What are the typical symptoms and physical signs of neurosyphilis?

Neurosyphilis: Clinical Presentation

Neurosyphilis presents with a highly variable spectrum of neurological and psychiatric symptoms, most commonly including personality changes, cognitive dysfunction, headache, pupillary abnormalities, gait disturbances, and ocular manifestations—with ophthalmological symptoms now representing the predominant presentation in early neurosyphilis. 1, 2

Cardinal Symptoms

Neurological Manifestations

• Cognitive and psychiatric symptoms are the most common presentation of late neurosyphilis, including personality changes, confusion, disorientation, impaired memory, and bizarre behavior 3, 4
• Headache occurs in approximately 33-57% of patients with early neurosyphilis 3, 5
• Gait disturbances and ataxia are present in 71% of cases, often due to cerebellar involvement or tabes dorsalis 3, 6
• Seizures occur in approximately 29% of patients 3
• Stroke-like episodes from syphilitic vasculitis with lacunar infarctions 3
• Movement disorders including parkinsonism (18.4%), choreiform movements (15.8%), and dystonia (15.8%) 6

Cranial Nerve Involvement

• Pupillary abnormalities are the most important diagnostic sign, present in 71% of cases—including Argyll Robertson pupils (small, irregular pupils that accommodate but do not react to light) 3, 1
• Hearing loss and tinnitus occur in 22-43% of patients 3, 5
• Visual complaints including diplopia and visual loss 3
• Cranial nerve palsies, particularly affecting the second (optic) and sixth (abducens) nerves 3, 1

Ocular Manifestations (Critical Recognition)

• Ophthalmological symptoms are now present in 65-80% of all neurosyphilis cases, representing a major shift in disease presentation 2, 7
• Uveitis (posterior and panuveitis most common) is the predominant ocular finding 7
• Neuroretinitis and optic neuritis are frequently associated with neurosyphilis 8, 9
• Syphilitic eye disease should always prompt CSF examination regardless of other findings, as 10-60% will have concurrent CSF abnormalities 7

Sensory and Motor Deficits

• Hemiparesis or paraparesis in 57% of cases 3
• Hypesthesia for light touch and impaired position sense 3
• Lancinating (shooting) pains characteristic of tabetic neurosyphilis 4
• Loss of sphincter control in severe cases 3

Psychiatric Symptoms

• Mood disorders including depression and hypomania in 43% 3
• Forgetfulness and cognitive decline 3, 10
• Insidious onset of personality changes is the typical presentation, often mistaken for primary psychiatric illness 10

Physical Examination Findings

Key Neurological Signs

• Pupillary changes (71% of cases)—the single most important physical finding pointing to neurosyphilis 3
• Cerebellar signs including ataxia, dysmetria, and intention tremor (57%) 3
• Dysarthria (43%) 3
• Tremor of tongue and hands (43%) 3
• Positive release signs indicating frontal lobe dysfunction 3
• Orofacial "candy sign" (repetitive chewing movements) in 7.9% of movement disorder cases 6

Meningeal Signs

• Meningismus may be present in acute syphilitic meningitis 1, 8
• Signs of increased intracranial pressure in cases with hydrocephalus 6

Clinical Syndromes and Timing

Early Neurosyphilis (Most Common in Modern Era)

• Occurs within the first 1-2 years of infection 2
• Represents 75% of all neurosyphilis cases in contemporary series 2
• Predominantly presents with ocular symptoms (80% of early cases) 2
• Neurological symptoms occur in 47% of early cases, with 26% having both ocular and neurological manifestations 2

Late (Tertiary) Neurosyphilis

• General paresis: progressive dementia, personality changes, tremor 4
• Tabes dorsalis: lancinating pains, ataxia, loss of position sense, Argyll Robertson pupils 4
• Meningovascular syphilis: stroke-like presentations from arteritis 3, 4

Asymptomatic Neurosyphilis

• 27.8% of neurosyphilis cases may be completely asymptomatic 5
• Detected only through CSF examination in high-risk patients (HIV-infected, high serum RPR titers ≥1:32) 11, 5

Critical Clinical Pitfalls

Common diagnostic errors include:

• Attributing symptoms solely to psychiatric illness without considering neurosyphilis, particularly in patients with personality changes 10
• Failing to examine pupils carefully—pupillary abnormalities are the most reliable physical sign 3
• Missing ocular syphilis by not performing ophthalmologic examination in all syphilis patients with any visual complaints 8, 7
• Assuming absence of symptoms excludes neurosyphilis—asymptomatic cases are common, especially in HIV-infected patients 5, 11
• Overlooking neurosyphilis in patients with movement disorders that mimic Parkinson's disease, progressive supranuclear palsy, or autoimmune encephalitis 6

High-Risk Populations Requiring Enhanced Vigilance

• HIV-infected patients with CD4 counts ≤350 cells/µL have increased risk of CNS involvement 11
• Patients with serum RPR titers ≥1:32 consistently show higher likelihood of neurosyphilis 7, 11
• Men who have sex with men (MSM) represent the majority (90%) of contemporary neurosyphilis cases 2
• Any patient with syphilis presenting with neurological, psychiatric, or ophthalmologic symptoms should be presumed to have neurosyphilis until proven otherwise 1, 8