Biomedical subjects
Publications and source records attributed to T C Quah.
Forty-eight patients with recurrent abdominal pain were studied endoscopically for the presence of gastritis and Helicobacter pylori infection. Fifteen of these children had histological evidence of gastritis with eight of them having concomitant H. pylori infection. The majority of those with H. pylori infection had severe degrees of acute following chronic gastritis.
Non-Hodgkin's lymphomas (NHL) are part of an overlapping spectrum of lympho-proliferative diseases in childhood. In the first of this 2 part series, the clinicopathological aspects of NHL in childhood are discussed. The rapid progression of disease, the high incidence of micrometastases (over 80%) at diagnosis, and the propensity of hematogenous spread to the bone marrow and the central nervous system (CNS) as well as the clinico-pathologic 'clusters' associated with particular presenting sites distinguish the pediatric forms of disease. Abdominal primary sites most frequently manifest diffuse undifferentiated (Burkitt's or non-Burkitt's) histopathology, B-cell immunophenotype, FAB-L3 cytomorphology and specific karyotypic and/or genotypic alterations of the immuno-globulin genes and the c-myc oncogene. Mediastinal presentation is associated with lymphoblastic histopathology, T-cell immunophenotype and a variety of less consistent karyotypic and genotypic aberrations. Ki-1 lymphoma, a rare subtype of large cell NHL with specific features is often of T cell origin. The requirements for diagnosis, staging and monitoring are presented in the context of the associations between clinico-pathological presentation and subsequent behavior. The most frequent sites of disease progression and relapse are involvement of the bone marrow and the CNS. For Burkitt's lymphoma there is a historic perspective and a description of particular epidemiologic, clinical, virologic, immunophenotypic and genotypic features. Cytogenetic and molecular biologic studies of genomic rearrangements are advancing the understanding of oncogenesis, clonality, lineage, and clinical behavior. The capacity to detect and amplify DNA from submicroscopic disease may contribute to prognostic stratification both at diagnosis and during subsequent monitoring.
The prognosis of non-Hodgkin's lymphoma (NHL) in childhood has improved steadily in the last 2 decades. This is primarily the result of increasingly effective chemotherapy regimens tailored to defined and relatively homogeneous prognostic categories and tested in prospective clinical trials. Surgical excision remains of prognostic benefit only when near-total resection can be performed without delay of chemotherapy. The role of radiation therapy is now limited to the treatment of overt central nervous system (CNS) lymphoma, disease unresponsive to chemotherapy, and certain emergencies. Effective 'prophylactic' treatment of the CNS has been achieved in most series by intrathecal and systemic chemotherapy alone. The most relevant modality of treatment is chemotherapy and a very large number of protocols have been published. The origins of current multi-agent regimens stem both from early experience with cyclophosphamide in endemic Burkitt's lymphoma and from therapeutic studies of acute lymphoblastic leukaemia. Sub-stratification of non-localized NHL has produced protocols designed for either lymphoblastic (mostly T cell) or non-lymphoblastic (mostly B cell) categories. While the cure rate for lymphoblastic lymphoma now exceed 70%, the non-localized non-lymphoblastic disease remains a major obstacle to cure. These patients frequently present with large abdominal primaries and are prone to regional as well as hematogenous dissemination. In particular, involvement of the CNS is now considered to be the most adverse prognostic variable in this group. Recently, highly intensive regimens are addressing these obstacles. On the other hand, NHL defined as localized has been shown to be curable in up to 95% of children with the use of simple chemotherapy regimens as short as 6 months in duration. Salvage of patients who relapse during or after chemotherapy remains bleak but cures are possible with regimens incorporating bone marrow transplantation from either an autologous or allogeneic source. Experimental methods, including biologic and immune response modifiers may also offer future promise.
Dyskeratosis congenita has been found to be associated with abnormal immune function. In this study we report a patient with this association. He developed Pneumocystis carinii interstitial pneumonia, and impaired cell mediated immunity was confirmed by the presence of depressed lymphoproliferative responses to in vitro stimulation with mitogen. Enumeration of T cell subsets showed a severely depressed CD4:CD8 ratio (0.38), which is the likely cause for impaired cell mediated immunity. The T cell activation pathway appeared intact, as his T lymphocytes were able to express activation markers (CD25 and HLA-DR) after mitogen stimulation.
To evaluate the effect of leukaemia and its treatment on growth and puberty, we studied retrospectively the serial heights and pubertal development of 37 children with acute leukaemia. The age of diagnosis ranged from 10 months to 13 years, with a duration of follow-up varying from 2 years to 14 years. The SDS (Z score) which reflects the deviation of height measurements from the population mean was used to assess height change at yearly intervals. Pubertal assessment was also made using the Tanner standards. 25 (69%) children showed a falling trend in mean Z scores over a 5 year follow-up period. The difference between the mean Z scores at 0 and 5 years was statistically significant (p < 0.035). However, there was no significant correlation between age of onset of disease and duration of survival with the deviation in the Z score. 11 children did not demonstrate a fall in the Z scores. There were, however, no defined factors such as age of onset, duration of follow-up, and sex distribution which could predict growth failure. Pubertal assessment showed normal development in all children with the pubertal age group (n = 11), except for 3 boys, two of whom had received testicular irradiation.
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We report a patient with acute lymphoblastic leukemia who underwent treatment comprising chemotherapy, radiotherapy (cranial and testicular) and then a bone marrow transplant from an identical twin. He was cured of his leukemia and has been disease-free for nine years. With long term survival, there were problems, notably those of growth and endocrine insufficiency, which needed special considerations in management.
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The hypochromic, microcytic anemias are the most frequently encountered anemias on a world-wide scale, with iron deficiency anemia ranking as the commonest. Severe iron deficiency anemia seldom poses a problem in diagnosis if all the classical features are present. However, subclinical mild iron deficient states often require several laboratory tests to determine the diagnosis with certainty. To begin, the initial suspicion of an underlying subclinical iron deficient state is dependent on the laboratory method used to determine the red blood cell parameters. Next, many common conditions in children can influence the results of classical iron studies. Finally, iron deficiency has to be distinguished from other hypochromic, microcytic anemias, in particular the heterozygous thalassemic states which are so prevalent here in South-East Asia. This paper outlines some of these problems encountered in pediatric clinical practice.
Recent discoveries have allowed a considerable insight into the nature of the erythrocyte membrane in health and disease. The component proteins of the erythrocyte membrane and its underlying membrane skeleton have been isolated, studied and the various genes have been assigned to particular chromosomes. Many defects in these proteins have been characterized and correlations between these defects and the resultant clinical states have been hypothesized. We briefly review these recent findings, and some of the more common abnormalities in the erythrocyte membrane that are of significance to the practising pediatrician.
A case of histiocytosis X (Langerhans-cell histiocytosis) occurring in the maxilla of a two-year-old boy is presented. Common dental and oral conditions were considered and eliminated. Diagnosis was made through a biopsy which showed aggregates of histiocytes. Management consisted of multi-modal treatment. Full skeletal radiographic survey and review were essential to detect other possible sites of involvement. None was found in this case over a four-year review.
Complications of chemotherapy for a synovial sarcoma in an eight-year old boy included cisplatinum nephrotoxicity and adriamycin cardiotoxicity. The resultant renal failure and fluid overload necessitated peritoneal dialysis. Intractable hypomagnesemia was also a prominent feature.
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Anemia is a common finding in children with systemic lupus erythematosus (SLE). Anemia in SLE may result from several mechanisms and more than one may be operative at any time. Anemia of chronic disease is the most common, but a low hemoglobin can be caused by auto-antibodies to red cells as part of the auto-immunity, or it may be the result of impaired erythropoietin production by kidneys involved in the SLE, gastrointestinal blood loss from anti-inflammatory therapy, increased red cell destruction from hypersplenism or a drug-induced immune phenomenon. We briefly review the important processes that can lead to a low hemoglobin in children with SLE, their clinical features and their treatment.
A case of eosinophilic meningitis in a young boy from Indonesia is reported. Clinically, he had a subacute meningitis with eosinophilic pleocytosis in the cerebrospinal fluid. The clinical and laboratory findings strongly suggest Angiostrongylus cantonensis as the aetiologic agent although the parasite was not found. The other most likely causes in the region are also considered and the life-cycle of Angiostrongylus cantonensis and the epidemiology of its infection are briefly reviewed.
A clinical trial using four different oral refeeding regimes was conducted in 100 patients following acute gastro-enteritis. There was no difference in terms of the diarrhoea-relapse rates among the four groups of patients. However, a better weight gain was recorded in the groups using a lactose-free soy formula and a low-lactose low-fat cow's milk formula.
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