A 21-month-old with abnormal gait

A 21-month-old girl was seen in emergency room due to an abnormal gait and refusal to walk. Two weeks before presentation, she had a five-day febrile illness (Tmax 103ºF) with mild cough and rhinorrhea.

A couple days after her fever resolved, her parents noted that, rather than walking down the stairs, she would sit and scoot downstairs on her bottom. Twenty-four hours after these changes, she began to demonstrate an abnormal gait, with wider stance and knees flexed. She began to refuse to sit up or get out of bed in the morning but, after receiving ibuprofen, she would sit comfortably and walk with encouragement for the remainder of the day. On the day of presentation to the ER, however, she refused to walk altogether.

Her recent personality was described by her parents as clingy, clarifying that she was irritable and cranky unless held by her parents. Labs obtained in the ER showed a normal WBC (6.0 × 103/L) and creatine kinase (127 U/L), but an elevated sedimentation rate (49 mm/hr) and C-reactive protein (2.7 mg/dL). A hip ultrasound and plain films of the knees and hips were normal. Blood culture yielded no growth of an organism.

Review of systems was negative for a history of trauma, vomiting, awakening at night, change in bowel or bladder function, rash, easy bruising, loss of milestones or a change in speech. Sick contacts included several children at day care who also had a similar upper respiratory tract infection the past week. The patient lives at home with her parents and older brother, who are all healthy. Her parents denied any animal exposure or recent travel history. Her past medical history was notable only for moderate eczema and a food allergy to peanuts.

In the ER, she was noted to be a well-appearing young girl, lying comfortably supine in her father’s lap. When placed in a standing position, she was initially very hesitant but soon bore her own weight without distress. When asked to walk to her father’s arms, she began to whine and needed considerable coaxing before ambulation, demonstrating significant irritability with each step. Her gait was slightly wide-based, hesitant, and stiff, but with symmetric stride length. She demonstrated extreme back arching (hyperlordosis) and forward pelvic tilt throughout ambulation, with knees slightly flexed. She was able to walk in a straight line for approximately 3 m without falling or staggering.

Examination of the joints demonstrated no swelling, tenderness, erythema, or warmth at the hip, knee, or ankle. She displayed no tenderness with a log-roll test of the lower extremity and she had full and symmetric range of motion of the hip, knee, ankle and foot when supine and full internal and external rotation of the hip when prone. Her lower extremity motor strength was 5/5 and symmetric. There was no appreciable tenderness to muscle squeeze or palpation of the buttocks, thighs or calves.

Her back examination, however, demonstrated mild mid-line lower back tenderness with percussion. The patient resisted flexion and extension of her spine. Neurologic examination was unremarkable, with deep tendon reflexes 2+ and symmetric. Cranial nerves were intact. Her heart and lung exam were normal and she did not have any appreciable lymphadenopathy. There was no abdominal tenderness or hepatosplenomegaly. Her skin demonstrated generalized xerosis, with eczematous lesions in the antecubital and popliteal fossae, as well as marked lichenification and hyperpigmentation of the knees.

An MRI of the spine was obtained (Figure 1).

What is your diagnosis?

The MRI demonstrates increased T2 signal intensity within the right posterolateral aspect of the L3 vertebral body and within the L3-L4 intervertebral disc consistent with discitis and vertebral osteomyelitis.

Vertebral osteomyelitis refers specifically to infection of the vertebral bodies, whereas infection and inflammation localized to the intervertebral disc and vertebral body endplates is termed discitis.

Discitis is more common than vertebral osteomyelitis in young children, likely secondary to the rich vascular anastomoses in the cartilaginous disc space that disappear with age. Patients with discitis alone are thought to have a more benign clinical course than those with vertebral osteomyelitis, who tend to be more ill-appearing, have higher fevers and have a greater duration of symptoms. Nonetheless, these two likely represent two ends of the same spectrum of disease. Infection of the intervertebral disc and adjacent vertebral bodies typically results from hematogenous spread, with Staphylococcus aureus being the most commonly isolated organism. However, blood cultures are negative in most cases. Serologic testing for Bartonella henselae should be considered in those with cat exposure; tuberculosis and brucellosis should be entertained if symptoms and radiographs suggest chronic infection in a patient with the proper exposure history.

Vertebral osteomyelitis is a relatively uncommon condition in children, which is particularly difficult to diagnose in the uncommunicative or uncooperative toddler.

Children with vertebral osteomyelitis or discitis may present with a broad range of non-specific symptoms to include abdominal complaints such as pain or constipation. Whereas older children may complain of back pain, the young child may simply demonstrate an abnormal gait or refusal to walk. Ironically, gait observation is crucial in any child who is refusing to ambulate to narrow down a broad differential diagnosis. This can often be achieved, as with this patient, by separating the child from the caregiver and observing as the child walks back to the caregiver. If the patient prefers to crawl rather than walk, this is at least useful in suggesting that the hip is not the source of discomfort. The most consistent and remarkable aspect of her abnormal gait was a hyperlordotic posture, likely a consequence of paraspinous muscle spasm. The gait of toddlers with vertebral osteomyelitis is typically described as stiff and awkward due to an attempt to reduce painful flexion or extension of the spine. In this case, the presence of mild lower back tenderness to percussion and a thorough examination of her gait prompted the MRI, which allowed for timely diagnosis.

Complications of vertebral osteomyelitis include epidural abscess, paravertebral abscess and acute spinal cord paralysis due to paraspinal compression, thus emphasizing the importance of a thorough neurologic examination. Children with uncomplicated vertebral osteomyelitis should be treated with at least four weeks of parenteral antibiotics. Surgical decompression or debridement may be indicated in cases of epidural abscess, spinal cord compression or significant vertebral body destruction.

Our patient received six weeks of intravenous clindamycin. Marked improvement in overall patient comfort was achieved early-on by externally stabilizing the patient with a body corset. After nearly one month from initiating medical therapy, the patient’s hyperlordosis had resolved and her gait had returned to baseline.

Disclaimer: The opinions or assertions contained herein are the private views of the authors and do not reflect the official policy of the Department of Defense or the U.S. Government

Justin Hollon, MD, is a Captain in the U.S. Air Force. He is currently a Resident in pediatrics with the National Capital Consortium in Washington.

Matthew Eberly, MD, is a Major in the U.S. Air Force. He is currently an Assistant Professor of Pediatrics and a Pediatric Infectious Disease physician at the F. Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences in Bethesda, Md.

For more information:

• Berbari EF, Steckelberg JM, and Osmon DR. Osteomyelitis, in Principles and Practice of Infectious Diseases. Mandell GL, Douglas RG, and Bennett JE, eds. 2004. Churchill Livingstone: Philadelphia.

• Gutierrez KM. Osteomyelitis, Disctis, in Priniciples and Practice of Pediatric Infectious Disease. Long SS, Pickering LK, and Prober CG, eds. 2007. Churchill Livingstone: Philadelphia.

• Fernandez M, Carrol CL, and Baker CJ. Discitis and vertebral osteomyelitis in children: an 18-year review. Pediatrics. 2000. 105(6): 1299-1304.