What Caused a Geriatric Gait in a Homebound Adolescent?

AUTHORS:
Deeksha Borkar, MD¹ • Tara Holm, MD² • Jonathan Strutt, MD³

AFFILIATIONS:
¹Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota
²Department of Radiology, Division of Pediatric Radiology, University of Minnesota Medical School, Minneapolis, Minnesota
³Department of Pediatrics, Division of Pediatric Emergency Medicine, University of Minnesota Medical School, Minneapolis, Minnesota

CITATION:
Borkar D, Holm T, Strutt J. What caused a geriatric gait in a homebound adolescent? Consultant. 2021;61(12):e17-e20. doi:10.25270/con.2021.05.00008

Received January 1, 2021. Accepted February 19, 2021. Published online May 24, 2021.

DISCLOSURES:
The authors report no relevant financial relationships.

CORRESPONDENCE:
Deeksha Borkar, MD, University of Minnesota Medical School, 2450 Riverside Ave, Room M136, Minneapolis, MN 55454 (borka015@umn.edu)

An 11-year-old boy with a medical history significant for autism spectrum disorder and attention-deficit/hyperactivity disorder (ADHD) presented to the emergency department (ED) with a 1-month history of progressive pain and swelling of the right lower extremity. He discloses a history of right foot trauma at an indoor gymnasium around the time of symptom onset with predominance of pain and swelling over the right calf, ankle, and midfoot. He denied fever, chills, nausea, vomiting, chest pain, shortness of breath, abdominal pain, and problems with bowel or bladder continence. His immunizations were up to date, and he had no history of travel or sick contacts before development of symptoms. He was taking methylphenidate and dexmethylphenidate for ADHD.

His most recent visit with his primary care provider was 2 weeks before presenting to the ED. At that visit, his parents had discussed their concerns that he may have lost muscle mass from spending too much time in his room playing video games during the summer. They had also reported that he “walked like an 80-year-old man” and had described feeling weak. On further discussion, the patient had revealed that his diet was consistently limited to eating only pancakes and eggs for breakfast, skipping lunch, and sometimes eating popcorn as an evening meal/snack, without any dietary or vitamin supplementation.

Physical examination. The patient was thin with vital signs in the normal limits. His examination was notable for pale skin with perifollicular hyperkeratotic papules noted over bilateral feet and shins. He had ecchymosis over the dorsal aspect of his right foot (Figure 1). A musculoskeletal examination was notable for right knee prepatellar effusion without warmth, erythema, or tenderness to palpation. Right lower leg swelling was noted with multiple areas of ecchymosis, tense but compressible muscle tissue, and tenderness to palpation. There was associated right ankle swelling with edema and ecchymosis of the right mid-foot as well (Figures 1 and 2). Decreased active and passive range of motion of the right ankle was also present.

Figure 1. Perifollicular hyperkeratosis and ecchymosis was seen on the medial aspect of the right foot (A), left foot (B), and right shin (C).

Figure 2. Bilateral lower extremities demonstrating right knee and lower leg swelling with distinct differences in size.

Diagnostic testing. Initial laboratory findings were notable for anemia with a hemoglobin level of 9.9 g/dL, mild leukopenia with a white blood cell count of 3.9 × 10⁹/L, and mild hypocalcemia with a serum calcium concentration level of 8.3 mg/dL. Laboratory findings of iron deficiency anemia were noted, with a total iron level of 20 ug/dL, iron binding capacity of 340 ug/dL, and a low iron saturation index of 6%. Total creatine kinase, uric acid, ferritin, and lactate dehydrogenase levels were within normal limits. Magnetic resonance imaging (MRI) studies of the bilateral lower extremities revealed long bone metaphyseal marrow signal abnormalities, bilateral proximal tibial periostitis (right greater than left), right-sided myositis, and bilateral subcutaneous edema (right greater than left) (Figures 3-5).

Figure 3. T1-weighted coronal MRI scans of both knees demonstrated abnormal dark metaphyseal bone marrow signal, isointense to skeletal muscle in the proximal tibia and distal femur bilaterally.

Figure 4. Coronal STIR sequence scans demonstrated abnormal high metaphyseal marrow signal and high signal periostitis in the tibial metaphysis, greater on the right.

Figure 5. Lower right leg axial T2-weighted scan with fat saturation demonstrated high signal in the subcutaneous tissues and calf musculature (gastrocnemius and soleus muscles) consistent with subcutaneous edema and myositis.