PRATICHI K. GOENKA
HISTORY OF PRESENT ILLNESS
A 9-year-old girl who was previously healthy presented with a complaint of constipation. She had developed lower back pain approximately 3 months ago and at that time complained of some difficulty stooling. She tried various therapies including mineral oil, senna, and phosphate supplemented enemas with an improvement in stooling pattern. However, her back pain did not remit. Initially, the pain was intermittent and controlled to some extent with ibuprofen. It began in the lower back and flank and then radiated down the buttocks to both lower legs. It was worse with standing and walking. During the past 2 weeks the pain increased in intensity and was more constant. It now interfered with her daily activities. The mother initially felt that the child was about to start menstruating.
She was evaluated in the emergency department of a nearby hospital about 2 weeks prior to admission where she was diagnosed with pyelonephritis and treated with ciprofloxacin without improvement. One week prior to admission she was reevaluated and computed tomography of the abdomen was normal, specifically there were no renal stones. She now presented in with severe low back pain and had not stooled in 4 days. There had been no recent dysuria, urgency, or frequency. There was no headache, fatigue, weight loss, night sweats, or abdominal pain. Menarche has not occurred. She denies recent trauma or infection.
The girl had problems with constipation as an infant and received mineral oil periodically until 3 years of age. She has not previously required hospitalization. She takes no medications. There is no family history of thyroid disorders or autoimmune diseases.
T 37.4°C; HR 90 bpm; RR 16/min; BP 110/65 mmHg
Weight 25th percentile for age
On examination, she was alert, cooperative, but in obvious distress. She was lying on the examination table moaning and holding her back. Her conjunctivae were pink and anicteric. Her neck was supple. There were no murmurs on cardiac examination. Her abdomen was soft without hepatosplenomegaly. The back was tender along the lumbar spine and flanks bilaterally with significant muscle spasm. The range of motion was limited due to pain. Straight leg raise produced pain in the posterior thighs at approximately 45 bilaterally. The sensation in the lower extremities was intact at all levels. Motor tone was normal. Deep tendon reflexes at the patellar tendon and ankles were normal bilaterally.
Laboratory evaluation included a WBC count, 4100/mm3 (35% segmented neutrophils, 55% lymphocytes, 8% monocytes, and 2% eosinophils); hemoglobin, 12.0 g/dL; and platelets, 204 000/mm3. Mean corpuscular volume was 87 fL and red cell distribution width was normal at 12.4. Serum chemistries included sodium, 141 mmol/L; potassium, 3.9 mmol/L; chloride, 105 mmol/L; bicarbonate, 25 mmol/L; blood urea nitrogen, 11 mg/dL; creatinine, 0.5 mg/dL; and glucose, 97 mg/dL. The total bilirubin was 0.2 mg/dL and serum albumin, alkaline phosphatse, and transaminases were normal. Urinalysis revealed a specific gravity of 1.011, pH 6.5, and no white blood cells, red blood cells, or protein. Fibrinogen was 411 mg/dL. Prothrombin and partial thromboplastin times were 13.7 seconds and 31.5 seconds, respectively.
Radiographs of the lumbar spine showed no fracture, dislocation, or degenerative changes of the vertebral bodies. MRI of the spine revealed an intradural, intramedullary lesion measuring 5.2 cm × 2.0 cm at the level of T12-L1. There was displacement of the nerve roots and the distal tip of the cauda equina ventrally.
DISCUSSION CASE 12-5
While this patient’s most consistent symptom is back pain, functional constipation must be considered. Constipation can also lead to difficulty urinating, however this patient has not complained of urinary symptoms despite her earlier diagnosis of pyelonephritis.
Back pain and tenderness along the spine are abnormal and potentially serious findings in a child. Once this history and examination have been elicited, spinal cord processes must be considered. There are several disease processes that can affect the spinal cord and cause the symptoms described. Trauma must be considered in any child with severe back pain. Trauma can lead to hematomas, vertebral fractures, and dislocations in the spine. Bacterial infections can cause epidural abscesses, while viral infections can cause transverse myelitis. Intervertebral disc herniation and spinal tumors also cause back pain in children. Guillain-Barré is occasionally considered in the evaluation of back pain. Table 12-5 includes the differential diagnosis of back pain in the pediatric population. In this child’s presentation there was neither a history of trauma nor signs of infection. Imaging studies and biopsy were warranted to make the final diagnosis.
TABLE 12-5.Differential diagnosis of back pain in the pediatric population.
Diagnosis by frozen section was intramedullary spinal ependymoma.
Tumors of the spinal cord can be extramedullary or intramedullary. Extramedullary tumors erode the bony vertebral column and compress sensory and motor tracts located laterally within the spinal cord. Extramedullary lesions are usually due to metastases from primary tumors such as neuroblastoma, sarcoma, and lymphoma. Dysembryoblastic extramedullary tumors are associated with teeth, bones, or calcification and may be associated with a sinus tract leading from the surface and extending intraspinally. Intramedullary tumors are usually either astrocytomas or ependymomas, though oligodendrogliomas also occur.
Ependymomas are CNS intramedullary tumors that arise within or adjacent to the ependymal lining of the ventricular system or the central canal of the spinal cord. They account for 5%-10% of primary childhood CNS tumors. Most ependymomas are located in the posterior fossa but approximately 10% of ependymomas occur in the spinal cord. Ependymomas vary from well-differentiated tumors with no anaplasia and little polymorphism to highly cellular lesions with significant mitotic activity and necrosis.
Signs and symptoms of spinal cord tumors can be insidious and misleading. Complaints may be vague and few specific signs occur early in the disease. Most children with a spinal cord tumor ultimately present with a combination of extremity weakness, gait disturbance, scoliosis, and back pain, depending on the location of the tumor. Incontinence as a presenting sign may be overlooked in very young children who may not be fully toilet trained. A clue to the presence of neurogenic bladder is incontinence of urine associated with crying or straining at stool.
Changes in posture, nonspecific complaints of back pain, or even unexplained abdominal pain can be associated with disease of the spinal cord. The child may have difficulty sleeping because of pain. Any pain exacerbated by either valsalva maneuvers, such as straining at stool, or coughing should be evaluated. Tumor attached to nerve roots may cause segmental pain, paresthesias, and weakness. The presence of hyperreflexia, clonus, and up-going toes suggests corticospinal tract disease. Defects in proprioception, vibration sense, or sensory level should also raise suspicion for an intraspinal process.
Spine radiographs. Obtain anterior-posterior, lateral, and for the cervical spine, oblique projections. Destructive bone lesions are associated with meta-static disease. Increased interpedicular distance suggests a long-standing intramedullary process. Slow-growing spinal tumors may cause scoliosis.
Spine MRI with gadolinium. MRI allows for differentiation of intramedullary from extramedullary masses.
Cystourethrogram. This study can evaluate bladder function and can confirm the diagnosis of neurogenic bladder.
Ophthalmologic examination. Spinal cord tumors are occasionally associated with increased intracranial pressure and papilledema, probably related to decreased CSF absorption due to hemorrhage within the tumor or dramatically elevated CSF protein.
After confirmation by neurodiagnostic procedures, surgical laminectomy and exploration with removal of the tumor should be considered. Ependymomas expand symmetrically in a rostral caudal fashion. A tissue plane can be readily identified, facilitating surgical excision. Radiation is recommended for most spinal cord tumors but adjuvant chemotherapy is not generally effective. Five-year survival rates for spinal cord ependymomas range from 95% to 100%.
Children with spinal cord tumors often face long-term deficits ranging from partial paralysis of one limb to quadriplegia. Physical therapy, serial casting, and tone-reducing medication may be required for moderate spasticity. Neurogenic bladder problems also require appropriate prophylactic antibiotics, intermittent catheterization, and cystometric evaluation. Multidisciplinary postoperative care includes input from pediatrics, oncology, orthopedics, urology, neurosurgery, and physical therapy.
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