P0896 - Refusal to walk in a 2-year-old female

Initial Presentation:
A previously healthy 2-year-old female presents with a new left leg limp and refusal to walk. There is no recent history of trauma, fevers, cough, congestion, vomiting, diarrhea, or dysuria. She has had decreased appetite and lost 2 pounds in the past month. She sometimes wakes up at night crying due to her leg pain. NSAIDs have not improved her symptoms. Per parents there has been concern for speech delay, but she has been meeting developmental milestones otherwise.

Physical Exam:
Vital signs are within normal limits. On exam she is diffusely tender to palpation of her lower extremities. She resists passive range of motion bilaterally and refuses to stand. There is no joint erythema/edema, rashes or petechiae/purpura. The rest of her physical exam is unremarkable.

Diagnostic Evaluation:
X-rays reveal lucent lines through the distal metaphysis of the femur (Figure 1). Lower extremity MRI shows symmetrically abnormal marrow signal in the metaphysis of the long bones (Figure 2). CBC shows a hemoglobin of 9.2 g/dL and MCV of 67. WBC count is 8.7 K/uL, without any abnormal cells noted. Platelets are 353 K/uL. Electrolytes are within normal limits. ESR is elevated at 37 mm/hr. CT of the neck, chest, abdomen, and pelvis is unremarkable. Bone marrow biopsy shows normal trilineage hematopoiesis without an infiltrative process.

Further history reveals that the patient had an extremely restricted diet consisting of mainly yogurt for the past year. Parents also endorse that the patient’s gums bleed when brushing her teeth. Serum vitamin C level results as < 5 (23 – 114 umol/L) leading to vitamin C deficiency (scurvy) as the patient’s final diagnosis.

Diagnosis:
Vitamin C deficiency develops within 1 to 3 months of inadequate intake, as humans cannot synthesize vitamin C. Clinical symptoms may include fatigue, follicular hyperkeratosis, purpura, or bleeding gums. Musculoskeletal symptoms may include bone pain, limp, and refusal to walk. Sclerotic and lucent metaphyseal bands on x-ray (Figure 1) or diffuse increased T2-weighted signal in the bilateral long bone metaphysis (Figure 2) are common radiographic presentations in scurvy. These signs and symptoms have a broad overlap with several malignant diagnoses such as leukemia or neuroblastoma.

Discussion:
Often thought as a rare disease in developed nations, scurvy is an important diagnosis to appreciate in children with restricted diets such as those with developmental delay or autism. In children with musculoskeletal complaints at risk for vitamin C deficiency, scurvy should be considered to potentially avoid further invasive work up, such as in our case.