Key facts:
Authors: Katharine Elliott and Andrew Stein
Top Tips: Missing this diagnosis can have devastating consequences; cauda equina lesions often missed
Key Differential Diagnoses
- Demyelination/transverse myelitis
- Parasagittal cranial meningioma
Key Investigations
- FBC, ESR, CRP
- Coagulation screen
- U+E, LFT, Bone, Glucose
- PSA, PEP, SFLC
- ECG, CXR
- MRI spine
Key Treatments
- IV/O DEXAMETHASONE 10 mg, then 4 mg qds for 2-4d
- ± Decompressive laminectomy
- ± Radiotherapy/chemotherapy (some malignancies)
- ± IV ANTIBIOTICS (eg, epidural abscess)
Key Management Decision
- MRI spine
Background
This is a medical and neurosurgical emergency. It is often missed, with devastating consequences to the patient. It usually presents first to general physicians. Urgent surgery and/or radiotherapy may be required
Introduction
- Early diagnosis and decompression is vital because prognosis depends primarily on severity of neurological deficit and duration of deficit before decompression (ie rather than benign/malignant). Ie, non malignant spinal cord compression can have devastating consequences of the patient; not just malignant spinal cord compression
- Neck pain or back pain are common presentations; symptoms related to the limb can be subtle; eg stiffness in both legs (UMN)
- But, uUntreated, irreversible loss of power and sensation at the level of the lesion can occur; then neurogenic bladder and bowel
- Metastatic disease is commonest cause. The commonest neoplastic causes are prostate, breast, and lung. Other causes include Non-Hodgkin’s lymphoma, myeloma, and kidney cancer
- Although most cases of SCC develop in patients who are known to have cancer, 20% of all cases arise as the initial manifestation of cancer
- Cauda equina lesions are often missed as leg weakness is less obvious
- Hours make a difference [Ref]
Definition
- Develops when the spinal cord is compressed by bone, soft tissue, infection or tumour
Causes
Benign
- Prolapsed intervertebral disc (especially cervical)
- Collapsed vertebral body (fracture)
- Cervical spondylosis
- Other:
- Infection: TB; epidural abscess (esp ESRF pts); discitis
- Intrinsic cord tumour; eg meningioma
- Haematoma; warfarin?
- Atlanto-axial subluxation
- Cyst (arachnoid, syringomyelia)
- Skeletal deformity (kyphoscoliosis); Cervical/lumbar stenoses
Malignant
- Primary (eg intrinsic cause tumour eg glioma)
- Secondary:
- Solid organ (eg carcinoma lung, breast, prostate, thyroid and kidney)
- Haematological (eg myeloma)
Note: metastatic disease is commonest cause
[Ref]
Symptoms
- Back pain
Note: back pain may precede leg weakness, and a sensory level; arm weakness often less severe than legs (suggests cervical lesion) - Weakness, and/or paraesthesia in arms/legs
- Difficulty in controlling urination/defecation (eg, hesitancy, frequency, later painless retention)
Note: enquire about symptoms of cause (eg breast lump, generalised bone pain)
Key questions
- "When did the back pain start, and is it different from your normal back pain?"
- "Do you have a history of cancer?"
- "When did you last pass urine, open your bowels, normally?"
Signs
Motor (60-85%; ie absence does not exclude diagnosis)
- Spastic paraparesis/tetraparesis (ie upper motor neurone weakness in arms /legs, below the level of the lesion)
Note: patients can have lower motor neurone signs at the level of the lesion; or mixed upper/lower motor neurone signs if lesion is partly lateral eg prolapsed disc
Sensory
- Sensory loss arms/legs (level?); abdominal reflexes may be lost if lesion is in/above thoracic cord
Note: Sensory level indicates the lowest possible level of neurological lesion, that can be anatomically 2+ vertebrae higher (much of cord is lower than the corresponding vertebral level) - Loss sensation in perineum (loss of sphincter control is ominous sign)
Note: look for signs of underlying cause (eg clubbing, breast, thyroid or kidney lump, malignant prostate)
Cauda equina lesions
- Spinal cord finishes at L1. Lesions below that may compress the spinal nerves of the cauda equina. Leg weakness is not as obvious as higher lesions, and low back (lumbosacral) pain occurs early, though not severe. May have antalgic gait
- Diagnosis depends on a high index of suspicion ie ask re perianal anaesthesia. Examine for perianal sensation and do a PR. Without Rx, flaccid, areflexic, often asymmetrical paraparesis, can occur; bladder/bowel dysfunction is late
- When diagnosis missed, litigation is common
Investigation
Contact your local neurosurgical centre ASAP, after thinking of diagnosis. If you cannot get a MRI very soon, don't delay referral
Blood
- FBC, ESR (myeloma), CRP
- Coagulation screen
- U+E, LFTs, Bone, Glucose
- PSA (Ca prostate)
- Protein electrophoresis, serum free light chains (myeloma)
Other
- Spinal XRs useful, but do not answer the question
- CXR (primary? TB?)
- CT head (eg to exclude parasagittal meningioma)
- MRI spine
Key investigation (MRI spine)
MRI is the most important investigation
Specialist investigations
- B12/folate (SACD)
- Parietal cell/intrinsic factor antibodies (SACD)
- Syphilis serology (TPHA/VDRL)
- Bone marrow aspirate
- Tumour markers
Differential diagnoses
Other causes of spastic paraparesis
- Demyelination/transverse myelitis
- Parasagittal cranial meningioma
- Subacute combined degeneration of cord
- Anterior spinal artery thrombosis
- Motor neurone disease
- Other: trauma, aortic dissection, carcinomatous meningitis, cord vasculitis (small vessel vasculitis, eg ANCA+; syphilis)
Treatment
Treatment (first line)
Drugs
- IV/O DEXAMETHASONE 10 mg, then 4 mg qds for 2-4d
- Analgesia
Procedures
- IV line (+ fluids, if dry)
- ± urinary catheter
Stop
- Warfarin/aspirin
Key management decisions
- MRI
- Decompressive laminectomy
Treatment (second line)
- Decompressive laminectomy
- ± radiotherapy (may be needed urgently)
- ± chemotherapy (may be needed urgently)
- ± IV ANTIBIOTICS (epidural abscess)
- ± Biphosphonates (in myeloma or breast cancer; to reduce pain and the risk of vertebral fracture/collapse)
Prescribing issues
- Dexamethasone is not a definitive treatment; what is following it?
Admit?
- Always
Bed plan
- Neurology or neurosurgery
Referrals
Medical
- Neurology/neurosurgery
Other
- Spinal rehabilitation
The Rest
Litigation is common if the diagnosis is missed. So, do not miss this diagnosis
Complications
- Autonomic dysfunction; if the sympathetic pathways involved (especially in high thoracic and cervical lesions) hypotension, bradycardia and cardiac arrest can occur; may be precipitated by pain, UTI or bladder/bowel dysfunction
- Of surgery
Prognosis
- Depends on severity of neurological deficit and duration of deficit before decompression (rather than benign/not)
- If paraplegia and sphincter involvement have occurred then recovery is uncommon
Don't forget
- To look at CXR and chase PSA/PEP
- To examine breasts, perineum and do a PR
- TB
- Spinal cord finishes opposite L1
- Malignant and non-malignant spinal cord compression are medical and neurosurgical emergencies
Red flags
- 3/5 weakness, or worse
- Loss of sphincter control
