False-positive result of a captopril-enhanced radionuclide renogram in a child secondary to dehydration

PURPOSE

Renovascular hypertension is an unusual cause of elevated mean arterial pressure in children. When suspected, angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy is usually one of the initial studies done to evaluate patients. The accuracy of this test depends not only on patient selection but also on technical factors involved in performing the study. We report a case of a false-positive angiotensin-converting enzyme inhibitor-enhanced radionuclide renogram in a 5-year-old boy with hypertension.

METHODS

Angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy was performed and the result was interpreted as positive for bilateral renovascular disease. A review of the anesthesia record from the study revealed that the patient was hypotensive. A repeated study with adequate hydration and blood pressure stability was then done.

RESULTS

The result of the second examination was interpreted as normal, without evidence of abnormal renovascular physiology.

CONCLUSIONS

The cause of the initial false-positive result was determined to be dehydration with secondary hypotension. Dehydration, with secondary hypotension, can cause a diminished glomerular filtration rate and mimic bilateral renovascular physiology on angiotensin-converting enzyme inhibitor-enhanced renal scans.

Time interval between the last dose of propylthiouracil and I-131 therapy influences cure rates in hyperthyroidism caused by Graves' disease

PURPOSE

To examine the effects of propylthiouracil (PTU) pretreatment on the outcome of initial I-131 therapy for Graves' disease.

DESIGN

A retrospective chart review was done.

PATIENTS AND METHODS

The authors studied 106 patients in an outpatient nuclear medicine setting who were given initial I-131 therapy for Graves' disease from September 1989 to March 1993 and followed for at least 6 months after therapy. These patients were divided into groups based on whether they had ever received PTU or, if they had received PTU, the length of time between the last dose of PTU and the I-131 therapy dose. Measured failure rates of initial I-131 therapy were based on recurrent or continued hyperthyroidism.

RESULTS

Treatment failure rates increased markedly from 2.5% in non-PTU-treated patients (n = 80) to 23.1% (n = 26) in patients pretreated with PTU (P = 0.003). Although not significant, two PTU-pretreated subgroups showed a trend toward increased failure rates. The failure rate was 15.4% (n = 13) in patients whose last dose of PTU was 7-14 days before I-131 therapy, and it increased further to 30.8% (n = 13) in patients whose last dose of PTU was within 1 week of I-131 therapy.

CONCLUSIONS

PTU pretreatment within 2 weeks of I-131 treatment is a strong independent risk factor in failure rates after initial I-131 therapy in patients with Graves' disease. Patients should be free of PTU for 2 weeks before I-131 therapy if they are able to tolerate it, otherwise the dose of I-131 may need to be adjusted upward to diminish the risk that the initial I-131 therapy will fail.

Chronotropic competence of the sinus node in congenital complete heart block

Electrocardiograms taken at rest of 2 children with transplacental exposure to anti-Ro antibody but 1:1 atrioventricular conduction demonstrated sinus node disease. Treadmill exercise testing of 28 patients with congenital complete heart block found 3 patients with chronotropic incompetence of the sinus node.

Investigative methods of congenital complete heart block

Congenital heart block (CHB) has been described for a century and related to the presence of maternal autoimmune disease for three decades, but little is understood about its mechanism. To explore the pathophysiology of CHB, technologies in both basic and clinical electrophysiology are being developed and applied. Human fetal rhythm is currently inferred from cardiac mechanical events by using fetal ultrasound, allowing for the detection of second and third-degree heart block. Fetal electrocardiography is being explored to assess its feasibility as a clinical tool to detect fetal first-degree block in the mid trimester. Sequential composite digital recordings from the maternal abdomen are made every 4 weeks from pregnancies at risk for congenital heart block. Filtering and averaging techniques are used to enhance the fetal signal. So far, these techniques have produced a fetal QRS complex trigger signal for use in three-dimensional fetal echocardiography. Because the human fetus cannot be studied directly, a Langendorff rabbit model of CHB has been developed. With 5-10 mL of human serum in 150-300 mL of Krebs solution, prolongation of the Wenckebach second-degree atrioventricular block cycle length occurred. This was reproduced by using serum from seven of eight CHB mothers as compared with none of six controls mothers.

Cyclosporine in the treatment of an unusual case of juvenile systemic sclerosis

We describe a child who initially presented with juvenile dermatomyositis (JDM). Four years after the complete remission of JDM she developed systemic sclerosis without internal organ involvement. She was unresponsive to a combination of systemic corticosteroid therapy and pencillamine. The institution of cyclosporine induced a complete remission.

Single photon emission computed tomography scanning in childhood systemic lupus erythematosus

OBJECTIVE

To determine the role of central nervous system (CNS) perfusion scanning in detecting CNS disease in childhood onset systemic lupus erythematosus (SLE) and serial single photon emission computed tomography (SPECT) scans in monitoring CNS disease activity in childhood.

METHODS

The charts of 108 patients with a confirmed or suspected diagnosis of SLE during the period February 1987 to June 1992 were reviewed. Twenty patients with a diagnosis of CNS SLE and 10 patients without CNS involvement had at least one SPECT scan. Patients were divided into (a) focal CNS SLE, when there were clinical manifestations that could be attributed to localized lesions of the CNS (6 patients); and (b) diffuse CNS SLE, when there was a global defect in CNS function including organic brain syndrome, psychosis, and depression (14 patients). If a patient had both diffuse and focal CNS disease that patient was designated as having diffuse disease. Forty-three patients with a diagnosis other than SLE comprised our non-SLE control group.

RESULTS

SPECT scans were performed in 20 patients with acute CNS involvement. In patients with acute diffuse CNS disease, diffuse patchy areas of hypoperfusion were seen in 86% of patients at presentation of the CNS event. In the focal CNS disease subgroup, 33% of patients had an abnormal scan at CNS presentation. In these patients focal rather than diffuse abnormalities were seen. Eight patients with diffuse CNS SLE had at least one followup study at intervals ranging from 1 month to 3 years after initial scan. In 50% of these patients with diffuse CNS involvement, improvement in their abnormal scan correlated with clinical improvement, while in the other 50% clinical improvement was not associated with SPECT scan improvement. The most common abnormal SPECT scan pattern in patients with CNS SLE was one of widespread multiple small areas of decreased uptake at multiple sites, suggestive of generalized patchy hypoperfusion. Although SPECT scans were sensitive to the presence of CNS disease, the diffuse hypoperfusion was not specific for clinically detectable CNS involvement. In patients with SLE, a diffusely abnormal scan had a specificity of 69% and a likelihood ratio of 2.2 to correctly detect overt diffuse CNS disease.

CONCLUSION

Although we found that SPECT scanning was a highly sensitive method, it was not a specific method in correctly diagnosing diffuse CNS SLE in children. However, the presence of an abnormal SPECT scan in SLE patients with no history of overt CNS SLE may suggest that subclinical CNS disease may be more common in children than previously suggested.

Intravenous immunoglobulin therapy in a child with cutaneous polyarteritis nodosa

Cutaneous polyarteritis nodosa (CPAN) may have a prolonged recurrent course which needs chronic corticosteroids treatment to achieve remission. In this report we describe a 9 year old boy who developed CPAN, which we treated with high dose intravenous immunoglobulin (IVIG), with an immediate favourable response. We discuss the advantages of IVIG over corticosteroids and speculate on its pathogenesis and mechanism of action.

Assessment of myocardial perfusion and function in childhood systemic lupus erythematosus

OBJECTIVES

To determine the prevalence of abnormalities in myocardial perfusion or function in children with systemic lupus erythematosus (SLE), and describe potential factors that may predict their development.

STUDY DESIGN

Patients (n = 40; 30 female) were enrolled through the Lupus Clinic at The Hospital for Sick Children between 1990 and 1992. Resting and exercise thallium myocardial perfusion scans, radionuclide angiography with multiple gated acquisition (MUGA), and resting M-mode and two-dimensional echocardiography were performed.

RESULTS

All patients were free of symptoms, and none had a history of ischemic heart disease. Their median age was 15.9 years (range 10.5 to 19.8 years) at enrollment. Abnormalities of coronary perfusion were found in 5 (16%) of 31 patients (95% confidence interval: 3%, 29%) and included a large fixed perfusion defect in 1; 5 of 27 MUGA scans showed marginally low left ventricular ejection fractions at rest, whereas all had normal exercise responses. In the group with abnormal thallium scans, three of five patients had antiphospholipid antibodies detected, and two of four had an abnormal plasma lipid profile. This group tended to have a shorter disease duration and had received a lower cumulative dose of corticosteroids; these differences were not statistically significant compared with the group with normal scans.

CONCLUSION

Asymptomatic abnormalities of myocardial perfusion occur in children with SLE and are more common than previously suspected. Patients with these abnormalities of myocardial perfusion may be predisposed to the previously recognized early-onset ischemic heart disease seen in adults with SLE.

PET versus SPECT for determining myocardial tissue viability using fluorine-18-fluorodeoxyglucose

The U.S. Food and Drug Administration regulates the manufacture and distribution of 18F-FDG. Acquisition and use of this radiopharmaceutical for myocardial imaging at our institution required approval by our Institutional Review Board. Our initial objective was to present a scientific validation for use of this radiopharmaceutical in adjudicating the "viable versus scarred myocardium question," using either a PET scanner or a gamma camera equipped with 511-keV collimators. We believe that our nuclear medicine colleagues who find themselves in a similar business/legal situation regarding the acquisition and use of 18F-FDG will find this review useful. We reviewed the literature to document the efficacy of 18F-FDG, in general, in assessing myocardial viability. We then did a literature-based comparison of PET scanner methodology versus modified gamma camera methodology for imaging 18F-FDG emissions. Imaging 18F-FDG with a modified gamma camera appears to be an effective alternative to imaging with a standard PET camera for assessing myocardial viability.

Persistent pulmonary hemorrhage as the sole initial clinical manifestation of pediatric systemic lupus erythematosus

Pulmonary hemorrhage (PH) is a rare but potentially life-threatening manifestation of systemic lupus erythematosus (SLE). In this report we describe a 13 year old girl with PH as the sole presenting clinical manifestation of her SLE. Her serology was diagnostic of SLE and one year after presentation she developed arthritis. She had a rapid serologic but delayed clinical response to combination therapy of intravenous pulse methylprednisolone, pulse cyclophosphamide and daily prednisone. Awareness of the possibility of pulmonary hemorrhage as a presentation of SLE may aid in the diagnosis and early, aggressive management of this condition.

Scintigraphic detection of an occult bleed into a retroperitoneal mass using Tc-99m labeled red blood cells

A 45-year-old man with chronic lymphocytic leukemia and a retroperitoneal mass underwent Tc-99m labeled red blood cell bleeding imaging to localize a bleeding source. The bleeding scan showed a linear accumulation of radiotracer obliquely oriented along the left upper epigastrium to the right midepigastrium. This area of uptake increased in intensity and assumed a more globular appearance throughout the study, but did not change in location. This is the pattern of a retroperitoneal bleed resulting from active hemorrhage into the retroperitoneal mass.

An overview of the treatment of childhood SLE

Current recommendations for the treatment of pediatric SLE are from uncontrolled trials, case reports, retrospective descriptive data or extrapolation from studies in adults. Glucocorticoids are the mainstay of therapy and the doses depend on the disease severity. Diffuse proliferative glomerulonephritis (DPGN) requires high-dose prednisone for prolonged periods of time. We suggest the addition of azathioprine for DPGN at the time of diagnosis of DPGN and reserve cyclophosphamide for refractory cases. While we do not recommend the routine use of cyclophosphamide in this or other forms of lupus nephritis, others advocate the aggressive use of intravenous cyclophosphamide and prednisone. Severe central nervous system disease should be treated with high dose prednisone and immunosuppressive agents are reserved for life-threatening disease or steroid failure or dependency. We suggest the routine use of hydroxychloroquine in all cases of SLE at a dose of 5 mg/kg/day (maximum of 400 mg/day). Methotrexate has been recently used with some success in both children and adults, the safety profile appears to be very good and therefore further studies of this drug are warranted. Collaboration in the development of a limited number of defined treatment protocols and large scale collection of data on a multicenter and multinational basis is needed if we hope to improve the outcome of patients with severe disease.

Neonatal lupus erythematosus

This article discusses neonatal lupus erythematosus, which is a disease of the newborn defined by the presence of maternal autoantibodies and characteristic clinical features in the neonatal period. Although the autoantibodies often are not associated with clinical disease in the mother, neonatal lupus erythematosus is likely the result of fetal or neonatal tissue damage caused by maternally transmitted IgG autoantibodies.

Evolution of the T cell receptor beta repertoire from synovial fluid T cells of patients with juvenile onset rheumatoid arthritis

OBJECTIVE

To determine the level of T cell clonal expansion and the proportion of T cells that persist over time in the synovial fluid (SF) of patients with juvenile onset rheumatoid arthritis (JRA).

METHODS

We collected SF samples from each of 3 patients with JRA at 2 to 3 year intervals. To measure expression across the entire spectrum of Vbeta families in each of 7 fluids examined, we synthesized and amplified dscDNA from all 24 Vbeta families with a single reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

The proportion of clonally expanded T cells and persistent T cells is low and variable among patients.

CONCLUSION

The data are supportive of disease models not centered on T cells but centered on the changing nature of the disease over time.

Evidence for RANTES, monocyte chemotactic protein-1, and macrophage inflammatory protein-1 beta expression in Kawasaki disease

OBJECTIVE

Patients with Kawasaki disease mount an immune response directed to their abnormally stimulated vascular endothelium, that is associated with vascular inflammation and injury and a predisposition to arterial aneurysm formation. This suggests that specific pro-inflammatory cytokines may mediate these hyperreactive responses. The selective chemoattractant and activation effects of chemokines on lymphocytes identifies them as potential candidates in mediating selective inflammatory processes in Kawasaki disease. We examined peripheral blood from patients with Kawasaki disease for chemokine gene expression.

METHODS

Consecutive samples from 14 patients during the acute, subacute, and convalescent phases of their illness were collected and elaborated for RANTES, macrophage inflammatory protein-1 beta (MIP-1 beta) and monocyte chemotactic protein-1 (MCP-1) expression.

RESULTS

RANTES and MCP-1 gene expression levels were significantly elevated in 12 of the 14 patients, and MIP-1 beta gene expression was elevated in 13 of the 14 patients. There was no obvious correlation between clinical phase of the disease and chemokine expression level, yet elevated expression levels were detected in all phases, including the convalescent phase, when laboratory evidence of lymphocyte activation has been shown to return to normal. Serial samples showed persistence or increased expression of chemokine genes into the convalescent phase in patients with coronary artery lesions.

CONCLUSION

Chemokine mediated inflammatory events may persist in the convalescent phase of Kawasaki disease and may contribute to further risk of vascular endothelial cell injury, specifically coronary aneurysm formation.

Patellar enthesopathy in childhood: a new clinical and radiographic observation

Enthesitis occurs commonly in patients with seronegative spondyloarthropathies. The patella is frequently affected by enthesopathy, but overgrowth has not been reported as a manifestation of enthesitis in pediatrics. We describe 3 patients with seronegative enthesopathy and arthropathy syndrome and patellar overgrowth.

Autopsy of a cadaver containing strontium-89-chloride

An autopsy was performed on a patient who died after receiving 89Sr-chloride for treatment of bone pain from metastatic prostate carcinoma. Coordination between nuclear medicine physicians, radiation safety division personnel and pathologists resulted in minimal radiation exposure and the acquisition of dosimetry data.

Clinical significance of specific autoantibodies in juvenile dermatomyositis

OBJECTIVE

To determine the prevalence and clinical association of myositis specific antibodies in an unselected group of patients with juvenile dermatomyositis (DM).

METHODS

The sera of 42 subjects, representing an unselected group of patients from a single center, with juvenile DM and 7 others with idiopathic inflammatory myopathy (IIM) were examined for the presence of myositis specific antibodies by immunodiffusion against calf thymus extract and immunoprecipitation with HeLa extract.

RESULTS

Of the subjects with juvenile DM, only 2 had evidence of antibodies specific to myositis (anti-Mi2). Three other patients with juvenile DM had defined autoantibodies not usually considered to be specific to myositis. Two of the 3 subjects had anti-PM-Scl; both developed features of scleroderma after the juvenile DM remitted. The 5 subjects with defined autoantibodies did not differ clinically from the remainder of the subjects with the exception of the late development of scleroderma features in 2. Fourteen other subjects with juvenile DM had unidentified bands on immunoprecipitation, which may represent as yet undiscovered myositis specific antibodies. No myositis specific antibodies were detected in any of the 7 subjects with other IIM syndromes.

CONCLUSION

Based on our findings, we do not recommend routine clinical testing for these antibodies in children with typical juvenile DM. Further study of the unidentified bands seen in our subjects may lead to better understanding of the clinical groupings and etiopathogenesis of childhood myositis.

Seasonal onset of systemic-onset juvenile rheumatoid arthritis

OBJECTIVE

This study was undertaken to investigate the recent finding of a seasonal difference in the onset of systemic-onset juvenile rheumatoid arthritis (SoJRA). We hypothesized that a seasonal onset pattern might implicate on infectious agent as a cause of SoJRA.

METHODS

The date of onset was collected from the records of all patients with SoJRA from 1980 to 1992 at presentation to pediatric rheumatology clinics across Canada. The onset pattern of SoJRA was then compared with incidence data on viral infections obtained for the same period.

RESULTS

Across Canada the onset of SoJRA was constant across the seasons. However, in the Prairie region there was a statistically significant seasonal pattern, with peaks in autumn and early spring. We could find no evidence that viral incidence correlated with disease incidence either throughout Canada or in the Prairie region.

CONCLUSIONS

If a seasonal infectious agent causes SoJRA, then it is likely only one of several causes and may act only in certain regions. Future studies should be carried out in those areas where SoJRA does have a seasonal onset pattern.

Tl-201 scintigraphy in multivessel exercise-induced variant angina

A 53-year-old man presented for evaluation of nocturnal chest pain, consistent with angina pectoris. An exercise stress test reproduced his symptoms, however, exercise electrocardiograms were nondiagnostic. An exercise-thallium perfusion study confirmed vasospasm as the cause. This knowledge guided subsequent successful medical therapy.

Analysis of T cell receptor gamma transcripts in right and left knee synovial fluids of patients with rheumatoid arthritis

OBJECTIVE

To establish the extent of clonal expansion of T cell receptor (TCR) gamma delta + T cells in synovial fluid (SF), and the sharing of the clones between affected knee joints from patients with rheumatoid arthritis (RA).

METHODS

We quantified, using the polymerase chain reaction (PCR), the level of expression from each of the 4 V gamma gene families. We resolved PCR products on denaturing polyacrylamide gels to measure the proportion of mRNA transcripts contributed by clonally expanded gamma delta T cells. We subcloned and sequenced 509 cDNA clones derived from 8 SF and one peripheral blood sample from 2 patients with RA and one patient with juvenile onset RA to fully characterize the populations of T cell receptor gamma mRNA sequences.

RESULTS

We found in each patient disproportionate expression of a subpopulation of T cell receptor gamma mRNA transcripts. Some of these transcripts are expressed by T cells found in both joints.

CONCLUSION

Synovial TCR gamma delta + T cells are oligoclonal and some of these T cell clones are common to SF of both joints. The finding of identical T cell sequences from SF of both affected joints from each patient points to a role for gamma delta + T cells in disease progression.