Pulmonary alveolar proteinosis (PAP) is a diffuse lung disease caused by problems with: surfactant metabolism, alveolar macrophage function, granulocyte-macrophage colony stimulating factor, or an unknown etiology. These can lead to the deposition of surfactant and apoproteins within the alveoli. Symmetric alveolar opacities in a classic “bat-wing” distribution are characteristic chest…
A left ventricular (LV) pseudoaneurysm is an LV outpouching devoid of myocardium/endocardium contained by the pericardium and adhesions. As one can imagine, this pathology carries a high risk of rupture and mortality. LV pseudoaneurysms are most commonly linked to myocardial infarction (inferior > anterior) but can also follow open-heart surgery…
Iodixanol (Visipaque) is an iodinated intravenous (IV) contrast agent which is iso-osmolar with plasma. Unlike the non-ionic monomer iohexol (Omnipaque), Visipaque is a non-ionic dimer; however, both agents are routinely utilized for angiography, venography, contrast-enhanced CT scans, and other diagnostic/interventional procedures. Tissue extravasation can result in localized necrosis, and certain…
Persistent left superior vena cava (PLSVC) is a rare (~0.5% of the general population) venous anomaly when the left superior cardinal vein fails to degenerate. This can make entering the right heart from the left upper body (e.g., pacing leads, PA catheters, etc.) more challenging as the PLSVC drains directly…
Cerebral perfusion scans are nuclear medicine studies utilizing agents like DTPA or NEUROLITE to confirm a clinical diagnosis of brain death. NEUROLITE is a radioactive diagnostic agent (technetium Tc99m bicisate) which passively diffuses across the intact blood-brain barrier and remains stable in the brain for ~6 hours. As such, this…
Subcutaneous emphysema occurs when air gets trapped within the subcutaneous regions of the face, neck, chest wall, abdomen, and even down to the thighs/legs. The characteristic physical exam finding of crepitus (“snap-crackle-pop”) is caused by air traversing tissue planes during palpation.
In severe COVID-19 pneumonia with refractory hypoxemia, patients are often proned (put on their abdomen), deeply sedated, and paralyzed to improve synchrony with the ventilator. The goal with proning is to create a more homogenous alveolar recruitment thereby decreasing shunting (parts of the lung where there is pulmonary blood flow…
A pneumothorax occurs when air fills the pleural space between the lungs and chest wall. This can cause partial or total lung collapse leading to difficulties with alveolar ventilation, hemodynamic lability, etc.
Here’s an example of a large, right-sided tension pneumothorax (PTX). Disruption in the lung leads to a one-way valve where air fills the pleural space and expands the PTX during inspiration but cannot escape during expiration.
In this portable x-ray of a patient with COVID-19 pneumonia, one can clearly see the right and left mainstem bronchi as well as more distal segments (arrows indicate several “air bronchograms”). This occurs because the air-filled, patent bronchi don’t attenuate x-ray radiation and appear dark compared to the surrounding airspace…