It is a question whether scarlatina or diphtheria tends to produce in children a valvular endocarditis which is followed by mitral stenosis. It seems plausible, since in many young children it is certain that mitral stenosis has not resulted from either rheumatism or chorea. Finally, with the exception of atheroma, all the causes enumerated in the etiology of aortic stenosis may be the cause of mitral stenosis.
SYMPTOMS.—Rational Signs.—The subjective cardiac symptoms of mitral stenosis are few. There may be no such symptoms. Usually, after violent exercise there is more or less cardiac palpitation, but this will cease as soon as the auricle can relieve itself, which is readily accomplished by the patient's assuming a recumbent position on the right side with the head slightly elevated. This class of patients as a rule are pale and anæmic. There is a sharp pain frequently felt in the region of the apex, which is always suggestive of mitral stenosis. The pulse is regular and normal in character so long as the auricular hypertrophy compensates for the auricular dilatation.
When the ventricle is unable to receive and discharge its normal quantity of blood with normal regularity, the pulse becomes small in volume, feeble in force, rapid and irregular in rhythm. The sphygmograph exhibits a tracing, frequently called the mitral pulse; the sphygmograph tracing is the same as when the ventricle throws a greatly diminished blood-current into the aorta (Fig. 44). This is asystolism, and the pulse is a clear indication of the condition.
| FIG. 44. |
| Mitral Obstruction (from Patient in Bellevue Hospital). |
Balfour differs from other authorities in the statement that among the most remarkable subsidiary phenomena of mitral stenosis is irregularity of cardiac rhythm, which, always present in a greater or less degree, is sometimes a diagnostic phenomenon. The auricular systole commences earlier than normal on account of its hypertrophy. This premature contraction of the auricle, stimulating ventricular contraction, is indicated by a second ventricular systole which is much less forcible than the first.
The passive pulmonary hyperæmia attending the advanced stages of this form of cardiac disease causes habitual dyspnoea, which is exaggerated by physical exertion and is attended by a dry, hacking, teasing cough which resembles the so-called nervous cough.
After violent or prolonged exertion there may be bronchorrhoea, a pint of glairy, watery mucus often being expectorated in a few moments. Not infrequently severe exercise induces attacks of profuse, watery, blood-stained expectoration, indicative of pulmonary congestion and oedema. Sometimes the exertion of walking rapidly against a strong wind will induce such intense congestion and oedema of the lungs in one with extensive mitral stenosis as to cause sudden death.
Hæmoptysis is not infrequent, small quantities of pure florid blood being expectorated.
Orthopnoea is not a frequent symptom of mitral stenosis, for even in extensive and long-standing cases the pulmonary congestion is not constant, as the auricle is able ordinarily to empty itself, and only becomes engorged during active physical exertion or great mental excitement.