Pediatric Annals

URGENT AND EMERGENT CASES WITH A TWIST 

A Leg to Stand On

Eron Friedlaender, MD; Elizabeth Alpern, MD

Abstract

CASE PRESENTATION

A concerned mother and father brought their 15-day-old male neonate to the emergency department when they noticed that he was not moving his left leg. Their unease began earlier the same day when he seemed less active than usual. They kept him swaddled until late afternoon, when they found that his left leg was limp. The parents denied any history of trauma to his lower extremities.

The neonate had no fever, cough, rhinorrhea, recent emesis, or diarrhea. He awakened for feeding every 3 to 4 hours and was taking several ounces of formula at a time. His parents changed at least 6 wet diapers every 24 hours and he stooled at least once a day. His mother did note that she had seen a change in his urinary stream during the preceding couple of days; his urine tended to leak or dribble out rather than form a distinct arc.

His medical history included an uncomplicated delivery following a full-term gestation. The neonate's pediatrician saw him at 1 week of age for repeated emesis and assessed him with an upper gastrointestinal tract study at that time. The results were unremarkable and the vomiting had resolved without intervention. He took no medications and had received his first hepatitis B vaccine.

On physical examination, the neonate had a rectal temperature of 37.8°C, a heart rate of 192 beats per minute, a respiratory rate of 40 breaths per minute, and a blood pressure of 82/46 mm Hg. His oxygen saturation was 99% on room air. He weighed 7 pounds, 9 ounces (50%) and had a head circumference of 36.5 cm (50% to 75%). He was a vigorous, alert neonate in no acute distress. His anterior fontanelle was open and flat. His lungs were clear to auscultation and the cardiovascular examination revealed a regular rhythm and strong, equal central and distal pulses, including strong bilateral dorsalis pedis pulses. His abdomen was soft, nontender, and nondistended, and there was no evidence of hepatosplenomegaly or a mass. He was circumcised and both testes were palpable. He had normal anal tone. All extremities were warm and well perfused. His hips were in place and there were no deformities or swelling of the arms or legs. There were no midline defects along his back.

His neurologic examination demonstrated equal and reactive pupils, a strong suck, an intact doll's eye reflex, and symmetric facial expressions. He had normal tone and 5/5 strength in his upper extremities and right lower extremity. There was flaccid paralysis of his left lower extremity. He had 2+ deep tendon reflexes in his arms and right leg. There were no deep tendon reflexes in his left leg and no plantar grasp. He also had decreased pinprick sensation on his left side below the umbilicus, including the left lower extremity.

INITIAL DIAGNOSIS

The acute presentation in this neonate of a unilateral flaccid lower extremity was extremely concerning. The initial evaluation, with identification of normal results on peripheral vascular examination but loss of strength and sensation to the affected limb, suggested that either musculoskeletal pathology or a neurologic process was responsible. The distinction of true paralysis from pseudoparalysis secondary to pain is difficult to make in the preverbal child. Trauma to the leg resulting in fracture with pseudoparalysis was investigated. Radiographs of his hips and entire left lower extremity were completed; there was no evidence of fracture, dislocation, or deformity.

The absence of deep tendon reflexes in the affected extremity indicated a dysfunction somewhere along the reflex pathway, calling into question the function of the sensory nerve fibers, the spinal cord synapse, the motor nerve fibers,…

CASE PRESENTATION

A concerned mother and father brought their 15-day-old male neonate to the emergency department when they noticed that he was not moving his left leg. Their unease began earlier the same day when he seemed less active than usual. They kept him swaddled until late afternoon, when they found that his left leg was limp. The parents denied any history of trauma to his lower extremities.

The neonate had no fever, cough, rhinorrhea, recent emesis, or diarrhea. He awakened for feeding every 3 to 4 hours and was taking several ounces of formula at a time. His parents changed at least 6 wet diapers every 24 hours and he stooled at least once a day. His mother did note that she had seen a change in his urinary stream during the preceding couple of days; his urine tended to leak or dribble out rather than form a distinct arc.

His medical history included an uncomplicated delivery following a full-term gestation. The neonate's pediatrician saw him at 1 week of age for repeated emesis and assessed him with an upper gastrointestinal tract study at that time. The results were unremarkable and the vomiting had resolved without intervention. He took no medications and had received his first hepatitis B vaccine.

On physical examination, the neonate had a rectal temperature of 37.8°C, a heart rate of 192 beats per minute, a respiratory rate of 40 breaths per minute, and a blood pressure of 82/46 mm Hg. His oxygen saturation was 99% on room air. He weighed 7 pounds, 9 ounces (50%) and had a head circumference of 36.5 cm (50% to 75%). He was a vigorous, alert neonate in no acute distress. His anterior fontanelle was open and flat. His lungs were clear to auscultation and the cardiovascular examination revealed a regular rhythm and strong, equal central and distal pulses, including strong bilateral dorsalis pedis pulses. His abdomen was soft, nontender, and nondistended, and there was no evidence of hepatosplenomegaly or a mass. He was circumcised and both testes were palpable. He had normal anal tone. All extremities were warm and well perfused. His hips were in place and there were no deformities or swelling of the arms or legs. There were no midline defects along his back.

His neurologic examination demonstrated equal and reactive pupils, a strong suck, an intact doll's eye reflex, and symmetric facial expressions. He had normal tone and 5/5 strength in his upper extremities and right lower extremity. There was flaccid paralysis of his left lower extremity. He had 2+ deep tendon reflexes in his arms and right leg. There were no deep tendon reflexes in his left leg and no plantar grasp. He also had decreased pinprick sensation on his left side below the umbilicus, including the left lower extremity.

INITIAL DIAGNOSIS

The acute presentation in this neonate of a unilateral flaccid lower extremity was extremely concerning. The initial evaluation, with identification of normal results on peripheral vascular examination but loss of strength and sensation to the affected limb, suggested that either musculoskeletal pathology or a neurologic process was responsible. The distinction of true paralysis from pseudoparalysis secondary to pain is difficult to make in the preverbal child. Trauma to the leg resulting in fracture with pseudoparalysis was investigated. Radiographs of his hips and entire left lower extremity were completed; there was no evidence of fracture, dislocation, or deformity.

The absence of deep tendon reflexes in the affected extremity indicated a dysfunction somewhere along the reflex pathway, calling into question the function of the sensory nerve fibers, the spinal cord synapse, the motor nerve fibers, the neuromuscular junction, the muscle fibers themselves, or all of these. The associated lower extremity paresthesia and evolving autonomic urinary dysfunction also pointed toward lower motor neuron involvement. A spinal cord lesion was considered most likely.

DIFFERENTIAL DIAGNOSIS

The differential diagnosis for decreased movement of a lower extremity in a newborn includes musculoskeletal dysplasia, injury, or trauma; infection of the central nervous system, bones, or joints; neurologic disease; or spinal cord compression. Historical clues such as the duration of symptoms, the degree of disability, associated constitutional complaints such as weight loss, fever, or irritability, and findings on physical examination of a focal deformity, erythema, or edema help to focus further laboratory and radiologic testing.

Musculoskeletal processes affecting the newborn include pathologic fractures secondary to an underlying connective tissue or neoplastic disease, fractures resulting from nonacddental trauma, or developmental dysplasia of the hip. A thorough physical examination usually reveals whether there is an abnormality of the bones or joints. Careful examination may uncover joint instability or dislocation, whereas localized tenderness, discoloration, and swelling suggest a broken bone.

Infections leading to paresis or pseudoparesis of an extremity in a newborn include botulism, congenital syphilis, tick paralysis, epidural abscess, osteomyelitis, or a septic joint. Infectious infant botulism occurs after exposure to and resultant colonization with Clostridium botulinum. Spores may be found in the soil near construction sites and in contaminated food products, such as honey. The toxin released from these bacteria causes generalized weakness, hypotonia, feeding difficulties, constipation, a decreased gag reflex, and mydriasis. Sensation remains intact, although deep tendon reflexes may be lost. Stool may be examined for botulinum spores to confirm this process.

Congenital syphilis presents with hepatosplenomegaly, a characteristic violaceous rash on the palms and soles, and osteochondritis. Patients may experience pseudoparalysis of a limb secondary to bone pain. Serologic testing confirms the diagnosis. Meningeal infection with enterovirus, poliovirus, or herpes virus has been reported to cause varying degrees of limb weakness. Spinal cord compression from an epidural abscess may cause flaccid paralysis. It most commonly results from hematogenous spread of a Staphylococcus aureus infection. Similarly, the most common causative agents of osteomyelitis and septic arthritis in the newborn are S. aureus and group B streptococcus following either bacteremia or direct inoculation. A focal bone infection leads to necrosis and periosteal rupture, typically causing significant pain in the affected area of the body. Infection within a joint capsule also restricts range of motion secondary to pain. Finally, a postinfectious toxic synovitis may also present with decreased movement of an extremity.

Congenital malformations of the spinal canal frequently result in decreased motor activity and lack of sensation in the lower extremities. Such neural tube defects include a tethered cord, spina bifida occulta, and myelomeningocele. Patients may have dorsal midline defects, including cutaneous hemangiomas, hair tufts, or subcutaneous lesions overlying the malformed spinal canal, spinal cord, or both. Less common neurologic processes causing paralysis include a spinal cord stroke or a cerebral venous or dural sinus thrombosis with a venous infarct. Newborns at risk for these cerebrovascular insults include those with a history of polycythemia, dehydration, or perinatal asphyxia.

Compression of the spinal cord characteristically causes both motor and sensory deficits, also often with associated autonomic dysfunction. A traumatic injury to the back may lead to a hematoma or generalized inflammation within the spinal cord itself or in the surrounding tissues. Spinal cord compression from a malignancy is unusual in the newborn population. Primary tumors include intraspinal lipomas, dermoids, and malignant osseous disease of the vertebral bodies. More common, however, are secondary tumors invading the spinal column by growth through intervertebral foramina, hematogenous dissemination, or leukemic infiltration. The solid tumors that may lead to spinal cord paralysis presenting in the neonatal period include Wilms' tumor, neuroblastoma, teratoma, lymphoma, and sarcoma.

FINAL DIAGNOSIS

Our patient had emergent magnetic resonance imaging of his thoracic, lumbar, and sacral spine, given the concern over possible spinal cord compression with the history of changes in his urinary stream, the absence of systemic signs of infection, and the asymmetry of the paralysis. Sagittal and coronal images before and after the infusion of gadolinium demonstrated a large right paravertebral mass from TIl to L3 with extension through corresponding neural foramina, resulting in cord impingement (Figure). An exploratory laparotomy and tumor biopsy the following day confirmed the diagnosis of neuroblastoma, stage 2A (a localized tumor with incomplete gross resection and negative lymph nodes). Chemotherapy was immediately started. There was no evidence of metastatic disease on bone marrow biopsy, bone scan, or metaiodobenzylguanidine scan. The concentrations of his urinary catecholamines included a vanillylmandelic acid level of 105.3 mg/ g (normal range 0 to 16 mg/g) and a homo vanillic acid level of 167.7 mg/g (normal range 0 to 29.8 mg/g).

Neuroblastoma is a malignancy of sympathetic neural tissue with a predilection to metastasize to bone, liver, skin, and lymph nodes. It disproportionately affects the very young; 80% of diagnoses are made in children younger than 5 years.1 Furthermore, neuroblastoma arising from the adrenal gland is the most common malignant tumor in neonates.2

Figure. Right-sided paravertebral mass extending through several neural foramina into the spinal canal (arrows).

Figure. Right-sided paravertebral mass extending through several neural foramina into the spinal canal (arrows).

The clinical presentation of neuroblastoma in the neonate varies greatly, largely because of the wide distribution of sympathetic ganglia throughout the body. Side effects from an enlarging mass in the neck, chest, abdomen, or pelvis may include difficulty swallowing, compromise of the airway, abdominal distention, or intestinal or ureteral obstruction, respectively. In addition, symptoms related to metastatic disease from lymphatic or hematogenous spread bring patients to medical attention. In fact, 60% of neonates with neuroblastoma have metastatic disease at the time of their diagnosis.3 Hepatomegaly, possibly with evidence of hepatocellular destruction, bony lesions, or skin eruptions, is most common. As in this case, spinal cord compression may also occur with intraspinal extension of a primary mass or a metastatic tumor.

The first symptom of spinal cord compression is pain that is made worse when lying flat or with movement, neck flexion, straight leg raises, or Valsalva maneuvers. In infants, this may manifest as persistent irritability. Proximal weakness beginning in the lower extremities is another common finding in patients with spinal cord compression. Rapid progression to paresis may occur. Sensory changes are a later finding. The paresthesias characteristically progress from distal to proximal up to the level of the spinal cord lesion. Finally, patients with subacute or chronic spinal cord compression may demonstrate urinary and fecal retention or incontinence from autonomic disregulation.4

Serologic and radiographic tests are available to aid in the diagnosis of neuroblastoma. Patients may have elevated levels of catecholamine metabolites in the urine and elevated serum ferritin levels. Plain x-rays of the body cavity with a mass lesion may reveal calcifications characteristic of neuroblastoma. However, definitive diagnosis requires a tissue biopsy. Treatment options depend largely on the age of the patient, the biology of the tumor, and the extent of the disease. Tumor excision may be curative in less aggressive, localized disease, whereas more advanced and extensive cases may require radiation therapy, chemotherapy, surgical debulking, and possibly bone marrow transplantation.

The evaluation of a patient with evidence of spinal cord compression includes emergent spinal magnetic resonance imaging. However, appropriate management in this case is controversial. The prognosis for survival in most neonates with neuroblastoma is excellent, but available chemotherapy and radiation therapy have the potential for severe toxicity. Furthermore, decompressive laminectomy does not consistently reverse neurologic deficits and the extensive surgery results in predictable spinal deformities with significant associated morbidity later in life.5,6

LESSONS LEARNED

Spinal cord compression is a medical emergency. Presenting symptoms include extremity weakness, sensory changes, and bowel or bladder dysfunction. Symptoms may be rapidly progressive. Emergent magnetic resonance imaging is indicated to evaluate the integrity of the spinal cord. When compression is secondary to a malignancy, medical options include high-dose systemic steroids, radiation therapy, and chemotherapy. Some cases require surgical intervention.

REFERENCES

1. Hogarty M, Lange B. Oncologic emergencies. In: Fleisher GR, Ludwig S, eds. Textbook of Pediatric Emergency Medicine, 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2000:1157-1190.

2. Hartman GE, Shochat SJ. Abdominal mass lesions in the newborn: diagnosis and treatment. Clin Perinatol. 1989;16:123-135.

3. Lukens JN. Neuroblastoma in the neonate. Semin Perinatol. 1999;23:263-273.

4. Quinn JA, DeAngelis LM. Neurologic emergencies in the cancer patient. Semin Oncol. 2000;27:311-321.

5. Munro FD, Carachi R, Fyfe AH. Congenital neuroblastoma presenting with paraplegia. Arch Dis Child. 1991; 66:1246-1247.

6. Christiansen GM, Pulley SA. Two cases of neuroblastoma presenting to the emergency department. J Emerg Med. 1999;17:265-268.

10.3928/0090-4481-20011001-07

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