The list of bacteria that invade the nervous system is endless, but some stand out because of the fear they evoke, and the peril they pose. Here are our 7 most horrifying bacterial infections that threaten the nervous system.
Many bacteria primarily invade the covering of the brain, the meninges, and the commonest are Neisseria meningitidis, causing meningococcal meningitis, and Streptococcus pneumoniae, causing pneumococcal meningitis. Other relatively frequent meningeal intruders include Listeria monocytogenes and Haemophilus influenzae. Bacteria may get into the brain following infections elsewhere, such as sinusitis or otitis media (inner ear infection). There are many complications of bacterial meningitis such as cerebral venous thrombosis (CVT) and brain abscess. There are very helpful management guidelines for bacterial meningitis which cover such details as when to do a CT head scan before lumbar puncture, contact prophylaxis, and vaccination.
Tuberculosis (TB) is probably as old as history. It is caused by mycobacterium tuberculosis, a slow-growing but pernicious organism. TB spares no part of the nervous system, and manifests often as tuberculous meningitis (TBM) and Pott’s disease of the spine. Amongst many manifestations, nervous system TB may also present as an encephalopathy, tuberculoma,spinal meningitis,radiculomyelitis, and calvarial TB. At the heart of its management are CSF analysis and anti-TB drugs.
Treponema pallidum, the bacterium behind the dreaded syphilis, is another ancient bug. It has a variety of ways it terrorises the nervous system, and the longer it inhabits the neurones, the worse the outcome. Typical manifestations of neurosyphilis are tabes dorsalis, general paresis of the insane (GPI), taboparesis, stroke, meningovascular syphilis, optic neuritis (ON), and several movement disorders. The management of neurosyphilis involves screening, CSF analysis, brain imaging, and antibiotics.
Lyme disease has acquired an infamy which is probably beyond its real notoriety. It is best known for its tick-borne transmission, and for its classical dermatological feature, erythema chronicum migrans. It affects the nervous system in diverse ways such as encephalomyelitis, lymphocytic meningitis, cranial neuropathies, spinal radiculitis, stroke, diaphragmatic paralysis, and peripheral neuropathy. The management of Lyme neuroborelliosis is wide-ranging, from serology and microbiology to prevention and treatment.
Neurobrucellosis is a rarely-discussed bacterial infection but it is a significant contributor to neurological morbidity and mortality around the world. It is caused by various brucella species usually grouped under the name Brucella militensis. It has a long reach in the nervous system, causing a variety of insults such as encephalitis, meningoencephalitis, cranial neuropathies, intracerebral haemorrhage (ICH), subarachnoid haemorrhage (SAH), transverse myelitis, radiculitis, and peripheral neuropathy. You may also explore the management of neurobrucellosis.
Leprosy, perhaps the most distasteful of infectious diseases, unfortunately has a strong affinity for the nervous system. Unlike its distant cousin, TB, leprosy favours the peripheral nerves over the central nervous system. Its hallmark is thickening of the nerves or nerve hypertrophy. Caused by Mycobacterium leprae, leprosy has a legion of neurological manifestations such as mononeuritis, mononeuritis multiplex, cranial and peripheral neuropathy, myelitis, and leprous ganglionitis. The management of leprosy involves microbiology, various nerve imaging modalities, and immunosuppressive and antimicrobial drugs.
Botulism is the end result of damage by the toxin of Clostridium botulinum. This toxin produces a deadly paralysis by blocking neural transmission across the neuromuscular junction (NMJ). Botulinum toxin respects no borders, able to gain access to the nervous system through the gut, the skin, or the lungs. It paralyses everything, causing acute limb, ocular, and bulbar weakness. Left unchecked, botulism results in autonomic dysfunction and respiratory failure. The differential diagnosis of botulism includes such disorders as myasthenia gravis and Guillain Barre syndrome, and treatment may require admission to intensive care.
Explore more neurological infections on Neurochecklists!