C-reactive protein of ≥ 20 mg/L and ultrasound finding of an effusion ≥ 7 mm has a high specificity and sensitivity in diagnosing paediatric hip septic arthritis

PURPOSE

Differentiating septic arthritis (SA) from transient synovitis (TS) in children remains a diagnostic challenge. Several algorithms have been developed to diagnose SA including Kocher's criteria and its subsequent modifications, but reports show variable efficacy. This study aims to examine the diagnostic utility of a novel method only using C-reactive protein (CRP) and ultrasound (US) findings of effusion in differentiating SA from TS, determine the optimal values for these predictors and validate this method against existing clinical predictors.

METHODS

A 5-year retrospective study was performed including all paediatric patients with acute, non-traumatic hip pain with a suspicion of SA. All patients were evaluated using Kocher's criteria, Caird's criteria, and the novel method. Multivariate logistic regression was performed to identify independent clinical predictors of SA. The degree of agreement between the various methods were assessed using Cohen's kappa (k). Receiver operating characteristics (ROC) curves were used to examine the diagnostic accuracy of this novel method as well as to determine optimal cut-offs for US effusion and CRP in diagnosing SA.

RESULTS

Hundred and one patients were recruited. CRP and effusion on US were found to be independent predictors of SA. Both Kocher's and Caird's method showed good specificity (98.9%) but extremely poor sensitivity for SA (0%). When Kocher's four clinical predictors were present, probability of SA was only 59.16%. The k for both Kocher's and Caird's methods, was -0.017 indicating poor agreement. However the k in the novel method was 0.641, indicating good agreement.

CONCLUSION

Our study showed that the novel method using CRP (≥ 20 mg/L) and US finding of effusion (≥ 7 mm) has a high specificity (97%) and sensitivity (71%) in diagnosing SA.

Coronal STIR MRI sequences in unexplained limping in children under 6 years old: A single-center retrospective study of 130 cases

INTRODUCTION

Limping is a common presenting symptom in young children. Clinical examination backed up by laboratory analysis, standard radiography, and/or ultrasound may fail to determine the diagnosis, and limping may prove persistent, requiring repeated consultation. Magnetic resonance imaging (MRI) can suggest the etiology or provide welcome reassurance when normal. We advocate the use of MRI in cases of persistent unexplained limping in young children. The study hypothesis was that coronal short TI inversion recovery (STIR) MRI has good negative predictive value (NPV) in unexplained limping in children under 6 years of age.

MATERIAL AND METHOD

Coronal STIR MRI sequences were analyzed in 130 children younger than 6 years (84 boys, 46 girls) during the period April 2007 to May 2017. They extended from the lower thoracic spine down to the feet. Agreement was analyzed between the radiologist's initially suggested diagnosis and the pediatric orthopedic specialist's final diagnosis.

RESULTS

Overall, 49 scans were normal (37.7%) and 81 abnormal (62.3%). The mean age at MRI was 32.3 months. Coronal STIR MRI had 98% NPV. There was 99.2% agreement between the radiologist's diagnosis and the final diagnosis.

DISCUSSION

The recently reported contribution of STIR MRI in bone and joint infections was extended to unexplained limping.

CONCLUSION

First-line MRI with coronal STIR sequences improved the diagnostic efficacy, thanks to its speed and relative lack of movement artifacts.

Natural cases of polyarthritis associated with feline calicivirus infection in cats

The limping syndrome is occasionally reported during acute feline calicivirus (FCV) infections or as consequence of vaccination. In this retrospective study, three clinical cases of lameness in household cats naturally infected by FCV were described and phylogeny of the virus were investigated by analysing the hypervariable E region of the ORF2 viral gene. Cats were diagnosed with polyarthritis and FCV RNA or antigens were detected in symptomatic joints. One cat, euthanized for ethical reasons, underwent a complete post-mortem examination and was subjected to histopathological and immunohistochemical investigations. No phylogenetic subgrouping were evident for the sequenced FCV. Histopathology of the euthanized cat revealed diffuse fibrinous synovitis and osteoarthritis eight months after the onset of lameness and the first detection of FCV RNA, supporting the hypothesis of a persistent infection. FCV was demonstrated by immunohistochemistry in synoviocytes and fibroblasts of the synovial membranes. This study provides new data on the occurrence of polyarthritis in FCV-infected cats, demonstrates by immunohistochemistry the presence of FCV in the synovial membranes of a cat with persistent polyarthritis and supports the absence of correlation between limping syndrome and phylogenetic subgrouping of viruses.

[Hip necrosis. A severe complication after intragluteal injection of quinine salt in Bangui, Central African Republic]

Introduction

Intramuscular injection of quinine has been for long the most common treatment for malaria in children in endemic areas of Africa, especially sub-Saharan Africa, and remains too often used. However, it is frequently wrongly performed by unqualified people. When administered in a poorly developed or malnourished child, the injection can be done too deeply in the hip joint instead of the gluteus muscle area.

Materials and Methods

The files of 3012 children examined in out-patient clinics in Bangui, Central African Republic, between 2011 and 2020 were reviewed. Sequelae of intramuscular injections were observed in 307 cases, including intraquadricipital injection in 170 cases (56%) and intragluteal injection in 137 cases (44%). The latter included 115 sciatic paralysis and 22 hip sequelae with stiffness, shortening of the limb, limping and pain at walking. In these 22 cases, an intragluteal injection was incriminated by the families. However, 16 files were considered as insufficient because of imprecise history or because poor quality or no radiograph was available. Although suspected of being hip necrosis, these files were excluded. Six cases presented specific clinical pictures and interpretable radiographs and were included in this study.

Results

The clinical and the radiographic aspects of this severe complication apparently not documented in the literature are analyzed. The well-known toxicity of quinine may be responsible of a necrosis involving both the femoral head and the acetabular roof, resulting in a painful joint, stiff in adduction, with limping and with an apparent marked shortening of the lower limb. Radiographs show a subtotal femoral head necrosis associated to an acetabular roof necrosis with an upward displacement of the epiphyseo-metaphysal femoral stump, the latter keeping a roughly spherical aspect and remaining well-covered and fitted in a relatively deep neo-acetabulum.

Discussion

In the African background, this picture of coxopathy occurring in childhood may suggest an avascular necrosis of the femoral head complicating a sickle-cells disease, or above all sequelae of septic osteoarthritis. Treatments are limited to the prescription of a partial weight bearing of the hip.

Conclusion

Although no irrefutable arguments are existing, the observed clinical and radiographic pictures are sufficiently clear and typical to individualize this severe iatrogenic complication which should be avoided by a good technic or by using the intravenous way when necessary.

Post SARS-CoV-2 infection reactive arthritis: a brief report of two pediatric cases

BACKGROUND

Although, preliminary reports of Severe Acute Respiratory Syndrome (SARS)-CoV-2 infection suggest that the infection causes a less severe illness in children, there is now growing evidence of other rare or even serious complications of disease.

CASE PRESENTATION

During the recent COVID-19 pandemic in Kerman, Iran, two children (an 8 year-old boy and a 6 year-old girl) were referred to outpatient Clinic of Pediatric Rheumatology with complaints of limping. Both children had experienced fever and mild respiratory tract infection. At the beginning of the second week of infection, they developed joint effusion. They both tested positive for coronavirus infection and were therefore diagnosed with post Coronavirus reactive arthritis. Both children were treated successfully with rest and Non-Steroidal Anti-Inflammatory Drugs (NSAID). They did not have any medical problems in the two months fallow up.

CONCLUSIONS

These two cases suggest that COVID-19 may be rheumatogenic. Highlighting the need for awareness of physicians, especially pediatricians, regarding the pathogenesis margins of this virus, as late presentations are of great importance.

Contributions of nuclear medicine in paediatric non-tumour musculoskeletal pathology

Non-tumour musculoskeletal pathology in children represents a high percentage of the nuclear medicine studies requested by paediatricians. As these are immature bones and joints, in constant growth and remodelling, they present their own physiological and anatomical peculiarities that require a specific management for the paediatric age group. Using different clinical scenarios frequently observed in medical appointments (limping, back pain or fever, among others), we have summarised the possible findings or artefacts that can be obtained in the different Nuclear Medicine explorations, including bone scintigraphy and hybrid images such as PET/CT. To obtain high quality images requires careful attention to technique and positioning in children. Bone scintigraphy is a common paediatric nuclear medicine procedure and plays an important role in the diagnosis of musculoskeletal pathologies and can be complemented by techniques such as SPECT to improve localisation and diagnostic accuracy. In addition, ¹⁸F-FDG PET/CT is increasingly applied in the evaluation of children. This article reviews the usual indications of, mainly, bone scintigraphy and ¹⁸F-FDG PET/CT in paediatric non-tumour musculoskeletal diseases, how to interpret them properly, being essential to know the normal physiological distribution of each radiopharmaceutical, as well as the common variants of paediatric growth that can simulate disease, implying possible misinterpretations between normal and pathological structures.

Iliopsoas Abscess

Iliopsoas abscess (IPA) is uncommon condition in children, diagnosis might be delayed because of nonspecific signs and symptoms. Only few patients have classical clinical triad at presentation in the form of fever, back pain, and inguinal pain at hip flexion. The diagnosis most likely to be reached in the first time by the use of abdominal computed tomography (CT) scan. We present a Saudi child with nonspecific signs and symptoms of fever, flank pain, and limping who was diagnosed as IPA by abdominal ultrasound and CT scan. The case was managed with intravenous antibiotics along with transcutaneous abscess drainage.

Features distinguishing juvenile idiopathic arthritis among children with musculoskeletal complaints

BACKGROUND

Musculoskeletal (MSK) complaints in children vary, ranging from benign, self-limited conditions to serious disorders. Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease, initially presenting with MSK complaints. Delayed diagnosis and appropriate treatment have an enormous impact on the long-term outcomes and the level of disability. This study aimed to identify the features distinguishing JIA among children presenting with MSK complaints and to describe the spectrum of diseases at a large, single, tertiary center.

METHODS

A retrospective chart review was performed of patients evaluated by pediatric rheumatology consultation at the Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, from July 2011 to June 2015.

RESULTS

Of 531 patients, 285 (53.6%) had at least one MSK complaint. The mean age of the patients was 9.1 ± 4.1 years. Joint pain was the most common MSK complaint (86.3%), followed by limping (33%) and refusal to walk (19.6%). Joint swelling and limited range of motion were found in 146 (51.2%) and 115 (40.4%) patients, respectively. Seventy-three (25.6%) patients were diagnosed as JIA. The other common diagnoses included Henoch-Schönlein purpura (16.1%), reactive arthritis (14.2%), and systemic lupus erythematosus (13.7%). Morning stiffness  ≥ 15 minutes [odds ratio (OR) 8.217 (3.404-19.833)]; joint swelling on MSK examination [OR 3.505 (1.754-7.004)]; a duration of MSK complaints of more than 6 weeks [OR 2.071 (1.120-3.829)]; and limping [OR 1.973 (1.048-3.712)] were significantly associated with the ultimate diagnosis of JIA.

CONCLUSIONS

Morning stiffness ≥ 15 minutes is a strong predictor of JIA. Comprehensive history taking and an MSK examination will provide clues for making the ultimate diagnosis for children with MSK complaints.

The role of hybrid bone SPECT/CT imaging in the work-up of the limping patient: a symptom-based and joint-oriented review

A vast spectrum of lower limb bone and joint disorders (hip, knee, ankle, foot) present with a common clinical presentation: limping. Too often this symptom generates an inefficient cascade of imaging studies. This review attempts to optimise the diagnostic effectiveness of bone scintigraphy using the hybrid SPECT/CT technique in relation to the diagnostic clues provided by other imaging modalities, discusses the appropriate clinical indications, optimal scintigraphic procedures and illustrates updated image pattern-oriented reporting. Frequent lower limb bone and joint pathologies that can now be reliably diagnosed using hybrid bone SPECT/CT imaging will be reviewed. Bone SPECT/CT can be an effective problem-solving tool in patients with persistent limping when careful history taking, clinical examination, and first-line imaging modalities fail to identify the underlying cause.

Diskitis as Manifestation of Gait Disturbance

Gait disturbance is a common presentation of neurologic disease in children. Limping is a kind of gait dysfunction that occurs due to neurologic & skeletal diseases. Diskitis is an inflammatory process noted as one of the significant causes of limping especially in children aged less than 3 yr. Here we report case of diskitis and limping as the significant manifestation of Gait disturbance in A 22 months old boy from 17 Shahrivar Hospital in 2016, Rasht, northern Iran. Regarding normal neurologic exam, nervous system involvement was less possible. About 60% of gait cycle related to stance phase.

Dynamics of dimeric kinesins: Limping, effect of longitudinal force, effects of neck linker extension and mutation, and comparison between kinesin-1 and kinesin-2

Conventional kinesin (kinesin-1) can walk on microtubule filaments in an asymmetric hand-over-hand manner, exhibiting a marked alternation in the mean dwell time in successive steps. Here, we study computationally the asymmetric stepping dynamics of the kinesin-1 homodimer, revealing its origin and providing quantitative explanations of the available experimental data. The alternation in the mean dwell time in successive steps arises from the alternation in the mechanochemical coupling ratio, which is in turn caused by the alternation in the slight variation of the stretched neck linker length. Both the vertical and backward longitudinal forces can enhance the asymmetric ratio. Additionally, other aspects of the stepping dynamics of the dimer such as the velocity versus longitudinal force, extended neck linker, etc., are also studied. In particular, the conflicting experimental data, with some showing that the velocity does not change with the forward longitudinal load while others showing that the velocity increases largely with the forward longitudinal load, are explained quantitatively and consistently. The intriguing experimental data showing that cysteine-light Drosophila and human kinesin-1 mutants have different load-dependent velocity from the wild-type cases as well as that kinesin-2 dimers have different load-dependent velocity from the kinesin-1 are also explained consistently and quantitatively.

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Zusammenfassung. Hinken ist ein häufiger Vorstellungsgrund in der pädiatrischen Praxis und stellt wegen der vielfältigen Differenzialdiagnosen, der teilweise schwierigen Anamnese und den möglicherweise sehr unspezifischen klinischen Befunden eine diagnostische Herausforderung dar. Die Kunst besteht darin, bei häufigen und selbstlimitierenden, harmlosen Krankheitsbildern (z.B. Coxitis fugax, Myositis) die diagnostischen Untersuchungen zurückhaltend einzusetzen und gleichzeitig potenziell schwerwiegende Ursachen (z.B. septische Arthritis, Epiphysiolysis capitis femoris) nicht zu verpassen. Eine sorgfältige Anamnese und körperliche Untersuchung grenzen die umfangreiche Liste der Differenzialdiagnosen entscheidend ein und helfen bei der Wahl allenfalls nötiger Zusatzuntersuchungen wie Bluttest oder bildgebender Verfahren.

Muscle contributions to center of mass acceleration adapt to asymmetric walking in healthy subjects

Symmetrical limb movement requires complex muscle coordination patterns. Consequently, coordination impairments lead to asymmetric gait patterns, as often seen in stroke subjects. Split-belt walking has previously been used to induce limping-like walking in able-bodied adults. The goal of this study is to analyze how muscle coordination patterns that control the centre of mass are modulated during an asymmetric gait pattern imposed on healthy subjects. These modulations can be uniquely related to the biomechanics of limping as no pathology is present. Forward simulations of limping-like walking (split-belt) and corresponding symmetric conditions (tied-belt) were generated for twelve healthy subjects. Our results show that the differences between 'fast' and 'slow' leg contributions during split-belt walking are not attributable to simple differences in speed between the belts, because most split-belt muscle contributions differ from tied-belt walking. Different types of modulations, inducing increased, decreased or even reversed asymmetry (e.g. plantarflexors, biceps femoris short head, and quadriceps respectively), underlie limping-like walking in healthy subjects. In general, these patterns present large similarities with adaptations previously described in hemiplegic subjects. However, differences were found with gluteus medius and biceps femoris short head contributions in hemiplegic subjects, suggesting that the latter are not just related to limping, but to concomitant deficits.

Unicameral bone cyst of the proximal tibia in a five year old girl

Unicameral bone cysts (UBCs) are benign, osteolytic lesions which are often asymptomatic and are commonly seen in the proximal of humerus and femur. The average age at diagnosis is 9-11 years and there is a male preponderance with a male-to-female ratio of approximately 2-2.5 to 1. We describe a case of 5-year-old girl who presented to orthopedic clinic with a 4-month history of painful limping. Plain radiography of the right knee demonstrated a well-defined lytic lesion in the proximal of the tibia. Open biopsy and then curettage and bone grafting with bone- substitute was performed. The diagnosis of this condition requires a high index of suspicion. This report demonstrates that all UBCs do not have the same clinical patterns and with adequate attention good results can be achieved.