<s>[INST] context: USG guided aspiration of hip There are two very common causes of an acute hip/groin pain, which commonly are very challenging to diagnose: septic ahritis and transient synovitis. Septic ahritis and transient synovitis are completely unrelated, although both might manifest with hip pain, restricted range of movement of the hip. Differentiating between these two is vital, because while transient synovitis is a benign self-limiting disorder, the septic ahritis if untreated is catastrophic with permanent damage to the hip. Treatment for septic ahritis and for transient synovitis is entirely different. While transient synovitis can be managed by observation and anti-inflammatory agents; septic ahritis needs aggressive management with intravenous antibiotics with or without surgical debridement. Lets, first see the two conditions and the differences between them: Transient synovitis (also k/a toxic synovitis, observation hip. irritable hip) Its a self-limiting, inflammatory condition of the synovium, that lasts only a sho time (therefore k/a transient) Its the most CO/11111On cause of hip pain and limp in children under 10 yrs of age. Although the cause of transient synovitis is unclear, evidence suggests it is associated with immune responses to viral or bacterial antigens, mediated through the synol membrane. Synol fluid rapidly accumulates under pressure in the hip joint, and there may be severe pain from capsular distension. The fluid is resorbed within 3-7 days, with no long term sequelae. Presentation is with hip pain or limp. Hip can be held in flexion, abduction and external rotation depending on the degree of effusion. Physical examination is characterized by guarded rotation of the hip joint. Pain can usually be elicited at the extremes of motion, especially abduction and medial rotation. The ESR and C-reactive protein are usually normal but may be mildly elevated. The WBC count is generally normal with a normal differential. Rest is the primary method of treatment (thus it's also k/a observation hip). In most patients the symptoms resolve in 3 to 7 days. Differentiation from septic ahritis: The very impoant distinction between transient synovitis and septic ahritis is in the first instance clinical. The patient with transient synovitis is not sick, appears cheerful and healthy and, if there is fever, it is usually of a low-grade nature. Whereas a child with septic process is seriously ill, with high grade fever. Pain is severe and the patient is unable to bear weight. A patient of transient synovitis may be able to walk with a limp, however depending on the extent of effusion the pain in transient synovitis may also be severe enough as to render the child incapable of walking. In septic ahritis, WBC count, ESR and C-reactive protein are significantly raised. U/S may show joint fluid in both the conditions. "Within the past 5 years three excellent papers have been published that help differentiate between benign, transient synovitis and the potentially dangerous septic ahritis. In the two studies by Kocher et al - A history of fever, together with - Non-Weight bearing, and - ESR higher than 40 mm, and - A serum WBC count higher than 12000 cells/mm3 all pointed clearly toward septic ahritis. The probability of having septic ahritis with all four predictor was 99.6%. However, in a study Luhmann et al the probability was only 59% with all four predictors. They found that a history of fever, a WBC> 12000. and a previous health care visit yielded a 71% probability of septic ahritis. "Current diagnosis & treatment in spos medicine By Patrick J. McMahon 1/e p210 Now lets come to the question. Here we see that the information supplied is insufficient. ESR is raised but how much, its not given. The WBC count is normal, so we can think in lines of Transient synovitis, but Turek ohopaedics writes about septic ahritis- "The peripheral WBC count is usually elevated, as is the sedimentation rate, although the diagnosis of septic ahritis should not be excluded simply on the basis of normal values for these two studies." So here the diagnosis is unceain. Thus we will proceed with usg guided aspiration of the hip as the next line of management. "Aspiration of the joint must be done when the diagnosis is unceain."- Turek Ohopaedics "Joint aspiration is mandatory for fluid analysis and culture of the synol fluid in cases of septic ahritis.: " - T14rek ohopaedics [/INST] question: A 7yr. old boy with abrupt onset of pain in hip with hip held in abduction. Hernogram is normal. ESR is raised. What is the next line of management: | options: A: Hospitalize and observe B: Ambulatory observation C: Intravenous antiobiotics D: USG guided aspiration of hip | answer: D </s>