagnosing acute lower back pain

As there are many different causes for low back pain that might present in a similar way. It is important to consult a doctor or health practitioner to discuss the symptoms and determine the cause of the pain. In this way, any serious or emergency conditions can be diagnosed or ruled out.

The doctor will likely ask about the background of the injury, the current symptoms, and any other relevant medical information. A physical examination will also help determine the cause of the pain. This may include checking various movements, the reflexes and sensations, and the strength of the legs and body.

In some cases, further testing may be required. This may include imaging such as x-rays, CT scans, MRIs, or ultrasounds. These tests check the health of the bones, nerves, and other soft tissue structures.

Other tests may include blood tests, bone density scans, or nerve conduction tests. These tests can help identify the cause of the pain.

Treatment for acute lower back pain

There are many different treatment options for treating acute lower back pain. However, the best option depends on the cause and severity of the injury. It is important to get a diagnosis before any treatment starts. A doctor can also rule out any more serious causes or underlying conditions.

Self-care

Common strategies to help manage and settle the symptoms of low back pain can include:

• Activity modification - Avoiding painful movements or activities for a short period can reduce the symptoms of low back pain and help healing.

• Rest - Relative rest is important as it offers a period of time where the body can rest and recover from the pain.

• Ice or heat - When used appropriately, ice packs or heat packs can provide short-term pain relief.

• Over-the-counter medications - Some medications can help relieve the pain and symptoms in the low back. If there are any concerns, it is important to consult a doctor.

Physiotherapy

A physiotherapist may be involved to help reduce pain, improve strength, and increase function after a low back pain injury.

Treatments may include:

• Strengthening exercises

• Stretching exercises

• A walking program

• Massage

• Taping.

Medical treatment

A doctor may recommend the following additional treatments:

• Prescription medications, such as anti-inflammatories or muscle relaxants

• Steroid injections

• Ultrasound-guided pain relief.

The doctor will determine the dosage and treatment option based on the symptoms and cause of pain.

Surgery

In some cases, a review with a neurosurgeon may be necessary to discuss surgical options to treat the pain and any underlying conditions. This treatment option is usually considered when other conservative (non-surgical) treatments are not successful.

Surgical procedures may include:

• Discectomy - For a discectomy, the surgeon removes the affected part of the disc between the vertebrae that has been causing the pain. This reduces the pressure on the affected nerves, and can relieve pain.

• Laminectomy - This procedure is also known as a spinal decompression. This surgery involves the removal of the lamina (a part of the vertebrae) to relieve pressure on the nerves, helping to resolve the pain.

• Foraminotomy - This procedure involves widening the intervertebral foramina, the pathway that nerves travel through. It helps widen the pathway for the nerves, therefore reducing the irritation on the nerves.

• Spinal fusion - A spinal fusion is an invasive surgery, where several vertebrae can be ‘fused’ together. This reduces painful movement in the joint. It is often used for spinal fractures, however it is also used in other situations to help resolve pain.

• Neurolysis or ablation - This procedure involves applying an agent (electrical, physical or chemical) to reduce the nerve signal transmission, thereby reducing pain signals.

Recovery post-surgery can be prolonged, and in some cases a brace may be required for a period of time. It is important to note that surgery is not always successful. Therefore, any procedures should be carefully considered and all the options should be discussed with the doctor.

Surgery may actually be a first line treatment when there are red flags, such as progressive leg weakness or sudden incontinence. In these situations, emergency surgery may be required.

Preventing acute lower back pain

Low back pain can occur to any one at any age. However, there are some preventative measures that can help reduce the risk of developing acute lower back pain.

These strategies can help keep the body fit and functional to avoid the risk low back injury:

• Maintain a regular exercise regime

• Maintain a healthy diet and weight

• Use the correct lifting technique

• Be mindful of posture throughout the day

• Use supportive chairs

• Set the desk height correctly

• Choose comfortable supportive footwear.

Things to consider about acute lower back pain

Low back pain is very common in the general population. There are many different causes of low back pain. The pain may simply resolve on its own or with conservative treatments. If symptoms are persistent or concerning, it is best to speak to a doctor to review the situation.