17. Churg-Strauss Syndrome
Definition
Churg-Strauss syndrome (CSS) is an allergic, granulomatous angitis that is a variant of necrotizing vasculitis in which there is significant lung involvement. It also affects the musculoskeletal, cardiac, and peripheral nervous systems. CSS is sometimes referred to as polyarteritis nodosa with lung involvement.
Incidence
The true incidence of CSS is uncertain, but it is less frequent than classic polyarteritis nodosa. It has been documented in all age groups but is extremely rare among infants.
Etiology
The etiology of CSS is unknown; however, there is a strong association with allergic diathesis and frequently severe and/or intractable asthma.
Signs and Symptoms
• Cerebral infarcts
• Congestive heart failure
• Coronary vasculitis
• Cutaneous nodules
• Diffuse interstitial lung disease
• Endocarditis
• Glomerulonephritis
• Hemoptysis
• Hypertension
• Ischemic optic neuropathy
• Myocardial infarction
• Myocarditis
• Nasal mucosa
• Nasal polyps
• Pericarditis
• Peripheral neuropathies
• Pleural effusions
• Radiculopathies
• Renal arteritis
• Sinusitis
• Transient pulmonary infiltrates
Medical Management
Positive diagnosis is based on the presence of at least four of the following symptoms.
1. Abnormalities of paranasal sinuses
2. Bronchospasm
3. >10% eosinophil count
4. Extravascular eosinophils
5. Nonfixed pulmonary infiltrates
6. Poly- or mononeuropathy
Patients usually have a very long history of asthma. Generalized treatment of asthma is continued vigorously and must be optimized. The box below lists physiologic/anatomical abnormalities associated with Churg-Strauss syndrome.
Physiologic/Anatomical Abnormalities Associated with Churg-Strauss Syndrome
• Abnormal urine sediment, proteinuria, microscopic hematuria, and RBC casts
• Anemia
• Antineutrophil cytoplasmic antibodies (ANCA) (70% of patients are perinuclear-ANCA positive)
• Blood urea nitrogen and creatinine levels are elevated
• Elevated eosinophil cationic protein (ECP), soluble interleukin-2 receptor (sIL-2R), and soluble thrombomodulin
• Elevated IgE levels
• Eosinophilia
• Eosinophilia in bronchoalveolar lavage
• Eosinophils ≥10%
• Erythrocyte sedimentation rate and C-reactive protein level are increased
• Hypergammaglobulinemia
• Positive for rheumatoid factor at low titer
Chest X-Ray
• Hilar nodal enlargement (occasionally)
• Local parenchymal opacities
• Pulmonary opacities
• Rare cavitation
• Transient pulmonary infiltrates
Complications
If left untreated, CSS can progress to extensive cardiac involvement, which can culminate in death. Exacerbation and/or extension of the asthmatic initiating component can lead to pulmonary infiltrates and/or pleural effusions. Renal involvement can initiate hypertension or lead to its exacerbation, if already present.
Anesthesia Implications
Any surgical intervention not of an emergent nature should be postponed, delayed, or rescheduled until the CSS treatment is well under way and the benefits of the treatment regimen are relatively easily observed. Before surgery and anesthesia, treatment of the patient’s asthma must be optimized. Pulmonary function testing is appropriate preoperatively. Cardiac, neurologic, renal, and hepatic functions should be evaluated preoperatively. The extent of the evaluation should be guided by the history/progress of CSS. Enzyme induction should be anticipated, particularly when treatment has included the chemotherapeutic agents listed above.
Development of nasal polyps may inhibit nasal intubation, which may be particularly important in a patient scheduled for a maxillofacial procedure.
Pulmonary involvement can produce patches of pneumonitis, which reduces the compliance of the lungs in areas. The reduced compliance of portions of the lungs leads to overdistention of alveoli in more compliant areas. Overdistention of more compliant areas increases the possibility of barotraumas during positive pressure ventilation. The development of patches of pneumonitis also produces areas of ventilation/perfusion mismatching and compounds any gas exchange abnormalities already present as a result of the asthma. Therefore, whenever possible, direct laryngoscopy, tracheal intubation, and positive pressure ventilation are best avoided. Spontaneous ventilation with regional anesthesia or with general anesthesia via mask is more advantageous for the patient. The laryngeal mask airway (LMA) may be used in appropriate surgical situations. If intubation and ventilation are unavoidable, longer expiratory phases and/or pressure-controlled ventilatory methods should be employed to minimize the potential for alveolar overdistention/barotrauma. Preoperative and/or intraoperative supplementation with a corticosteroid should be strongly considered to aid with the patient’s stress response.
