COMPUTED TOMOGRAPHY OF INTRAPERITONEAL MALIGNANCY

A review of 205 abdominal computed tomographic (CT) scans in 83 patients with gastric or ovarian neoplasms was performed in order to assess their contribution to management. Assessment of scan accuracy was based on results of invasive procedures, clinical data, and double-blind re-reporting. Scans appeared to be of greater value in patients with ovarian rather than gastric neoplasms (p< 0.001), and in patients undergoing clinically-indicated rather than routine scans (p< 0.001). No clinical benefit accrued from the use of pre-treatment scans. Overall accuracy of scanning was judged to be significantly greater for the ovarian than the gastric group (p< 0.001), while concordance of scan reports with re-reporting was also greater in the ovarian group (p<0.001). The data indicate the inherent limitations of the CT scan and the high degree of subjectivity in its interpretation, particularly when used in the follow-up of patients with known or suspected recurrent gastric cancer. CT scanning remains a potentially useful adjunct to clinical assessment of patients with intraperitoneal malignancy, but should not be regarded as obviating the need for clinical judgement in management decisions.     

PATHOGENESIS OF ALCOHOLIC PANCREATITIS

The pathogenesis of alcoholic pancreatitis continues to be a puzzle. Of the many theories as to how alcohol might cause pancreatic damage, none satisfactorily explains why only a minority of alcoholics develop clinical pancreatitis. Hypertriglyceridemia and inherited factors could be important antecedents in some individuals, and high fat and protein diets may favour the development of the disease. Disturbances of the sphincter of Oddi have been postulated, but there are experimental and theoretical objections to the view that alcoholic pancreatitis generally results from sphincter dysfunction (obstruction-hypersecretion, biliary-pancreatic reflux and duodeno-pancreatic reflux). Biochemical studies of the effect of alcohol on pancreatic tissue have so far been relatively unrewarding. The most widely held view is that alcohol causes the deposition of protein in peripheral ducts leading to obstruction, inflammation and degeneration. However, it remains to be shown that these deposits are the cause rather than a result of pancreatic inflammation. Research might be facilitated by the development of a suitable animal model of the disease.     

PATHOGENESIS OF HODGKIN'S DISEASE

A hypothesis, based on clinical and laboratory observations, relates viral infection and host immunity to the pathogenesis of Hodgkin's disease. In this hypothesis T cells (thymus- derived lymphocytes) during viral infection undergo antigenic alteration of their surface while normal immunocompetent T cells within the same lymphoid organ react against the antigenically altered cells. A chronic immune reaction (similar to graft-versus-host disease) then leads to the appearance of the neoplastic reticulum cells. The hypothesis is compatible with each of the salient clinical features of Hodgkin's disease, including primary site of the disease, histological pattern, preclinical status, loss of cell-mediated immunity, and prognosis.     

ENDOSCOPIC ULTRASOUND STAGING OF GASTRIC MALIGNANCY

Endoscopic ultrasound (EUS) has been well established as a good tool for the staging of gastric malignancy. So far, it is accepted as the most accurate image study for local staging of gastric malignancy. Staging of gastric carcinoma is important for decision‐making in management and prediction of prognosis. With the power of high‐resolution imaging on gastric layering, the overall accuracy rate of T staging by EUS ranges 70–98%. For T2 tumors, however, EUS assessment is less reliable. N staging by EUS for gastric carcinoma is unsatisfactory and its accuracy rate has been reported 55–87%. However, the application of EUS should depend on whether examination will alter the choice of therapeutic methods and whether patients benefit from EUS evaluation. Among the indications, EUS staging is very important for the patients referred for local endoscopic treatment, such as endoscopic mucosal resection, endoscopic submucosal dissection or tumor ablation by argon plasma coagulation (APC) tumor ablation. EUS can provide the depth of invasion of the gastric wall, and also the longitudinal spread of lymphoma in the gastric wall. The overall accuracy rate of depth staging is 80–96%. For the metastatic lymph nodes, accuracy rate of N staging is 72–90%. EUS is also applied to restaging of gastric lymphoma after chemotherapy. Mucosa‐associated lymphoid tissue (MALT) lymphoma is a subset of B‐cell lymphoma with good prognosis and high prevalence of Helicobacter pylori infection. EUS staging of depth invasion of MALT lymphoma can predict the outcome of antimicrobial treatment. Taiwan's experience shows that lesions limited to mucosal and submucosal layers respond better after treatment than lesions with deeper infiltration, no matter if the MALT lymphoma is low‐grade or high‐grade.     

DISCRIMINANT ANALYSIS IN THE DIFFERENTIAL DIAGNOSIS OF HYPERCALCAEMIA

Linear discriminant analysis, a multivariate statistical procedure, applied to serum calcium, phosphate, alkaline phosphatase, bicarbonate, chloride, creatinine and tubular reabsorption of phosphate, proved to be effective in distinguishing patients with Primary Hyperparathyroidism from other hypercalcaemic patients in eighty-four retrospective cases. The application of the model to thirty-four prospective cases enabled us to separate correctly, hyperparathyroid patients from non-parathyroid hypercalcaemic patients.     

VASOPRESSIN FUNCTION IN HYPERCALCAEMIA

Vasopressin function and thirst were studied in fourteen hypercalcaemic patients (ten hyperparathyroid and four disseminated malignant disease). Ten patients had decreased renal concentrating ability which reversed within a few days in the majority of patients whose hypercalcaemia was corrected by parathyroidectomy. Although eight patients complained of thirst, none showed a lowered threshold of thirst appreciation during hypertonic saline infusion. Osmoregulation of vasopressin secretion was not reduced in any patient, but the hyperparathyroid group had an exaggerated vasopressin response to osmotic stimulation. We conclude that a partial, reversible nephrogenic diabetes insipidus occurs in at least 70% of hypercalcaemic patients irrespective of cause, which accounts for the polyuria induced by hypercalcaemia.     

HYPERCALCAEMIA IN ASSOCIATION WITH RENAL FAILURE: THE ROLE OF IMMOBILISATION

Hypercalcaemia occurring after ten weeks of immobilisation was observed in four adult patients all of whom had had prior renal failure sufficient to require renal dialysis. In all patients parathyroid hormone levels were normal or low and in three plasma 1,25(OH)₂D₃ levels were low. These findings are consistent with immobilisation induced increases in bone calcium resorption. Renal excretion of calcium may have been impaired by renal dysfunction resulting in hypercalcaemia and suppression of plasma PTH and 1,25(OH)₂D₃ levels. Resolution of the hypercalcaemia was associated with remobilisation. Parathyroidectomy is inappropriate treatment.