Clinical Case Scenario

A 68-year-old male with a long-standing history of chronic kidney disease secondary to poorly controlled hypertension and type 2 diabetes mellitus has been managed conservatively with dietary restrictions and medications for the past five years. His estimated glomerular filtration rate (eGFR) has been progressively declining. Over the last six months, he has developed worsening symptoms of uremia, including fatigue, nausea, loss of appetite, and pruritus. His most recent laboratory results, obtained two days ago, showed a blood urea nitrogen (BUN) of 110 mg/dL and a creatinine level of 8.5 mg/dL. He has not yet received renal replacement therapy. Today, he presents to the emergency department complaining of new-onset, sharp, retrosternal chest pain that is exacerbated by lying flat and relieved somewhat by sitting forward. He also reports increasing shortness of breath and light-headedness. His wife mentions that he seems more tired and less responsive than usual.
On physical examination, he appears pale and diaphoretic. His vital signs are as follows:
Blood Pressure: 90/60 mmHg
Heart Rate: 115 beats per minute
Respiratory Rate: 28 breaths per minute, laboured
Oxygen Saturation: 90% on room air
Auscultation of his chest reveals distant heart sounds and a soft pericardial friction rub. His jugular veins are markedly distended even when sitting upright. Peripheral pulses are weak and thready. There is no evidence of peripheral oedema on this examination.
Repeat laboratory tests show worsening azotemia with a BUN of 125 mg/dL and creatinine of 9.1 mg/dL, along with elevated potassium and phosphate levels.

The following is the echocardiography image of the patient done as a routine NephroPOCUS scan

Wrong Answer: The apical four-chamber view allows visualisation of the heart within the pericardial sac; however, it is not suitable for differentiating pericardial from pleural effusion. The parasternal long axis view is the best view of the relationship of the effusion with the descending aorta. Pericardial effusions will typically be located anterior to the descending aorta, while pleural effusions will be posterior to it. This anatomical relationship is key for differentiation in this view

Right Answer: The patient is suffering from pericardial effusion leading to pericardial tamponade secondary to end-stage chronic kidney disease. The exact mechanism is not fully understood but is thought to involve the accumulation of uremic toxins leading to inflammation of the pericardium.

Justification The anechoic space between the parietal and visceral pericardium is assessed to quantify the pericardial effusion. Pericardial effusions are typically assessed throughout the cardiac cycle, and the maximum effusion size is often measured at end-diastole when the ventricles are most filled and the pericardial space is potentially more distended

Wrong Answer: The apical four-chamber view, and not the parasternal long-axis view is preferred for guiding drainage of the pericardial effusion. While the parasternal long axis view can help visualize a pericardial effusion, it's not the most useful view for guiding drainage. Subcostal view is also useful in emergency settings.

Wrong Answer: While quantification of the size of a pericardial effusion is an important factor, the rate of accumulation is often more critical in determining the severity and risk of tamponade. A large, slowly accumulating effusion may be tolerated better than a small, rapidly developing one. Clinical signs and symptoms are also crucial in assessing severity. Figure 1 below shows the delay in a slowly accumulating effusion becoming a symptomatic effusion.

This patient with CKD belongs to the curve of a slowly developing effusion.

Figure 1: Pericardial pressure-volume curve

The following are the features of pericardial tamponade:

The clinical picture, ECG findings, chest X-ray, and, most importantly, the echocardiogram confirm the diagnosis of pericardial tamponade secondary to uremic pericardial effusion in a patient with end-stage chronic kidney disease and severe uremia.
Electrocardiogram (ECG) shows sinus tachycardia with low-voltage QRS complexes and electrical alternans (alternating amplitude of the QRS complex).
A chest X-ray may reveal an enlarged cardiac silhouette, described as a "water bottle" appearance.
The echocardiogram in the following image demonstrates a large circumferential pericardial effusion with evidence of right atrial and ventricular diastolic collapse. The interventricular septum appears to bow towards the left ventricle during inspiration, consistent with ventricular interdependence. These findings are diagnostic of pericardial tamponade (Figure 2)

Figure 2: Echocardiography showing pericardial tamponade (white arrows)

Management of pericardial tamponade:
A. Immediate management focuses on relieving the pericardial tamponade:
1. Pericardiocentesis: An urgent pericardiocentesis should be performed under ultrasound guidance. A significant amount of serosanguinous fluid can be drained from the pericardial space, resulting in immediate haemodynamic improvement. The drained pericardial fluid should be sent for analysis (cell count, protein, glucose, cultures, and cytology) to rule out other potential causes of effusion, although in this context of severe uremia, it is the most likely aetiology.
2. Supportive Care: Continuous cardiac monitoring with oxygen administered to maintain adequate saturation. Intravenous fluids are given cautiously to maintain preload without exacerbating fluid overload after the tamponade is relieved.
3. Management of Uremia: Urgent initiation of renal replacement therapy (haemodialysis) to address the underlying uremia, which is the primary cause of the pericardial effusion.
B. Long-term management of pericardial tamponade in this patient will require regular haemodialysis. His hypertension and diabetes management should be closely monitored along with checking for recurrence of pericardial effusion.