40. Goodpasture Syndrome
Definition
Goodpasture syndrome is an autoimmune process composed of acute glomerulonephritis in conjunction with pulmonary alveolar hemorrhage and antiglomerular basement membrane antibodies.
Incidence
The incidence of Goodpasture syndrome is approximately 1:100,000. The disease is reported in all races, but occurs most frequently among Caucasians. Males are affected more than females at a ratio of 2.9:1.
Etiology
The cause of Goodpasture syndrome is the production of antiglomerular basement membrane antibodies, frequently as the result of exposure to an environmental insult in genetically predisposed people. The environmental triggers include cigarette smoke, hydrocarbon inhalation, and viral infections.
Signs and Symptoms
• Azotemia
• Bronchial breathing
• Cough
• Cyanosis
• Dyspnea (exertional)
• Edema
• Fatigue/weakness
• Fevers/chills/diaphoresis
• Gross hematuria
• Hemoptysis
• Inspiratory crackles
• Proteinuria
• Tachypnea
Medical Management
Treatment of Goodpasture syndrome involves two simultaneous interventions: (1) removing existing pathogenic antibodies and (2) preventing subsequent production of new antibodies. Antibody removal is best achieved via plasma exchange. Current recommendations for an adult patient present two options: either daily exchanges for 14 consecutive days or every third day for 1 month. A plasma exchange session involves total volumes of 3 L to 4 L, with volume replacement consisting of albumin and fresh frozen plasma.
Preventing new antibody production is best accomplished via immunosuppression. Immunosuppression therapy usually consists of administering corticosteroids and cyclophosphamide. An adult with serum creatinine levels of 8 generally has a poor renal outcome.
Immunosuppression treatment for a pediatric patient generally consists of 6 months of corticosteroid therapy combined with giving cyclophosphamide for 3 months.
Therapeutic response is monitored by serial measurements of antiglomerular basement membrane antibody titers, serum creatinine levels, and chest x-rays to measure progress and determine the duration of therapeutic interventions.
Sodium restriction may be implemented, particularly for a patient being treated with corticosteroids or a patient with severe proteinuria and nephrotic syndrome. Fluid intake may be restricted, depending on whether the patient’s renal function indicates it and whether cyclophosphamide is a component of the treatment regimen.
Liberal fluid intake is encouraged for the patient being treated with cyclophosphamide who has good urine output and stable blood pressure. The goal is to promote continued good urine output and reduce the risk of hemorrhagic cystitis.
Complications
• Anaphylactoid reactions
• End-stage renal disease
• Hemorrhage
• Metabolic alkalosis
• Opportunistic infection (bacterial or fungal)
• Post-transfusion hepatitis
• Recurrent pulmonary hemorrhage
• Thrombosis
Anesthesia Implications
If at all possible, any surgical procedure should be delayed or postponed until the patient’s condition is optimized. This is particularly important for a patient whose diagnosis of Goodpasture syndrome is relatively recent or a patient with a long-standing diagnosis but experiencing an acute exacerbation of symptoms. Medical treatment should be well established and any pulmonary problems treated and almost totally resolved before undertaking anything other than fully emergent surgery.
Preoperative evaluation must focus on the function of the pulmonary and renal systems. Blood urea nitrogen, serum creatinine, and urinary output/urinalysis are good indicators of renal function. Pulmonary evaluation should include arterial blood gas analysis, chest x-ray, diffusing capacity, and spirometry. Chest x-rays may demonstrate pulmonary infiltrates bilaterally secondary to alveolar hemorrhage. Hypoxemia and restrictive defects may be demonstrated in patients with ongoing pulmonary involvement.
Preoperative complete blood count may demonstrate microcytic anemia from hemorrhages. The patient may require preoperative blood transfusion, particularly before a large abdominal procedure or one anticipated to involve large volumes of blood loss intraoperatively. The patient is also more apt to require postoperative blood transfusion.
The anemia secondary to hemorrhage has a significant impact on oxygenation. With a low hemoglobin concentration, the O 2-dissociation curve is shifted to the right. If there is an ongoing alveolar hemorrhage, gas exchange is impaired and the anemia will be exacerbated. Any alveolar hemorrhage present can be worsened by use of high fractions of inspired oxygen (Fio 2) and high inspiratory pressures. As a result, oxygen delivery may be further compromised.
Fluid resuscitation should not be overly aggressive to help reduce further antiglomerular basement membrane antibody–mediated damage to the lungs.
Blood pressure should be monitored with an intra-arterial pressure catheter placement, particularly for a patient with anything more than the mildest expression of this disease and/or for a patient scheduled for large, intricate surgical procedures in which large fluid shifts are anticipated.
A pulmonary artery catheter and transesophageal echocardiogram are prudent monitors to include in the care of the patient scheduled for large, intricate surgical procedures and/or one with significant pulmonary manifestations of the disease. Both devices, together or singularly, provide indispensable information to guide the anesthetist in fluid resuscitation and management, both intra- and postoperatively.
The patient’s renal status has significant bearing on the selection of the volatile inhalational agent and any intravenous agent. Any medications that are potentially nephrotoxic should be avoided. Medications that depend on renal excretion will necessarily need the dose(s) customized based on the patient’s creatinine clearance level.
