10 Serious Infections of the Spinal Cord

HIV, Syphilis and Tuberculosis Can All Damage the Spinal Cord

Hospital Patient
Hospital Patient. Joe Raedle / Staff / Getty Images

The term "myelopathy" means a problem with the spinal cord, which can lead to numbness, weakness, dysautonomia, and more. There are many different possible causes of myelopathy. Infection is not the most common cause, but is important for doctors to recognize because infections require different types of treatment with antibiotics or antiviral agents. Viruses, bacteria, fungi, or parasites can all lead to spinal cord damage.

Viruses That Cause Myelopathy

  • Human Immunodeficiency Virus (HIV) - Neurological complications of HIV are very common during the disease course. Some of these complications are due to opportunistic infections that take advantage of the body's weakened immune system. HIV itself, though, can attack the nervous system, including the spinal cord. Studies investigating the spinal cords of people who have died with HIV have found a unique myelopathy in between 11 to 22 percent of spinal cords. When these patients had symptoms, they would complain of tingling and discomfort in their legs, followed by weakness and loss of balance. Often, loss of bowel or bladder control can follow. Usually the senses of vibration and position sense (proprioception) are diminished more than other senses like temperature or pain. In addition to treating the HIV, a thorough work-up is needed to exclude other infections or diseases such as lymphoma.

  • Human T-cell lymphotropic virus type 1 (HTLV-1) - This virus is most common in tropical regions, and so the myelopathy caused by this virus is known as tropical spastic paraparesis (TSP), or HTLV-1-associated myelopathy (HAM). Weakness slowly develops over years. Sensory changes and dysautonomias are also common.

  • Herpes viruses - The herpes family of viruses includes varicella zoster (VZV, the cause of chickenpox), herpes simplex virus (HSV, the classic herpes infection), Epstein-Barr virus (EBV, the cause of mononucleosis), and cytomegalovirus (CMV). All can cause disease in the spinal cord.

    VZV causes shingles after being reactivated in the dorsal root ganglion near the spinal cord, resulting in a very painful rash. A myelitis may come on at the same time as the rash, resulting in weakness, but may also come on slowly and without rash in people who are immunosuppressed.

    Myelitis caused by other herpes viruses, such as HSV, is rare in people with intact immune systems. In those whose immune systems are damaged, such as those with severe HIV infection, viruses like CMV can cause a myelitis with numbness, weakness, and urinary retention. Treatment with antiviral agents is the best course of action in this situation, as well as correcting the immunosuppression if possible.

  • Enteroviruses - The best known enterovirus to infect the spinal cord is polio, which thankfully has become very rare in developed countries. Like amyotrophic lateral sclerosis (ALS), polio affects the anterior horn cells of the spinal cord, leading to paralysis without sensory changes. Although the paralysis caused by polio is actually an uncommon complication (1-2%), the effects are severe and were a common cause of injury and hospitalization until the advent of immunization helped eradicate the illness.

Syphilis as a Cause of Myelopathy

Syphilis has been called a "great mimicker" in neurology, because the disease can do practically anything within the nervous system. The disease usually invades the nervous system within a year of infection, but only about 5 percent of people with syphilis develop clinical problems even without treatment. Because syphilis is usually caught before the opportunity for neurological problems can arise, these complications are now rare — but were once much more common. Among the many potential guises of syphilitic infection, spinal cord disease was ten times more common than others. After that was a meningomyelitis and spinal vascular disease. All in all, then, syphilis infections can impact the spinal cord in a variety of ways.

The term "tabes dorsalis" refers to the most common spinal cord disorder associated with syphilis, and usually came on 10 to 15 years after the initial infection. In 70 percent of these patients, a severe period of pain is the first symptom. This is followed by impotence and problems with bladder and bowel control. Numbness, tingling, and other problems with sensation result. The next phase involves severe ataxia of the legs, which makes it progressively difficult to walk. Ultimately, the final stage is complete paralysis of the legs.

Meningomyelitis is an inflammation of tissue surrounding the spinal cord as well as the spinal cord itself. The first symptom is a sense of leg heaviness. Sensory loss is minimal, but the legs become progressively weaker.

Syphilis can also cause a vasculitis that causes ischemic damage to the spinal cord by cutting off blood flow, or can cause abnormal growths called gummas that slowly compress the natural nerve fibers in the cord. Fortunately, the disease usually responds well to penicillin.

Tuberculosis as a Cause of Myelopathy

Like syphilis, tuberculosis can cause lots of different kinds of neurological trouble, but is thankfully rare in developed countries. The most common spinal cord problem results from bony lesions in the spine spreading to the spinal cord. Back pain is the most common initial symptom, as the cord is enveloped by pus from the infected vertebra.

Bacterial Abscesses as a Cause of Myelopathy

An abscess is an infection that has been walled off from the rest of the body by the body's immune system. The result is a contained collection of pus. This growth can sometimes swell, leading to compression of normal structures within the body, including the spinal cord. The most frequent cause of spinal cord abscesses is Staphylococcus aureus. Because the infection is separated from the rest of the body, giving antibiotics is usually not the best approach, since there is no way for the drugs to pass the barrier. A neurosurgeon may be needed to remove the abscess without rupturing it and spilling the infection into the body.

Fungal Infections as a Cause of Myelopathy

Fungal disease that infects just the spinal cord is rare, and usually only occurs in those with compromised immune systems. Some fungi, such as aspergillus, can invade the spinal epidural space, and others lead to growths called granulomas that may compress the spinal cord.

Parasitic Infections as a Cause of Myelopathy

While parasitic infections of the spinal cord are rare in industrialized countries, world-wide Schistosoma infections are one of the most common causes of infectious myelopathy. These are usually found in South America, Africa and Eastern Asia. The organisms normally live in fresh water, and people may be infected when swimming in that water. The canine tapeworm echinococcus granulosus can cause cysts that compress the spinal cord. Cysticercosis may also involve the spinal cord in about 5 percent of cases. Paragonimiasis is a lung fluke primarily found in Asia that can be acquired by eating poorly cooked freshwater crabs. All can ultimately result in the numbness, tingling, weakness and other problems caused by myelopathy.

While these infections can be dramatic and frightening, and often can be serious, the truth is that most of them are treatable if they are appropriately identified, especially if they are found as soon as possible.

Sources

Brent P. Goodman, Diagnostic Approach to Myeloneuropathy; Continuum: Spinal Cord, Root, and Plexus Disorders Volume 17, Number 4, August 2011

AH Ropper, MA Samuels. Adams and Victor's Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.

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