Fatty degeneration in a Wilms' tumour after chemotherapy

We report a case of extensive fatty change in a Wilms' tumour after chemotherapy demonstrated on CT associated with an increase in tumour volume, in a 10-month-old girl with Beckwith-Wiedemann syndrome. Changes in tumour characteristics after chemotherapy on imaging usually reflect necrosis, haemorrhage and calcification. Assessment of response to therapy is dependent on a documented reduction in tumour volume. In this case, CT showed an increase in tumour size with development of an extensive fatty component following treatment. Subsequent histological examination on the nephrectomy specimen confirmed an extensive fatty component with no evidence of residual blastema. The development of such an extensive fatty component is very unusual. In this case such fatty change was an indicator of tumour sensitivity and response to treatment.

The role of computed tomography in modern paediatric uroradiology

Computed tomography (CT) has developed a well-recognised role within paediatric uroradiology, especially in imaging of trauma, malignancy (in particular Wilms' tumour), atypical infection, and congenital urogenital abnormalities. CT can also be used for problem solving in nephrolithiasis and renal transplant assessment. These applications are illustrated and discussed, with an emphasis on particular information that can be gained from the CT study.

Localized paediatric orbital rhabdomyosarcoma: influence of imaging on treatment

AIM

Orbital rhabdomyosarcoma is the most common primary malignant orbital tumour in children and has a good prognosis. The purpose of this paper was to review the imaging and consequent treatment of patients with localized orbital rhabdomyosarcoma from around the U.K.

MATERIALS AND METHODS

Patients were identified through the U.K. Children's Cancer Study Group (UKCCSG) database. Investigations and therapy were dictated by the Malignant Mesenchymal Tumour '89 (MMT89) protocol. Imaging and radiological reports of 16 patients from 12 centres were reviewed. The number of patients receiving radiotherapy, timing of radiotherapy, and adherence to treatment protocols were assessed.

RESULTS

Local radiologists' reports and imaging techniques varied between sequential examinations and centres. The imaging was adequate for management. No reports quoted measurements of the tumours. Treatment protocols were not always followed rigidly with regard to a residual mass at day 80 post-diagnosis. However, the protocol was not explicit for all outcomes. Fifteen out of 16 patients eventually received radiotherapy.

CONCLUSION

There is no standardization of imaging between centres. The presence or absence of a post-therapeutic residue should be stated in the radiology report. Further investigation is needed to differentiate between fibrosis and recurrent tumour. Radiotherapy for residual mass at day 80 is probably more important than standardizing radiological technique.

Imaging in the preoperative assessment of conjoined twins

Conjoined twins are rare and present a unique challenge to pediatric surgeons and radiologists. Planning of surgical separation is aided by accurate preoperative imaging. Such twins are classified according to the most prominent site of connection: the thorax (thoracopagus), abdomen (omphalopagus), sacrum (pygopagus), pelvis (ischiopagus), skull (craniopagus), face (cephalopagus), or back (rachipagus). The area of fusion largely determines the imaging modalities used. Thoracic conjunction is most common and requires cardiac assessment. Magnetic resonance imaging and computed tomography provide excellent anatomic and bone detail, demonstrating organ position, shared viscera, and limited vascular anatomy. Contrast material radiography allows evaluation of the gastrointestinal and urogenital tracts, and a shared liver requires assessment of anatomy, vascularization, and biliary drainage. Angiography helps define specific vascular supply, which is useful in determining the distribution of shared structures between the twins at surgery. Each set of conjoined twins is unique. An imaging strategy to accurately define anatomic fusion, vascular anomalies, and other associated abnormalities is important for surgical planning and prognostic information.

Mediastinal mass obscured by a large pericardial effusion in a child: a potential cause of serious anaesthetic morbidity

Anaesthesia in the presence of a mediastinal mass is known to be hazardous. We report a case of a 5-year-old boy with a presumed postviral pericardial effusion presenting for pericardiocentesis under general anaesthesia. Cardiorespiratory collapse following induction of anaesthesia occurred due to an undiagnosed mediastinal tumour. The reasons for misdiagnosis, mechanisms for perioperative complications and optimal management are discussed. Mediastinal masses and underlying malignancy should always be considered in patients with large pericardial effusions.

Imaging of non-central nervous system primitive neuroectodermal tumours: diagnostic features and correlation with outcome

AIM

To document the varied radiological features before, during, and after treatment of non-Central Nervous System Primitive Neuroectodermal Tumours (PNETs), which are rare tumours of childhood.

MATERIALS AND METHODS

Thirty-three children with PNETs have been treated at our institution between 1990 and 1999. Full radiological and clinical follow-up was obtained in 29 (17 females, 12 males). Imaging was retrospectively reviewed, with particular attention to Computed Tomography (CT) and Magnetic Resonance Imaging (MRI).

RESULTS

Age range at diagnosis was 0-16 years old (mean 4.4 years). There were five main sites of tumour: head and neck (n = 7), scapula/axilla (n = 2), chest (n = 11), abdomen (n = 3), and spinal/paraspinal (n = 6). Overall mortality was 62%. Tumours of the scapula or paraspinal region appear to show better survival than other sites. Of 23 patients who had Tc99m-methylene diphosphonate (MDP) bone scans at diagnosis, four patients showed widespread distant metastases, seven showed focal increased uptake in an adjacent bone only, and 12 had normal examinations. CT was performed in 25 patients and MRI in 20, both at diagnosis and follow-up. Average size of tumours at presentation was 4.5 cm in the paraspinal, head and neck and scapular regions and 7.5 cm in the chest and abdomen. Tumours were typically of soft tissue density on CT with the larger (>5 cm) masses tending to be more heterogeneous in character. The lesions were slightly higher signal than muscle on T1-weighted (T1W) MRI and all masses were heterogeneous on T2W sequences. Calcification was uncommon (n = 6) and generally sparse. Tumours tended to displace adjacent soft tissue structures such as vessels and bronchi rather than invade or encase them. Tumours rarely crossed the midline. Local or bony invasion was seen in 12 patients at diagnosis. Metastases were identified in the lung (n = 5), pleura (n = 2), brain (n = 4), bone (n = 4), lymph nodes (n = 2), liver (n = 2), subcutaneous tissues (n = 2), kidney (n = 1) and peritoneum (n = 1).

CONCLUSIONS

Imaging characteristics of non-CNS PNETs are described. Tumours tend to displace rather than encase adjacent structures; local invasion occurred in 43%. Tumour calcification is uncommon. Poor prognostic features included the presence of distant metastases at diagnosis (all four patients with distant metastases at diagnosis died), but even patients without metastatic disease have a relatively poor prognosis.

Angiomatosis of bone and soft tissue: a spectrum of disease from diffuse lymphangiomatosis to vanishing bone disease in young patients

The application of cross-sectional imaging in the investigation of patients with angiomatosis reveals that lymphangiomatosis and vanishing bone disease should not be considered as separate entities, but rather as a spectrum of disease. We present a pictorial review of eight patients demonstrating the manifestations of soft tissue and bony involvement. We highlight a subgroup of patients with chyloid pleural effusions who have a poor prognosis.

Problems in the imaging of three common paediatric solid tumours

Modern radiologic techniques have led to a more accurate diagnosis and staging in many paediatric malignancies. The optimal imaging of some tumours is not, however, well defined and needs to be constantly re-assessed. Similarly with evolving clinical treatment protocols, recommended imaging strategies should be continually re-evaluated. The significance of some findings on radiologic examinations in paediatric oncology patients is disputed. A number of issues relating to the imaging of Wilms', neuroblastoma and rhabdomyosarcoma in childhood are discussed.

Discitis in young children

Discitis is uncommon in children and presents in different ways at different ages. It is most difficult to diagnose in the uncommunicative toddler of one to three years of age. We present 11 consecutive cases. The non-specific clinical features included refusal to walk (63%), back pain (27%), inability to flex the lower back (50%) and a loss of lumbar lordosis (40%). Laboratory tests were unhelpful and cultures of blood and disc tissue were negative. MRI reduces the diagnostic delay and may help to avoid the requirement for a biopsy. In 75% of cases it demonstrated a paravertebral inflammatory mass, which helped to determine the duration of the oral therapy given after initial intravenous antibiotics. At a mean follow-up of 21 months (10 to 40), all the spines were mobile and the patients free from pain. Radiological fusion occurred in 20% and was predictable after two years. At follow-up, MRI showed variable appearances: changes in the vertebral body usually resolved at 24 months and recovery of the disc was seen after 34 months.

Discitis in young children

Discitis is uncommon in children and presents in different ways at different ages. It is most difficult to diagnose in the uncommunicative toddler of one to three years of age. We present 11 consecutive cases. The non-specific clinical features included refusal to walk (63%), back pain (27%), inability to flex the lower back (50%) and a loss of lumbar lordosis (40%). Laboratory tests were unhelpful and cultures of blood and disc tissue were negative.

MRI reduces the diagnostic delay and may help to avoid the requirement for a biopsy. In 75% of cases it demonstrated a paravertebral inflammatory mass, which helped to determine the duration of the oral therapy given after initial intravenous antibiotics.

At a mean follow-up of 21 months (10 to 40), all the spines were mobile and the patients free from pain. Radiological fusion occurred in 20% and was predictable after two years. At follow-up, MRI showed variable appearances: changes in the vertebral body usually resolved at 24 months and recovery of the disc was seen after 34 months.

Cystic liver metastases from extracranial primitive neuroectodermal tumour: a case report

We report a rare case of cystic metastases to the liver from a peripheral primitive neuroectodermal tumour in a child. Ultrasound and CT appearances are described with a discussion on the histological findings and the differential diagnosis.

Decreases in endogenous opioid peptides in the rat medullo-coerulear pathway after chronic morphine treatment

Several biochemical changes have been described in noradrenergic neurons of the locus coeruleus (LC) after chronic morphine treatment. Changes in neurochemical expression in opioid afferent projections to the LC may be equally important in modulating noradrenergic neurons during chronic opiate exposure. To test the hypothesis that opioid peptides in LC afferents are altered after chronic opiate administration, we exposed adult male rats to either morphine or placebo pellets for 5 d. Tissue sections through the LC were processed for peroxidase or gold-silver labeling of methionine(5)-enkephalin (met-ENK) and analyzed using light or electron microscopy, respectively. Light level densitometry and ultrastructural analysis showed that there was a significant decrease in immunolabeling for ENK in LC-afferent terminals of morphine-treated rats. Western immunoblot analysis confirmed that protein levels for both leucine(5)- and methionine(5)-ENK were significantly decreased in tissue samples containing the LC after chronic morphine treatment. To test whether decreases in ENK protein expression were mirrored by decreases in gene expression, Northern blot analysis of preproenkephalin (PPE) mRNA was conducted in tissue samples obtained through the medulla, a brainstem area that contains the major opioid afferents to the LC. PPE mRNA was reduced in samples obtained from morphine-treated rats. Finally, in situ hybridization experiments confirmed significant decreases in PPE mRNA expression in the nucleus paragigantocellularis, a region known to provide a robust opioid input to the LC. These data suggest that there is a decrease in the synthesis of the opioid peptide mRNA and protein in the medullo-coerulear pathway after chronic exposure to morphine. Such alterations in opioid peptide levels during opiate dependence may contribute to the observed hyperactivity of LC neurons during opiate withdrawal.

Potential pitfalls in nuclear medicine: a paediatric teaching case

An infant with complex cardiac defects and isomerism had a persistent pyrexia of undetermined aetiology following cardiac surgery. Radionuclide leucocyte scan showed a focus of increased uptake in the right upper quadrant (RUQ) felt to be compatible with an abscess. However, correlation with clinical data and multimodality imaging allowed the correct diagnosis of ectopic splenic tissue in the RUQ to be made. This report emphasises the need for an integrated approach to imaging. Patients with abnormalities of viscero-atrial situs require careful assessment of their splenic status. Visceral heterotaxy may result in confusing imaging appearances unless the anatomy has been accurately documented.

Pericardial effusions in two boys with chronic granulomatous disease

Pericardial involvement in chronic granulomatous disease (CGD) is very rare. We present two children with known CGD and pericardial effusions in whom no microbial cause for the effusions was found.

Survey of intussusception reduction in England, Scotland and Wales: how and why we could do better

AIM

The aim of our study was to assess the variation in technique among hospitals in England, Wales and Scotland. In addition, local in hospital variation among paediatric radiologists at our own institution was assessed.

METHOD

Postal questionnaires were distributed to the radiology departments of 301 hospitals.

RESULTS

183 (60.8%) replies were received. 122 institutions reduced intussusceptions and 61 did not. A lack of paediatric surgical and/or anaesthetic cover, and a lack of radiological experience were the major reasons cited by the departments which did not attempt intussusception reduction. Sixty-five hospitals use barium for hydrostatic reduction, 43 employ pneumatic reduction, 10 use water-soluble enemas and four use ultrasound. Of the 65 centres using barium 16 (25%) reported a success rate of less than 50%, 24 (37%) had a 50-70% success rate, seven (11%) reduce greater than 70% of intussusceptions and 18 (27%) did not know. In the 43 institutions employing air reduction, one (2%) had a success rate less than 50%, 20 (47%) had a 50-70% success rate, 17 (40%) a success rate greater than 70% and five (11%) did not know. Overall, of the total number of hospitals which replied to our survey, 28 (23%) reported that they were not aware of their success rates. Within the pneumatic reduction group in particular there was marked variation in the methods and duration of attempted reduction - between different hospitals and within the same institution. In six departments the machine used for pneumatic reduction did not measure intraluminal pressure.

CONCLUSIONS

Ultrasound is underutilized despite being a sensitive method in diagnosis. There is almost certainly an over-reliance on plain radiographs and on the use of sedation, antibiotics and anti-spasmodics in general. We believe a 70% or greater success rate should be achievable in most institutions whether by pneumatic or hydrostatic reduction, and all departments should strive to achieve success rates in this range. Less than a quarter of centres who replied currently achieve this standard. Successful reduction rates below 50% are unacceptable in our opinion. Not surprisingly, success rates are generally highest in those centres treating more than 20 cases per annum. Twenty-eight (23%) of hospitals performing intussusception reductions did not know their success rates. Regular audits of intussesception figures should take place in all institutions. Unacceptably wide variations in intussusception reduction techniques currently exist. An accurate pressure release valve at least, and preferably intraluminal pressure monitoring should be an integral component of all pneumatic reduction devices. The British Paediatric Radiology and Imaging Group or the Royal College of Radiology should address these issues and introduce some standardization of practice.

Reversible ureteric and pelvicalyceal calcification in a 12-year-old boy

A 12-year-old boy was shown on CT to have unexplained pelvicalyceal and ureteric calcification which resolved over a 16-month period.

Evaluation of a method of assessing faecal loading on plain abdominal radiographs in children

BACKGROUND

Childhood constipation is common and assessment is often difficult. Plain abdominal radiography is simple and commonly used to assess constipation. The role of radiography with the use of a simple scoring system has not been fully evaluated.

OBJECTIVE

To assess the reliability of scoring faecal loading on plain abdominal radiographs in children with intractable constipation.

MATERIALS AND METHODS

Plain abdominal radiographs from 33 constipated and 67 control children were independently assessed by three observers on two separate occasions. A scoring system was devised with scores from 0 (no stool) to 5 (gross faecal loading with bowel dilatation) in three areas of the colon, giving a total score of 0-15.

RESULTS

There were significant differences between the scores of the constipated and control radiographs for each observer (P = 0.05). There was no intra-observer variation (P = 0.12-0.69), but significant inter-observer variation was demonstrated (P = 0.00).

CONCLUSIONS

We have found this scoring system to be a clinically useful and a reproducible tool in assessing childhood constipation. Assessment of faecal loading is subjective and varies between observers, although one observer will consistently score faecal loading on the same radiograph on successive occasions. To limit exposure to ionising radiation, we recommend that radiography be reserved for the investigation of intractable constipation, and its accuracy is improved if all radiographs are scored by the same observer.

Pleural pneumatocoeles mimicking congenital cystic adenomatoid malformation of the lung. A case report

We present the plain radiographic and CT appearances of large intrapleural pneumatocoeles in a 13-week-old infant, resulting in compression atelectasis of the left upper and lower lobes, and mimicking congenital cystic adenomatoid malformation.

The role of micturating cystourethrography in antenatally detected mild hydronephrosis

BACKGROUND

The postnatal imaging of infants with antenatally detected mild hydronephrosis remains controversial.

OBJECTIVE

Our aim was to establish the role and timing of micturating cystourethrography (MCUG) in mild hydronephrosis.

MATERIALS AND METHODS

We performed a retrospective study of 61 infants (122 kidneys) referred with an antenatal diagnosis of hydronephrosis who showed persistent postnatal dilatation. All had follow-up postnatal ultrasound (US) and MCUG performed. The degree of dilatation at each follow-up scan was recorded.

RESULTS

Of the 122 kidneys, 65 showed mild hydronephrosis. A substantial proportion of these (21.5%) demonstrated reflux. Serial US of these infants showed that the 6-week scan was the most informative and that any changes that warranted further investigation had occurred by this time.

CONCLUSION

We recommend that all infants with mild hydronephrosis should undergo MCUG. MCUG need not be delayed until 3 months but could be performed following a 6-week US scan.

Paediatric xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a well recognised but rare type of chronic pyelonephritis classically occurring in middle-aged women. It is increasingly being recognised in children in whom it can be mistaken for Wilms' tumour. Awareness of the possibility of this condition occurring in children may allow early recognition and possible treatment. Two cases of XGP in children are described and the literature reviewed.

The role of radiology in children with anorectal anomalies; with particular emphasis on MRI

Anorectal anomalies have a reported incidence of between 1 per 1000 and 1 per 9630 live births. The international classification subdivides anorectal malformations into high, intermediate, low and miscellaneous deformities with emphasis on the sex of the child. The classification is based on where the rectum terminates in relation to the levator ani muscles above the levator is termed a high (supralevator) lesion, at the level of the levator intermediate, and below is a low or translevator anomaly. A modified classification has recently been proposed by Pena based on his anatomic observations during posterior sagittal anorectoplasty-the terms high, intermediate and low lesions continue to be used but with slightly different connotations. Approximately 50% of all patients with anorectal anomalies have associated other congenital lesions. These lesions necessitate a variety of radiological investigations which will be outlined briefly. The pertinent muscular anatomy of the pelvic floor and recent advances in surgical techniques will be discussed. The particular role of MRI in the evaluation of the pre-operative newborn or infant prior to definitive pull-through repair surgery and the post-operative, older, paediatric patient with continuing problems will be reviewed. Reference to the other radiological options, and their usefulness, in the evaluation of anorectal malformations will be made throughout the text.

Factors influencing patient loyalty to dentist and dental practice

OBJECTIVE

To establish the factors considered by adult regular dental attenders to be the most important in choosing to stay with a particular dentist or practice.

DESIGN

An anonymous questionnaire to be completed by patients.

SETTING

General dental practices in England and Wales with a significant proportion of patients seen under some form of private contract.

SUBJECTS AND METHODS

13 practices in England and Wales were selected to represent a regional cross-section of the country. Up to 100 successive patients visiting each practice during the summer of 1995 were invited to complete the questionnaire. 1003 questionnaires were returned.

RESULTS

Notwithstanding regional, gender and socio-economic status related differences the most important factors were 'care and attention' rated as very important by 90% of respondents, 'pain control, 'dentist puts you at ease ', 'safety conscious' all rated as very important by 79-82% of respondents, and 'explanation of treatments' rated as very important by 73% of respondents. The importance attached to the dentist being 'safety conscious' suggests a change in emphasis from earlier studies.

CONCLUSIONS

The factors rated most important reflect the dentist's behaviour and personal skills in devoting time and attention to the patient.

Molecular marker for development of interstitial cystitis in rat model: isoactin gene expression

PURPOSE

To determine whether the differential expression of bladder smooth muscle isoactin can be used as a molecular marker for the development of interstitial cystitis (IC).

METHODS

Three groups of five female Sprague-Dawley rats each underwent urethral catheterization and intravesical instillation of 0.5 ml. of 0.4N HCl. One group was sacrificed one, two and four weeks after the application of HCl, and their bladders harvested for histologic examination and evaluation using Northern blot analysis of bladder smooth muscle isoactins. Five control animals were sacrificed and their bladders harvested to establish isoactin gene expression of bladder smooth muscle in the normal state. The bladders of the rats in each group were excised, immediately frozen in liquid nitrogen, pooled, then stored -70 degrees C until needed for RNA isolation. Isoactin cDNA probes have been developed, therefore isoactin specific cDNA insert fragments were isolated and insert DNA was purified by gel electrophoresis. Total cellular RNA was isolated from 1.0 gm. of bladder smooth muscle from each group. After spectrophotometric quantification, Northern Blot analysis was performed using 2% agarose-formaldehyde gels and Biotrans nylon membranes. Two complete Northern Blot series were run on a single gel and blotted to a single membrane to eliminate gel and blotting discrepancies.

RESULTS

Microscopic histologic analysis revealed detrusor mastocystosis and eosinophilia as has been noted in humans with chronic interstitial cystitis. Two weeks after the intravesical application of hydrochloric acid, the relative expression of gamma-smooth muscle isoactin was noted to increase by 1.7-fold, while alpha-smooth muscle isoactin expression increased by a factor of 9. These effects were seen to stabilize four weeks after acid application.

CONCLUSIONS

The intravesical application of dilute HCl in rats results in a histologic appearance which mimics that seen in humans with interstitial cystitis. The appearance of detrusor mastocytosis and eosinophilia was accompanied by a relative decrease in the expression of gamma- and a relative increase in alpha-smooth muscle isoactin gene expression. This pattern of smooth muscle isoactin expression is consistent with a more immature and possibly synthetic smooth muscle phenotype, which may be responsible for the clinical presentation of those with IC. Northern blot analysis of bladder smooth muscle cells may serve as an effective marker for the development of interstitial cystitis in humans.

The mechanism of altered neural function in a rat model of acute colitis

BACKGROUND & AIMS

Distal colitis induced in rats by trinitrobenzene sulfonic acid (TNBS) causes a suppression of [3H]noradrenaline release from the myenteric plexus, of inflamed distal colon, as well as in noninflamed regions of colon and ileum. The aim of this study was to explore the mechanisms underlying these neural changes in TNBS colitis.

METHODS

Colitis was induced by intrarectal administration of TNBS, and the animals were killed on day 5. Inflammation was assessed by measuring myeloperoxidase (MPO) activity, and noradrenaline release was measured as 3H release from rats myenteric plexus preparations preloaded with [3H]noradrenaline. These end points were examined: (1) after administration of the locally active steroid budesonide; (2) in congenitally athymic rats; and (3) in rats treated with the interleukin 1 receptor antagonist (IL-1ra) to interleukin 1 beta.

RESULTS

In colitis, both topical budesonide and systemic IL-1ra treatments attenuated the suppression of KCl-evoked 3H release from longitudinal muscle myenteric plexus in both inflamed and noninflamed segments. However, neither of these treatments altered MPO activity. A similar suppression of [3H]noradrenaline release was observed in athymic rats after TNBS, although there was a substantially greater increase in MPO activity compared with euthymic rats with colitis.

CONCLUSIONS

TNBS-induced colitis alters myenteric nerve function at inflamed and noninflamed sites via a steroid-sensitive and interleukin 1-mediated process that does not require T lymphocytes.

Previous inflammation alters the response of the rat colon to stress

BACKGROUND & AIMS

Patients with inflammatory bowel disease have symptoms of irritable bowel syndrome (IBS) with a higher than expected prevalence. Stress is an important factor in the pathogenesis of IBS. Thus, previous inflammation may predispose to IBS by rendering the bowel more susceptible to the impact of stress. The aim of this study was to examine the effect of previous colitis on stress-induced responses in rats.

METHODS

Acute colitis was induced in rats by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and the rats were allowed to recover for 6 weeks before application of mild restraint stress for 3 consecutive days. In vitro measurements included myeloperoxidase activity, plasma corticosterone levels, interleukin 1 beta messenger RNA expression, and [3H]noradrenaline release from the myenteric plexus.

RESULTS

Six weeks after administration of TNBS, stress caused a significant increase in myeloperoxidase activity in TNBS-treated rats but not in stressed controls; plasma corticosterone responses were similar. Stress also caused an exaggerated and significant suppression of [3H]noradrenaline release in TNBS-treated stressed rats compared with stressed controls. This was accompanied by a significant decrease in interleukin 1 beta messenger RNA expression in the colon.

CONCLUSIONS

Previous colitis rendered the colon more susceptible to effects of stress on enteric nerve function and also increased some parameters of inflammation in response to stress.

Clinical overlap between malaria and severe pneumonia in Africa children in hospital

Data collected from 200 children admitted to a hospital on the Kenyan coast who met a broad definition of severe acute respiratory infection (ARI) indicated that simple clinical signs alone are unable absolutely to distinguish severe ARI and severe malaria. However, laboratory data showed that marked differences exist in the pathophysiology of unequivocal malaria and unequivocal ARI. Children in the former group had a higher mean oxygen saturation (97 vs. 94, P < 0.001), mean blood urea level (5.3 vs. 1.9 mmol/L, P < 0.001) and geometric mean lactate level (4.5 vs. 2.1 mmol/L, P < 0.001), and lower mean haemoglobin level (5.3 vs. 9.0 g/dL, P < 0.001) and base excess (-9.4 vs. -2.6, P < 0.001) than those in the latter group. Using these discriminatory variables it was estimated that up to 45% of children admitted with respiratory signs indicative of severe ARI probably had malaria as the primary diagnosis. Radiological examination supported this conclusion, indicating that pneumonia characterized by consolidation was uncommon in children with respiratory signs and a high malarial parasitaemia (> or = 10,000/microliters). There is no specific radiological sign of severe malaria. In practice, all children with respiratory signs warranting hospital admission in a malaria endemic area should be treated for both malaria and ARI unless blood film examination excludes malaria. In those with malaria and clinical evidence of acidosis, but no crackles, antibodies may be withheld while appropriate treatment for dehydration and anaemia is given. However, if clinical improvement is not rapid, antibiotics should be started.

MRI findings in children with neurofibromatosis type 1: a prospective study

To determine the frequency and nature of MRI lesions in children with neurofibromatosis type I (NF1), 50 patients aged 8 to 16 years were evaluated prospectively with cranial MRI. Forty-one children were asymptomatic with respect to central nervous system pathology, and 50% were macrocephalic. Sixteen patients (32%) had normal MRI examinations. Thirty-two patients (64%) had high intensity lesions on T2-weighted images and 16 patients (32%) had hyperintense lesions on T1-weighted images. Seven patients (14%) had ventricular dilatation (associated with increased intracranial pressure in 2) and 11 patients (22%) had optic pathway lesions (optic glioma in 7). MRI was superior to CT in differentiating optic sheath thickening and optic nerve tortuosity from optic glioma in four patients. An intracranial tumour (ependymoma) and sphenoid wing dysplasia were evident in individual patients. Findings previously unreported in NF1 included an aqueductal web resulting in hydrocephalus, intraocular neurofibroma resulting in retinal detachment, and asymptomatic enlargement of the septum pellucidum. T1 and T2 signal abnormalities in isolation were not associated with neurological deficits or the occurrence of macrocephaly, and all lesions that required intervention were suspected clinically. Macrocephaly in the absence of increased intracranial pressure or accelerated head growth is not an indication for neuroimaging in children with NF1. However, the majority of children (68%) had disease-specific abnormalities and thus MRI may provide a useful adjunct to clinical evaluation in the diagnosis of equivocal cases.

Pre-operative MRI of anorectal anomalies in the newborn period

Nine infants (six boys, three girls) with anorectal anomalies were examined in the immediate newborn period, prior to corrective surgery, with MRI. Three high, one intermediate and five low anomalies were found at MRI - one patient with a low lesion was subsequently found at surgery 2 months later to have a high anorectal anomaly. This infant had passed meconium per urethram soon after the MRI study, prompting the need for a protective colostomy and stressing the importance of a thorough clinical examination of babies with anorectal malformations. The MRI results and findings at surgery were in agreement in all other patients (n = 8). Hydronephrosis was evident in two and renal agenesis in one patient. Sacrococcygeal hypoplasia was found in two and two hemivertebrae in one infant. No spinal cord lesion was identified. One fistula was evident on MRI but four were later found at surgery. Uniformly hyperintense T 1 signal meconium was seen in all nine newborns, allowing for easy differentiation of rectal contents from rectal wall and the adjacent musculature. MRI can provide useful information regarding the development of the puborectal and external anal sphincter muscles, can help guide the pull-through procedure and help predict future continence pre-operatively in the newborn period.

CT of staphylococcal anterior mediastinal abscess in an infant

A 6-week-old girl presented with bronchiolitis secondary to respiratory syncytial virus. Eight days after admission she developed a Staphylococcus aureus infection at a previous intravenous cannula site. Despite antibiotic therapy this led to an anterior mediastinal staphylococcal abscess, which was drained surgically and the patient recovered. Mediastinal abscesses are rare in children: haematogenous spread of infection is an unusual aetiological factor and we believe this to be the first case reported due to an infected cannula site.