Neurosyphilis

Content of This Page

 1- Introduction

2- Causes

3- Symptoms

4- Investigations & Lab Results

5- Complications

6- Treatment

Introduction

Neurosyphilis is a severe manifestation of syphilis that occurs when the Treponema pallidum bacteria invades the central nervous system (CNS). It can develop at any stage of syphilis but is more commonly seen in late stages, particularly in untreated or inadequately treated individuals. Neurosyphilis can present with a wide range of neurological and psychiatric symptoms, ranging from asymptomatic inflammation to progressive cognitive decline, paralysis, and sensory disturbances. It is especially common in immunocompromised individuals, such as those with HIV. Early recognition and treatment with high-dose intravenous penicillin are crucial to prevent irreversible damage.

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Causes

Neurosyphilis is caused by infection of the central nervous system (CNS) by the bacterium Treponema pallidum, the same organism responsible for syphilis.

Key Contributing Factors:

  • Untreated or inadequately treated syphilis

    • Especially in the secondary or latent stages

  • Hematogenous spread of the organism to the brain and spinal cord

  • Immunocompromised states

    • Most notably HIV infection, which increases susceptibility and alters the course of neurosyphilis

  • Delayed diagnosis or lack of access to healthcare, allowing the infection to progress

© image from radiopaedia.org

Symptoms

1. Asymptomatic Neurosyphilis

  • No symptoms, but abnormal cerebrospinal fluid (CSF) findings (elevated WBCs, protein, or positive VDRL)

2. Meningeal Neurosyphilis (Early form)

  • Headache

  • Nausea and vomiting

  • Neck stiffness

  • Cranial nerve palsies (especially II, VI, VII, VIII)

3. Meningovascular Neurosyphilis

  • Stroke-like symptoms in young adults

  • Hemiparesis or other focal neurological deficits

  • Seizures

4. General Paresis (Paretic Neurosyphilis) – Late form

  • Personality changes

  • Progressive cognitive decline (dementia)

  • Delusions or hallucinations

  • Dysarthria, tremors, and eventual paralysis

5. Tabes Dorsalis – Late form

    • Ataxia (sensory gait)

    • Lightning-like pains (especially in the limbs)

    • Bladder and bowel dysfunction

    • Argyll Robertson pupils (small pupils that accommodate but don’t react to light)

    • Loss of deep tendon reflexes and proprioception

Investigations & Lab Results

1. Blood Tests

    • VDRL (Venereal Disease Research Laboratory test)

    • RPR (Rapid Plasma Reagin)

      Non-treponemal tests:

    • FTA-ABS (Fluorescent Treponemal Antibody Absorption)

    • TP-PA (Treponema pallidum particle agglutination)

    • Treponemal tests (confirmatory):

2. Lumbar Puncture and CSF Analysis

Indicated in:

  • Neurological or psychiatric symptoms

  • HIV-positive patients with late syphilis

  • Positive serum tests with suspected CNS involvement

-CSF Findings in Neurosyphilis:

  • Elevated protein (often > 45 mg/dL)

  • Lymphocytic pleocytosis (WBCs > 5 cells/μL)

  • Positive CSF VDRL (specific but not very sensitive)

  • Positive CSF FTA-ABS (sensitive but less specific)

3. Imaging (if focal symptoms or seizures)

  • MRI or CT of the brain

    • May show infarcts (in meningovascular neurosyphilis)

    • Generalized cerebral atrophy in late stages

    • Spinal cord atrophy in tabes dorsalis

Complications

  • Progressive neurological deterioration:
    Untreated neurosyphilis can cause irreversible brain and spinal cord damage.

  • General paresis:
    Severe dementia, personality changes, psychosis, and paralysis.

  • Tabes dorsalis:
    Damage to the dorsal columns leading to sensory ataxia, severe pain, and bladder dysfunction.

  • Stroke:
    From meningovascular involvement causing cerebral infarctions.

  • Cranial nerve palsies:
    Resulting in vision or hearing loss.

  • Seizures:
    Due to cortical irritation or infarcts.

  • Death:
    In advanced untreated cases due to neurological decline or complications.

 

Treatment

1. Antibiotic Therapy

  • First-line treatment:
    Aqueous crystalline penicillin G

    • Dose: 18–24 million units per day, administered IV every 4 hours or continuous infusion

    • Duration: 10–14 days

  • Alternative (if penicillin allergy):

    • Desensitization to penicillin is preferred.

    • If not possible, ceftriaxone 2 g IV or IM daily for 10–14 days can be used.

2. Supportive Care

  • Manage symptoms such as seizures, psychiatric manifestations, and neurological deficits.

  • Regular follow-up with clinical and CSF examinations to monitor treatment response.

3. Treatment of Sexual Partners

  • Sexual contacts should be evaluated and treated appropriately to prevent reinfection

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