|Year : 2022 | Volume
| Issue : 11 | Page : 1936-1938
Diagnostic challenges in the management of septic arthritis of the neonatal hip: A case report
CO Anisi1, IE Abang1, OG Osakwe2, JE Asuquo1
1 Department of Orthopaedics and Traumatology, University of Calabar, Calabar, Nigeria
2 Department of Orthopaedics and Traumatology, University of Calabar Teaching Hospital, Calabar, Nigeria
|Date of Submission||12-Apr-2022|
|Date of Acceptance||13-Jun-2022|
|Date of Web Publication||18-Nov-2022|
Dr. C O Anisi
Department of Orthopaedics and Traumatology, University of Calabar, Calabar
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Septic arthritis of the neonatal hip is a very rare pathology. The clinical features may be different from those associated with older children, resulting in diagnostic challenges. Delay in instituting treatment, especially in neonates could be associated with severe dysfunction and deformity in a significant number of affected children. Therefore, treatment should be prompt and comprise broad-spectrum intravenous antibiotic therapy, surgical drainage, and general supportive care. The index patient is a 3-week-old neonate who had left hip arthrotomy on account of septic arthritis. The aim of this report is to highlight the challenges encountered in the diagnosis of septic arthritis of the hip in this patient.
Keywords: Challenges, diagnosis, hip, neonate, septic arthritis
|How to cite this article:|
Anisi C O, Abang I E, Osakwe O G, Asuquo J E. Diagnostic challenges in the management of septic arthritis of the neonatal hip: A case report. Niger J Clin Pract 2022;25:1936-8
|How to cite this URL:|
Anisi C O, Abang I E, Osakwe O G, Asuquo J E. Diagnostic challenges in the management of septic arthritis of the neonatal hip: A case report. Niger J Clin Pract [serial online] 2022 [cited 2022 Dec 2];25:1936-8. Available from: https://www.njcponline.com/text.asp?2022/25/11/1936/361453
| Introduction|| |
Septic arthritis is a microbial infection of the synovial joint which can affect all age groups in children but has a specific infantile form affecting the infant from birth to the first year of life. These infections are usually hematogenous but may occasionally result from contiguous spread or direct inoculation.,,
Septic arthritis of the neonatal hip is quite rare and could be associated with severe dysfunction and deformity in a significant number of affected children.,,, Diagnosis is usually based on clinical features, biochemical and hematological investigation results, as well as radiological studies.,, The clinical presentation in neonates may be different compared to older children, resulting in diagnostic challenges and delay in instituting appropriate treatment. In early infection, an older child usually presents with a limp in addition to constitutional symptoms. This is not the case in a neonate who is usually irritable, and its reluctance to move the affected limb can be easily missed. In a well-established infection, swelling of the affected joint, as well as redness of the overlying skin and tenderness, will be obvious.
Ultrasound scan is the most reliable method for detecting joint effusion in the early stage of infection, with the widening of the space between the capsule and bone of more than 2 mm considered significant, and more likely to be due to septic arthritis if echogenic. A plain radiograph may appear normal in early infection, but in established infection, it may include soft tissue swelling, loss of tissue planes, widening of the joint space, and subluxation, whereas narrowing and irregularity of the joint space are late features. The leukocyte count and erythrocyte sedimentation rate are usually raised, whereas blood culture may be positive. The joint aspirate may be clear in early infection but usually cloudy or frankly purulent in established infection. A joint aspirate leukocyte count greater than 50,000 per mL is highly suggestive of sepsis.
In a neonate, it is extremely difficult to differentiate between septic arthritis of the hip and metaphyseal osteomyelitis as clinical features of fever, reluctance to move the affected limb, and irritability would manifest in both cases. Ultrasonography easily clinches the diagnosis of septic arthritis by demonstrating joint effusion. In a plain radiograph, widening of the joint space differentiates septic arthritis of the hip from metaphyseal osteomyelitis, which is characterized by increased soft tissue shadow of the proximal thigh. Both conditions require early diagnosis, appropriate antibiotics, and surgical drainage.
Early diagnosis and management remains the most important prognostic factor in neonatal septic arthritis of the hip. Treatment should be prompt and comprise parenteral antibiotic therapy, surgical drainage, and supportive care.,,,, The aim of this report is to highlight the challenges encountered in the diagnosis of septic arthritis of the hip in a neonate.
| Case Report|| |
We present a case of a 3-week-old female neonate who was admitted to the Sick Baby Unit of our facility on account of reduced active movement of her left lower limb and excessive crying for about a 5-day duration. There was neither swelling nor deformity of any part of the left lower limb. However, there was a positive history of maternal preterm rupture of the membrane as well as neonatal jaundice and fever in the first week of life, for which the baby was admitted and discharged a week before presentation. On examination, the baby was irritable, afebrile to touch, anicteric, and not pale. Her left hip was held in a position of flexion, abduction, and external rotation with limited active movement of the left lower limb but marked resistance to passive movement. There was no swelling, differential warmth, or redness over the left hip. The left hip was markedly tender on gentle palpation. Left hip arthrocentesis yielded a dry tap. Findings on dynamic bilateral hip ultrasound scan included normal-appearing right hip joint and posteroinferior displacement of the left femoral head with respect to the acetabular labrum. Blood culture yielded no bacterial growth after 48 hours of incubation. The total white blood cell count was elevated. The erythrocyte sedimentation rate was equally elevated [see [Table 1]]. Plain radiograph of both lower limbs including the hip joints did not show any obvious soft tissue or bony changes [see [Figure 1]]. The child was treated with intravenous cefuroxime and metronidazole. Left hip arthrotomy and washout were performed. The joint capsule was bulging, hyperemic, and thickened and yielded 8 mL of pus following incision. The patient recovered uneventfully and was subsequently discharged 2 weeks later to the outpatient clinic.
|Figure 1: Plain radiograph of both lower limbs with absent features of osteoarticular infection|
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| Discussion|| |
Septic arthritis of the neonatal hip is quite rare but can be associated with far-reaching complications.,,, Challenges or delay in the diagnosis may be attributed to the fact that the clinical picture may be different when compared to older children. A high index of suspicion is therefore required to make diagnosis early and initiate timely intervention. In developed countries, invasive intrauterine procedures have been associated with neonatal septic arthritis. This is not the case in developing countries like ours where such procedures are rarely performed. In an established infection, clinical features such as fever and joint swelling with tenderness and redness of the overlying skin are usually obvious.
History of fever and jaundice in the index patient's first week of life necessitating hospital admission and aggressive intravenous antibiotic treatment may be responsible for the absence of some of the typical physical features of septic arthritis of the hip at the time of our review, as well as the negative blood culture result upon investigation. The misleading ultrasound scan features reported for the index patient may be explained by the fact that findings on ultrasound scan examination are largely dependent on the skill and experience of the examiner.
The plain radiograph did not show any obvious bony or soft tissue changes as expected in septic arthritis. This may not be unconnected to the early commencement of intravenous antibiotic therapy in the previous hospital admission and treatment. The leukocyte count and erythrocyte sedimentation rate were both elevated as expected.
The diagnosis of septic arthritis of the left hip in the index patient in spite of the absence of suggestive plain radiological and ultrasound findings was basically based on the perinatal history of premature rupture of membrane and neonatal sepsis, as well as physical examination and biochemical/hematological findings.
| Conclusion|| |
Detailed perinatal history is important for the early diagnosis of septic arthritis of the neonatal hip in a resource-poor setting.
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Conflicts of interest
There are no conflicts of interest.
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