Osmotic Demyelination Syndrome (ODS)
Cause
Rapid correction of hyponatremia
Affected Areas
Pons (CPM)
Thalamus
Extrapontine regions
Risk Factors
Chronic hyponatremia (>24 hrs)
Malnutrition
Alcoholism
Liver disease
Clinical Note
Symptoms may appear after initial improvement
SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion)
Essential Diagnostic Criteria
Serum
Effective serum osmolality <275 mOsm/kg
Effective osmolality = measured osmolality − (BUN / 2.8)
Urine
Urine osmolality >100 mOsm/kg
Urinary sodium >40 mEq/L (normal intake)
Volume Status
Clinically euvolemic
No orthostasis
No tachycardia
No dry mucosa
No edema or ascites
Exclusions
Normal renal function
Normal thyroid function
Normal adrenal function
No recent diuretic use
Ankylosing Spondylitis
Chronic inflammatory seronegative spondyloarthropathy primarily affecting the axial skeleton
Anatomy / Structural Changes
Progressive inflammation of:
1- Sacroiliac joints
2- Spine
Leads to:
1- Vertebral body squaring
2- Syndesmophyte formation
3- Progressive spinal rigidity
Characteristic Appearance
1- “Bamboo spine” due to fused vertebrae
2- Loss of normal spinal flexibility
Presentation, Diagnostic Features & Key Findings
Radiographic / Structural
1- Squared vertebral bodies
2- Syndesmophytes
3- “Bamboo spine”
4- Bilateral sacroiliitis
Genetic Association
HLA-B27 positive
Clinical Features
1- Chronic inflammatory back pain
2- Morning stiffness
3- Reduced spinal mobility
Treatment
Medical Management (Back Pain & Inflammation)
1- NSAIDs
2- Sulfasalazine
3- Immune-modulating medications (biologic agents)
Surgical Considerations — CAUTION
1- Airway management
2- Perform awake intubation
3- Rigid cervical spine increases risk during standard intubation
If instrumented fusion is required
Use long-segment fixation
Multiple fixation points recommended
Consider anterior and/or posterior instrumentation
Critical Reminder
Due to spinal rigidity:
Even minor trauma can cause severe spinal injury
Fracture-dislocation
High index of suspicion required in trauma patients
Atlanto Occiptal Dislocation: Cause, imaging, treatment
All what you need to know, in a simplified short video
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Where are they?
What is this angiogram showing?
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How do you differentiate between both?
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A decade long debate
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What are your thoughts?
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What is your differential diagnosis for this patient who is 55 coming with deterioration in lower limb neurology?
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A question for debate
Would you give much of your clinical work for management level work?
Is it worth it?
or not?





















