Intern Report 6.2

Case Presentation by Dr. Mike Antoniolli

Chief Complaint: “I can’t walk” 

History of Present Illness

This is a 60-year-old male with PMH of Multiple Myeloma on chemotherapy and HTN who presents to the ED with a 3-day history of bilateral lower extremity weakness.  He reports waking up 3 days ago with difficulty walking.  He states that his legs kept “giving out”, requiring him to use a cane to ambulate.  He says that he went to an outside hospital 3 days ago and underwent spine radiographs for severe back pain and was subsequently discharged. He has a history of chronic low back pain, but says that the pain is much worse the past 3 days.  The pain is midline and is exacerbated by movement.  He denies any loss of bowel or bladder continence, but notes urinary urgency and frequency.  He also describes a shooting sensation that travelled up and down his back when he was moved abruptly by EMS.  He denies headache, fever, nausea, vomiting, or altered mentation.

Review of Systems

Constitutional:  No fever, No chills.

Eye:  No recent visual problem, No blurring, No double vision.

Ear/Nose/Mouth/Throat:  No decreased hearing, No nasal congestion, No sore throat.

Respiratory:  No shortness of breath, No cough.

Cardiovascular:  No chest pain, No palpitations.

Gastrointestinal:  No nausea, No vomiting, No diarrhea, No abdominal pain.

Hematology/Lymphatics:  No bruising or bleeding tendencies

Musculoskeletal: Low back pain

Integumentary:  No rash, No abrasions.

Neurologic: +LE Weakness. No abnormal balance, No confusion, No numbness, No tingling.

 

PMH:  Multiple myeloma (diagnosed 2 years ago) s/p chemotherapy and radiation- still on chemo, HTN (patient believes this resolved after weight loss, but he is on multiple medications and is unsure if any of these are for hypertension).

Meds:  Multiple medications, patient is unaware of names

Allergies: No known allergies

PSH: Denies

SH: No tobacco, occasional alcohol, and occasional marijuana

FH: HTN, DM, CAD

Physical Examination

Vitals:  35.0, 150/59 (89), 66, 18, 99% RA

General:  Alert and oriented, no acute distress

Eye:  Pupils are equal, round and reactive to light, Extraocular movements are intact.

HENT:  Atraumatic/Normocephalic, Oral mucosa is moist.

Neck:  Supple, Non-tender, No jugular venous distention, No lymphadenopathy.

Respiratory:  Lungs are clear to auscultation, Respirations are non-labored, Breath sounds are equal.

Cardiovascular:  Normal rate, Regular rhythm, No murmur, 2+ radial/DP/PT bilaterally

Gastrointestinal:  Soft, Non-tender, Non-distended, Normal bowel sounds.  No organomegaly or pulsatile mass.  Decreased anal sphincter tone.

Musculoskeletal:  Patient is tender to palpation along the lumbar spinous processes, not extending laterally.

Integumentary:  Warm, Dry.  No rashes, ecchymosis, or petechiae

Neurologic:  Alert and Oriented to person, place, and time. Patient is unable to raise legs off of bed or keep legs elevated after being passively raised.  Hip flexion strength is 1/5 bilaterally, Knee flexion is 3/5, Plantarflexion/dorsiflexion of the foot is 4/5 bilaterally.  Strength in the upper extremities is 5/5 throughout.  Sensation to light touch is intact throughout.  Reflexes are diminished throughout.  Cranial nerves intact, no focal deficits.

Cognition and Speech:  Speech is clear and coherent.

Review / Management

Laboratory Results:

BNP:

137/3.5| 99/32| 31/2.2<143

Ca2+: 15.7

 CBC:

6.3> 11.8/33.8<185

Imaging Studies:

CT Head: Calvarial masses consistent with multiple myeloma

CT Lumbar Spine:  Innumerable lytic lesions throughout the lumbar vertebra

Questions:

1)    Which of the following must be considered first as a cause of this patient’s weakness?

a) Neoplastic epidural spinal cord compression (cauda equina)

b) Severe hypercalcemia

c)     Amyotrophic lateral sclerosis

d)    Sensorimotor peripheral neuropathy

e)     Neuromuscular junction disease

f)     Inflammatory myopathy

2)     What is the initial treatment for patients with symptomatic hypercalcemia?

a)     Thiazide Diuretics

b)    Calcium channel blockers

c)     IV hydration with normal saline

d)    Vitamin D

e)     Magnesium

3)     What else should be administered to this patient to correct his calcium?

a)     Pamidronate and calcitonin

b)    Vasopressin and Vitamin D

c)     Sodium bicarbonate and Dextrose

d)    Hydroclorthiazide, after restoration of intravascular volume

e)     Magnesium and KCl

 

Answers 

1)    Which of the following must be considered first as a cause of this patient’s weakness?

a.     Neoplastic epidural spinal cord compression (cauda equina)

-Although hypercalcemia can cause hyporeflexia and muscle weakness, spinal cord compression is a neurosurgical emergency and requires immediate attention.  Also, hypercalcemia typically causes diffuse muscle weakness, and so would not explain the patient’s localized symptoms.

2)    What is the initial treatment for patients with symptomatic hypercalcemia?

c.     IV hydration with normal saline

– Treatment for hypercalcemia should be initiated in any symptomatic patient, or if Ca2+ is >14 milligrams/dL. Treatment consists of volume repletion with normal saline (as these patients are volume depleted secondary to impaired renal tubular reabsorption of water), decreasing Ca2+ mobilization from bone, and correction of the underlying disorder.

It’s important to note that both a bisphosphonate and calcitonin (question 4) are part of the initial treatment as well.  Also, diuretics are still commonly employed in the treatment of hypercalcemia; however, there is no direct evidence to support the common practice of using loop diuretics to enhance Ca2+ elimination. In fact, because hypercalcemia itself results in hypokalemia and hypomagnesemia from renal wasting, diuretics (which can worsen volume depletion, hypokalemia, and hypomagnesemia) are no longer recommended for malignancy-related hypercalcemia.  If loop diuretics are to be used, it is important that the patient is adequately hydrated first.  Thiazide diuretics must be avoided at all times, as these will result in increased serum calcium.

3)    What else should be administered to this patient to correct his calcium?

a.     Pamidronate and calcitonin

See question 3 explanation

Bonus Question:

What imaging study should be obtained as soon as possible?

MRI entire spinal cord

See discussion for explanation

 

Follow up:

Neurosurgery was consulted for possible acute spinal cord compression. Initially, an MRI of the lumbosacral spine was obtained that revealed diffuse lesions consistent with multiple myeloma throughout the lumbosacral vertebrae; however, it did not reveal any compressive or infiltrative lesions.  At that time, neurosurgery believed that hypercalcemia might have been the cause of the patient’s weakness. Thus, he was admitted to the MICU for correction of his hypercalcemia and frequent neuro checks.  Because he continued to have localized weakness, an MRI of his cervical and thoracic spine was obtained, which revealed extensive posterior extraosseous epidural myeloma deposits compressing the cord from C6-C7 through T11-T12.  After discussion with radiation oncology and hematology, neurosurgery decided not to operate, and the patient was started on localized radiotherapy with some improvement in his symptoms after the first treatment.

Discussion:

This patient initially presented to the ED with acute onset bilateral lower extremity weakness, low back pain, and urinary retention. On examination he was found to have lower extremity proximal muscle weakness, hyporeflexia, and loss of anal sphincter tone.  This is highly concerning for acute spinal cord compression (SCC), which is a potentially devastating condition that requires immediate consideration.  His history of multiple myeloma makes a compressive or infiltrative process even more likely.

Given this patient’s preponderance of lower extremity symptoms, his pretest probability was highest for conditions involving his lumbar spine, such as cauda equina syndrome from metastatic disease or pathologic fracture. An MRI of the lumbosacral spine was obtained initially out of concern for cauda equina syndrome. However, when investigating the possibility of epidural compression secondary to a neoplasm, an MRI of the entire spine is warranted, for at least three reasons:

1) Physical examination may falsely localize the spinal lesions1

2) Nearly 20% of patients with tumor spread to the spine will have disease at multiple levels2

3) The presence of additional tumors may alter patient management1

This patient’s physical exam findings and Cervical/Thoracic MRI results support this assertion, and given the grave consequences of delaying treatment for SCC, it is clear that this imaging should have been obtained initially.

To avoid unnecessary scans, it is helpful to consider epidural compression syndrome as a collective term that includes SCC, cauda equina syndrome, and conus medullaris syndrome.  These three syndromes have similar presentations and require similar initial evaluation and management.

Detecting patients with early signs and symptoms of compression can be difficult, as the initial differential diagnosis for conditions that cause weakness, sensory changes, or autonomic dysfunction is broad.  The history usually includes back pain, saddle anesthesia, bowel or bladder incontinence with or without urinary retention, and multiple level radiculopathies often involving both legs.1,2  Diagnosis can sometimes be hindered by atypical presentations, with equivocal neurologic compromise and only mild to moderate pain.  Important red flags include history of malignancy and rapid progression of neurologic symptoms, especially bilateral symptoms.

Findings on physical examination will vary depending on the level and degree of compression, as well as the region of the spinal cord/cauda equina that is compressed. Lower extremity weakness/stiffness, gait difficulty, parasthesias or sensory deficits, and +SLR test are common exam findings in epidural compression.  Depending on the level of compression, reflexes may be exaggerated or diminished (would expect diminished reflexes in cauda equina syndrome because the nerve roots are being compressed; however overlap with the conus may occur resulting in mixed findings).  The same is true for more proximal compressions of the spinal cord with nerve root involvement. Saddle anesthesia is the most common sensory deficit with a sensitivity of 75%, and 60-80% of cases will have decreased anal sphincter tone on rectal examination.  Urinary retention with or without overflow incontinence is the most consistent finding, and is highly sensitive (90%) and specific (95%) for cauda equina syndrome.1,2

There are many possible causes of epidural compression including, but not limited to, malignancy, epidural abscess, disk herniation, and spinal canal hemorrhage (transverse myelitis and cord infarction are intrinsic cord lesions that can mimic epidural compression).  Of particular interest to this case is epidural compression secondary to a neoplasm, which constitutes an oncologic emergency requiring urgent treatment to prevent deterioration and preserve function.  When suspected, the initial management involves administration of dexamethasone 10 mg IV, before any confirmatory testing, to potentially minimize edema, progression of compression, and thus resultant neurologic damage.  As mentioned above, MRI of the entire spine should be obtained.  Often times, faster imaging modalities are utilized first. However, some authorities recommend preceding directly to MRI in patients with known neoplasm.2  These patients will often require surgical intervention, radiation therapy, and high dose steroids.  Oncology, neurosurgery, and interventional radiology are all appropriate consultations for this patient.1,2

Restoration of neurologic function in epidural compression from a neoplasm is dependent on symptoms at presentations.  Of patients who are paraplegic at the time of treatment, only 5% regain the ability to walk.  Patients who are not paraplegic and are able to walk with assistance have a 50% chance of ambulating again.  Of those who are able to walk without assistance, 60% remain ambulatory.  Of patients who require catheterization for urinary retention at the time of treatment, 82% require a catheter after treatment. This is particularly important given the large number of patients who present with urinary retention.1,2

 

References

1.  Tintinalli JE, Stapczynski JS. Tintinalli’s emergency medicine : a comprehensive study guide. New York: McGraw-Hill; 2011.

2. Marx JA, Hockberger RS, Walls RM, Adams J. Rosen’s emergency medicine : concepts and clinical practice. St. Louis: Mosby; 2002.

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