Tertiary syphilis. Pathomorphology of syphilitic specific inflammation (gumma). Visceral changes. Neurosyphilis.
Tertiary syphilis is the third stage of the above process, occurring over a year after an untreated infection in about ⅓ of patients. Complications related to this phase include three forms: Cardiovascular syphilis, Neurosyphilis and benign tertiary syphilis. These can occur together or separately.
Cardiovascular syphilis is specifically syphilitic aortitis, the most common of all complications. Syphilitic aortitis is inflammation of the aorta, beginning with the outermost layer (adventitia), SA worsens and affects the blood vessels that supply the aorta itself (vasa vasorum). Vasa vasorum undergoes hyperplastic thickening of wall and causes ischemia to outer ⅔ of the aortic media, this causes smooth muscle cells to die and leads to aortic aneurysms.
Remember: syphilitic aortitis affects the thoracic aorta (ascending part and arch). Endarteritis of the vasa vasorum with plasma cells destroys the media in patches, so the scarred intima looks wrinkled like "tree bark". Dilatation of the aortic root causes aortic valve insufficiency and can narrow the coronary ostia.
Neurosyphilis accounts for 10% of tertiary cases of syphilis, it is more common in those who are immunocompromised (e.g. HIV). The infection can produce chronic meningitis (meningovascular neurosyphilis), involving the base of the brain with an obliterative endarteritis rich in plasma cells and lymphocytes. We can also see parenchymal involvement, with loss of neurons and proliferation of microglia (rod cells). Clinical manifestations are loss of mental and physical function with severe dementia. Tabes dorsalis is another form of the disease, resulting from damage to sensory nerves in dorsal roots that produce impaired proprioception and ataxia, with loss of pain sensation.
Remember: tabes dorsalis damages the dorsal roots and posterior columns - loss of position and vibration sense, ataxia, lightning pains and painless destroyed (Charcot) joints. The Argyll Robertson pupil (small pupil that constricts on accommodation but not to light) is a classic sign of neurosyphilis.
Benign tertiary syphilis is marked by the formation of gumma at various sites, these are generally lesions on liver, bone, skin and mucous membrane of the upper airway, but can appear anywhere. There are rarely any spirochetes in these gummas, they are a form of granuloma, with a firm, necrotic center surrounded by inflamed tissue, with the center often become hyalinized prior to coagulative necrosis. Histologically, we see giant multinuclear cells, a peripheral zone with fibroblasts and capillaries, as well as our lymphoid and plasma cell invasion.