Limp In Children

Introduction

Limp in children is a common presenting complaint in pediatric practice and an important topic for MCCQE1 preparation. This article provides a comprehensive overview of the etiology, diagnosis, and management of limping in children, with a focus on Canadian healthcare practices and guidelines.

Epidemiology in the Canadian Context

• Limp affects approximately 1.8 per 1000 children in Canada annually
• Peak incidence occurs between 3-8 years of age
• Boys are more commonly affected than girls (ratio 2:1)

Etiology and Classification

Causes of limp in children can be classified based on age and onset:

Classification by Onset

1. Acute Onset

   • Trauma
   • Infection (septic arthritis, osteomyelitis)
   • Transient synovitis

2. Gradual Onset

   • Legg-Calvé-Perthes disease
   • Slipped capital femoral epiphysis (SCFE)
   • Juvenile idiopathic arthritis (JIA)

Clinical Approach

Key Differential Diagnoses

1. Transient Synovitis

• Most common cause of acute hip pain in children 3-10 years old
• Self-limiting condition
• Diagnosis of exclusion

2. Septic Arthritis

• Medical emergency
• Presents with fever, severe pain, and limited range of motion
• Requires prompt diagnosis and treatment

3. Legg-Calvé-Perthes Disease

• Idiopathic avascular necrosis of the femoral head
• Typically affects children 4-8 years old
• More common in boys

4. Slipped Capital Femoral Epiphysis (SCFE)

• Most common hip disorder in adolescents
• Higher incidence in obese children
• Requires urgent orthopedic consultation

Canadian Guidelines for Management

The Canadian Paediatric Society provides the following recommendations for managing limp in children:

1. Thorough history and physical examination are crucial for diagnosis
2. Consider septic arthritis in any child with fever and acute hip pain
3. Ultrasound is the preferred initial imaging modality for suspected hip effusion
4. MRI should be considered for cases where the diagnosis remains unclear after initial investigations
5. Prompt referral to pediatric orthopedics for conditions requiring surgical management (e.g., SCFE)

MCCQE1 High-Yield Points

• 🇨🇦 Remember the age-specific causes of limp in children
• 🇨🇦 Septic arthritis is a medical emergency requiring prompt diagnosis and treatment
• 🇨🇦 Transient synovitis is the most common cause of acute hip pain in children 3-10 years old
• 🇨🇦 SCFE is more common in obese adolescents and requires urgent orthopedic consultation
• 🇨🇦 Ultrasound is the preferred initial imaging modality for suspected hip effusion in Canada

MCCQE1 Mnemonic: "LIMPS"

L - Legg-Calvé-Perthes disease I - Infection (septic arthritis, osteomyelitis) M - Mechanical (trauma, fracture) P - Perthes disease (repetition for emphasis) S - Slipped capital femoral epiphysis

Sample Question

MCCQE1-Style MCQ

A 6-year-old boy presents to the emergency department with a 2-day history of left hip pain and limping. He has no history of trauma and his parents report a low-grade fever (38.1°C). On examination, he is reluctant to bear weight on his left leg and has limited range of motion of the left hip. Which one of the following is the most appropriate next step in management?

• A. Prescribe oral antibiotics and follow up in 48 hours
• B. Order an MRI of the hip
• C. Perform an ultrasound of the hip
• D. Recommend rest and NSAIDs for 5 days
• E. Immediately consult orthopedic surgery for surgical intervention

Explanation

The correct answer is:

• C. Perform an ultrasound of the hip

Explanation: In this case, the child presents with acute hip pain, limping, and low-grade fever. The differential diagnosis includes transient synovitis and septic arthritis. According to Canadian guidelines, ultrasound is the preferred initial imaging modality for suspected hip effusion. It can help differentiate between these conditions by detecting the presence and characteristics of an effusion.

Option A (antibiotics) is premature without confirming the diagnosis. Option B (MRI) is not the first-line imaging study in this scenario. Option D (rest and NSAIDs) may be appropriate for transient synovitis but could delay diagnosis of a more serious condition like septic arthritis. Option E (orthopedic consultation) may be necessary but is not the most appropriate next step before imaging.

References

1. Canadian Paediatric Society. (2020). The limping child: Evaluation and diagnosis. Paediatrics & Child Health, 25(1), 31-42.

2. Sawyer, J. R., & Kapoor, M. (2015). The limping child: a systematic approach to diagnosis. American Family Physician, 92(10), 908-916.

3. Aronsson, D. D., Loder, R. T., Breur, G. J., & Weinstein, S. L. (2006). Slipped capital femoral epiphysis: current concepts. Journal of the American Academy of Orthopaedic Surgeons, 14(12), 666-679.

4. Kocher, M. S., Zurakowski, D., & Kasser, J. R. (1999). Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. The Journal of Bone and Joint Surgery. American Volume, 81(12), 1662-1670.

5. Canadian Association of Radiologists. (2018). Diagnostic Imaging Referral Guidelines. Retrieved from https://car.ca/patient-care/referral-guidelines/ (opens in a new tab)