Tabes Dorsalis overview

# Historical Perspective
Marshall Hall an English physician found a patient with loss of postural control in darkness caused by severely compromised proprioception In 1836, but He did not develop more information about it. Tabes dorsalis was first discovered by Moritz Heinrich Romberg, a german physician, in 1840. He described that excessive drinking and sexual activity may be the causes of tabes dorsalis and he named it progressive locomotor ataxia but he did not find the relation between syphilis and tabes doesalis. The association between syphilis and tabes dorsalis first time was considered by Guillaume Duchenne a French neurologist in 1858. In 1875, Jean-Alfred Fournier a French dermatologist, firmly described the syphilis as the main cause of tabes dorsalis. In 1888, Sir William R. Gowers a British neurologist gave accurate details of the modern Romberg's test.

# Pathophysiology
It is understood that tabes dorsalis is caused by tertiary syphilis from treponema pallidum infection.
Tabes dorsalis is a manifestation of invasion of treponema pallidum spirochetes to the dorsal column of spinal cord in tertiary syphilis.
In tabes dorsalis, the preganglionic portion of the dorsal roots of spinal nerves is infiltrated with lymphocytes and plasma cells, and invasion of treponema pallidum spirochetes to posterior columns of the spinal cord makes it atrophic.
The demyelination of the axones of the neurons is the main cause of symptoms and it affects the neurons in the dorsal root ganglia and posterior columns of the spinal cord.

# Causes
Tabes dorsalis is a form of neurosyphilis, which is a complication of late or tertiary syphilis infection. Syphilis is a sexually transmitted infectious disease. The infection damages the spinal cord and peripheral nervous tissue.

# Differentiating Hereditary pancreatitis from Other Diseases
Tabes dorsalis must be differentiated from other diseases that cause lightning pains, impaired sensation, ataxia and unsteady gait, such as vitamin B12 deficiency, extrinsic spinal cord compression, vitamin E deficiency and multiple sclerosis.

# Epidemiology and Demographics
Tabes dorsalis is now very rare because syphilis is usually treated early in the disease.
In 2012, the incidence of syphilis was estimated to be 6 million cases worldwide. From year 2005 to 2014, the incidence of syphilis in the United States increased from 2.9 to 6.3 cases/100,000/year. The rate of reported cases increased by 15.1% between 2013 and 2014 in the United States. In 2012, the prevalence of syphilis was estimated to be approximately 18 million cases in men and women aged 15-29 worldwide. Among infected patients with Treponema pallidum only 3 to 5% develop neurosyphilis and only 5% of those individuals develop tabes dorsalis, 1020 years later.

# Risk Factors
The most potent risk factor in the development of tabes dorsalis is untreated syphilis infection. Tabes dorsalis is a form of neurosyphilis, which is a complication of late or tertiary syphilis infection. Syphilis is a sexually transmitted infectious disease. The infection damages the spinal cord and peripheral nervous tissue.

# Natural History, Complications, and Prognosis
The symptoms of tabes dorsalis usually develop secondary to long-term untreated syphilis, and start with symptoms such as lightning pains, impaired sensation and proprioception and hypesthesias. Common complications of tabes dorsalis include Dementia, stroke, eye disease, Paralysis, and Charcot arthropathy(Charcot joint).

# Diagnosis

## History and Symptoms
A positive history of unprotected sexual activity or an proved treponemal infection is suggestive of tabes dorsalis. The most common symptoms of tabes dorsalis include lightning pains, impaired sensation and proprioception, hypesthesias, diminished reflexes or loss of reflexes, Poor coordination or loss of coordination, Unsteady gait(locomotor ataxia), sexual function problems and progressive sensory ataxia(inability to feel the lower limbs).

## Physical Examination
Patients with tabes dorsalis usually appear normal. Physical examination of patients with tabes dorsalis is usually remarkable for: Argyll-Robertson pupils, impaired vibratory and proprioception sense, broad base and sensory ataxic gait and positive romberg's test.

## Laboratory Findings
Laboratory tests which may help diagnose syphilis include darkfield examinations and tests to detect T. pallidum in lesion exudate or tissue, PCR, nontreponemal (e.g., venereal disease research laboratory (VDRL) and rapid plasma reagent test) and treponemal tests (e.g., fluorescent treponemal antibody absorbed (FTA-ABS) tests, the T. pallidum passive particle agglutination (TP-PA) assay, various enzyme immunoassays, and chemiluminescence immunoassays).
Abnormalities in the CSF consistent with disease include; Pleocytosis, often lymphocytic predominant, mild protein elevation and positive CSF VDRL.

## CT scan
Spinal CT scan may be helpful in the diagnosis of tabes dorsalis. Findings on CT scan suggestive of of neurosyphilis include calcification in the soft tissues(posterior to the cord in cervical spine CT scan), ankylosis across the C45 disc and facet joints bilateral, areas of decreased density suggesting cerebral infarction, syphilitic gumma appear hypodense with precontrast, focal or diffuse extra-axial enhancement and non-specific white matter lesions.

## MRI
Spinal and brain MRI may be helpful in the diagnosis of tabes dorsalis. Findings on MRI suggestive of tabes dorsalis include, longitudinal T2-weighted hyperintensity in the dorsal columns of the spinal cord, narrowing between the cervical intervertebral discs and partial ankylosis of the cervical disc space, bilateral high intensity signals on the T2 weighted sequence located in mesiotemporal, insular, frontal regions, calcification of the ligamentum flavum.

# Treatment

## Medical Therapy
Penicillin, administered intravenously, is the treatment of choice of tabes dorsalis. Preventive treatment for those who come into sexual contact with an individual with tabes dorsalis is important. CNS involvement can occur during any stage of syphilis. However, CSF laboratory abnormalities are common in persons with early syphilis, even in the absence of clinical neurological findings. No evidence exists to support variation from recommended treatment for early syphilis for patients found to have such abnormalities. If clinical evidence of neurologic involvement is observed (e.g., cognitive dysfunction, motor or sensory deficits, ophthalmic or auditory symptoms, cranial nerve palsies, and symptoms or signs of meningitis), a CSF examination should be performed. Syphilitic uveitis or other ocular manifestations frequently are associated with neurosyphilis and should be managed according to the treatment recommendations for neurosyphilis. Patients who have neurosyphilis or syphilitic eye disease (e.g., uveitis, neuroretinitis, and optic neuritis) should be treated with the recommended regimen for neurosyphilis; those with eye disease should be managed in collaboration with an ophthalmologist. A CSF examination should be performed for all patients with syphilitic eye disease to identify those with abnormalities; patients found to have abnormal CSF test results should be provided follow-up CSF examinations to assess treatment response.  Associated pain can be treated with opiates, valproate, or carbamazepine. Patients may also require physical or rehabilitative therapy to deal with muscle wasting and weakness.

## Primary Prevention
There is no vaccine available for prevention of syphilis. However, effective measures for the primary prevention of syphilis include abstinence from intimate physical contact with an infected person, consistent use of latex condoms, limiting number of sexual partners, avoidance of sharing sex toys, practising safe sex, routine screening in pregnant females, individuals with high risk behaviours, and those residing in highly prevalent areas. In patients with diagnosed syphilis, early treatment with penicillin can completely prevent tabes dorsalis.

## Secondary Prevention
Secondary prevention strategies following syphilis include routine screening and follow up in patients with early syphilis to prevent complications, diagnosis and treatment of sexual partners of infected individuals, routine screening, diagnosis and treatment in pregnant females. In patients with diagnosed syphilis, early treatment with penicillin can completely prevent tabes dorsalis.