**39. Management**

Treatment of the pulmonary tumor embolism is directed at the primary tumor. Complete surgical resection of the primary tumor results in gradual resolution of the tumor emboli and reversal of the respiratory symptoms in patients with renal cell carcinoma, atrial myxoma and choriocarcinoma (C. K. Chan et al., 1987). The curative surgical resection in these cases may be due to early recognition or related to the less aggressive nature of the underlying malignancies. Embolectomy and IVC filter placement have been employed in the rare patients suffering from large, central pulmonary tumor emboli arising from infra-diaphramatic tumors. Chemotherapy generally does not affect the prognosis unless the primary tumor is very chemo-sensitive i.e. Wilm's tumor or trophoblastic tumors.

with proliferative endarteritis. Thus, PTE may be pathologically indistinguishable from other forms of pulmonary arterial hypertension, except for the notable absence of plexiform lesions. Some investigators describe tumor emboli as possessing an unusual level of resistance to recannulation (as compared to thromboembolism) and therefore likely lead to progressive and irreversible obstruction of the pulmonary vascular bed

**Pathophysiology:** Pulmonary vasculature provides the first capillary bed to the circulating tumor cells. The process of pulmonary metastasis consists of sequential steps that includes intravascular and/or lymphatic invasion of the lung by the neoplastic cells. Large scale autopsy studies suggest that tumor cells spread to the pulmonary vasculature in basically 4

1. Large tumor emboli to the main pulmonary artery or large lobar branches producing

2. Microscopic tumor embolization involving small arteries and arterioles accounting for

3. Generalized lymphatic dissemination leading to pulmonary microvascular involvement

**Clinical features:** In most patients, primary malignancy was established when tumor emboli were noted. The signs and symptoms are non-specific. Patients with large proximal emboli have rapid onset of symptoms due to acute right heart failure indistinguishable from the presentation of a massive thromboembolism. Lymphangitic carcinomatosis and microvascular disease involving small pulmonary arteries, follow a more deliberate and

**Physical examination** shows evidence of pulmonary hypertension and signs of right heart dysfunction. Common findings included: tachypnea, tachycardia, cyanosis, hypotension, elevated Jugular venous distension (JVD), audible pulmonic sound (P2), ascites and peripheral edema. Although considered "classic", signs of right heart failure are only

**Diagnosis:** Ante-mortem diagnosis of pulmonary tumor embolism can be very difficult due to lack of distinctive features compared to thrombo-embolism which is more common. Diagnosis often made via tissue specimens from open lung biopsy or autopsy. Pulmonary arterial sampling (in a wedge position) has resulted in diagnosis in a few cases (Masson &

Treatment of the pulmonary tumor embolism is directed at the primary tumor. Complete surgical resection of the primary tumor results in gradual resolution of the tumor emboli and reversal of the respiratory symptoms in patients with renal cell carcinoma, atrial myxoma and choriocarcinoma (C. K. Chan et al., 1987). The curative surgical resection in these cases may be due to early recognition or related to the less aggressive nature of the underlying malignancies. Embolectomy and IVC filter placement have been employed in the rare patients suffering from large, central pulmonary tumor emboli arising from infra-diaphramatic tumors. Chemotherapy generally does not affect the prognosis unless the primary tumor is very chemo-sensitive i.e. Wilm's tumor or

(Winterbauer et al., 1968).

ways (Kane et al., 1975; Winterbauer et al., 1968):

4. A combination of the above three mechanisms.

progressive course resulting in subacute cor pulmonale.

Ruggieri, 1985; K. E. Roberts et al., 2003).

**39. Management** 

trophoblastic tumors.

the syndrome of acute pulmonary hypertension.

progressive dyspnea and subacute pulmonary hypertension.

(lymphatic carcinomatosis) causing diffuse interstitial infiltrates.

reported in 15% to 20% of patients with this syndrome (Veinot et al., 1992).

#### **40. Pulmonary cement embolism**

Pulmonary Cement Embolism (PCE) is a complication of Percutaneous Vertebroplasy (PVP) and Balloon Kyphoplasty which are minimally invasive procedures used to treat osteoporotic and other vertebral fractures (Galibert et al., 1987; Garfin et al., 2001;Gigante & Pierangeli, 2008; McDonald et al., 2008; Oner et al., 2006; Stoffel et al., 2007; Wu & Fourney, 2005). Polymethylmethacrylate (PMMA, "cement" ) leakage is a frequent occurrence during these procedures and the source of PCE (Gangi et al., 1999; Garfin et al., 2001; Hauck et al., 2005; Hodler et al., 2003; R. Schmidt et al., 2005; Vasconcelos et al., 2002; Yeom et al., 2003). The risk of pulmonary cement embolism (PCE) ranges from 3.5% to 23% for osteoporotic fractures (Anselmetti et al., 2005; Choe et al., 2004; Duran et al., 2007; Y. J. Kim et al., 2009). A recent report suggested a prevalence of 8.8% (Gill et al., 2010). Exact incidence is difficult to estimate as many are asymptomatic and escape detection. Patients with malignant lesions of the vertebrae might be at a higher risk of developing PCE due to damaged cortical substance and increased vascularity, while technical factors such as inappropriate viscosity of the cement at the time of injection, lack of visual guidance and higher cement volume injected during the procedure increase the risk of PCE (Baroud et al., 2006; Bohner et al., 2003; Choe et al., 2004; Deramond et al., 1998).The clinical spectrum following PMMA leakage is broad: asymptomatic extravasation into surrounding tissues, features of nerve root compression (Kelekis et al., 2003; Laredo & Hamze, 2005; Ratliff et al., 2001), asymptomatic and symptomatic pulmonary cement embolism (Anselmetti et al., 2005; Choe et al., 2004; Duran et al., 2007; Y. J. Kim et al., 2009), even cardiac perforation (S. Y. Kim et al., 2005; Lim et al., 2008; Schoenes et al., 2008; Son et al., 2008) and death (H. L. Chen et al., 2002; Monticelli et al., 2005; Stricker et al., 2004; Yoo et al., 2004) have been reported. Fat embolism occurring simultaneously with cement embolism may also contribute to the clinical picture (Aebli et al., 2002; Rauschmann et al., 2004). Clinically PCE cannot be distinguished from thrombotic pulmonary embolism (Bernhard et al., 2003; Jang et al., 2002; Padovani et al., 1999; Tozzi et al., 2002). Diagnosis is based on history and imaging which shows presence of radio-opaque densities (Figs 6 a&b). There is not enough evidence to underlay treatment guidelines. Since cement is regarded as "thrombogenic", (Francois et al., 2003; Perrin et al., 1999; Righini et al., 2006; Tozzi et al., 2002) anticoagulation for 6 months is recommended for symptomatic patients or patients with central PCE. Asymptomatic patients with peripheral PCE should have close clinical follow up with no anticoagulation. Surgical embolectomy may be considered for exceptional cases of central embolism. Routine chest roentogenogram should be obtained after PVP and BKP regardless of the symptoms as many patients are asymptomatic.

#### **41. Gas embolism**

Gas embolism (GE) is mainly ambient "air" embolism (AE) but also includes other gases such as carbon dioxide, nitrous oxide, nitrogen and helium. It is a rare and potentially fatal condition. There are 2 main types of GE, i.e, venous and arterial. They are distinguished by the mechanism of entry. Venous GE (VGE) occurs usually as a complication of iatrogenic procedures such as vascular catheter placement, mechanical ventilation and rarely surgical procedures (pulmonary lung biopsy, open heart surgeries, craniotomy). Arterial GE causes ischemia. As little as 0.5ml of air can result in coronary ischemia, cardiac arrhythmias, serious brain damage and even death.

Non-Thrombotic Pulmonary Embolism 99

the bubbles (Muth & Shank, 2000; Van Liew et al., 1993). Adjunctive treatment, includes fluid administration and prophylaxis against venous thromboembolism in paralyzed patients. Treatment is effective in most cases, although residual deficits can remain in serious cases.

Silicone is thought to be an immunological inert substance and a component of many implantable medical devices. Silicone emboli (SIE) were first reported in trans-sexual males in 1970's and then later in young healthy women seeking low cost enhancements. Silicone implants are approved and widely used for breast augmentation, however liquid silicone used for aesthetic purposes cause significant morbidity when injected in the hips and buttocks, face, breasts, and vagina and is illegal in the US (Bartsich & Wu, 2010). Clinical features are similar to fat embolism with majority of patients meeting Schonfeld criteria (Schmid et al., 2005). The most common presentation is hypoxemia (92%) (Bartsich & Wu, 2010). Silicone embolic syndrome (SES) is a constellation of mainly pulmonary symptoms including dyspnea, fever, cough, hemoptysis, chest pain, hypoxia, alveolar hemorrhage, and altered consciousness presenting in patients shortly after silicone injection (within the first few hours) (Schmid et al., 2005). Later sequelae may occur within a few days and the possibility of delayed-onset pneumonitis or local inflammation at injection sites can occur up to years after administration (Chastre et al., 1987). Several factors have been implicated in leading to silicone emboli, including large volume injections, high-pressure infiltration, particle migration, and intravascular injection (Villa & Sparacio, 2000). It is thought that alveolar macrophages ingest silicone and fat to provoke an inflammatory response by increasing vascular permeability, activating endothelial cells, inducing the accumulation of activated neutrophils and modulating immunoregulatory responses in the lung. Imaging is usually suggestive of an embolic, congestive, pneumonitis or diffuse alveolar damage pattern. Treatment is supportive,

Hyaluronic acid (HA) is an approved dermal filler used for correction of facial wrinkles and folds (H. J. Park et al., 2010). All other uses are considered off label and illegal. HA associated pulmonary emboli (HAAPE) have been described in few case reports (Famularo et al., 2001; H.J. Park et al., 2010). Typical presentation of HAAPE is acute respiratory failure within hours after the HA injection in the anterior wall of the vagina, G-Spot amplification or for lip amplification by an unlicensed medical practitioner. Due to the extensive venous plexus, procedures involving injections in and around the injection site can cause NTPE. Although HA is thought to be non-immunogenic, it can cause localized granulomatous foreign body reactions with multinucleated giant cells around amorphous basophilic materials in the pulmonary vessels and lung parenchyma, as seen on video-assisted lung biopsy (Fernandez-Acenero et al., 2003; Honig et al., 2003; Raulin et al., 2000). Treatment is mainly supportive.

Any material that is injected intravenously can potentially enter the pulmonary circulation leading to pulmonary embolism. Foreign materials such as talc, starch, cotton, and cellulose

consisting mainly of supplemental oxygen and steroid therapy.

**43. Hyaluronic acid embolism** 

**44. Others** 

**42. Foreign body embolism** 

**42.1 Silicone embolism** 

Fig. 6. a: Chest radiograph showing radio-opaque density in right main pulmonary artery

Fig. 6. b: CT Chest revealing bright intravascular densities in segmental and subsegmental pulmonary arteries

In venous GE, manifestations include cough, dyspnea, tachypnea and a hypoxemic ''gasp'' reflex when 10% or more of the pulmonary vessels are occluded (Souders, 2000; Sviri et al., 2004). Arterial embolization into the coronary arteries induces a specific drum-like or ''millwheel'' murmur along with electrocardiographic changes of ischemia (Rossi et al., 2000).

The key to controlling air embolism lies in prevention. First line of treatment includes administration of 100% oxygen, placing the patient in left lateral decubitus position to prevent right ventricular outflow obstruction by airlock. Hyperbaric Oxygen (HBO) may be used. 100% oxygen decreases the size of the gas bubbles by increasing the ambient pressure and by establishing a diffusion gradient that favors the elimination of gas from the bubbles and by increasing the gradient for the egress of nitrogen from the bubbles (Muth & Shank, 2000; Van Liew et al., 1993). Adjunctive treatment, includes fluid administration and prophylaxis against venous thromboembolism in paralyzed patients. Treatment is effective in most cases, although residual deficits can remain in serious cases.
