Learning objectives

• Describe ankylosing spondylitis
• Recognize the symptoms and signs of ankylosing spondylitis
• Anesthetic management of a patient with ankylosing spondylitis

Definition and mechanisms

• Ankylosing spondylitis (AS), autoimmune seronegative spondyloarthropathy, is a painful chronic inflammatory arthritis characterized by exacerbations (flares) and quiescent periods
• AS primarily affects the spine and sacroiliac joints, eventually causing fusion and rigidity of the spine → bamboo spine
• Joint mobility in the affected areas worsens over time
• The areas most commonly affected are
  • Sacroiliac joints
  • Vertebrae in the lower back
  • Places where tendons and ligaments attach to bones, mainly in the spine
  • Cartilage between the breastbone and the ribs (sternum)
  • Hip and shoulder joints
• Linked to HLA-B27 gene

Signs and symptoms

Symptoms might worsen (flares), improve, or stop at irregular intervals

• Chronic dull pain in the lower back or gluteal region combined with stiffness of the lower back, especially in the morning and after periods of inactivity
• Hip pain
• Joint pain
• Neck pain
• Fatigue
• Difficulty breathing
• Loss of appetite and unexplained weight loss
• Abdominal pain and diarrhea
• Skin rash
• Vision problems

Complications

• Spinal compression fractures
• Atlanto-axial subluxation possible (21% of AS patients)
• Eye inflammation (iritis or uveitis) and sensitivity to light (photophobia)
• Fused vertebrae (ankylosis)
• Kyphosis (forward curvature of the spine)
• Osteoporosis
• Cardiovascular abnormalities: Aortic insufficiency/aortitis, arrhythmias, angina, cardiomyopathy
• Respiratory abnormalities: Chest pain that affects breathing, restrictive disease, upper lobe fibrosis
• Jaw inflammation
• Cauda equina syndrome (rare)
• Patients with AS may also have psoriasis and/or inflammatory bowel disease

Extra-articular manifestations

Treatment

• Medications: Relieve pain and reduce inflammation
  • Non-steroidal anti-inflammatory drugs (NSAIDs): Ibuprofen and naproxen
  • Corticosteroids: i.v. methylprednisolone 
  • Disease-modifying anti-rheumatic drugs (DMARDs): Sulfasalazine 
  • TNF-α inhibitors: Infliximab, adalimumab, and etanercept
• Exercise: To reduce pain and stiffness
• Physical therapy: Improve comfort and spinal flexibility
• Surgery (rare): Repair significantly damaged joints or correct severe bends in the spine

Management

Obstetrical anesthesia

• Complicated due to difficult airway and difficult neuraxial techniques → have multiple plans in place
• Consider paramedian approach and ultrasound guidance for neuraxial anesthesia

Keep in mind

• AS is a challenge for the anesthesiologist because the rigid, immobile, fragile spine makes intubation, general anesthesia, and neuraxial anesthesia difficult
• Awake fiberoptic intubation is the safest method of securing the airway in AS patients, but supraglottic airway devices such as laryngeal masks can also be used
• The use of alternative approaches, such as the paramedian approach or the use of ultrasound guidance, may improve success with neuraxial anesthesia in AS patients

Suggested reading

• Pahwa D, Chhabra A, Arora MK. Anaesthetic management of patients with ankylosing spondylitis. Trends in Anaesthesia and Critical Care. 2013;3(1):19-24.
• Woodward LJ, Kam PC. Ankylosing spondylitis: recent developments and anaesthetic implications. Anaesthesia. 2009;64(5):540-548.