Pyogenic Spondylodiscitis - Causes, Symptoms, Diagnosis, and Treatment

What Is Pyogenic Spondylodiscitis?

Pyogenic spondylodiscitis combines other conditions, such as epidural abscess, vertebral osteomyelitis, and spondylodiscitis. Out of these three, the most common type is vertebral osteomyelitis infection. The causes of pyogenic spondylodiscitis may include trauma or injury to the spinal cord, infection in the surrounding structures of the spinal cord, the spread of bacterial infection through the bloodstream to the vertebra, or bacterial spread due to the post-operative infection. The condition may cause infection in the vertebra or intervertebral disc region, a rare condition in the normal population and ESRD (end-stage renal disease) patients. As the condition rarely occurs, this may result in delayed and inappropriate diagnosis due to poor knowledge about the symptoms and the condition.

Pyogenic spondylodiscitis is seen mostly in adults, especially in their late 50s, and males have a high rate of incidence than females. The most commonly involved regions are the vertebra and intervertebral discs. Pyogenic infections may result in localized inflammation of soft tissues or skin and a few other body parts primarily due to the invasion and doubling of microbes. The microorganisms release certain cellular or toxic metabolites, such as leukocidins, that may target and destroy neutrophils forming abscesses and pus discharge.

What Are the Subtypes of Pyogenic Spondylodiscitis?

The following are the subtypes of spondylodiscitis:

• Epidural abscess

• Vertebral osteomyelitis.

• Spondylodiscitis.

Epidural Abscess:

An epidural abscess is a term that indicates an infection in the epidural space, especially in the skull or spine region. This may require immediate medical intervention. The condition can be treated by antibiotic therapy.

The symptoms of epidural abscess include the following:

• Headache.

• Fever.

• Loss of consciousness.

• Nausea.

• Vomiting.

• Loss of sensation.

• Difficulty while walking and moving.

• Urinary incontinence or loss of bladder control.

• Loss of bowel control.

Vertebral Osteomyelitis:

Vertebral osteomyelitis is the most common subtype of vertebral infection. The causes of pyogenic spondylodiscitis may include trauma or injury to the spinal cord, infection in the surrounding structures of the spinal cord, the spread of bacterial infection through the bloodstream to the vertebra, or bacterial spread due to the post-operative infection.

Spondylodiscitis:

"Spondylodiscitis" is a term that indicates the major infection of the intervertebral disc by a pathogen or any bacteria, with secondary infection of neighboring vertebral bodies.

What Is the Pathophysiology of Pyogenic Spondylodiscitis?

The condition is caused by bacterial infection, which may gain access to the infection site with the following mechanisms.

• Infection that spreads through the bloodstream from the focal infection site.

• The infected neighboring site may directly affect the adjacent structures in conditions such as discitis-osteomyelitis and septic arthritis.

• Iatrogenic spread of infection that includes epidural or spinal anesthesia, iatrogenic surgical procedures, or may be due to steroid injections.

The most common cause of the infection is bacterial invasion, especially Staphylococcus aureus and Streptococcus spp. Few other microorganisms may also result in pyogenic infection of vertebrae, such as Escherichia coli and Proteus spp. in the urinary tract, Pseudomonas aeruginosa in intravenous drug users, and Klebsiella pneumoniae in alcohol abusers.

What Are the Risk Factors for Pyogenic Spondylodiscitis?

The following are the risk factors for pyogenic spondylodiscitis:

• Any trauma to the spine.

• Surgical intervention to the spine.

• Infection.

• Diabetes mellitus.

• Poor immunity includes the following:

1. HIV infection.

2. Benign or malignant Tumours.

3. Undernutrition.

4. Chronic steroid use.

5. Chronic renal problems.

6. Cirrhosis of the liver.

• Drug abuse:

1. Illegal drugs.

2. Intravenous drug use.

3. Alcohol abuse.

What Are the Symptoms of Pyogenic Spondylodiscitis?

The symptoms of pyogenic spondylodiscitis may be confused with the other symptoms which include the following:

• Fever.

• Severe back pain.

• Spinal cord or spinal nerve compression.

• Nausea.

• Vomiting.

• Anorexia.

• Unusual weight loss.

• Weakness.

• Confusion.

• Difficulty while walking and moving.

• Difficulty in eating and swallowing food.

Like other infections, people with this condition may rarely have a fever, accounting for at least 20 % of the affected individuals, which delays the diagnosis.

What Are the Diagnostic Methods for Pyogenic Spondylodiscitis?

The diagnosis of pyogenic depends on the following things such as:

• Blood tests.

• Serological tests.

• Radiological findings or image tests.

• Tissue sampling.

• Microbial culturing.

• Molecular analysis.

• Histology.

Bone scans are the commonly used diagnostic methods that are most sensitive in detecting patients with pyogenic spondylodiscitis; the reports may be sensitive, which shows an accuracy of 90 to 95 %. Even though there is good accuracy in the result, there are very high chances of errors or downfall of this method of diagnosis due to its image modality.

Magnetic Resonance Imaging (MRI)-

Magnetic resonance imaging is a non-invasive type of imaging procedure that will produce a three-dimensional image of the internal organs with the help of a high magnetic field and radiowaves. When pyogenic spondylodiscitis is detected, MRI is the diagnostic procedure of choice. This helps make a clear image of the whole length of the spinal column so that infection of other regions in the spine can also be detected.

What Is the Differential Diagnosis of Pyogenic Spondylodiscitis?

The following are the differential diagnosis of pyogenic spondylodiscitis:

• Inflammatory conditions such as pyelonephritis, appendicitis, abdominal abscess, and bowel infarction.

• Neoplastic conditions may have a similar clinical presentation.

• Granulomatous conditions mimic spondylodiscitis clinically.

What Is the Treatment of Pyogenic Spondylodiscitis?

The following are the different ways to treat pyogenic spondylodiscitis:

• The basic essential thing in treating pyogenic spondylodiscitis may include fixing the affected portion of the spinal cord.

• Antibiotic therapy plays a major role in treating pyogenic infection, which helps treat neurological infections, sepsis, intra-spinal emphysema, and spinal instability. Antibiotic therapy should be given for at least a few months until the infection clears off completely.

• Debridement of infection.

• Nerve decompression.

• Surgical intervention in the severe form of the condition.

Conclusion

Pyogenic vertebral osteomyelitis is the most commonly encountered vertebral infection. It is caused majorly due to spinal cord trauma, infections in adjacent structures, the spread of the infection in the bloodstream, or may be caused due to postoperative infections. The diagnosis is tough and may get confused with other conditions, so in case of severe back pain, contact the healthcare provider immediately.