Infectious Disease · Treponema pallidum
The facts most likely to be tested
Tertiary syphilis manifests as gummas, which are granulomatous lesions that can cause destructive tissue necrosis in the skin, bone, or liver.
Cardiovascular syphilis typically presents as aortitis due to vasa vasorum endarteritis, leading to ascending aortic aneurysm and aortic regurgitation.
Neurosyphilis in the tertiary stage manifests as tabes dorsalis, characterized by demyelination of the dorsal columns and dorsal sensory nerve roots.
Patients with tabes dorsalis exhibit sensory ataxia, loss of proprioception and vibration sense, and Charcot joints (neuropathic arthropathy).
Argyll Robertson pupils are a pathognomonic finding in neurosyphilis, characterized by pupils that accommodate but do not react to light.
The diagnosis of neurosyphilis requires a reactive VDRL or RPR in the serum followed by a reactive CSF-VDRL, which is highly specific despite low sensitivity.
The treatment of choice for all stages of neurosyphilis is intravenous aqueous crystalline penicillin G administered for 10–14 days.
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A 62-year-old male presents to the clinic complaining of difficulty walking and shooting pains in his legs. Physical examination reveals wide-based gait, absent deep tendon reflexes in the lower extremities, and impaired vibration and position sense. On ophthalmologic exam, his pupils accommodate but fail to constrict to light. He has a history of an untreated genital ulcer 30 years ago.
What is the most likely diagnosis and the most appropriate diagnostic test to confirm the central nervous system involvement?
Tabes dorsalis (Tertiary Syphilis); CSF-VDRL
The patient's presentation of sensory ataxia and Argyll Robertson pupils is classic for tabes dorsalis, a form of neurosyphilis. The diagnosis is confirmed by a reactive CSF-VDRL test, which is highly specific for neurosyphilis.
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Etiology / Epidemiology
Occurs 1-20 years post-infection in untreated patients. High risk in HIV-positive individuals and those with inadequate primary/secondary treatment.
Clinical Manifestations
Presents as gummatous lesions, tabes dorsalis, or aortic regurgitation from aortitis.
Diagnosis
FTA-ABS is the confirmatory test. CSF VDRL is highly specific for neurosyphilis.
Treatment
Penicillin G is the only curative agent. Penicillin allergy requires desensitization.
Prognosis
Irreversible damage to CNS and cardiovascular systems. 100% mortality if untreated.
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Epidemiology & Etiology
Caused by the spirochete Treponema pallidum. Primarily affects patients who missed the latent phase diagnosis or received suboptimal antibiotic therapy. Incidence is rising in MSM populations and those with co-infection of HIV.
Pertinent Anatomy
Targets the vasa vasorum of the ascending aorta, leading to vessel wall necrosis. CNS involvement targets the dorsal columns of the spinal cord and the cranial nerves.
Pathophysiology
Chronic inflammation leads to gummas—granulomatous lesions that destroy soft tissue and bone. Cardiovascular damage results from obliterative endarteritis of the vasa vasorum. Neurosyphilis involves direct spirochete invasion of the parenchyma or meninges.
Clinical Manifestations
Patients present with gummas (necrotic granulomas), tabes dorsalis (dorsal column degeneration causing sensory ataxia and Argyll Robertson pupils), and general paresis. Cardiovascular signs include a wide pulse pressure and a diastolic murmur at the left sternal border. Sudden aortic dissection is a life-threatening complication.
Diagnosis
Screening with RPR or VDRL is often non-reactive in late stages; FTA-ABS or TP-PA are required for confirmation. If neurosyphilis is suspected, lumbar puncture is mandatory. A positive CSF VDRL is diagnostic, though sensitivity is low.
Treatment
Intravenous Penicillin G is the gold standard. Do not use oral antibiotics as they fail to achieve therapeutic CNS levels. Patients with a documented severe penicillin allergy must undergo desensitization in an inpatient setting.
Prognosis
Treatment halts progression but cannot reverse fibrotic or neurologic damage. Patients require serial RPR titers to monitor treatment response and ensure no serologic failure.
Differential Diagnosis
Neuroborreliosis: history of tick bite and erythema migrans
Multiple Sclerosis: relapsing-remitting course and MRI plaques
B12 Deficiency: subacute combined degeneration with macrocytic anemia
Aortic Stenosis: systolic murmur and exertional syncope
Sarcoidosis: hilar adenopathy and elevated ACE levels