LETTER TO EDITOR
|Year : 2008 | Volume
| Issue : 2 | Page : 172-173
A teenager with progressive lower extremity weakness and pain
Pedro Weisleder1, Addie Hunnicutt2
1 Department of Neurology, The Children's Medical Center of Dayton, Dayton, OH, USA
2 Division of Pediatric Neurology, Duke University Medical Center, Durham, NC, USA
Department of Neurology, The Children's Medical Center of Dayton, Dayton, OH 45404
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Weisleder P, Hunnicutt A. A teenager with progressive lower extremity weakness and pain. J Pediatr Neurosci 2008;3:172-3
We describe the case of a 12-year-old boy who presented with a 2-week history of progressive ascending weakness, hypoesthesia, dysesthesia, and hypo- and arreflexia in the absence of mental status changes, followed by difficulty ambulating. The symptoms were more severe in lower than upper extremities. The neurological examination revealed normal mental status and speech, intact cranial nerve function, mild weakness of neck flexion, and intact upper extremity strength. Lower extremity exam revealed slightly decreased tone, and weakness of hip flexors bilaterally; distal musculature strength was intact. The child's sensory exam revealed diminished sensation to pinprick in a stocking-glove distribution, bilaterally. He also had diminished vibration and proprioceptive sensation in the lower extremities. The patient had trace reflexes in upper extremities and absent reflexes in lower extremities. The boy had normal coordination on finger-to-nose testing, but had difficulty with lower extremity coordination. The patient was able to ambulate short distances (8-10 meters) without assistance, but his gait was ataxic and he had to hyperextend ("lock") his knees to avoid falling. Creatine kinase was normal at 45 units/l, with normal chemistries, liver function tests, and blood counts. Cerebro-spinal fluid analysis revealed protein of 237 mg/dL, normal glucose, one white blood cell and no red blood cells. The contrast-enhanced, sagital T1-weighted magnetic resonance (MR) imaging revealed evident enhancement of nerve roots [see arrows in [Figure 1]] which, together with the rest of the information, supported the diagnosis of Guillain-Barrι syndrome (GBS).
This case provides us the opportunity to review the diagnosis, differential diagnosis, pathophysiology, and treatment of acute demyelinating disorders in children. It also affords us the opportunity to discuss changes in the classification of these conditions. The classification has more than academic significance; it has implications for treatment and likelihood of recovery.
The differential diagnosis for this patient includes: Guillain-Barrι syndrome (GBS), poliomyelitis (especially in underdeveloped nations), tick paralysis (in tick-infested areas), periodic paralysis, polio-virus or other viral myelitis, vasculitis involving the anterior spinal artery, botulism (where the paralysis is descending), paralytic fish poisoning (from eating contaminated fish from warm, tropical waters) and transverse myelitis. The diagnosis of GBS is suggested by the clinical scenario; it is supported by evaluation of the spinal fluid, imaging studies, and if necessary electrodiagnostic testing.  In this particular case, the patient's contrast enhanced magnetic resonance imaging of the lumbar spine revealed with remarkable clarity the contour of the spinal-nerve roots.
GBS is the most common cause of acute flaccid paralysis in childhood; , in addition to muscles of the extremities, it may also affect facial, swallowing, and breathing muscles. The overall incidence of GBS is 0.8 per 100,000 children per year, with a 1.5:1 male to female ratio.  The condition is an immune-mediated response directed against peripheral nerves, and sensory and motor spinal-nerve roots initiated by an antecedent viral infection.  A documented illness or history of immunization in the weeks preceding the syndrome is, however, present in 50-70% of patients only. In most cases, tissue damage is limited to the myelin sheath; in severe cases the axons themselves are involved. There are three predominant forms of GBS: (1) acute inflammatory demyelinating polyradiculoneuropathy (AIDP), (2) acute motor axonal neuropathy (AMAN), and (3) acute motor-sensory axonal neuropathy (AMSAN). , These forms may be distinguished from each other by electrodiagnostic studies. , Forms of GBS that affect cranial nerves are also recognized including: (1) Miller-Fisher syndrome with abnormalities of movement of the extraocular muscles, ataxia, and areflexia, and (2) polyneuritis cranialis with involvement of multiple cranial nerves except the optic nerve. Antibodies associated with GBS are: those to the ganglioside GQ1b in Miller-Fisher syndrome and polyneuritis cranialis, and to the ganglioside GM1 in the axonal variants. ,
The most common presenting symptom in children with GBS is weakness; pain, however, is the most salient.  Patients also report other sensory complaints such as numbness or paresthesia. A true sensory level, which would be concerning for spinal cord injury, is usually absent. The aforementioned symptoms are rapidly followed by symmetric weakness of the extremities over a 24-hour period; these may continue to worsen for up to four weeks before reaching a plateau. Proximal muscle weakness, as described in this case, is the primary complaint in only 15-20% of patients. The physical exam of patients with GBS reveals diminution or loss of deep tendon reflexes. Autonomic dysfunction such as abdominal pain, postural hypotension, cardiac dysrrhythmia, bowel and bladder incontinence are not uncommon. GBS is potentially a lethal condition; patients should be monitored for respiratory insufficiency and cardiac arrhythmia in hospital.  Patients need to remain hospitalized until symptom progress halts.
Most patients with GBS improve without directed therapy. There is good evidence, however, that treatment with intravenous immunoglobulin (2 g/kg over 2 to 5 days) hastens recovery. , Plasmapharesis to remove antibodies against myelin also has therapeutic effect. , It may, however, be more costly  and is associated with higher morbidity especially if central venous access is necessary. Plasmapheresis for GBS is typically done every other day; four to six treatments are commonly prescribed. Corticosteroids have been proven to be ineffective in GBS. The mortality in GBS, a consequence of respiratory failure, is 1-2%. Relapses are uncommon, but some patients may develop long-lasting polyneuropathy. 
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