Some notes on the history of rheumatic carditis

The history of rheumatic heart disease is briefly surveyed. Mitral regurgitation was recognized as the dominant leison in acute carditis in the 1830s. This diagnosis fell out of favour in the early twentieth century. Also valvular leisons were then considered to be less important than myocardial disease as a cause of symptoms in chronic rheumatic heart disease. Successful mitral valvotomies in 1948 corrected this view. Mitral stenosis takes years to develop after acute valvulitis. Studies from the rheumatic fever research unit at Taplow showed absence of cardiac dilatation in first attacks of rheumatic carditis, poor prognosis with pericardial effusions, changing murmurs recorded by phonocardiography and cardiac output studies that satisfied treatment by bed rest. The multicentre trial of cortisone, adrenocorticotrophic hormone (ACTH) and salicylates showed no differences in development of chronic valvular disease. There is need for a more specific test for rheumatic activity than the erythrocyte sedimentation rate (ESR). It is hoped that test can be developed to identify the minority of children at risk from rheumatic fever after a streptococcal throat infection in order to target antibiotic use. The declining prevalence of rheumatic fever is confined to the more prosperous countries. It remains common in the developing world. Penicillin prophylaxis is the sole advance in therapy. Better socio-economic environments are needed to reduce prevalence. (AU)

Understanding the mechanism of action of Cytochrome c Oxidase in normal and disease states: shark heart enzyme, a potential model

Cytochrome c oxidase, the final member of the electron transport chain, is crucial to respiration and also contributes to the synthesis of cellular ATP. The total absence of this enzyme is incompatible with life and its deficiency or malfunction leads to a number of serious disease states. Understanding the mechanism of action of this enzyme, which is an important prerequisite to unravelling its role in the pathogenesis of disease states, is hampered by the lack of suitable enzyme models. The bovine enzyme, which are structually simple, appear to follow a different mechanism of action. The hammer head shark is a seasonal resident of the warm waters of the Caribbean Sea. The work presented here indicates that, like the bovine enzyme, the enzyme of the heart of this shark (i) possesses thirteen subunits and two substrate binding sites and (ii) exhibits biphasic kinetics. The work also confirms that, unlike the bovine enzyme which is dimeric, the shark enzyme functions as a monomer. Given this latter simplifying feature, in conjunction with its kinetic and structural similarities to the more complex mammalian varieties, we propose that shark heart cytochrome c oxidase replace the bovine and bacterial forms as the enzyme of choice for model studies.(Au)

Acute myocarditis following Tityus trinitatis envenoming: morphological and pathophysiological characteristics

The clinicopathological features of four cases of scorpion envenoming by Tityus trinitatis are presented. The cardiac histopahtology is recorded in the two fatal cases. The pathology of the acute myocarditis was a mixed picture of a toxic myocarditis and coagulative myocytolysis. These cardiac lesions are also seen in catecholamine induced cardiotoxicity and lend support to the theory that an adrenergic surge follows scorpion envenoming. A brief review of scorpion envenoming syndrome is undertaken in the light of these findings (AU)

Acute myocarditis induced by scorpion sting: a report of five cases and a review of the literature - abstract

The clinical features in five cases (two fatal) of acute myocarditis induced by scorpion stings in Trinidad included hypovolaemic shock, restlessness, convulsions, cerebral oedema, pulmonary oedema, pancreatitis and myocarditis. The 2 fatal cases showed myocarditis (round cell perivascular infiltrate) and marked perivascular oedema of the endomysium, pulmonary oedema and marked cerebral oedema. The clinical course in these 5 patients suggests that generalized oedema occurred within minutes which would indicate that vascular endothelial damage occurred early, It is postulated that the venom complex of the scorpion, Tityus trinitatis, acts directly on endothelial cells leading to marked vascular permeability, and/or indirectly through agents such as serotonin and kinins to produce the same effect. Therapy should therefore be directed towards correction of the hypovolaemic shock, removal of oedematous fluid from the extravascular space, maintenance of adequate ventilation, reduction of cerebral oedema, digitalization and stabilization of the vascular endothelial membrane (AU)

Cardiac involvement in severe leptospirosis

Eleven patients with severe leptospirosis and myocarditis are described. Widespread ST-T wave changes on the electrocardiogram were found in nine patients. Three had atrial arrhythmias, two had frequent premature ventricular contractions and two had conduction disturbances. In two patients, there were generalized low voltage. Pathological examination revealed interstitial myocarditis in five patients and perivascular infiltrates in two. It is important to recognize that myocarditis may occur in leptospirosis. Serial electrocardiograms should be performed in severe cases to detect this complication (AU)

Cardiac involvement in polymyositis: a clinicopathologic study of 20 autopsied patients

Cardiac involvement in polymyositis was investigated in 20 autopsied cases. Clinically, 13 of 18 patients had abnormal electrocardiograms, and 9 of the 20 patients had previous evidence of congestive heart failure. Histologically documented myocarditis was detected in 6 patients (4 with congestive heart failure and 2 without), 4 of whom also had small vessel disease of the myocardium. Patients with polymyositis may have a cardiopathy in the absence of overt myocardial inflammatory disease. (AU)

Gonococcaemia with arthritis, dermatitis and myocarditis

Six cases of gonococcaemia seen at the University Hospital of the West Indies are described. All presented with polyarthritis and all but one had skin lesions. They varied widely in severity and chronicity and included one case with rigors and myocarditis. Emphasis is placed on the diagnostic value of the scanty skin lesions, and the importance of repeated examination of cervical swabs (Summary)

Myocarditis in Jamaica

A review of the histology of heart muscle from 3000 necropsies in Jamaica has shown 102 cases with myocarditis (3.4 percent). The relevant clinical and pathological features are documented. Excluding 30 cases of rheumatism, myocarditis was most frequently associated with some form of septicaemia, wheras tropical diseases were of minor importance. An attempt to relate mycocarditis with unexplained heart enlargement in Jamaica was inconclusive. The results are discussed with reference to the findings in some earlier reported series (AU)

Trypanosoma cruzi infection in blood-sucking reduviid bugs in Trinidad

Wild reduviid bugs from Trinidad were examined for the presence of T. cruzi, which was found in an appreciable proportion of them. The likelihood of human infection, and its epidemiology, are discussed. Further clinical and epidemiological studies of trypanosome infection in man are in progress and will be reported later. (AU)

Myocarditis from scorpion stings

This paper deals with the clinical and electrocardiographic study of 45 patients who had been stung by the common scorpion of Trinidad, Tityus trinitatis (family Buthidae). The patients were examined soon after admission, and serial 12-lead electrocardiograms were done on admission and at approximately 24, 48, and 72 hours after the scorpion sting. If the E.C.G. was still abnormal at the end of 72 hours it was repeated at the end of the week. The fasting blood sugar, urinary sugar, serum amylase, serum electrolytes, and blood urea estimations were done within 24 hours of admission. The common clinical findings were pain at the site of the sting, excessive salivation, vomiting, epigastric pain, abdominal tenderness, disturbance of heart rate and rhythm, glycosuria, pyrexia, and profuse sweating. Nine patients were shocked, and three had muscular twitchings and carpoped spasms. Thiry-four patients had electrocardiographic evidence of myocarditis that is, inversion of the T waves in several leads, significant deviation of the RST segment, prolongation of Q-Tc and conduction defects with complete restoration to normal in three to six days. Toxic myocarditis has not been previously described after scorpion stings. Death is usually ascribed to a toxic effect on the medullary centres. Myocarditis is the commonest complication following stings by Tityus trinitatis, and it would be reasonable to postulate that it is a frequent cause of death in this condition (AU)

Electrocardiographic changes associated with scorpion stings (abstract only)

A study was made of 45 patients admitted to the General Hospital, San Fernando, Trinidad, following scorpion sting by Tityus Trinitatis. The age of these patients ranged from 9 to 50 years but 29 of them were under 25 years of age and the sex incidence was approximately equal. The common clinical findings were: pain at the site of the sting, excessive salivation, vomiting, epigastric pain, abdominal tenderness and disturbances of heart rate or rhythm. Glycouria, prexia and profuse sweating occurred in 30-40 percent of cases. Nine patients were shocked and 3 had carp-pedal spasm and muscular twitchings. Tachycardia was present in 17 patients, brady-cardia in 8, pulsus alternans in 8 and extrasystoles in 11. Triple rhythm was heard in 5 cases and a Grade I to II apical systolic murmur in 9 cases. Glycouria was present in 19 patients and in 16 was due to a low renal threshold. Four patients had serum potassium levels below 3.5mm EG/litre and 27 had a high serum amylase. Thirty-nine of the 45 patients had abnormal electro-cardiograms. Thirty-four patients had electro-cardiographic evidence of myocarditis - i.e. inversion of the T waves in several leads, significant deviations of the RS-T segment, prolongation of Q-T and conduction defects with complete restoration to normal in 3 to 8 days. Four patients had incomplete right bundle branch block and 5 had extrasystoles without evidence of myocarditis. Clinical evidence of myocarditis was not striking even in the presence of marked electrocardiographic changes. Toxic myocarditis has not been previously described in scorpion stings. Death is usually ascribed to a toxic effect on the medullary centres. It is suggested that myocarditis is the commonest complication of scorpion stings from Tityus Trinitastis (AU)