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Zorluk: Çok zorPediatric Musculoskeletal Disorders

A 7-year-old girl is brought to the clinic by her parents due to a worsening "waddling" gait and a limp. The parents first noticed the gait abnormality 8 months ago, but it has become more pronounced recently. The patient does not complain of pain in her hips, knees, or back, and she has no history of trauma. Her parents note that she has been less energetic lately, frequently falling asleep after school, and her teacher reported a decline in her academic performance over the past two terms. She also has a history of chronic constipation requiring daily osmotic laxatives. Her height is at the 3rd percentile for her age, and her weight is at the 85th percentile. Vital signs are within normal limits. Physical examination reveals a wide-based gait. There is restricted internal rotation and abduction of both hips. Neurologic examination shows normal muscle bulk and tone, but deep tendon reflexes demonstrate delayed relaxation phases. Bilateral radiographs of the pelvis demonstrate symmetric fragmentation, flattening, and sclerosis of both capital femoral epiphyses. Which of the following is the most appropriate next step in evaluating the underlying cause of this patient's orthopedic findings?

  1. A
    Genetic analysis for a mutation in the COMP gene
  2. B
    Hemoglobin electrophoresis
  3. Measurement of serum thyroid-stimulating hormoneCevap
  4. D
    Arthrocentesis of the hip joints
  5. E
    MRI of the lumbar spine

Cevap

Measurement of serum thyroid-stimulating hormone
The correct answer is the measurement of serum thyroid-stimulating hormone. This patient presents with acquired pediatric hypothyroidism, characterized by short stature, weight gain, fatigue, cognitive decline, constipation, and delayed relaxation of deep tendon reflexes (Woltman sign). Thyroid hormone is essential for normal endochondral ossification. Severe deficiency in children can lead to defective mineralization of the epiphyses, known as epiphyseal dysgenesis. Radiographically, this presents as symmetric fragmentation, flattening, and stippling of the capital femoral epiphyses, which can closely mimic Legg-Calvé-Perthes disease (LCPD). However, LCPD is characteristically unilateral, and when it is bilateral (seen in 10-15% of cases), it is almost always asynchronous (the hips are in different stages of necrosis and healing). The presence of symmetric bilateral epiphyseal fragmentation should immediately raise suspicion for a systemic condition such as hypothyroidism or multiple epiphyseal dysplasia, and a TSH level is the definitive next step to confirm the endocrine etiology.

Adım Adım Çözüm

1
Analyze the patient's gait and orthopedic findings
The patient has a chronic, painless waddling gait with restricted hip internal rotation and bilateral symmetric fragmentation of the capital femoral epiphyses.
To localize the primary musculoskeletal pathology, which is identified at the bilateral femoral heads.
2
Differentiate between isolated orthopedic disease and systemic disease
Legg-Calvé-Perthes disease is typically unilateral or asynchronous. Symmetric bilateral involvement strongly suggests a systemic, genetic, or endocrine etiology.
To narrow the differential diagnosis from local mechanical issues to systemic disorders.
3
Integrate systemic signs and symptoms
The patient exhibits short stature, weight gain, fatigue, cognitive decline, constipation, and delayed relaxation of deep tendon reflexes (Woltman sign).
To identify the specific systemic disorder causing the epiphyseal dysplasia.
4
Synthesize findings to determine the most likely diagnosis
The combination of acquired symmetric epiphyseal dysgenesis and classic hypothyroid symptoms points to severe, prolonged pediatric hypothyroidism.
To select the definitive diagnostic test, which is a TSH level.

Anahtar Kavram

Severe pediatric hypothyroidism can cause defective endochondral ossification leading to symmetric bilateral epiphyseal dysgenesis. This mimics Legg-Calvé-Perthes disease radiographically but is distinguished by its perfect symmetry and accompanying systemic endocrine symptoms.
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Pediatric Musculoskeletal Disorders

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