Can a patient with hydrostatic pulmonary edema due to severe hypertension (hypertension) and acute agitation have a normal B-type natriuretic peptide (BNP) level?

From the Guidelines

Yes, it is possible to have normal BNP levels with hydrostatic pulmonary edema in this case. The patient's pulmonary edema is likely due to a combination of severe hypertension (SBP 200-220) and sympathetic surge from acute agitation and substance abuse, rather than heart failure. This represents a form of non-cardiogenic pulmonary edema or "flash pulmonary edema" that can occur with extreme blood pressure elevations. BNP is primarily released in response to cardiac chamber stretch and ventricular dysfunction, which may not be present in this acute scenario 1. The normal renal function suggests this is not a chronic condition, and the absence of jugular venous pressure elevation on exam further supports a non-cardiogenic etiology.

Some key points to consider in this case include:

• The diagnostic accuracy of BNP in heart failure, particularly in the acute care setting, has been evaluated in several studies, including a systematic review and diagnostic meta-analysis 1.
• The use of natriuretic peptides, such as BNP and NT-proBNP, can help rule out heart failure, but their sensitivity and specificity can be influenced by various factors, including age, sex, and comorbidities 1.
• In cases of flash pulmonary edema, natriuretic peptides may be slightly elevated at presentation but can rise markedly over time despite adequate treatment 1.
• Management should focus on blood pressure control with agents like nicardipine or labetalol, continued ventilatory support, sedation with propofol as already initiated, and addressing the underlying substance abuse.
• Once stabilized, a thorough cardiac evaluation including echocardiography would be appropriate to rule out underlying cardiac pathology. The rapid improvement in oxygenation with mechanical ventilation and sedation also supports the theory that this is primarily a pressure-mediated, reversible process rather than heart failure.

From the Research

Patient Presentation

• The patient is a 46-year-old male with a history of poly substance abuse, presenting with acute agitation, severely elevated blood pressure (SBP 200-220), and hypoxia respiratory failure.
• Chest X-ray (CXR) shows pulmonary edema, but brain natriuretic peptide (BNP) levels are normal, and renal function and white blood cell (WBC) count are within normal limits.
• The patient required intubation and was managed with mechanical ventilation and propofol.

Possible Causes of Normal BNP with Hydrostatic Pulmonary Edema

• It is possible that the patient's normal BNP levels are due to the fact that BNP is not always elevated in cases of hydrostatic pulmonary edema, especially if the condition is caused by severe hypertension and agitation, as seen in this patient 2, 3.
• The patient's presentation is consistent with sympathetic crashing acute pulmonary edema (SCAPE), a condition characterized by severe hypertension, pulmonary edema, and hypoxia, which can be caused by a sympathetic surge and increased peripheral vascular resistance 2, 4.

Management of SCAPE

• The use of high-dose nitroglycerin (NTG) and noninvasive ventilation (NIV) has been shown to be effective in managing SCAPE, with rapid improvement in symptoms and reduction in the need for intubation 2, 5, 3, 4.
• The administration of NTG can help to reduce pre- and afterload, thereby improving cardiac function and reducing pulmonary edema 3.
• The patient's management with mechanical ventilation and propofol is consistent with standard care for patients with severe respiratory failure, but the use of high-dose NTG and NIV may have been beneficial in reducing the need for intubation and improving outcomes 2, 4.