Visual Diagnosis: Rapid Deterioration of Respiratory Status and Lower Limb Hypotonia in a 6-month-old Infant.

Abstract

1. Guillaume J. LimFat, BMSc* 2. Vinay Kukreti, MD†,‡ 1. *Undergraduate Medicine, Queen’s University School of Medicine, Kingston, ON, Canada 2. †Department of Pediatrics, Queen’s University School of Medicine, Kingston General Hospital, Kingston, ON, Canada 3. ‡Department of Pediatrics, Lakeridge Health Oshawa, Oshawa, ON, Canada A 6-month-old previously healthy boy presents to the local emergency department with a 1-week history of progressive lethargy, irritability, and anorexia. Two days before presentation he developed an unusual breathing pattern and worsening respiratory distress, and he had a fever of 101.3°F (38.5°C). There was no rhinorrhea, coryza, cough, vomiting, or diarrhea. He appears unwell, with respiratory distress, tachypnea, and grunting. His blood pressure is 80/45 mm Hg, heart rate is 200 beats/min, respiratory rate is 60 breaths/min, and oxygen saturation is 77% in room air. He is afebrile. There is significantly decreased air entry bilaterally, most impressively over the right lung field. His neurologic examination reveals a mild right-sided ptosis. Although he moves both arms normally, there is a noticeable paucity of movements in his lower limbs, with decreased tone in both legs. The remainder of his examination findings are normal. On further questioning the parents clarify that for the past 2 months there has been a relative decrease in leg movements, and he had stopped attempting to bear weight when made to stand with support. His respiratory status does not improve, and he requires supplemental oxygen to maintain appropriate oxygen saturation. Clinical laboratory tests reveal a white blood cell count of 18,800/ μ L (18.8×109/L) (neutrophil count, 6,200/ μ L [6.2×109/L]; lymphocyte count, 11,100/ μ L [11.1×109/L]; and monocyte count, 1,100/ μ L [1.1×109/L]) and normal electrolyte levels. A chest radiograph reveals a large right paravertebral mass with significant left mediastinal shift associated with rib and vertebral destruction and moderate right-sided pleural effusion (Fig 1). Given these findings and worsening …