Learning Objectives
- The combination of numbness, weakness, pain and a decreased reflex in a single limb is suggestive of radiculopathy
- Diagnosis is typically confirmed by spinal MRI or by EMG
- Treatment ranges from conservative (PT, medication) to interventional (paraspinal injection, surgery).
History
JS, a 64 year old accountant, limps into the office complaining of lower back pain, trouble walking, and numbness of the right foot. He spends a lot of time sitting at his desk. He did not have an injury to his back. This problem seemed to start after waking up one day. The symptoms have been present every day for the past two weeks. He has tried sleeping on a flat surface at home and he has tried extra strength ibuprofen to treat this symptom. They have not been helpful. He denies having symptoms of urinary retention, constipation, or incontinence.
He has been taking ibuprofen. He also takes hydrochlorothiazide. He has a medical history of hypertension and cholecystectomy.
He quit smoking 10 years ago. He has 4 beers, on average, each week.
He has a family history of myocardial infarction in his father, who passed away at age 68. His mother, who is 89, has a history of hypertension.
He has not had chest pain, palpitations, or trouble breathing or coughing. He has not had bruising or bleeding. His mood has been well. Urinary and bowel function are normal. He denies pains or swelling in the hips, knees, ankles and shoulders. He denies a rash or changes in his moles. He has not had fevers, headaches, visual symptoms, tremor, hair loss, or changes in his weight.
Examination
His blood pressure is 146/86, pulse 78, temperature 98.5 F. He is an overweight, uncomfortable-appearing fellow. His heart sounds are normal, there are no murmurs. His pupillary and funduscopic exams are normal. He is alert, he is oriented, and three word recall is normal. His visual fields are full to confrontation. His eye movements are conjugate, there is no nystagmus, and there is no ptosis. Facial sensation is normal to pinprick. Upper and lower facial expression is normal. Auditory sensation is normal to finger rub. The palate moves symmetrically. His shoulder shrug is normal. His tongue protrudes in the midline. Deltoid, biceps, triceps, and extensor digitorum strength is 5/5. Psoas, quadriceps, hamstrings and tibialis anterior are 5/5 in strength. The left gastrocs is 5, the right is 4 in strength. Biceps and triceps reflexes are 2/2. Quadriceps are 2/2. The left Achilles is 2, the right is absent. The toes go downwards to plantar stimulation. There is normal pin sensation in the arms. There is normal pin sensation in the left leg. In the right leg, there is no pin sensation on the sole of the foot. Heel knee shin movements are normal. His gait is abnormal, he takes small steps with the right leg, and he cannot walk on his toes on the right side.
Localization and Neuroanatomy
This examination shows an absent right Achilles reflex, weakness of the right gastrocs, and decreased sensation of the sole of the right foot. The localization of this process could be in the right S1 nerve root, the sciatic nerve, or the posterior tibial nerve. The femoral nerve could not be a site of this disorder, since the quadriceps strength and quadriceps reflex are intact.
Diagnosis
Although there are other causes, the site of this kind of illness is usually located in the nerve roots. A presentation of pain, numbness, weakness and depressed reflexes in one limb is often present in the setting of nerve root irritation, otherwise known as radiculopathy. The human body is most susceptible to radiculopathy of the lower cervical and lumbar spines, especially at C6/7/8 and L4/5/S1levels. The causes of radiculopathy vary, from aberrant disc and nucleus pulposus material, to inflammation, to anatomical changes, such as bone spurring and degenerative changes of the intervertebral foramina. Injury to the spine, such as in tackle football, prolonged sitting, excessive body weight and diabetes mellitus are known to increase the risk of developing radiculopathy.
The diagnosis of radiculopathy can be a clinical one. The appropriate clinical setting, and a mild degree of severity, may justify conservative therapy. For more severe cases, interventional therapy may be warranted, and diagnostic testing is useful to be sure this is appropriate.
MRI imaging of the cervical or lumbar spine is often helpful for showing anatomical changes that lead to radiculopathy. Bulging discs and neural foramina architecture are commonly reported in these studies regardless of symptoms. This testing may be sufficient for making a diagnosis. MRI testing may also lead to false positive results, as it is common for patients to have degenerative changes within the lumbar and cervical spine regions.
EMG testing is also helpful for diagnosing radiculopathy. Unlike MRI, EMG is a physiological test. Important findings that are consistent with radiculopathy are normal peripheral nerve conduction velocities, prolonged or absent F-responses, and evidence of denervation within muscles supplied by a particular nerve root, but not by other nerve roots. The last of these findings is in particular handy to differentiate radiculopathy from peripheral nerve damage. Several muscles may be supplied by a single nerve root, but by different peripheral nerves. The difficulty with EMG is that it is prone to subjective interpretation, and the findings vary with time. The muscle findings on needle EMG will be different depending on whether the symptoms are days, weeks or months old.
Treatment
Assuming the diagnosis of radiculopathy is certain, treatment would be useful. For mild cases, patients respond well to spinal traction and physical therapy. Spinal traction gently increases the spaces between the vertebral bodies. This prevents compression and in principle it allows for swelling of nerve roots to diminish. Therapy helps call on muscles to rebuild their power and fitness and promotes reorganization of the neuromuscular junction when nerve fibers have been damaged. Strengthening of abdominal core muscles can help to support a weakened lumbar spine. Motivated patients tend to do better than unengaged patients.
Patients with pain symptoms of radiculopathy may have difficulty participating in therapy due to pain. This symptom may respond to NSAID analgesics, corticosteroids, opioid medications, gabapentin, or tricyclic antidepressants. The last two options can be effective even at minimal doses.
Sometimes treatment of radiculopathy requires intervention. Patients with radiculopathy are known to respond to paraspinal nerve root blockade with injection of corticosteroid, lidocaine, and sometimes other medications. The medical literature suggests mixed results with this approach. When the more conservative treatments are ineffective this is a common next step. At times, destruction of disc material or nerve structures with relatively noninvasive procedures is helpful. Some of these approaches remain under development.
For very severe cases, or cases with obvious, delicate anatomical pathology, surgery may be needed. This may be a neural foraminotomy or a spinal laminectomy. Although both procedures relieve pressure on the nerve roots, neither is known to provide universal relief. Treatment for weakness tends to be more effective than treatment for numbness or pain. Conservative treatments are not usually recommended for anatomic pathology or for cases of higher clinical severity.
Review Questions
- History and Examination findings that support the diagnosis of radiculopathy are:
a. numbness in one limb
b. numbness and decreased reflexes in both legs
c. weakness, decreased reflexes, and bladder incontinence
d. weakness, numbness and decreased reflexes in one limb
e. weakness in one limb - The diagnosis of radiculopathy may be confirmed by
a. brain MRI
b. spine MRI
c. EMG
d. both A and C
e. both B and C
3. Treatment of radiculopathy may include
a. medication such as gabapentin
b. physical therapy
c. paraspinal injection
d. laminectomy
e. All of the above