Acute Myocarditis

Categories: Uncategorized
Sources: Disturbances Of The Heart

Probably most acute infections cause more or less myocarditis,

depending on their intensity and their prolongation. This

disturbance of the heart is often unrecognized, and has been simply

referred to as "the heart growing weaker from the fever process."

The acute infections most likely to cause a myocarditis are

rheumatism, influenza, sepsis, cerebrospinal meningitis, diphtheria,

typhoid fever, scarlet fever, and mout and throat infections. It is

probably rare when acute endocarditis occurs that more or less

myocarditis is not present. The acute myocarditis may develop some

fatty degeneration, and with this softening and weakening of the

heart muscle acute dilatation readily occurs, which may be a cause

of sudden death, or, if less serious, may be the cause of prolonged

disability, if the heart ever recovers its original size and

strength.



The symptoms are often indefinite, and the diagnosis of the

condition hardly possible. It may be taken for granted, however,

that hardly any serious illness can long continue without cardiac

muscle disturbance. If endocarditis is present, soft systolic

murmurs soon appear. With the acute myocarditis developing, the apex

beat is less positive, less accentuated, and later it becomes

diffuse and even feeble. The closure of the aortic valve is less

typically sharp, showing that the blood vessels are not so

thoroughly filled. The peripheral circulation is not so active, the

blood pressure falls, and the heart becomes more rapid, especially

on the least exertion. All of these signs indicate myocardial

weakness.



The treatment of this condition is largely preventive. It should be

well recognized that prolonged high fever, prolonged insufficient or

improper nutrition, prolonged acute pain, and especially prolonged

septic processes will always cause myocardial degeneration. It

should be recognized that after ether and chloroform anesthesia,

especially after chloroform, the heart muscle may be disturbed and

the tonicity be lost. Therefore after anesthesia, after operations,

and after all illnesses which have lasted more than a few days, the

convalescence of the patient must be more or less deliberate. Sudden

rising, sudden erect posture, the exertion of walking too early,

going up stairs too early or taking moderate, and later severe

exercise too early, may cause dilatation of the heart muscle that

has become weakened by acute myocarditis. If acute myocarditis is

believed or known to be present, cardiac tonics such as digitalis

should not be given; large doses of strychnin should not be given;

vasocontractors such as ergot should not be given; large amounts of

food or large bulks of liquid should not be taken into the stomach

at one time; in fact, unless there is some special indication, the

twenty-four hour amount of fluid should be diminished. The surface

circulation and the muscle circulation should be improved by such

cold or warm water applications as the disease or condition calls

for. Massage should be early inaugurated to promote the return

circulation. The heart should be treated as though it were the

frailest of Venetian glass and would crack with the least rough

handling, or even with a rapid change of temperature, great cold or

too much heat. A prolonged, tedious convalescence, with the return

to activity so graded as to give the heart no strain, and to keep

its work always just below what it is able to do, will often mean

return to perfect strength and health.



No cardiac debilitating drug should be administered when myocarditis

has been surmised or diagnosed. The safest hypnotic, if one is

needed, is morphin in small doses. If there are weakening

perspirations, atropin should be given, especially as it is also a

circulatory stimulant. Calcium in almost any form seems to be of

value in the majority of heart conditions. It is a sedative to the

nervous system, and is certainly indicated in acute myocarditis.

Calcium lactate is perhaps the best salt to administer, in doses of

0.25 gm. (4 grains), three or four times in twenty-four hours.

Calcium glycerophosphate may be used, in powder form or in capsule,

in doses of 0.30 gm. (5 grains) three or four times in twenty-four

hours; or lime-water may be given.



An exact prognosis of this inflammation is impossible. We do not

know how far an acute myocarditis may progress and entire recovery

take place; we do not know how slight a myocarditis may cause

serious symptoms. Clinically we know that many patients after

serious illness never again have perfect circulatory strength. Other

patients almost die of heart failure and yet apparently absolutely

recover their ability to do hard physical work.