Cardiac tamponade

Vignette says a 38 year old male with a history of stage 5 chronic kidney disease on maintenance dialysis presents to the emergency department with chief complaints of progressive shortness of breath, chest discomfort and fatigue over the past few days; He has a history of hypertension, diabetes mellitus and chronic kidney disease and takes medications for hypertension, diabetes and dyslipidemia; Vital signs show blood pressure of 90/60 mm of Hg, pulse rate of 120 bpm, respiratory rate of 22 breaths/min, oxygen saturation of 92% in RA and temperature of 97.2 F; His pulses are thready, weak and becomes even fainter during inspiration; Examination shows jugular venous distension, muffled heart sounds and cool extremities; ECG shows electrical alternans, low voltage QRS complexes; Echocardiography shows pericardial effusion with right ventricular collapse during diastole; Diagnosis?

Diagnosis is Cardiac tamponade.

Cardiac tamponade is a medical emergency condition characterized by excessive accumulation of fluids in the pericardial space restricting the filling of cardiac chambers and subsequent low cardiac output and shock.

Etiologies:-

1. Trauma (penetrating > blunt) 

2. Malignancy (e.g. lung, breast, lymphoma) 

3. Uremia (ESRD) 

4. Pericarditis 

5. Post-MI (especially ventricular wall rupture, Dressler's syndrome) 

6. Iatrogenic (e.g. catheter placement, cardiac surgery)

Pathophysiology:- Increased pericardial pressure → restricts ventricular filling → ↓ preload → ↓ stroke volume → ↓ CO → shock.

Clinical features:-

1. Beck’s triad:- Muffled heart sounds, jugular venous distension and hypotension.

2. Reflex tachycardia, cool extremities, tachypnea with clear lungs.

3. Pulsus paradoxus (i.e. decreased SBP >10 mmHg during inspiration).

Diagnosis:-

1. ECG shows electrical alternans, low voltage QRS complexes.

2. Chest x-ray shows enlarged cardiac silhouette (i.e. water bottle sign).

3. Echocardiography shows pericardial effusion, diastolic collapse of the right atrium and right ventricle, plethoric inferior vena cava (i.e. lack of inspiratory collapse) and impaired ventricular filling.

4. Cardiac catheterization shows elevation and equalization of intra pericardial and diastolic pressures in all chambers of the heart; shows elevated JVP with loss of the x descent.

Treatment:- Immediate pericardiocentesis.