CARDIOMEGALY
CARDIOMEGALY: Excerpt from Differential Diagnosis in Primary Care
If an x-ray film demonstrates cardiomegaly, the physician must find out
what is causing this condition (Table 13). You have already
listened to the patient and he or she does not have a murmur. This seems to
exclude the common groups of causes—congenital and rheumatic heart
disease. (It really does not.) The patient does not have hypertension and
denies symptoms of heart failure. The ECG is normal. Now what do you do?
This situation is all too common, and I hope this chapter will remedy that
situation. The basic sciences of histology and physiology are,
of course, the key to an immediate differential diagnosis. Remember that the
heart is divided into three basic layers: endocardium, myocardium, and
pericardium; each of these can be cross-indexed with the etiologic
classification using the mnemonic VINDICATE. The pathophysiologic
mechanism, obstruction, provides the remaining disorders in the
differential diagnosis. This is applied to the pulmonary and systemic
circulations and cross-indexed with the various etiologic groups. Beginning
with the endocardium,
V—Vascular lesions include the ball–valve thrombosis.
I—Inflammatory lesions bring to mind acute and subacute bacterial
endocarditis and syphilitic valvular disease.
N—Neoplasms suggest an atrial myxoma.
D—Degenerative disease signals atherosclerotic valvular disease.
I—Intoxication does not suggest any particular con-
dition, because most toxins involve the myocardium.
C—Congenital suggests a host of valvular and septal defects and
transposition of the blood vessels of the heart.
A—Autoimmune suggests the important rheumatic carditis and also
Libman–Sack endocarditis of lupus erythematosus.
T—Trauma suggests all the valvular or septal defects that can occur
from surgery.
E—Endocrine suggests the pulmonic and tricuspid valvular defects
that result from carcinoid syndrome.
In the myocardium, one encounters a large number of diseases;
thus, only the most common ones will be mentioned here.
V—Vascular should immediately suggest coronary insufficiency and
myocardial infarction.
I—Inflammation could indicate viral myocarditis, but it would hardly
be expected to remind one of diphtheria and syphilitic myocarditis because
these rarely are seen.
N—Neoplasms of the myocardium are rare, thus rhabdomyosarcoma needs
to be mentioned here for completeness only.
D—Degenerative and deficiency diseases should signal beriberi
and muscular dystrophy, but these are also infrequently encountered.
I—Intoxicating and idiopathic disorders of the myocardium,
especially alcoholism, are much more common. Others include hemochromatosis,
amyloidosis, and gout.
C—Congenital disorders include Von Gierke disease and myocardial
fibroelastosis.
A—Autoimmune again suggests rheumatic fever and the collagen
diseases.
CARDIOMEGALY
|
| V | I | N | D |
|
| Vascular | Inflammatory | Neoplasm | Degenerative |
|
| and Deficiency |
|
Endocardium
| Ball valve thrombus
| Bacterial endocarditis Subacute bacterial endocarditis Syphilis
| Myxoma
| Atherosclerotic valvular disease |
Myocardium |
Coronary insufficiency Myocardial infarction Congestive heart failure |
Diphtheria Trypanosomiasis Syphilis Viral myocarditis |
Rhabdomyosarcoma |
Beriberi Muscular dystrophy |
Pericardium |
Hemopericardium |
Tuberculosis Viral pericarditis |
Metastatic carcinoma |
Systemic Circulation
| Renal artery stenosis
| | Polycythemia vera Hypernephroma
| Anemia Paget disease |
Pulmonary Circulation |
Pulmonary embolism and infarction |
Chronic bronchitis and emphysema Tuberculosis Fungi |
Carcinomatosis |
|
T—Trauma suggests posttraumatic aneurysms.
E—Endocrine disorders include two treatable disorders:
hyperthyroidism and hypothyroidism.
The pericardium is not frequently the cause of “cardiomegaly,”
but tuberculosis and idiopathic pericarditis should be considered, as should
hemopericardium, especially in the course of a myocardial infarction.
Obstruction in the pulmonary circulation from the following:
V—Vascular from pulmonary infarction.
I—Inflammatory from chronic bronchitis and emphysema or from chronic
infections such as tuberculosis and various fungi.
N—Neoplastic from primary or metastatic carcinoma.
D—Degenerative
I—Idiopathic or Intoxication in pulmonary fibrosis and primary
pulmonary hypertension.
C—Congenital disorders include pulmonic stenosis and hemangiomas.
A—Autoimmune diseases include collagen diseases.
T—Trauma may cause an arteriovenous aneurysm or pneumothorax
obstructing the pulmonary circulation.
E—Endocrine disorders do not obstruct the pulmonary vasculature.
Under systemic circulation comes essential or secondary
hypertension caused by coarctation of the aorta, periarteritis nodosa, or
the many renal and adrenal diseases. Dissecting aneurysms of the aorta may
rupture into the pericardium causing cardiomegaly.
Approach to the Diagnosis
The diagnosis of cardiomegaly can be further developed by a good
history and the association of other symptoms and signs. Is there a history
of hypertension, alcoholism, rheumatic fever, or other systemic disease? Has
the patient experienced shortness of breath, angina, fever, joint pains, and
so forth? Are there findings of pedal edema, hepatomegaly, or jugular venous
distention (CHF)? Are there hypertension and proteinuria (renal disease or
essential hypertension)? Is there a significant heart murmur (congenital
heart disease, rheumatic heart disease)?
The diagnostic workup will include a CBC, urinalysis, chemistry panel,
sedimentation rate, chest x-ray, and ECG. At this point, it is wise to
consult a cardiologist. Echocardiography will be helpful in diagnosing
valvular heart disease, myocardiopathy, and pericardial effusion. If CHF is
suspected, a venous pressure and circulation time as well as spirometry will
support the diagnosis. Echocardiography can diagnose CHF by determining the
left ventricular ejection fraction (LVEF). If there is unexplained fever, an
antistreptolysin O (ASO) titer or streptozyme test should be ordered to rule
out rheumatic fever, and perhaps serial blood cultures should be done to
exclude subacute bacterial endocarditis. If there is hypertension, the
patient may need a hypertensive workup .
Other Useful Tests
-
Exercise tolerance test (coronary insufficiency)
-
Thallium scan (coronary insufficiency)
-
Phonocardiogram (valvular heart disease)
-
Antinuclear antibody (ANA) analysis (collagen disease)
-
Cardiac catheterization studies (congenital heart disease,
rheumatic heart disease)
-
Angiocardiogram (valvular heart disease)
-
Coronary arteriogram (coronary insufficiency)
-
Thyroid profile (myxedema)
-
24-Hour urine catecholamine (pheochromocytoma)
-
Urine thiamine afterload (beriberi)
-
Muscle biopsy (collagen disease, trichinosis)
-
Computed tomography (CT) scan (mediastinal mass)
-
Magnetic resonance imaging (MRI) (dissecting aneurysm)
Pictures
Book Source Details
- Book Title: Differential Diagnosis in Primary Care
- Author(s): R. Douglas Collins MD, FACP
- Year of Publication: 2007
- Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2007 Lippincott Williams & Wilkins.
More About Heart failure
More Medical Textbooks Online about Heart failure
Review other book chapters online related to Heart failure:
Medical Books Excerpts
- Cardiomegaly
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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