SPINAL ARACHNOIDITIS

Clinical syndrome

• Pain: Low back & radiating down both legs
• Weakness: One or multiple lumbar or sacral root distribution
• Sensory loss: One or multiple lumbar or sacral root distribution

Causes

• Spinal surgery: Especially multiple
• Chemical
  • Oil based radiographic contrast agents
  • Spinal drugs: Anesthetics; Steroids; Amphotericin B; Methotrexate
• Infections: Tuberculosis; Cryptococcosis; Syphilis; Viral
• Trauma: Vertebral injuries; Disc herniation
• Spinal subarachnoid hemorrhage

TOXIC MYELOPATHIES

Systemic

• Organophosphates: TOCP
  • Source: Contaminants in cooking oil or flour; Alcohol substitute
  • Myelopathy & polyneuropathy
  • Pathology: Distal axonal degeneration: CNS & PNS
• Iodochlorhydroxyquinoline (Clioquinol)
  • Source: Used as anti-diarrheal drug
  • Epidemiology: Predominantly in Japan
  • Clinical features
    • Myelopathy
      • Dose: Oral intake of 2 g/day for >3 weeks
      • Onset: Numbness & pain in legs
      • Signs: Decreased Sensation, especially vibration; Hyperesthesia; Leg weakness & stiffness (50%)
    • ± Optic neuropathy: Especially children
    • Course: Rapid onset; Slow recovery
• Nitrous oxide
• Source: Gas used in general anesthesia & Dental analgesia
• Some patients with associated cobalamin deficiency
• Myelopathy or polyneuropathy
• Onset: Delayed; 3 months to 5 years after exposure
• Prognosis: Slow, often incomplete recovery
• Substance abuse
• Heroin; ? Cocaine
• Anterior spinal artery syndrome
• Hexacarbons: Occasional delayed myelopathy
• Muzolimine
• Use: Diuretic
• Toxicity especially with renal insufficiency
• Myelopathy
• Polyneuropathy: Demyelination

Direct

• Angiographic contrast agents
• Myelographic contrast agents
  • Acute onset spinal cord irritability: Often transient
  • Arachnoiditis
• Chymopapain: Used to treat herniated discs
• Spinal anesthesia: ? direct toxic vs. vascular
• Chemotherapeutic agents: Methotrexate; Cytosine arabinoside
  • Often in patients treated with both systemic & intrathecal drugs
  • Onset: Acute (Hours) to Subacute
  • Increased Risk
    • More frequent treatments;
    • High cumulative dose
    • Concurrent methotrexate & cytarabine
    • Spinal radiotherapy
  • Pathology: 2 types
    • Spinal white matter: Peripheral cord; Lateral & posterior funiculi
    • Grey matter lesions
• Amphoterecin B
• Focal myelopathy
• Diffuse radiculopathy

RADIATION MYELOPATHY

Clinical: 4 syndromes; Dose related (> 4,000 rads)

• Transient sensory symptoms
  • Onset: 2 to 37 weeks after treatment
  • Lhermitte sign: Shock-like sensation after neck flexion
  • Course: resolution after 2 to 36 weeks
• Chronic progressive myelopathy
  • Onset: Mean 17 months after Rx; Range 3 months to 5 years
  • Asymmetric; Brown-Séquard syndrome
  • Course: Progression over months
  • Treatment: ? Anticoagulation
  • Pathology: Vasculopathy; White matter > Grey
• Acute transverse myelopathy
• Local amyotrophy: ? spinal lesion vs. radiculopathy

ELECTRICAL INJURY

Clinical

• Most often cervical
• < 1,000 volts: Predominantly anterior horn cell damage
• > 1,000 volts, or with burns near spinal cord: Lateral & posterior column damage
• Acutely: Associated encephalopathy
• Course: Progressive for few months or static

Pathology

• Perivascular & petechial hemorrhages