PAINFUL HIP



PAINFUL HIP


Christopher G. Anton, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Transient Synovitis


  • Septic Arthritis


  • Osteomyelitis


  • Slipped Capital Femoral Epiphysis (SCFE)


  • Legg-Calvé-Perthes (LCP)


  • Juvenile Idiopathic Arthritis (JIA)


  • Trauma


Less Common



  • Idiopathic Chondrolysis


  • Osteoid Osteoma


  • Osteonecrosis


  • Malignancy


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Age and history are helpful in narrowing differential diagnosis


Helpful Clues for Common Diagnoses



  • Transient Synovitis



    • a.k.a. irritable hip, toxic synovitis


    • Age: 18 months to 10 years; most common from age 4-7


    • Typically follows recent upper respiratory infection


    • Radiographs



      • Normal


      • Widening of medial joint space, lateral displacement of femoral head


    • 70% hip effusion on ultrasound


    • Hip held in flexion, external rotation, and abduction, restricted abduction and internal rotation


    • ± fever (often < 38° C)


    • May have mildly elevated erythrocyte sedimentation rate and white blood cell


    • Symptoms improve (usually within 48 hours) in 1-5 weeks



      • If symptoms persists beyond 1 week, consider another diagnosis


      • Recur in up to 17%


      • Legg-Calvé-Perthes develops in 1-3%


  • Septic Arthritis



    • Important to diagnose early to avoid destruction of joint



      • Delay in treatment ≥ 4 days results in suboptimal recovery


    • Age: < 4 years old


    • Staphylococcus aureus most common cause



      • Umbilical catheter, sepsis, and prior venous puncture have been implicated


    • Hip held in flexion


    • Infants can present with low-grade fever and feeding intolerance


    • Radiographs



      • Normal


      • Periostitis of proximal femur in neonates within days after start of symptoms


    • Treatment: Surgical drainage, IV antibiotics, traction


  • Osteomyelitis



    • Staphylococcus aureus most common


    • Streptococcus pneumonia (hypogammaglobinemia, sickle cell disease, asplenia)


    • Referred pain from spine or sacroiliac joints



      • Importance of scrutinizing spine and sacroiliac joints when imaging hips


    • May take up to 10-14 days before radiographs depict changes or osteomyelitis


    • Treatment: Abscess drainage, debridement, IV antibiotics


  • Slipped Capital Femoral Epiphysis (SCFE)



    • Salter-Harris type 1 femoral epiphyseal fracture


    • Age: 10-15 years old


    • M:F = 2:1; occurs earlier in girls


    • Predisposed: Obesity and endocrine disorders


    • Bilateral (18-36%)



      • Opposite side occurs within 18-24 months of 1st occurrence


    • Presentations: Acute, chronic, and acute on chronic


    • Radiographs



      • Widened femoral physis, medial and posterior displacement of femoral head (best seen frog leg lateral view)


      • Capital femoral epiphysis displacement without intersection of Klein line


      • Klein line: Line along lateral femoral neck and continuing toward acetabulum; ordinarily crosses small portion of femoral ossification center


  • Legg-Calvé-Perthes (LCP)



    • Osteonecrosis of femoral head of unknown etiology



    • Age: 3-12 years old; peak: 6-8 years old


    • Bilateral (10-20%)


    • Radiographs



      • Normal


      • Flattening, fragmentation, and sclerosis of femoral head


    • Key: Prognosis heavily depends on containment of femoral head


  • Juvenile Idiopathic Arthritis (JIA)



    • a.k.a. juvenile rheumatoid arthritis (JRA)


    • Age: < 16 years old


    • Symptoms with > 6 week duration


    • Other causes of arthritis are excluded


    • Stiff, swollen, painful, warm, and decreased motion in joint involved


    • MR: Synovitis, ± erosions, ± rice bodies


    • Joint space narrowing and ankylosis are late findings


  • Trauma



    • Acute (fracture) or repetitive (stress fracture) trauma


Helpful Clues for Less Common Diagnoses



  • Idiopathic Chondrolysis



    • Destruction of articular cartilage of femoral head and acetabulum


    • Stiffness, limpness, and pain around hip


    • Radiographs



      • Concentrically joint space narrowing, < 3 mm with osteopenia and pelvic tilt


    • MR: Rectangular hypointense T1 and hyperintense T2WI signal abnormality of center 1/3 of femoral head, ± ill defined within acetabulum


  • Osteoid Osteoma



    • Benign composed of osteoid and woven bone


    • 3 types: Cortical (most common), cancellous, or subperiosteal


    • < 2 cm nidus surrounded by dense sclerotic bone


    • Most common location is femur


    • Age: 10-30 years old, uncommon before age 5


    • Classic history: Pain at night relieved by nonsteroidal anti-inflammatory agents


    • NECT: Depicts nidus better than MR


    • Bone scan: Increased flow, “double density” pattern



      • Intense uptake by nidus surrounded by less intense activity of reactive bone


  • Osteonecrosis



    • Most commonly located in anterolateral weightbearing portion of femoral head


    • T2WI: “Double line” sign


    • Many causes, including sickle cell disease, trauma, steroid therapy, vasculitis, Gaucher disease, hemophilia


  • Malignancy



    • Primary such as chondroblastoma


    • Metastatic disease: Most commonly neuroblastoma


    • ± pathologic fracture






Image Gallery









Longitudinal ultrasound shows a widened anechoic joint space image with a convex outer margin, consistent with a hip effusion. Note the synovial thickening image along the femoral neck and joint lining.






Longitudinal ultrasound shows a normal hip for comparison with no significant joint fluid, evidenced by a normal joint space with a concave anterior margin image along the anterior femoral neck.

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Aug 10, 2016 | Posted by in PEDIATRICS | Comments Off on PAINFUL HIP

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