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Emergency And Acute Medicine - Ankylosing Spondylitis
Core Overview: Ankylosing spondylitis (AS) is a chronic inflammatory condition that primarily targets the axial skeleton, with a strong predilection for the sacroiliac (SI) joints and spine (SI joints ~100%, cervical ~75%, thoracic ~70%, lumbosacral ~50%; hips and shoulders each ~30%). Inflammation begins at vertebral entheses (outer annulus fibrosus insertions); progressive ossification with syndesmophyte formation can lead to fusion (ankylosis) and the classic brittle “bamboo spine” appearance on imaging. Typical onset is age 15–35 years, with a male predominance (about 2–3:1). ALERT: Patients with AS have markedly increased risk of spinal fracture and paralysis—serious injury can occur after relatively minor trauma.
Risk Profile: Genetics are strongly associated with AS; HLA-B27 is present in roughly 80–90% of affected patients.
Likely Cause: AS is thought to be triggered by environmental factors (often presumed infectious exposures) in genetically predisposed individuals.
Clinical Presentation: The most common presentation is inflammatory low back pain with sacroiliitis—often worse with rest and improved with movement/exercise, and may wake the patient in the second half of the night. Because the spine may be rigid and brittle, patients are at higher risk for major injury from low-energy mechanisms. Extraspinal inflammatory manifestations may occur and sometimes precede spinal symptoms, including uveitis (common; often acute, unilateral, alternating), mild increased CAD risk and valvular disease over time, restrictive lung disease from limited chest expansion and fibrosis, GI associations (notably inflammatory bowel disease in a minority), and renal risks (IgA nephropathy/amyloidosis and NSAID-related nephropathy). Enthesitis is common, frequently presenting as Achilles tendinopathy or plantar fasciitis.
History And Examination: History often features insidious back pain for >3 months in patients <40 years, radiating into the gluteal region from si area and gradually involving more of spine; ask about prior uveitis, ibd, pulmonary restriction, enthesitis, or migrating />olyarthritis. On exam, SI joint tenderness may be reproduced with direct pressure over both ASIS simultaneously; additional findings can include enthesitis or dactylitis, loss of lumbar lordosis, increased thoracic kyphosis, reduced spinal mobility, and decreased chest expansion. Pediatric Note: Juvenile AS (often boys, late childhood/adolescence) may be mistaken for recurrent sprains; it more commonly involves extraspinal joints and lower-extremity entheses—look for asymmetric pauciarthritis and ankle/knee/tarsal enthesitis, plantar fasciitis, and Achilles tendinopathy.
Key Emergency Evaluation: In any patient with known or suspected AS who develops new spinal pain (even without clear trauma), prioritize exclusion of fracture and neurologic injury; also exclude sepsis or septic joint when clinically suspected. Sacroiliitis can be assessed with pelvic compression (“pelvic rock”) or Patrick/FABER-type maneuvers that stress the SI region.
Investigations And Interpretation: CBC may show mild leukocytosis, mild–moderate anemia, and thrombocytosis; BMP can help assess renal involvement, and ESR/CRP may be elevated but are not reliably decisive in the ED. HLA-B27 testing is typically arranged by specialists and a negative result does not exclude AS. Pelvic radiographs are appropriate when undiagnosed AS is suspected; early sacroiliitis may appear as iliac-side subchondral erosions that later progress to sclerosis and bony proliferation—if plain films are unrevealing and suspicion remains, MRI should be considered. For any new spinal pain, obtain spine imaging to exclude fracture; CT is often needed to further evaluate suspected fractures, and MRI is urgent when neurologic deficits are present. CXR may show apical fibrosis or patchy inflammatory changes. ECG is reasonable with ACS symptoms or arrhythmia concerns (including AV block), and echocardiography is indicated for a new murmur or new heart-failure evidence given the increased risk of aortic insufficiency over time.
Conditions To Distinguish From AS: Consider juvenile AS (onset <20 with more enthesitis />xtraspinal involvement), reactive arthritis, enteropathic arthritis (Crohn/UC-associated), psoriatic arthritis (rash; dactylitis), septic arthritis (arthrocentesis if suspected monoarthritis), mechanical low back pain (improves with rest; worsens with exertion; lacks systemic inflammatory features), spinal epidural abscess (often constant, severe, may have fever/IVDA/immunosuppression), and neoplastic back pain (older age, night pain, persistent/unremitting).
Prehospital Priorities: ALERT: Because minor trauma can cause unstable spinal injury, immobilization should avoid forcing the spine into a neutral position; cushioning and transport in the position of comfort (e.g., scoop stretcher with padding) may be safer than rigid collar/backboard alone. Anticipate difficult airway management due to cervical/TMJ limitation—fiberoptic techniques are often preferred; consider temporizing strategies (e.g., LMA or BVM with airway adjunct) until a definitive airway can be secured safely. Ventilation may be challenging due to chest-wall restriction and fibrosis, and CPR may carry higher rib-fracture risk.
Emergency Department Management: If cord compression is suspected, obtain MRI urgently. For any new spinal pain, aggressively evaluate for fracture—CT may be required even when initial radiographs are unrevealing. If infection is a concern, pursue labs and arthrocentesis as indicated. Treat pain and inflammation, typically starting with NSAIDs when appropriate.
Medications: Use nonselective NSAIDs such as ibuprofen, indomethacin (often limited by GI/CNS adverse effects), or naproxen; COX-2 inhibitors (e.g., celecoxib) can be considered, especially when GI bleeding risk is elevated. TNF-α inhibitors (e.g., adalimumab, etanercept) are disease-modifying options typically initiated in specialist care. In pregnancy, avoid NSAIDs when possible—use acetaminophen first-line and opioids second-line if needed. In older adults, weigh NSAID risks (CV, GI bleed, renal injury, hypertension) and consider gastroprotection (H2 blocker/PPI) or COX-2 selection when appropriate. If NSAIDs/acetaminophen are ineffective at appropriate doses, second-line options may include opioid analgesics, muscle relaxants, or short courses of low-dose steroids in select cases.
Disposition Planning: Admit for acute neurologic deficits, uncontrolled pain, or when sepsis/septic joint cannot be excluded. Discharge may be reasonable when serious injury and neurologic deficit have been ruled out and pain is controlled to a safe level.
Referral And Follow-Up: Encourage a medical alert bracelet due to high trauma risk. Arrange rheumatology referral for suspected new AS or for escalation to immunomodulating therapy, and consider physical medicine/rehab for splints and orthoses (e.g., heel cushioning to unload Achilles enthesis). Advise primary care reassessment within 1–2 weeks to gauge response, with earlier review for patients at higher risk of NSAID complications (elderly, hypertensive, high GI-bleed risk).
Clinical Tips And Common Traps: Anticipate a difficult airway and avoid neck repositioning because cervical instability and severe rigidity can make standard techniques hazardous—use airway adjuncts and pursue fiberoptic intubation when feasible. Immobilization should prioritize the patient’s position of comfort with padding rather than forcing standard collar/backboard alignment. Maintain high suspicion for fracture and cord injury after even low-energy trauma, as seemingly minor mechanisms can cause catastrophic spinal injury in AS.
Core Overview: Ankylosing spondylitis (AS) is a chronic inflammatory condition that primarily targets the axial skeleton, with a strong predilection for the sacroiliac (SI) joints and spine (SI joints ~100%, cervical ~75%, thoracic ~70%, lumbosacral ~50%; hips and shoulders each ~30%). Inflammation begins at vertebral entheses (outer annulus fibrosus insertions); progressive ossification with syndesmophyte formation can lead to fusion (ankylosis) and the classic brittle “bamboo spine” appearance on imaging. Typical onset is age 15–35 years, with a male predominance (about 2–3:1). ALERT: Patients with AS have markedly increased risk of spinal fracture and paralysis—serious injury can occur after relatively minor trauma.
Risk Profile: Genetics are strongly associated with AS; HLA-B27 is present in roughly 80–90% of affected patients.
Likely Cause: AS is thought to be triggered by environmental factors (often presumed infectious exposures) in genetically predisposed individuals.
Clinical Presentation: The most common presentation is inflammatory low back pain with sacroiliitis—often worse with rest and improved with movement/exercise, and may wake the patient in the second half of the night. Because the spine may be rigid and brittle, patients are at higher risk for major injury from low-energy mechanisms. Extraspinal inflammatory manifestations may occur and sometimes precede spinal symptoms, including uveitis (common; often acute, unilateral, alternating), mild increased CAD risk and valvular disease over time, restrictive lung disease from limited chest expansion and fibrosis, GI associations (notably inflammatory bowel disease in a minority), and renal risks (IgA nephropathy/amyloidosis and NSAID-related nephropathy). Enthesitis is common, frequently presenting as Achilles tendinopathy or plantar fasciitis.
History And Examination: History often features insidious back pain for >3 months in patients <40 years, radiating into the gluteal region from si area and gradually involving more of spine; ask about prior uveitis, ibd, pulmonary restriction, enthesitis, or migrating />olyarthritis. On exam, SI joint tenderness may be reproduced with direct pressure over both ASIS simultaneously; additional findings can include enthesitis or dactylitis, loss of lumbar lordosis, increased thoracic kyphosis, reduced spinal mobility, and decreased chest expansion. Pediatric Note: Juvenile AS (often boys, late childhood/adolescence) may be mistaken for recurrent sprains; it more commonly involves extraspinal joints and lower-extremity entheses—look for asymmetric pauciarthritis and ankle/knee/tarsal enthesitis, plantar fasciitis, and Achilles tendinopathy.
Key Emergency Evaluation: In any patient with known or suspected AS who develops new spinal pain (even without clear trauma), prioritize exclusion of fracture and neurologic injury; also exclude sepsis or septic joint when clinically suspected. Sacroiliitis can be assessed with pelvic compression (“pelvic rock”) or Patrick/FABER-type maneuvers that stress the SI region.
Investigations And Interpretation: CBC may show mild leukocytosis, mild–moderate anemia, and thrombocytosis; BMP can help assess renal involvement, and ESR/CRP may be elevated but are not reliably decisive in the ED. HLA-B27 testing is typically arranged by specialists and a negative result does not exclude AS. Pelvic radiographs are appropriate when undiagnosed AS is suspected; early sacroiliitis may appear as iliac-side subchondral erosions that later progress to sclerosis and bony proliferation—if plain films are unrevealing and suspicion remains, MRI should be considered. For any new spinal pain, obtain spine imaging to exclude fracture; CT is often needed to further evaluate suspected fractures, and MRI is urgent when neurologic deficits are present. CXR may show apical fibrosis or patchy inflammatory changes. ECG is reasonable with ACS symptoms or arrhythmia concerns (including AV block), and echocardiography is indicated for a new murmur or new heart-failure evidence given the increased risk of aortic insufficiency over time.
Conditions To Distinguish From AS: Consider juvenile AS (onset <20 with more enthesitis />xtraspinal involvement), reactive arthritis, enteropathic arthritis (Crohn/UC-associated), psoriatic arthritis (rash; dactylitis), septic arthritis (arthrocentesis if suspected monoarthritis), mechanical low back pain (improves with rest; worsens with exertion; lacks systemic inflammatory features), spinal epidural abscess (often constant, severe, may have fever/IVDA/immunosuppression), and neoplastic back pain (older age, night pain, persistent/unremitting).
Prehospital Priorities: ALERT: Because minor trauma can cause unstable spinal injury, immobilization should avoid forcing the spine into a neutral position; cushioning and transport in the position of comfort (e.g., scoop stretcher with padding) may be safer than rigid collar/backboard alone. Anticipate difficult airway management due to cervical/TMJ limitation—fiberoptic techniques are often preferred; consider temporizing strategies (e.g., LMA or BVM with airway adjunct) until a definitive airway can be secured safely. Ventilation may be challenging due to chest-wall restriction and fibrosis, and CPR may carry higher rib-fracture risk.
Emergency Department Management: If cord compression is suspected, obtain MRI urgently. For any new spinal pain, aggressively evaluate for fracture—CT may be required even when initial radiographs are unrevealing. If infection is a concern, pursue labs and arthrocentesis as indicated. Treat pain and inflammation, typically starting with NSAIDs when appropriate.
Medications: Use nonselective NSAIDs such as ibuprofen, indomethacin (often limited by GI/CNS adverse effects), or naproxen; COX-2 inhibitors (e.g., celecoxib) can be considered, especially when GI bleeding risk is elevated. TNF-α inhibitors (e.g., adalimumab, etanercept) are disease-modifying options typically initiated in specialist care. In pregnancy, avoid NSAIDs when possible—use acetaminophen first-line and opioids second-line if needed. In older adults, weigh NSAID risks (CV, GI bleed, renal injury, hypertension) and consider gastroprotection (H2 blocker/PPI) or COX-2 selection when appropriate. If NSAIDs/acetaminophen are ineffective at appropriate doses, second-line options may include opioid analgesics, muscle relaxants, or short courses of low-dose steroids in select cases.
Disposition Planning: Admit for acute neurologic deficits, uncontrolled pain, or when sepsis/septic joint cannot be excluded. Discharge may be reasonable when serious injury and neurologic deficit have been ruled out and pain is controlled to a safe level.
Referral And Follow-Up: Encourage a medical alert bracelet due to high trauma risk. Arrange rheumatology referral for suspected new AS or for escalation to immunomodulating therapy, and consider physical medicine/rehab for splints and orthoses (e.g., heel cushioning to unload Achilles enthesis). Advise primary care reassessment within 1–2 weeks to gauge response, with earlier review for patients at higher risk of NSAID complications (elderly, hypertensive, high GI-bleed risk).
Clinical Tips And Common Traps: Anticipate a difficult airway and avoid neck repositioning because cervical instability and severe rigidity can make standard techniques hazardous—use airway adjuncts and pursue fiberoptic intubation when feasible. Immobilization should prioritize the patient’s position of comfort with padding rather than forcing standard collar/backboard alignment. Maintain high suspicion for fracture and cord injury after even low-energy trauma, as seemingly minor mechanisms can cause catastrophic spinal injury in AS.
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