Klippel-Trenaunay syndrome as a rare cause of chronic thromboemboembolic pulmonary hypertension.

Klippel-Trenaunay syndrome (KTS) is a congenital disorder characterized by cutaneous capillary malformations, soft tissue and bone hypertrophy, and multiple capillary, venous or lymphatic malformations. KTS is associated with recurrent thromboembolic events. We reported herein five cases of chronic thromboembolic pulmonary hypertension (CTEPH) associated with KTS (age minimum-maximum 26-50 years old, 3 males/2 females). Hemodynamics showed severe pulmonary hypertension (PH) with pulmonary vascular resistance ranging from 5.6 to 18.3 Wood units (WU), associated with marked clinical impairment (NYHA functional class III or IV in 4 patients). Computed tomography (CT) of the chest and pulmonary angiography confirmed proximal CTEPH accessible to surgical intervention in one patient and distal forms of CTEPH in 4 patients. Evolution after pulmonary endarterectomy showed hemodynamic normalization, while the patients with distal CTEPH had severe outcomes with 2 early deaths after PH diagnosis (44 and 35 months respectively). One patient with distal CTEPH was still alive 16 years after diagnosis on specific PH therapy and one was transplanted after 15 years because of right heart failure (death after 12 months). Histological analysis of the lung explants showed typical chronic thromboembolic material specific for CTEPH. In conclusion, KTS may be complicated by severe CTEPH requiring careful anticoagulation and multidisciplinary follow-up in expert centers to screen for disease potentially accessible to endarterectomy. In the modern management era of CTEPH, balloon pulmonary angioplasty will certainly be an interesting option in patients with inoperable disease.

[Pulmonary veno-occlusive disease]. / La maladie veino-occlusive pulmonaire.

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension (PH) characterized by preferential remodelling of pulmonary venules and angioproliferation. PVOD term includes idiopathic, heritable (biallelic mutations of EIF2AK4 gene), drugs and toxins induced (alkylating agents, organic solvents) and connectivite-associated forms (especially systemic-sclerosis associated form). PVOD and pulmonary arterial hypertension (PAH) share a similar clinical presentation. Lung biopsy is contraindicated in PVOD due to high risk of life-threatening bleeding. A noninvasive diagnostic approach, including oxygen parameters, low diffusing capacity for carbon monoxide and characteristic signs on high-resolution computed tomography of the chest, is used to support a diagnosis of PVOD. PVOD prognosis is worse than other forms of PAH. There is no evidence-based medical therapy for PVOD and life-threatening pulmonary edema may occur following PAH targeted therapy in PVOD. Lung transplantation remains the preferred definitive therapy for eligible patients.

Noncardiothoracic nonobstetric surgery in mild-to-moderate pulmonary hypertension.

The anaesthetic management and follow-up of well-characterised patients with pulmonary arterial hypertension presenting for noncardiothoracic nonobstetric surgery has rarely been described. The details of consecutive patients and perioperative complications during the period January 2000 to December 2007 were reviewed. Repeat procedures in duplicate patients were excluded. Longer term outcomes included New York Heart Association (NYHA) functional class, 6-min walking distance and invasive haemodynamics. A total of 28 patients were identified as having undergone major (57%) or minor surgery under general (50%) and regional anaesthesia. At the time of surgery, 75% of patients were in NYHA functional class I-II. Perioperative deaths occurred in 7%. Perioperative complications, all related to pulmonary hypertension, occurred in 29% of all patients and in 17% of those with no deaths during scheduled procedures. Most (n = 11, 92%) of the complications occurred in the first 48 h following surgery. In emergencies (n = 4), perioperative complication and death rates were higher (100 and 50%, respectively; p<0.005). Risk factors for complications were greater for emergency surgery (p<0.001), major surgery (p = 0.008) and a long operative time (193 versus 112 min; p = 0.003). No significant clinical or haemodynamic deterioration was seen in survivors at 3-6 or 12 months of post-operative follow-up. Despite optimal management in this mostly nonsevere pulmonary hypertension population, perioperative complications were common, although survivors remained stable. Emergency procedures, major surgery and long operations were associated with increased risk.

Pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) is currently classified as a subgroup of pulmonary arterial hypertension (PAH) and accounts for 5-10% of cases initially considered to be idiopathic PAH. PVOD has been described as idiopathic or complicating other conditions, including connective tissue diseases, HIV infection, bone marrow transplantation, sarcoidosis and pulmonary Langerhans cell granulomatosis. PVOD shares broadly similar clinical presentation, genetic background and haemodynamic characteristics with PAH. Compared to PAH, PVOD is characterised by a higher male/female ratio, higher tobacco exposure, lower arterial oxygen tension at rest, lower diffusing capacity of the lung for carbon monoxide, and lower oxygen saturation nadir during the 6-min walk test. High-resolution computed tomography (HRCT) of the chest can be suggestive of PVOD in the presence of centrilobular ground-glass opacities, septal lines and lymph node enlargement. Similarly, occult alveolar haemorrhage is associated with PVOD. A noninvasive diagnostic approach using HRCT of the chest, arterial blood gases, pulmonary function tests and bronchoalveolar lavage could be helpful for the detection of PVOD patients and in avoiding high-risk surgical lung biopsy for histological confirmation. PVOD is characterised by a poor prognosis and the possibility of developing severe pulmonary oedema with specific PAH therapy. Lung transplantation is the treatment of choice. Cautious use of specific PAH therapy can, however, be helpful in some patients.

[Postembolic pulmonary hypertension]. / Hypertension pulmonaire postembolique.

INTRODUCTION: Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease characterized by the persistence of thromboemboli obstructing the pulmonary arteries as an organized tissue. The consequence is an increase in pulmonary vascular resistance resulting in pulmonary hypertension (PH) and progressive right heart failure. BACKGROUND: It is difficult to recognize the postembolic nature of PH because there is no known history of thromboembolic disease in more than 50% of cases. Diagnosis is based on the presence of mismatched segmental defects in the ventilation-perfusion scanning. When CTEPH is suspected, pulmonary angiography and high-resolution CT scan are required to establish the diagnosis and to assess the operability. Pulmonary angiography is always performed in conjunction with a diagnostic right heart catheterization, which is required to confirm the diagnosis of PH and to determine the degree of hemodynamic impairement. If there is a good correlation between the pulmonary vascular resistance and the anatomical obstruction, pulmonary endarterectomy (PEA) must be proposed. Otherwise, vasodilator and antiproliferative treatments and lung transplantation represent interesting alternatives. VIEWPOINT AND CONCLUSION: PEA remains the treatment of choice for eligible patients. Nevertheless, there is a need to conduct randomized trials to assess the efficacy of novel medical therapies in some situations: (1) in inoperable CTEPH due to distal lesions, (2) before PEA (therapeutic bridge) in patients who are considered "high risk" due to extremely poor hemodynamics, (3) in patients with persistent pulmonary hypertension after surgery.

[Pulmonary arterial hypertension due to tumor emboli]. / Hypertension artérielle pulmonaire postembolique tumorale.

INTRODUCTION: Pulmonary arterial hypertension (PAH) is rare in the presence of malignancy and tumour embolisation is one of several possible pathological mechanisms. CASE REPORTS: We report our experience of 5 clinical cases and undertake a literature revue of the pathophysiological mechanisms and of the possible diagnostic and therapeutic approaches. CONCLUSIONS: Neoplastic PAH due to tumour micro-emboli is rare and the diagnosis difficult to establish. Cytological examination of pulmonary arterial blood could allow early institution of appropriate chemotherapy and lead to an improvement in the grave prognosis of this condition.

Occult alveolar haemorrhage in pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary arterial hypertension that affects predominantly post-capillary pulmonary vessels. A major concern with PVOD is the poor response to available therapies and the risk of pulmonary oedema with continuous intravenous epoprostenol. The present authors hypothesised that alveolar haemorrhage may be a characteristic feature of pulmonary veno-occlusive disease, as compared with other forms of pulmonary arterial hypertension that predominantly involve pre-capillary pulmonary arteries. This paper reports a series of 19 patients with either PVOD (n = 8) or idiopathic pulmonary arterial hypertension (IPAH; n = 11) who underwent bronchoalveolar lavage. Cytological analyses were performed and differential counts were made on Perls-stained preparations. The Golde score was used to assess alveolar haemorrhage. As compared with IPAH, PVOD was characterised by a higher percentage of haemosiderin-laden macrophages (40+/-37 versus 3+/-6%), resulting in elevated Golde scores (81+/-88 versus 4+/-10). It was concluded that occult alveolar haemorrhage is a common feature of pulmonary veno-occlusive disease. Detecting occult alveolar haemorrhage may be of interest in the diagnostic approach of pulmonary veno-occlusive disease.

Reversibility of pulmonary arterial hypertension in HIV/HHV8-associated Castleman's disease.

The present study describes a case of pulmonary arterial hypertension (PAH) associated with multicentric Castleman's disease in a patient infected with HIV type 1 and human herpes virus 8. Therapy included highly active antiretroviral therapy, warfarin, diuretics, continuous i.v. epoprostenol and 12-monthly pulses of cyclophosphamide. The patient's condition improved dramatically with complete reversibility of PAH, allowing weaning of continuous i.v. epoprostenol therapy. After 5 yrs, both Castleman's disease and PAH have not relapsed. This supports the hypothesis that control of inflammation and retroviral replication may be of interest in the context of PAH, complicating the course of an inflammatory condition associated with viral infection. In conclusion, further studies should help in characterising the best candidates for anti-inflammatory treatment in the setting of pulmonary arterial hypertension.

[Diagnosis and classification of pulmonary arterial hypertension]. / Diagnostic et classification des hypertensions artérielles pulmonaires.

The clinical classification of types of pulmonary hypertension has made it possible to better standardize the approach to the diagnosis and treatment of patients, to perform clinical studies among homogeneous patients, and to discover common laboratory abnormalities that may serve as markers or help elucidate mechanisms of disease. Pulmonary arterial hypertension groups together different diseases that affect the small-caliber pulmonary arteries and lead to a progressive increase in pulmonary arterial resistance and right heart failure. A specific diagnosis of pulmonary arterial hypertension is generally based on a detailed and methodical clinical evaluation. Pulmonary biopsy is rarely indicated. Work-up in a center specialized in the management of this disease is frequently appropriate when the cause of the hypertension is not clear or when a specific treatment is envisaged.

[Treatment for pulmonary arterial hypertension under the new French hospital financing system. Recommendations of the Pulmonary Vascular Diseases Working Group of the French Society of Pulmonary Medicine]. / Les traitements de l'hypertension artérielle pulmonaire à l'heure de la T2A. Recommandations du groupe de travail "Maladies vasculaires pulmonaires" de la Société de pneumologie de langue française.

Activity-based financing (that is, casemix-based hospital payments, known as T2A) is intended to harmonize and improve the fairness of remuneration of public and private hospitals. T2A will ultimately rely mainly on a flat rate per admission, set according to the diagnosis-related group (DRG). Although payment for drugs is usually included in the DRG price, some expensive drugs will be reimbursed on an additional cost basis after implementation of a "best practices" agreement. Four drugs used for treatment of pulmonary arterial hypertension are eligible for this additional reimbursement: 3 prostacyclin derivatives (intravenous epoprostenol, inhaled iloprost, and subcutaneous treprostinil), and oral bosentan, an endothelin receptor antagonist. The Pulmonary Vascular Diseases working group of the French Society of Pulmonary Medicine has developed guidelines for the best practices in use of these drugs.

[Surgical treatment of chronic thromboembolic pulmonary hypertension]. / Traitement chirurgical de la maladie thromboembolique pulmonaire chronique.

Chronic thromboembolic pulmonary hypertension is a condition that has long remained in the shadows, a kind of orphan disease, because of the lack of any curative treatment. The renewal of interest by pulmonary specialists, cardiologists and thoracic surgeon is due to the development over the past 20 years of major new treatments: lung transplantation, continuous prostacyclin infusion, and pulmonary endarterectomy, in chronological order. Most patients with postembolic pulmonary arterial hypertension (PEPAH) in a sufficiently proximal location can benefit from curative surgical treatment by bilateral endarterectomy of the pulmonary arteries. This complex surgery, performed under deep hypothermic circulatory arrest, clears out the pulmonary vascular bed down through its subsegmental branches and results in a frank reduction in pulmonary vascular resistance and normalization of cardiopulmonary function. It is a curative procedure with a perioperative mortality rate less than 7% and a definitive result, unlike pulmonary and cardiopulmonary transplantation, which have a postoperative mortality rate of 20% and a 5-year survival rate of 50%. It is difficult to recognize the postembolic nature of pulmonary hypertension because there is no known history of venous thrombosis or embolic phenomena in more than 50% of cases. Diagnosis is based on the presence of mismatched segmental defects in the radioisotopic ventilation-perfusion scanning. To be accessible to endarterectomy, lesions must involve the main, lobar, or segmental arteries. When conducted by experienced operators according to specific protocols, pulmonary (frontal and lateral views of each lung) and multislice CT angiography optimize assessment of the lesion site. When the pulmonary vascular resistance evaluated by catheterization is correlated with the anatomical obstruction visible on the images, pulmonary endarterectomy has a mortality rate below 4% and offers the patient a substantial chance to regain normal cardiorespiratory function. In cases of pulmonary arterial hypertension due to older embolisms, major arteriolitis occurs in the nonobstructed areas and aggravates the pulmonary hypertension, which may become suprasystemic. The endarterectomy mortality rate is then higher, and in specific cases justifies preoperative medical treatment. Pulmonary or cardiopulmonary transplantation is indicated in this disease only when the lesions are too distal and thus inaccessible to endarterectomy.

[Clinical, haemodynamic and genetic features of familial pulmonary arterial hypertension]. / Caractéristiques cliniques, hémodynamiques et génétiques de l'hypertension artérielle pulmonaire familiale.

INTRODUCTION: Pulmonary arterial hypertension (PAH) is defined by a raised pressure in the pulmonary arterial circulation associated with small vessel narrowing due to proliferation of the endothelium and vascular smooth muscle. Idiopathic PAH should be distinguished from PAH associated with a causal disease. One familial type (familial PAH), gathered from one family, has recently been linked to a mutation of the BMPR 2 (bone morphogenetic protein receptor 2) gene. It seems important to compare the idiopathic form of PAH with these familial forms to confirm that the same diagnostic and therapeutic principles can be applied to familial PAH. MATERIAL AND METHODS: The demographic, clinical, haemodynamic and prognostic data from 34 cases of familial PAH were compared with those of 451 cases of idiopathic PAH. The genetic characteristics of the familial forms were also defined. RESULTS: Familial PAH presented at a younger age than idiopathic PH (31 +/- 15 vs. 45 +/- 18 years p=0.002) without any other demographic difference (sex-ratio 2.09/1 et 1.42/1 p=NS). There was no difference in exercises tolerance (6 minute walking test 341 +/- 98 and 289 +/- 135 metres p=NS), in haemodynamic parameters (mean PAP 65 +/- 12 and 62 +/- 15 mmHg, p=NS), or in prognosis, with the exception of an absence of a vasodilator response in the familial group to nitric oxide challenge. We found the BMPR 2 gene mutation to be quantitatively and qualitatively comparable to previously published data. CONCLUSION: The only difference between these two forms of this illness were of a younger age at presentation and an absent vasodilator response in the familial PAH group. We do not propose that familial PAH should be treated any differently from the idiopathic form. Genetic counselling will need to be developed in line with the progress being made in the understanding of this condition.

Pathobiology of pulmonary hypertension. The role of platelets and thrombosis.

With the rare exceptions of PAH associated with antiphospholipid antibodies, genetic platelet dysfunction, or inherited deficiencies of antithrombotic pathways, the thrombotic lesions are secondary, but frequently occurring, in most cases of primary or secondary PAH. Pulmonary arterial hypertension is associated with thrombotic lesions and persistent vasoconstriction and structural remodeling of PA. Activated platelets interact with the PA wall and may contribute to the functional and structural alterations of pulmonary vessels by releasing vasoactive factors and mitogenic mediators.

Risk factors for pulmonary arterial hypertension.

The present limitations in knowledge of the potential risk factors for PPH undoubtedly are attributable to the facts that PPH is a rare disease with an unknown pathogenesis and lacking large case series. Moreover, definite epidemiologic data are rare and ideally should be obtained from epidemiologic surveys such as large case-control studies. The increased incidence of the disease in young women, the familial cases, the association with autoimmune disorders, and the recent discovery that mutation of the PPH1 gene may not be restricted to familial PPH support the hypothesis that the development of pulmonary hypertension likely implies an individual susceptibility or predisposition, which is probably genetically determined. It is also now commonly believed that the development of pulmonary hypertension in some of these predisposed individuals could be hastened or precipitated by various expression factors (some of them yet unrecognized), such as ingestion of certain drugs or diets, portal hypertension, or HIV infection.

Imbalance between platelet vascular endothelial growth factor and platelet-derived growth factor in pulmonary hypertension. Effect of prostacyclin therapy.

Focal vascular injury and impaired endothelial function are features of pulmonary hypertension (PH) that lead to enhanced platelet endothelial cell interactions. Vascular endothelial growth factor (VEGF) is contained in platelets and released at sites of vascular injury to promote endothelial repair and wound healing in combination with platelet-derived nonspecific mitogens such as platelet-derived growth factor (PDGF). The overall balance between platelet VEGF and PDGF was investigated in 21 patients with primary PH, 8 with secondary PH, and 27 with chronic hypoxemic lung disease (CHLD), as well as in 29 control subjects. Platelet VEGF content was increased in patients with primary and secondary PH as compared with control subjects (518 +/- 89, 675 +/- 156, and 166 +/- 29 fg/10(5) platelets, respectively; p < 0.01), whereas platelet PDGF content was similar in the three groups (31 +/- 2, 36 +/- 4, and 33 +/- 3 pg/10(5) platelets, respectively; NS). Patients treated with a continuous prostacyclin infusion had a higher platelet VEGF but a similar platelet PDGF content as compared with untreated patients. Moderate increases in platelet VEGF and PDGF contents were observed in the CHLD patients. We conclude that patients with primary or secondary PH have an increase in platelet VEGF content, but not in platelet PDGF content, and that their platelet VEGF content increases further in response to prostacyclin infusion. We suggest that imbalance between platelet VEGF and PDGF is beneficial to patients with PH.

Severe pulmonary hypertension in histiocytosis X.

Diminished exercise capacity in advanced pulmonary histiocytosis X does not appear to be related to ventilatory limitation but may be related to pulmonary vascular dysfunction. Pulmonary hemodynamics and respiratory function were studied in 21 consecutive patients with advanced pulmonary histiocytosis X, and compared with parameters of patients with other severe chronic lung diseases (29 patients with chronic obstructive pulmonary disease and 14 patients with idiopathic pulmonary fibrosis). All patients with pulmonary histiocytosis X displayed severe pulmonary hypertension: mean pulmonary arterial pressure, 59 +/- 4 mm Hg; cardiac index, 2.6 +/- 0.8 L/min/m(2); and total vascular pulmonary resistance, 25 +/- 3 IU/m(2) (p < 0.05, as compared with patients with other chronic lung diseases). Pa(O(2)) was similar in the three groups, whereas FEV(1) was lower in patients with other chronic lung diseases (p < 0.05). In contrast to other chronic lung diseases, the degree of pulmonary hypertension was not related to variables of pulmonary function in pulmonary histiocytosis X. Histopathology was available for 12 patients with pulmonary histiocytosis X and revealed proliferative vasculopathy involving muscular arteries and veins, with prominent venular involvement. Two consecutive lung samples (taken before and after the occurrence of pulmonary hypertension) were available for six patients with pulmonary histiocytosis X, and showed that pulmonary vasculopathy worsened, whereas parenchymal and bronchiolar lesions remained relatively unchanged. These results indicate that pulmonary hypertension in pulmonary histiocytosis X might be related to an intrinsic pulmonary vascular disease, in which the pulmonary circulation is involved independent of small airway and lung parenchyma injury.

Increased interleukin-1 and interleukin-6 serum concentrations in severe primary pulmonary hypertension.

Primary pulmonary hypertension (PPH) is characterized by the proliferation of smooth-muscle cells, fibroblasts, and endothelial cells in the walls of small pulmonary arteries. In order to evaluate a role for proinflammatory cytokines in this process, we studied the concentration of interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor-alpha (TNF alpha) in the serum of 29 patients with severe PPH referred to our center for lung transplantation. Results were compared with those obtained in 15 normal controls and nine patients with pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD-PH). TNF alpha serum levels were within the normal range in each group. This contrasted with increased IL-1 beta serum levels in severe PPH (118 +/- 36 pg/ml, mean +/- SEM) as compared with controls (3 +/- 1 pg/ml, p < 0.001) or COPD-PH patients (3 +/- 1 pg/ml, p < 0.001). IL-6 serum concentrations were also higher in severe PPH (66 +/- 20 pg/ml) than in controls (14 +/- 6 pg/ml, p < 0.01). This study demonstrates increased serum levels of IL-1 beta and IL-6 in severe PPH, and suggests a role for proinflammatory cytokines in PPH.

[Acute lipid pneumopathy]. / Pneumopathie aiguë lipidique.

BACKGROUND: Lipid pneumonia in children has rarely been described in Europe. In some countries, due to local customs, the course is chronic. This study describes an acute lipid pneumonia in a young boy. CASE REPORT: A 12 year-old boy, previously treated for a rhabdomyosarcoma, developed acute fever with thoracic pain. A chest radiograph revealed heterogenous consolidation. The patient was given oral antibiotics, although no improvement was observed. The diagnosis of lipid pneumonia was made by a bronchoscopy with bronchoalveolar lavage. Treatment with corticosteroids was started. Clinical manifestations improved rapidly. One month later, chest radiograph and biological findings were normal. CONCLUSION: Diagnosis of lipid pneumonia should be considered in children with an acute febrile pneumonitis non resolving with antibiotic treatment. Examination of the fluid obtained by bronchoalveolar lavage confirms the diagnosis.

[Pulmonary arterial hypertension of chronic thromboembolic origin; therapeutic indications]. / Hypertension artérielle pulmonaire d'origine thrombo-embolique chronique; indications thérapeutiques.

Chronic thromboembolic pulmonary hypertension is a rare complication of acute pulmonary embolism. The therapeutic approach to the disease is addressed, based on a series of 81 patients referred to our department between 1984 and 1993. Medical treatment associates long-term anticoagulant therapy and, in some cases, inferior vena cava interruption. Two surgical procedures are available in selected patients: lung transplantation and pulmonary thrombo-endareterectomy. Lung transplantation has been performed in 8 patients since 1988 with 6 survivors with a maximal follow-up of 5 years. Twelve patients underwent pulmonary thromboendareterectomy with in 9 patients a dramatic functional and haemodynamic improvement. Chronic thromboembolism should be systematically investigated as the cause of pulmonary hypertension considering that in selected cases, curative surgery is possible.

Minocycline pneumonitis and eosinophilia. A report on eight patients.

We identified eight patients (six women and two men) who had pulmonary infiltrates during treatment with minocycline hydrochloride between 1989 and 1992 in French referral centers for drug-induced pulmonary diseases. Clinical files, chest roentgenograms, computed tomographic scans, pulmonary function, and bronchoalveolar lavage data were reviewed. Minocycline treatment was given for acne (n = 4), genital infection (n = 3), and Lyme disease (n = 1). The duration of treatment averaged 13 +/- 5 days (mean +/- SE); the total dose, 2060 +/- 540 mg. Patients presented with dyspnea (n = 8), fever (n = 7), dry cough (n = 5), hemoptysis (n = 1), chest pain (n = 2), fatigue (n = 3), and rash (n = 3). Chest roentgenograms showed bilateral infiltrates in all cases. Pulmonary function was measured in five patients; four had airflow obstruction and two had mild restriction. Blood gas tests demonstrated hypoxemia in seven patients (58 +/- 3 mmHg). Seven patients had blood eosinophilia (1.76 +/- 0.2 x 10(9)/L). Bronchoalveolar lavage (performed in seven patients) showed an increased proportion of eosinophils (0.30 +/- 0.07). The Cd4+/CD8+ ratio was determined in four cases and was low in three. Transbronchial lung biopsy, performed in two patients, showed interstitial pneumonitis in both patients, with marked infiltration by eosinophils in one patient. The outcome was favorable in all patients. Because of severe symptoms, steroid therapy was required in three patients. Rechallenge was not attempted. We conclude that minocycline can induce the syndrome of pulmonary infiltrates and eosinophilia, that presenting symptoms may be severe and may culminate in transient respiratory failure, and that the disease has a favorable prognosis.