Sample size determination in bioequivalence studies using statistical assurance

AIMS

Bioequivalence (BE) trials aim to demonstrate that the 90% confidence interval of the T/R-ratio of the pharmacokinetic metrics between two formulations (test [T] and reference [R]) of a drug is fully included in the acceptance interval [0.80, 1.25]. Traditionally, the sample size of BE trials is based on a power calculation based on the intrasubject variability coefficient of variation (CV) and the T/R-ratio of the metrics. Since the exact value of the T/R-ratio is not known prior to the trial, it is often assumed that the difference between the treatments does not exceed 5%. Hence, uncertainty about the T/R-ratio is expressed by using a fixed value for the sample size calculation. We propose to characterise the uncertainty about the T/R-ratio by a (normal) distribution for the log(T/R-ratio), with an assumed mean of  log θ = 0.00 (i.e. θ = 1.00) and a standard deviation σ_u , which quantifies the uncertainty. Evaluating this distribution leads to the statistical assurance of the BE trial.

METHODS

The assurance of a clinical trial can be derived by integrating the power over the distribution of the input parameters, in this case, the assumed distribution of the log(T/R)-ratio. Because it is an average power, the assurance can be interpreted as a measure of the probability of success that does not depend on a specific assumed value for the log(T/R)-ratio. The relationship between power and assurance will be analysed by comparing the numerical outcomes.

RESULTS

Using the assurance concept, values of the standard deviation for the distribution of potential log(T/R)-ratios can be chosen to reflect the magnitude of uncertainty. For most practical cases (i.e. when 0.95 ≤ θ ≤ 1.05), the sample size is not, or only slightly, changed when σ = |log(θ)|.

CONCLUSION

The advantage of deriving the assurance for BE trials is that uncertainty is directly expressed as a parameter of variability.

Team-based learning pedagogy enhances the quality of Chinese pharmacy education: a systematic review and meta-analysis

BACKGROUND

Recent years have witnessed the wide application of team-based learning(TBL) pedagogy in Chinese pharmacy education. However, the relevant systematic review evaluating the effects of such new pedagogical approach has not been established. The present study was designed to examine systematically the effect of using TBL approach in pharmacy education in China.

METHODS

Six databases were searched from the inception to January 2019. The studies reporting the performance of pharmacy students in Chinese university or college receiving TBL pedagogy compared to those receiving traditional lecture-based learning (LBL) were enrolled to be analyzed. Scores of the objective theoretical test were considered as the primary outcome, and the results from questionnaires about the number of students who approved the effects of TBL pedagogy on improving their learning enthusiasm, self-study ability, thinking ability, and communication skills were considered as the secondary outcome. A meta-analysis was conducted following the guidelines of the Cochrane Reviewer's Handbook and the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement.

RESULTS

A total of 1271 students in 12 studies published from 2013 to 2018 were enrolled in present analysis. Compared with traditional LBL pedagogy, TBL pedagogy exhibited more effectiveness in developing the objective tests scores of pharmacy students from both universities (SMD = 1.69, 95% CI [1.10, 2.28], p < 0.00001) and colleges (SMD = 4.37, 95% CI [1.33, 7.40], p < 0.00001), and such pedagogy applied well in experiments-oriented courses (SMD = 2.14, 95% CI [0.86, 3.43], p < 0.00001) and theory-oriented courses (SMD = 2.77, 95% CI [1.41, 4.14], p < 0.00001). In addition, it developed students' learning enthusiasm, students' self-study ability, thinking ability, and enhanced students' communication skills.

CONCLUSIONS

TBL pedagogy has developed rapidly and applied widely in Chinese pharmacy education during the last decade. The results indicated that such novel pedagogy is compatible with the present situation of Chinese pharmacy education. And it could be considered as an effective method to enhance both the theoretical test scores and various abilities of Chinese pharmacy students.

Comparison of the efficacy and safety of remifentanil versus different pharmacological approaches on prevention of etomidate-induced myoclonus: a meta-analysis of randomized controlled trials

Objective: Myoclonus was considered as one conundrum in etomidate induction, which led to multiple risks during clinical anesthesia. The present study was conducted to compare the efficacy of pretreatment with remifentanil to different pharmacological approaches on reducing etomidate-induced myoclonus.

Methods: We searched PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure from the inception to October 2018. Randomized controlled trials comparing remifentanil versus other pharmacological approaches in reducing etomidate-induced myoclonus were eligible to be analyzed.

Results: Overall, 13 trials with 1,392 patients met with the inclusion criteria. 1) Pretreatment with remifentanil could reduce the incidence of etomidate-induced myoclonus compared to placebo and fentanyl; few differences were found between the use of remifentanil and the use of midazolam: (incidence of myoclonus: 5.56% with remifentanil vs 71.65% with saline, RR=0.08, with 95% CI [0.05, 0.12], P<0.0001; 3.80% with remifentanil vs 13.33% with fentanyl, RR with 95% 0.31 [0.11, 0.86], P=0.02; 46.00% with remifentanil vs 55.45% with midazolam, RR=0.82, with 95% CI [0.64, 1.06], P=0.13). 2) Compared with placebo, pretreatment with remifentanil could reduce the incidence of mild, moderate, and severe myoclonus; compared with midazolam, patients receiving remifentanil experienced lower occurrence of severe myoclonus; compared with fentanyl, pretreatment with remifentanil associated with significant low occurrence of moderate and severe myoclonus. 3) The outcomes also indicated that pretreatment with remifentanil could prevent excessive hemodynamic changes after endotracheal intubation compared to fentanyl.

Conclusions: Pretreatment with remifentanil could be considered as one operative option to reduce both incidence and severity of etomidate-induced myoclonus. Compared with fentanyl, it also provides efficacy in preventing excessive hemodynamic changes after endotracheal intubation. However, the best treatment and the proper prophylactic dosage calls for more high quality evidence with large sample size.

Acquired neuromyotonia in thymoma-associated myasthenia gravis: a clinical and serological study

Background and purpose

Acquired neuromyotonia can occur in patients with thymoma, alone or in association with myasthenia gravis (MG), but the clinical prognostic significance of such comorbidity is largely unknown. The clinico‐pathological features were investigated along with the occurrence of neuromyotonia as predictors of tumour recurrence in patients with thymoma‐associated myasthenia.

Methods

A total number of 268 patients with thymomatous MG were studied retrospectively. Patients with symptoms of spontaneous muscle overactivity were selected for autoantibody testing using immunohistology for neuronal cell‐surface proteins and cell‐based assays for contactin‐associated protein 2 (CASPR2), leucine‐rich glioma inactivated 1 (LGI1), glycine receptor and Netrin‐1 receptor antibodies. Neuromyotonia was diagnosed according to the presence of typical electromyography abnormalities and/or autoantibodies against LGI1/CASPR2.

Results

Overall, 33/268 (12%) MG patients had a thymoma recurrence. Five/268 (2%) had neuromyotonia, four with typical autoantibodies, including LGI1 (n = 1), CASPR2 (n = 1) or both (n = 2). Three patients had Netrin‐1 receptor antibodies, two with neuromyotonia and concomitant CASPR2+LGI1 antibodies and one with spontaneous muscle overactivity without electromyography evidence of neuromyotonia. Thymoma recurrence was more frequent in those with (4/5, 80%) than in those without (28/263, 10%, P < 0.001) neuromyotonia. Neuromyotonia preceded the recurrence in 4/5 patients. In univariate analysis, predictors of thymoma recurrence were age at thymectomy [odds ratio (OR) 0.95, 95% confidence interval (CI) 0.93–0.97], Masaoka stage ≥IIb (OR 10.73, 95% CI 2.38–48.36) and neuromyotonia (OR 41.78, 95% CI 4.71–370.58).

Conclusions

De novo occurrence of neuromyotonia in MG patients with previous thymomas is a rare event and may herald tumour recurrence. Neuronal autoantibodies can be helpful to assess the diagnosis. These observations provide pragmatic risk stratification for tumour vigilance in patients with thymomatous MG.

Pretreatment with lidocaine reduces both incidence and severity of etomidate-induced myoclonus: a meta-analysis of randomized controlled trials

Objective

One conundrum that frequently occurs during clinical anesthesia is etomidate-induced myoclonus, which results in multiple risks. The aim of the study was to evaluate systematically the effect of pretreatment with lidocaine on preventing etomidate-induced myoclonus.

Materials and methods

The literature search was performed from the inception to April 2018 in PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure. All randomized controlled trials that used lidocaine to prevent etomidate-induced myoclonus were enrolled. The primary outcome included the incidence and severity of etomidate-induced myoclonus. The data were combined to calculate the risk ratio and relevant 95% CI. A meta-analysis was performed following the guidelines of the Cochrane Reviewer’s Handbook and the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement.

Results

A total of eight studies were enrolled, and the existing evidence indicated that 1) pretreatment with lidocaine can reduce the incidence of etomidate-induced myoclonus (the incidence of myoclonus: 37.6% in lidocaine vs 73.6% in saline, risk ratio =0.46, with 95% CI [0.34, 0.63], P<0.0001); 2) the pretreatment with lidocaine can reduce the incidence of mild, moderate, and severe myoclonus; 3) a dose of pretreatment with lidocaine cannot significantly decrease the duration of myoclonus compared to placebo; 4) the administration of lidocaine produced no effect on the stable hemodynamic parameters and no more additional adverse effects.

Conclusion

Pretreatment with lidocaine could be served as one effective approach to decrease both the incidence and the severity of etomidate-induced myoclonus, with limited influence on the hemodynamic stability of patients. However, to confirm precise safety and efficacy of such intervention, more high-quality evidence is necessary.

Szintigraphie mit111 ln-markiertem Antimyosin bei Churg-Strauss-Vaskulitis mit myokardialer Beteiligung

A case of Churg-Strauss vasculitis in a young woman is reported. Diagnosis was confirmed by muscle biopsy. Affection of lungs, kidneys and skin was evident. In addition, myocarditis was suspected on clinical evidence. A highly positive scintigraphy with 111 In-anti myosin enabled diagnosis and assessment of damage to the myocytes. With a heart-to-lung ratio of 3.0 the accumulated activity in the myocardium was higher than usually found in myocarditis. This finding supports the hypothesis of an additional ischemic necrosis.

Myeloid differentiation primary response gene (MyD) 88 signalling is not essential for intestinal fibrosis development

Dysregulation of the immune response to microbiota is associated with inflammatory bowel disease (IBD), which can trigger intestinal fibrosis. MyD88 is a key component of microbiota signalling but its influence on intestinal fibrosis has not been clarified. Small bowel resections from donor-mice were transplanted subcutaneously into the neck of recipients C57BL/6 B6-MyD88tm1 Aki (MyD88^-/-) and C57BL/6-Tg(UBC-green fluorescence protein (GFP))30Scha/J (GFP-Tg). Grafts were explanted up to 21 days after transplantation. Collagen layer thickness was determined using Sirius Red stained slides. In the mouse model of fibrosis collagen deposition and transforming growth factor-beta 1 (TGF-β1) expression was equal in MyD88^+/+ and MyD88^-/-, indicating that MyD88 was not essential for fibrogenesis. Matrix metalloproteinase (Mmp)9 expression was significantly decreased in grafts transplanted into MyD88^-/- recipients compared to MyD88^+/+ recipients (0.2 ± 0.1 vs. 153.0 ± 23.1, respectively, p < 0.05), similarly recruitment of neutrophils was significantly reduced (16.3 ± 4.5 vs. 25.4 ± 3.1, respectively, p < 0.05). Development of intestinal fibrosis appears to be independent of MyD88 signalling indicating a minor role of bacterial wall compounds in the process which is in contrast to published concepts and theories. Development of fibrosis appears to be uncoupled from acute inflammation.

Biologic therapies for refractory juvenile dermatomyositis: five years of experience of the Childhood Arthritis and Rheumatology Research Alliance in North America

BACKGROUND

The prognosis of children with juvenile dermatomyositis (JDM) has improved remarkably since the 1960's with the use of corticosteroid and immunosuppressive therapy. Yet there remain a minority of children who have refractory disease. Since 2003 the sporadic use of biologics (genetically-engineered proteins that usually are derived from human genes) for inflammatory myositis has been reported. In 2011-2016 we investigated our collective experience of biologics in JDM through the Childhood Arthritis and Rheumatology Research Alliance (CARRA).

METHODS

The JDM biologic study group developed a survey on the CARRA member experience using biologics for Juvenile DM utilizing Delphi consensus methods in 2011-2012. The survey was completed online by the CARRA members interested in JDM in 2012. A second survey was similarly developed that provided more opportunity to describe their experiences with biologics in JDM in detail and was completed by CARRA members in Feb 2013. During three CARRA meetings in 2013-2015, nominal group techniques were used for achieving consensus on the current choices of biologic drugs. A final survey was performed at the 2016 CARRA meeting.

RESULTS

One hundred and five of a potential 231 pediatric rheumatologists (42%) responded to the first survey in 2012. Thirty-five of 90 had never used a biologic for Juvenile DM at that time. Fifty-five of 91 (denominators vary) had used biologics for JDM in their practice with 32%, 5%, and 4% using rituximab, etanercept, and infliximab, respectively, and 17% having used more than one of the three drugs. Ten percent used a biologic as monotherapy, 19% a biologic in combination with methotrexate (mtx), 52% a biologic in combination with mtx and corticosteroids, 42% a combination of a biologic, mtx, corticosteroids (steroids), and an immunosuppressive drug, and 43% a combination of a biologic, IVIG and mtx. The results of the second survey supported these findings in considerably more detail with multiple combinations of drugs used with biologics and supported the use of rituximab, abatacept, anti-TNFα drugs, and tocilizumab in that order. One hundred percent recommended that CARRA continue studying biologics for JDM. The CARRA meeting survey in 2016 again supported the study and use of these four biologic drug groups.

CONCLUSIONS

Our CARRA JDM biologic work group developed and performed three surveys demonstrating that pediatric rheumatologists in North America have been using multiple biologics for refractory JDM in numerous scenarios from 2011 to 2016. These survey results and our consensus meetings determined our choice of four biologic therapies (rituximab, abatacept, tocilizumab and anti-TNFα drugs) to consider for refractory JDM treatment when indicated and to evaluate for comparative effectiveness and safety in the future. Significance and Innovations This is the first report that provides a substantial clinical experience of a large group of pediatric rheumatologists with biologics for refractory JDM over five years. This experience with biologic therapies for refractory JDM may aid pediatric rheumatologists in the current treatment of these children and form a basis for further clinical research into the comparative effectiveness and safety of biologics for refractory JDM.

[Focal meningitis in a California sea lion (Zalophus californianus)--diagnostic procedure and pathology]

A 15-year-old female California sea lion (Zalophus californianus) with progressive lameness of the hindlimbs and a chronic skin lesion was presented for clinical examination. The clinical neurological examination, showing a paraparesis, was completed by magnetic resonance imaging. MR images of the cervical and thoracic spine showed a well-defined muscle infiltrating lesion between the seventh cervical vertebra (C7) and the second thoracic vertebra (T2), which extended through the intervertebral foramina between C7 and T1 into the vertebral canal, causing spinal cord compression and displacement. Pathological examination revealed focal purulent meningitis resulting from widespread fistulas of the chronic skin leasion, which was infected with Escherichia coli var. haemolytica and Clostridium perfringens.

The ELPA library: scalable parallel eigenvalue solutions for electronic structure theory and computational science

Obtaining the eigenvalues and eigenvectors of large matrices is a key problem in electronic structure theory and many other areas of computational science. The computational effort formally scales as O(N(3)) with the size of the investigated problem, N (e.g. the electron count in electronic structure theory), and thus often defines the system size limit that practical calculations cannot overcome. In many cases, more than just a small fraction of the possible eigenvalue/eigenvector pairs is needed, so that iterative solution strategies that focus only on a few eigenvalues become ineffective. Likewise, it is not always desirable or practical to circumvent the eigenvalue solution entirely. We here review some current developments regarding dense eigenvalue solvers and then focus on the Eigenvalue soLvers for Petascale Applications (ELPA) library, which facilitates the efficient algebraic solution of symmetric and Hermitian eigenvalue problems for dense matrices that have real-valued and complex-valued matrix entries, respectively, on parallel computer platforms. ELPA addresses standard as well as generalized eigenvalue problems, relying on the well documented matrix layout of the Scalable Linear Algebra PACKage (ScaLAPACK) library but replacing all actual parallel solution steps with subroutines of its own. For these steps, ELPA significantly outperforms the corresponding ScaLAPACK routines and proprietary libraries that implement the ScaLAPACK interface (e.g. Intel's MKL). The most time-critical step is the reduction of the matrix to tridiagonal form and the corresponding backtransformation of the eigenvectors. ELPA offers both a one-step tridiagonalization (successive Householder transformations) and a two-step transformation that is more efficient especially towards larger matrices and larger numbers of CPU cores. ELPA is based on the MPI standard, with an early hybrid MPI-OpenMPI implementation available as well. Scalability beyond 10,000 CPU cores for problem sizes arising in the field of electronic structure theory is demonstrated for current high-performance computer architectures such as Cray or Intel/Infiniband. For a matrix of dimension 260,000, scalability up to 295,000 CPU cores has been shown on BlueGene/P.

The expression and roles of Nde1 and Ndel1 in the adult mammalian central nervous system

Mental and neurological illnesses affect one in four people. While genetic linkage analyses have shown an association of nuclear distribution factor E (NDE1, or NudE) and its ohnolog NDE-like 1 (NDEL1, or Nudel) with mental disorders, the cellular mechanisms remain unclear. In the present study, we have demonstrated that Nde1 and Ndel1 are differentially localised in the subventricular zone (SVZ) of the forebrain and the subgranular zone (SGZ) of the hippocampus, two regions where neurogenesis actively occurs in the adult brain. Nde1, but not Ndel1, is localized to putative SVZ stem cells, and to actively dividing progenitors of the SGZ. The influence of these proteins on neural stem cell differentiation was investigated by overexpression in a hippocampal neural stem cell line, HCN-A94. Increasing Nde1 expression in this neural stem cell line led to increased neuronal differentiation while decreasing levels of astroglial differentiation. In primary cultured neurons and astrocytes, Nde1 and Ndel1 were found to have different but comparable subcellular localizations. In addition, we have shown for the first time that Nde1 is heterogeneously distributed in cortical astrocytes of human brains. Our data indicate that Nde1 and Ndel1 have distinct but overlapping distribution patterns in mouse brain and cultured nerve cells. They may function differently and therefore their dosage changes may contribute to some aspects of mental disorders.

Farm-related trauma in the west of Ireland: an occupational hazard

BACKGROUND

Farm fatalities in Ireland remain at their highest recorded levels despite the introduction and implementation of several farm safety initiatives during recent years.

AIMS

The aim of this study was to examine all farm-related morbidity and mortality presenting to a general hospital in the west of Ireland.

METHODS

A consecutive series of all farm-related fatal and non-fatal injuries presenting to our institution over a 7-year period (2005-2011) was compiled by examining the hospital inpatient enquiry system and mortuary records.

RESULTS

One hundred and thirty patients were admitted to Mayo General Hospital with non-fatal farm-related injuries during the study period. This cohort was comprised 104 males and 26 females with an average age at presentation of 46 (range 19-75) years. The most common mechanism of non-fatal injury was animal attack. The mean length of hospital stay, mean length of ICU stay and total number of bed days used were 5.2, 5.3 and 677 days, respectively. There were seven farm-related fatalities during the same study period. Four were livestock-related, two due to machinery accident and one due to fall of a heavy object. The post-mortem findings were analysed in each case.

CONCLUSIONS

This analysis outlines the incidence and severity of fatal and non-fatal injuries sustained in the farming workplace and presenting to a general hospital serving a rural catchment population. Greater awareness of our results may help reduce the longterm incidence and magnitude of such injuries.

The development of bone mineral lateralization in the arms

Bone mineral content (BMC) is known to be greater in the dominant arm after the age of 8 years. We studied a group of children and found that BMC sidedness gradually increased up to the age of 6 years and then remained stable into late adolescence.

INTRODUCTION

Bone mineral content (BMC) exhibits sidedness in the arms after the age of 8 years, but it is not known whether BMC is greater in the dominant arm from birth or whether lateralization develops in early childhood. To address this, we examined bone mineral status in relation to handedness and age.

METHODS

Subjects (N = 158) were children recently initiating glucocorticoids for underlying disease (leukemia 43 %, rheumatic conditions 39 %, nephrotic syndrome 18 %). Handedness was determined by questionnaire and BMC by dual-energy X-ray absorptiometry.

RESULTS

Median age was 7.2 years (range, 1.5 to 17.0 years), 49 % was male, and the spine BMD Z-score was -0.9 (SD, 1.3). By linear regression, BMC sidedness in the arms was significantly related to age (r = 0.294, p = 0.0005). Breakpoint analysis revealed two lines with a knot at 6.0 years (95 % CI, 4.5-7.5 years). The formula for the first line was: dominant:nondominant arm BMC ratio = 0.029 × age [in years] + 0.850 (r = 0.323, p = 0.017). The slope of the second line was not different from 0 (p = 0.332), while the slopes for the two lines were significantly different (p = 0.027).

CONCLUSIONS

These results show that arm BMC sidedness in this patient group develops up to age 6 years and then remains stable into late adolescence. This temporal profile is consistent with mechanical stimulation of the skeleton in response to asymmetrical muscle use as handedness becomes manifest.

Voltage-gated potassium channel (K(v) 1) autoantibodies in patients with chagasic gut dysmotility and distribution of K(v) 1 channels in human enteric neuromusculature (autoantibodies in GI dysmotility)

BACKGROUND

Autoantibodies directed against specific neuronal antigens are found in a significant number of patients with gastrointestinal neuromuscular diseases (GINMDs) secondary to neoplasia. This study examined the presence of antineuronal antibodies in idiopathic GINMD and GINMD secondary to South American Trypanosomiasis. The GI distribution of voltage-gated potassium channels (VGKCs) was also investigated.

METHODS

Seventy-three patients were included in the study with diagnoses of primary achalasia, enteric dysmotility, chronic intestinal pseudo-obstruction, esophageal or colonic dysmotility secondary to Chagas' disease. Sera were screened for specific antibodies to glutamic acid decarboxylase, voltage-gated calcium channels (VGCCs; P/Q subtype), nicotinic acetylcholine receptors (nAChRs; α3 subtype), and voltage-gated potassium channels (VGKCs, K(V) 1 subtype) using validated immunoprecipitation assays. The distribution of six VGKC subunits (K(V) 1.1-1.6), including those known to be antigenic targets of anti-VGKC antibodies was immunohistochemically investigated in all main human GI tract regions.

KEY RESULTS

Three patients (14%) with chagasic GI dysmotility were found to have positive anti-VGKC antibody titers. No antibodies were detected in patients with idiopathic GINMD. The VGKCs were found in enteric neurons at every level of the gut in unique yet overlapping distributions. The VGKC expression in GI smooth muscle was found to be limited to the esophagus.

CONCLUSIONS & INFERENCES

A small proportion of patients with GI dysfunction secondary to Chagas' disease have antibodies against VGKCs. The presence of these channels in the human enteric nervous system may have pathological relevance to the growing number of GINMDs with which anti-VGKC antibodies have been associated.

Adult-onset Still's disease and chronic recurrent multifocal osteomyelitis: a hitherto undescribed manifestation of autoinflammation

Still's disease and chronic recurrent multifocal osteomyelitis (CRMO) are febrile rheumatic diseases of unknown etiology, which predominantly affect children but can also have their initial manifestation in adults. Both can present as intermittent, relapsing episodes and are considered potential candidates within the expanding spectrum of autoinflammatory disorders, although no genetic abnormalities have been described for either of them. Here, we describe a man with an initial manifestation of abacterial multifocal osteitis at the age of 41. During a relapsing-remitting course of his illness, he increasingly developed symptoms of adult-onset Still's disease (AOSD), and the diagnosis was established according to the Yamaguchi criteria. When treated with anakinra, not only the acute symptoms disappeared promptly, but also the osteitis went into complete remission. This is to our knowledge the first description of a simultaneous occurrence of these two manifestations of autoinflammation in adulthood.

Recognizing Kawasaki disease

Kawasaki disease (KD) occurs most often in children from one to three years of age. It is a common systemic vasculitis that is rare in children older than eight years of age or younger than six months of age; however, it may occur in these age groups. Boys are affected more often than girls by a ratio of 1.5 to 1. The mean annual incidence rate reported in a recent Canadian study was 13/100,000 children younger than five years of age. The highest incidence rates occur in Japan. The purpose of the present paper is to help the clinician to recognize KD in children. In particular, the paediatrician must be aware of situations in which KD poses a diagnostic challenge, such as KD in an infant younger than six months of age and the child who presents with a prolonged, unexplained fever but insufficient criteria to make a diagnosis of KD.