Medication Summary
Appropriate analgesia should be provided for a patient with cauda equina syndrome. Anti-inflammatory medication may prevent worsening of injury. Anticoagulants provide prophylaxis against thrombotic complications. Use of antispasticity medications to reduce muscle tone is encouraged. Bisphosphonates may be beneficial in patients with bony lesions. Phosphodiesterase type 5 inhibitors treat erectile dysfunction (ED).
Corticosteroids
Class Summary
These agents have anti-inflammatory properties and cause profound and varied metabolic effects. Corticosteroids modify the body's immune response to diverse stimuli.
Methylprednisolone (DepoMedrol, Medrol, Medrol Dosepak)
This agent decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability. This prevents further worsening of injury.
Treatment must be started within 8 h of injury; treatment apparently has no benefit if started later than 8 h after injury. Late treatment may have detrimental effects.
Anticoagulants
Class Summary
These agents are taken as prophylaxis for deep venous thrombosis and/or pulmonary embolism.
Heparin
Heparin augments the activity of antithrombin III and prevents conversion of fibrinogen to fibrin. It does not actively lyse clot but is able to inhibit further thrombogenesis. It prevents re-accumulation of clot after spontaneous fibrinolysis. Administer low dose.
Skeletal Muscle Relaxants
Class Summary
These agents are thought to work centrally by suppressing conduction at the spinal level.
Baclofen (Lioresal, Gablofen)
Baclofen may induce hyperpolarization of afferent terminals and inhibit both monosynaptic and polysynaptic reflexes at the spinal level.
Dantrolene (Dantrium, Revonto)
Dantrolene stimulates muscle relaxation by modulating skeletal muscle contractions at sites beyond the myoneural junction and acting directly on muscle itself. It prevents calcium release from sarcoplasmic reticulum.
Benzodiazepines
Class Summary
These agents may act in the spinal cord to induce muscle relaxation.
Diazepam (Diastat, Valium)
Diazepam depresses all levels of the CNS (eg, limbic and reticular formation), possibly by increasing activity of gamma-aminobutyric acid (GABA). Individualize dosage and increase cautiously to avoid adverse effects.
Alpha 2-adrenergic Agonist Agents
Class Summary
These agents may reduce sympathetic outflow, which may produce a reduction in muscle tone.
Clonidine (Catapres)
Clonidine stimulates alpha2-adrenoreceptors in the brain stem, activating an inhibitory neuron, which in turn results in reduced sympathetic outflow.
Tizanidine (Zanaflex)
Tizanidine is a centrally acting muscle relaxant that is metabolized in the liver and excreted in urine and feces.
Neuromuscular Blocker Agent, Toxin
Class Summary
These agents inhibit transmission of impulses in neuromuscular tissue.
OnabotulinumtoxinA (BOTOX)
This agent binds to receptor sites on motor nerve terminals and inhibits release of acetylcholine, which in turn inhibits transmission of impulses in neuromuscular tissue.
It is most useful for treating spasticity in the gastrocnemius and soleus muscles; less effective in larger muscles such as quadriceps. Re-examine patients 7-14 d after initial dose, to assess for response. It may be repeated q3-4mo.
Also indicated for urinary incontinence in patients with neurologic conditions (eg, spinal cord injury, multiple sclerosis) in adults who have an inadequate response to or are intolerant of an anticholinergic medication. Intradetrusor injections are administered about every 9 months.
Bisphosphonate Derivatives
Class Summary
These agents are analogs of pyrophosphate. They act by binding to hydroxyapatite in bone-matrix, thereby inhibiting the dissolution of crystals. They prevent osteoclast attachment to the bone matrix and osteoclast recruitment and viability.
Etidronate disodium
Etidronate inhibits normal and abnormal bone resorption. It appears to inhibit bone resorption without inhibiting bone formation and mineralization.
Alendronate (Fosamax, Binosto)
Alendronate inhibits bone resorption via actions on osteoclasts or osteoclast precursors. It is used to treat osteoporosis in both men and women and it may reduce bone resorption and incidence of fracture at spine, hip, and wrist by approximately 50%. Alendronate should be taken with a large glass of water, at least 30 min before eating and drinking, to maximize absorption. Because of possible esophageal irritation, patients must remain upright after taking the medication. Since it is renally excreted, it is not recommended in patients with moderate-to-severe renal insufficiency (ie, CrCl < 30 mL/min or CrCl >3.0 mg/dL), thus its use in perirenal transplantation is limited.
Ibandronate (Boniva)
Ibandronate inhibits osteoclast-mediated bone resorption. In postmenopausal women, it reduces bone turnover rate, leading to a net gain in bone mass.
Phosphodiesterase (type 5) Enzyme Inhibitors
Class Summary
These agents increase the vasodilatory effects of nitric oxide by inhibiting the enzyme phosphodiesterase type 5, which in turn increases sensitivity for erections.
Sildenafil (Viagra)
Sildenafil is a phosphodiesterase type 5 (PDE5) selective inhibitor. Inhibition of PDE5 increases the activity of cyclic guanosine monophosphate (cGMP), which increases the vasodilatory effects of nitric oxide. This agent is effective in men with mild-to-moderate ED.
Vardenafil (Levitra, Staxyn)
Vardenafil is a PDE5 selective inhibitor. Inhibition of PDE5 increases cGMP activity, which increases the vasodilatory effects of nitric oxide. It is effective in men with mild-to-moderate ED.
Take on an empty stomach about 1 h before sexual activity. Sexual stimulation is necessary to activate response. Increased sensitivity for erections may last 24 h. Vardenafil is available as 2.5-mg, 5-mg, 10-mg, and 20-mg tabs.
Tadalafil (Cialis)
Tadalafil is a PDE5 selective inhibitor. Inhibition of PDE5 increases cGMP activity, which increases the vasodilatory effects of nitric oxide. Sexual stimulation is necessary to activate response. Increased sensitivity for erections may last 36 h. Tadalafil is available as 2.5-mg, 5-mg, 10-mg, and 20-mg tabs.
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Muscle groups, surface anatomy, peripheral sensory innervation, and dermatomes of the anterior lower limb. This image should be correlated with Tables 1 and 2 in the text. Image courtesy of Nicholas Y. Lorenzo, MD.
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Muscle groups, surface anatomy, peripheral sensory innervation, and dermatomes of the posterior lower limb. This image should be correlated with Tables 1 and 2 in the text. Image courtesy of Nicholas Y. Lorenzo, MD.
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Conus/epiconus infarction in the setting of sickle cell crisis. Image courtesy of Matthew J. Baker, MD.
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Conus/epiconus infarction in the setting of sickle cell crisis in the same patient shown in the above image. Image courtesy of Matthew J. Baker, MD.
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Conus/epiconus infarction in the setting of sickle cell crisis in the same patient shown in the images above. Image courtesy of Matthew J. Baker, MD.
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Illustration demonstrating the relevant anatomy of the cauda equina region.
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Illustration demonstrating an example of cauda equina syndrome secondary to a spinal neoplasm.
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Sagittal MRI of a patient with cauda equina syndrome secondary to a large lumbar disk herniation.
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Epidural abscess with effacement of thecal sac in a 56-year-old man.
Tables
|
Conus Medullaris Syndrome |
Cauda Equina Syndrome |
Presentation |
Sudden and bilateral |
Gradual and unilateral |
Reflexes |
Knee jerks preserved but ankle jerks affected |
Both ankle and knee jerks affected |
Radicular pain |
Less severe |
More severe |
Low back pain |
More |
Less |
Sensory symptoms and signs |
Numbness tends to be more localized to perianal area; symmetrical and bilateral; sensory dissociation occurs |
Numbness tends to be more localized to saddle area; asymmetrical, may be unilateral; no sensory dissociation; loss of sensation in specific dermatomes in lower extremities with numbness and paresthesia; possible numbness in pubic area, including glans penis or clitoris |
Motor strength |
Typically symmetric, hyperreflexic distal paresis of lower limbs that is less marked; fasciculations may be present |
Asymmetric areflexic paraplegia that is more marked; fasciculations rare; atrophy more common |
Impotence |
Frequent |
Less frequent; erectile dysfunction that includes inability to have erection, inability to maintain erection, lack of sensation in pubic area (including glans penis or clitoris), and inability to ejaculate |
Sphincter dysfunction |
Urinary retention and atonic anal sphincter cause overflow urinary incontinence and fecal incontinence; tend to present early in course of disease |
Urinary retention; tends to present late in course of disease |
Nerve Root |
Pain |
Sensory Deficit |
Motor Deficit |
Reflex Deficit |
L2 |
Anterior medial thigh |
Upper thigh |
Slight quadriceps weakness; hip flexion; thigh adduction |
Slightly diminished suprapatellar |
L3 |
Anterior lateral thigh |
Lower thigh |
Quadriceps weakness; knee extension; thigh adduction |
Patellar or suprapatellar |
L4 |
Posterolateral thigh, anterior tibia |
Medial leg |
Knee and foot extension |
Patellar |
L5 |
Dorsum of foot |
Dorsum of foot |
Dorsiflexion of foot and toes |
Hamstrings |
S1-2 |
Lateral foot |
Lateral foot |
Plantar flexion of foot and toes |
Achilles |
S3-5 |
Perineum |
Saddle |
Sphincters |
Bulbocavernosus; anal |
Muscle |
Nerve |
Root |
Iliopsoas |
Femoral |
L2, 3, 4 |
Adductor longus |
Obturator |
L2, 3, 4 |
Gracilis |
Obturator |
L2, 3, 4 |
Quadriceps femoris |
Femoral |
L2, 3, 4 |
Anterior tibial |
Deep peroneal |
L4, 5 |
Extensor hallucis longus |
Deep peroneal |
L4, 5 |
Extensor digitorum longus |
Deep peroneal |
L4,5 |
Extensor digitorum brevis |
Deep peroneal |
L4, 5, S1 |
Peroneus longus |
Superficial peroneal |
L5, S1 |
Internal hamstrings |
Sciatic |
L4, 5, S1 |
External hamstrings |
Sciatic |
L5, S1 |
Gluteus medius |
Superior gluteal |
L4, 5, S1 |
Gluteus maximus |
Inferior gluteal |
L5, S1, 2 |
Posterior tibial |
Tibial |
L5, S1 |
Flexor digitorum longus |
Tibial |
L5, S1 |
Abductor hallucis brevis |
Tibial (medial plantar) |
L5, S1, 2 |
Abductor digiti quinti pedis |
Tibial (lateral plantar) |
S1, 2 |
Gastrocnemius lateral |
Tibial |
L5, S1, 2 |
Gastrocnemius medial |
Tibial |
S1, 2 |
Soleus |
Tibial |
S1, 2 |
Features |
Cauda Equina Syndrome |
Conus Medullaris |
Vertebral level |
L2-sacrum |
L1-L2 |
Spinal level |
Injury to the lumbosacral nerve roots |
Injury of the sacral cord segment (conus and epiconus) and roots |
Severity of symptoms and signs |
Usually severe |
Usually not severe |
Symmetry of symptoms and signs |
Usually asymmetric |
Usually symmetric |
Pain |
Prominent, asymmetric, and radicular |
Usually bilateral and in the perineal area |
Motor |
Weakness to flaccid paralysis |
Normal motor function to mild or moderate weakness |
Sensory |
Saddle anesthesia, may be asymmetric |
Symmetric saddle distribution, sensory loss of pin prick, and temperature sensations (Tactile sensation is spared.) |
Reflexes |
Areflexic lower extremities; bulbocavernosus reflex is absent in low CE (sacral) lesions |
Areflexic lower extremities (If the epiconus is involved, patellar reflex may be absent, whereas bulbocavernosus reflex may be spared.) |
Sphincter and sexual function |
Usually late and of lesser magnitude; lower sacral roots involvement can cause bladder, bowel, and sexual dysfunction |
Early and severe bowel, bladder, and sexual dysfunction that results in a reflexic bowel and bladder with impaired erection in males |
EMG |
Multiple root level involvement; sphincters may also be involved |
Mostly normal lower extremity with external anal sphincter involvement |
Outcome |
May be favorable compared with conus medullaris syndrome |
The outcome may be less favorable than in patients with CES |
