In this article, we will discuss the Differential Diagnosis and Investigations of Cardiogenic Shock. So, let’s get started.
Differential Diagnosis
It is based on the cause of cardiogenic shock:
- Acute MI is diagnosed by cardiac pain, typical ECG changes and raised cardiac enzymes. Echocardiography will give estimate of extent of myocardial damage and is useful to detect mechanical complications such as acute MR and VSD.
- Valvular heart lesions are diagnosed by clinical features, echocardiography and cardiac catheterization.
- Cardiac tamponade presents with raised JVP, pulsus paradoxus X-ray chest for pericardial effusion and echocardiography.
- Massive pulmonary embolism with shock. Echocardiography may demonstrate a small vigorous left ventricle with dilated right ventricle. Sometimes a thrombus in right ventricular outflow tract may also be seen. Spiral CT confirm the diagnosis which is nowadays preferred over ventilation perfusion scan and pulmonary angiography.
- Myocarditis is diagnosed by systemic illness supported by identification of the virus and endomyocardial biopsy can be can be used for confirmation.
- Aortic dissection presents with classical tearing or stabbing pain with pulse deficit, acute AR and neurological manifestations. Echocardiography confirm the diagnosis.
Investigations
- Routine blood tests and kidney function tests.
- ECG and cardiac enzymes may point to myocardial infarction. Cardiac markers, i.e. troponins (I and T) are elevated.
- X-ray chest may show signs of pulmonary edema. Heart size is usually enlarged with bilateral hilar haze.
- Arterial blood gas analysis may show hypoxemia, metabolic acidosis, may be compensated by respiratory alkalosis.
- Echocardiogram will show depressed LV functions, and helps to find out the cause, e.g. left to right shunt (Doppler study) due to rupture of interventricular septum, pericardial effusion, aortic dissection, etc.
- Measurement of pulmonary capillary wedge pressure (PCWP) and cardiac output by pulmonary artery catheterization to confirm the diagnosis and to optimise treatment (fluids and vaso-pressure).
- Left heart catheterization and coronary angiography to measure LV pressure and to define coronary anatomy.