Key points
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Patients with Huntington’s disease are at higher risk of pulmonary aspiration, altered anesthetic pharmacology, and worsening generalized tonic spasms. Rapid-sequence induction with cricoid pressure is recommended for general anesthesia.
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Autonomic dysfunction from amyloidosis has dramatic perioperative ramifications. Administering anesthetics to patients with amyloidotic polyneuropathy risks significant hypotension; depolarizing muscle relaxants are controversial.
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In patients with idiopathic pulmonary fibrosis, anesthetic evaluation focuses on degree of disease progression and available pulmonary reserve.
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Uncontrolled polycythemia vera is associated with a high risk of perioperative bleeding and postoperative thrombosis, requiring aggressive disease control preoperatively.
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Elderly patients with essential thrombocytosis are at high risk for thrombotic and hemorrhagic complications. Perioperative management of the patient with essential thrombocythemia focuses on whether to normalize the platelet count.
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Perioperative considerations in myeloid metaplasia with myelofibrosis include careful platelet count monitoring and attention to hemorrhagic complications.
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In patients with polymyalgia rheumatica, preoperative history and physical examination focus on the airway and symptoms related to systems affected by rheumatoid arthritis (neurologic, pulmonary, cardiovascular). Advanced planning is anticipated for identified or potentially difficult intubation.
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In Goodpasture’s syndrome, patients at risk for perioperative renal failure have pre-existing renal insufficiency or diabetes or require contrast procedures. Dialysis-dependent patients require careful coordination of dialysis and elective surgery.
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Preoperative evaluation of male patients with breast cancer is similar to that of female breast cancer patients and should focus on the heart, lungs, and neurologic and hematologic systems.
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In patients with primary hepatic lymphoma, degree of hepatic dysfunction and infection risk must be determined preoperatively.
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In patients with suspected Creutzfeldt-Jakob disease, any tissue or body fluid is potentially infectious, and precautions should be taken to prevent transmission.
Elderly surgical patients are subject to many of the same rare diseases seen in younger populations. The focus in this chapter is on several uncommon diseases that are more unique to aged individuals.
Huntington’s chorea (huntington’s disease)
Huntington’s chorea is a rare, autosomal dominant, inherited degenerative disorder of the nervous system with an incidence of 5 to 10 per 100,000 population. It is characterized by the clinical hallmarks of progressive chorea and dementia. The onset is usually in the fourth or fifth decade of life, but there is a wide range in age at onset, from childhood to late life (> 75 years). Symptoms appear to worsen progressively with age.
Pathophysiology
Huntington’s disease is an autosomal dominant disorder with complete penetrance. The Huntington’s disease gene, IT15 , is located on chromosome 4p, contains CAG-trinucleotide repeats, and codes for a protein called huntingtin. The protein is found in neurons throughout the brain; its normal function is unknown. Transgenic mice with an expanded CAG repeat in the Huntington’s disease gene develop a progressive movement disorder. It is a basal ganglia disease; caudate and putamen are the regions most severely affected. The most significant neuropathologic change is a preferential loss of medium-spiny neurons in the neostriatum. Neurochemically, there is a marked decrease of γ-aminobutyric acid (GABA) and its synthetic enzyme glutamic acid decarboxylase throughout the basal ganglia, as well as reductions of other neurotransmitters (e.g., substance P, enkephalin). The movement disorder is slowly progressive and may eventually become disabling.
Diagnosis and Differential
The DNA-repeat expansion forms the basis of a diagnostic blood test for the disease gene. Patients having 38 or more CAG repeats in the Huntington’s disease gene have inherited the disease mutation and will eventually develop symptoms if they live to an advanced age. Each of their children has a 50% risk of also inheriting the abnormal gene; a larger number of repeats is associated with an earlier age at onset. Huntington’s can also be diagnosed by caudate atrophy on magnetic resonance imaging (MRI) in the context of an appropriate clinical history.
Differential diagnosis of Huntington’s disease includes other choreas, hepatocerebral degeneration, schizophrenia with tardive dyskinesia, Parkinson’s disease, Alzheimer’s disease, and other primary dementias and drug reactions.
Preoperative Preparation
Even though memory in patients with Huntington’s chorea is frequently not impaired until late in the disease course, attention, judgment, awareness, and executive functions may be seriously deficient at an early stage. Depression, apathy, social withdrawal, irritability, fidgeting, and intermittent disinhibition are common. Delusions and obsessive-compulsive behavior may occur. These signs, along with poor articulation of speech, make preoperative evaluation and obtaining consent arduous tasks. Characteristic choreoathetoid movements, along with frequent, irregular, sudden jerks and movements of any of the limbs or trunk, make physical examination, as well as regional anesthesia, difficult to perform.
Cachexia and frailty may be observed in the elderly Huntington’s patient. Pharyngeal muscle involvement leads to dysphagia and makes these patients susceptible to pulmonary aspiration. Before elective surgery, it is important to rule out ongoing aspiration pneumonitis or pneumonia by careful physical examination and chest radiography.
There is no specific treatment to stop progression of Huntington’s disease, but the patient’s movements and behavioral changes may partially respond to phenothiazines, haloperidol, benzodiazepines, or olanzapine. Selective serotonin reuptake inhibitors (SSRIs) may help with associated depression.
Anesthetic considerations
Major concerns in anesthetic management of Huntington’s disease are potential difficult airway, sleep apnea, risk of aspiration, and altered reactions to various drugs. A difficult airway may result from a rigid, stiff, unstable posture with hyperextension of the neck. Sleep apnea may also be present. It is controversial whether the pharmacology of anesthetic agents is altered in Huntington’s disease. Authors have reported a decrease in plasma cholinesterase activity and a prolonged effect of succinylcholine. In addition, patients may have an exaggerated response to sodium thiopental or midazolam. On the other hand, both thiopental and succinylcholine , have been used safely in Huntington patients. Other agents used safely include propofol and sevoflurane. The safety profile and pharmacokinetics of the nondepolarizing muscle relaxants mivacurium and rocuronium are similar to those in patients without Huntington’s disease. , ,
It is generally recommended that rapid-sequence or modified rapid-sequence induction with cricoid pressure be used for induction of general anesthesia in Huntington patients. Others suggest a total intravenous anesthesia (TIVA) technique to reduce the risk of postoperative shivering related to inhalational agents and thus avoid initiating generalized tonic spasms.
Amyloidosis
Amyloidosis results from the deposition of insoluble, fibrillar proteins (amyloid), mainly in the extracellular spaces of organs and tissues in amounts sufficient to impair normal function. Amyloid fibrils can be deposited locally or may involve virtually every organ system of the body. Symptoms and signs depend on the organs and tissues involved.
Pathophysiology
The cause of amyloid production and its deposition in tissues is unknown. All amyloid fibrils share an identical secondary structure, the β-pleated sheet conformation. The polypeptide backbone of these protein precursors assumes similar fibrillar morphology that renders them resistant to proteolysis. The amyloidoses have been classified into many subtypes, based on the amyloid protein involved. The name of the amyloidosis subtype uses the capital letter A as the first letter of designation and is followed by the protein designation. Three major types of amyloid and several less common forms have been defined biochemically.
Whether an amyloidosis is systemic or localized (organ limited) depends on the biochemical structure of the amyloid protein. Systemic amyloidoses include biochemically distinct forms that are neoplastic, inflammatory, genetic, or iatrogenic, whereas localized or organ-limited amyloidoses are associated with aging and diabetes and occur in isolated organs, often endocrine, without evidence of systemic involvement. Despite their biochemical differences, the various amyloidoses have similar pathophysiologic features ( Table 20-1 ).
| Involvement | Manifestations |
|---|---|
| Nervous system | |
| Polyneuropathy | Sensory loss, carpal tunnel syndrome, myopathy, myelopathy, vitreous opacities |
| Autonomic neuropathy | Postural hypotension, inability to sweat, sphincter incompetence |
| Respiratory system | |
| Upper respiratory tract | Localized tumor can be found in respiratory tracts and lungs |
| Nasal sinuses, larynx, and trachea | Tracheobronchial lesions, or diffuse alveolar deposits |
| Tongue | Macroglossia |
| Lower respiratory tract and lung parenchyma | Accumulation of amyloid, which block the ducts; may resemble a neoplasm |
| Cardiovascular system | |
| Conduction system | Arrhythmia, heart block |
| Endocardium and valves | Valvular diseases |
| Myocardium | Cardiomyopathy: dilated, restrictive, and obstructive forms; congestive heart failure |
| Pericardium | Pericarditis |
| Gastrointestinal system | |
| Liver | Hepatomegaly, abnormal liver function, portal hypertension |
| Gastrointestinal tract | Unexplained GI disease, malabsorption; unexplained diarrhea or constipation; obstruction, ulceration, and protein loss; esophageal motility disorders |
| Kidney | Nephrotic syndrome, proteinuria, renal failure; renal tubular acidosis or renal vein thrombosis |
| Spleen | Spleen enlargement; not associated with leukopenia or anemia |
| Musculoskeletal system | Pseudomyopathy; cystic bone lesions |
| Endocrine system | |
| Thyroid gland | Hypothyroidism; full-blown myxedema (almost invariably accompanies medullary carcinoma of thyroid) |
| Adrenal gland | Type II diabetes |
| Pituitary gland, pancreas | Other endocrine abnormalities |
| Skin | Lichen amyloidosis; papules; plaques; ecchymoses |
| Hematologic system | Fibrinogenopenia, including fibrinolysis |
| Endothelial damage | Selective deficiency of clotting factors (factor X) Clotting abnormalities, abnormal bleeding time |
| Other | Rheumatoid arthritis; chronic inflammation and infection |
The three major systemic clinical forms currently recognized are primary or idiopathic amyloidosis (AL), secondary amyloidosis (AA), and hereditary amyloidosis ( Table 20-2 ). The most common form of systemic amyloidosis seen in current clinical practice is AL (light-chain amyloidosis, primary idiopathic amyloidosis, or associated with multiple myeloma). A fourth type of systemic amyloidosis is seen only in patients with long-standing dialysis.
| Primary (AL) * | Secondary (AA) † | Hereditary | |
|---|---|---|---|
| Organs typically involved | Localized amyloid tumors may be found in respiratory tract. Vascular system, especially heart Other organs: tongue, thyroid gland, heart, lung, liver, intestinal tract, spleen, kidney, skin | Spleen, liver, kidney, adrenal glands, lymph nodes; vascular involvement No organ spared, but significant involvement of the heart is rare | Peripheral sensory and motor neuropathy, often autonomic neuropathy Carpal tunnel syndrome Vitreous abnormalities Cardiovascular and renal amyloid |
| Associated diseases | Multiple myeloma | Infection (tuberculosis, bronchiectasis, osteomyelitis, leprosy) Inflammation (rheumatoid arthritis, granulomatous ileitis) Familial Mediterranean fever Tumors such as Hodgkin’s disease | |
| Diagnosis | Monoclonal immunoglobulin in urine or serum plus any of following: macroglossia, cardiomyopathy, hepatomegaly, malabsorption or unexplained diarrhea or constipation, unexplained nephrotic syndrome, carpal tunnel syndrome, or peripheral neuropathy | Chronic infection (osteomyelitis, tuberculosis), chronic inflammation (rheumatoid arthritis, granulomatous ileitis) plus any of following: hepatomegaly, unexplained GI disease, or proteinuria | Family history of neuropathy plus any of following: early sensorimotor dissociation, vitreous opacities, cardiovascular disease, GI disease, autonomic neuropathy, or renal disease |
Diagnosis and Differential
Symptoms and signs of amyloidosis vary depending on the involved systems and organs. The nephritic syndrome is the most striking early manifestation. The renal lesion is usually not reversible and progressively leads to azotemia and death.
Regardless of etiology, the clinical diagnosis of amyloidosis is usually not made until the disease is far advanced, because of its nonspecific symptoms and signs. The diagnosis is made by identification of amyloid fibrils in biopsy or necropsy tissue sections using Congo red stain. A unique protein (member of the pentraxin family of proteins) called AP (or serum AP) is universally associated with all forms of amyloid and forms the basis of a diagnostic test. Once amyloidosis is diagnosed, it can be further classified by genomic DNA, protein, and immunohistochemical studies; the relationship of immunoglobulin-related amyloid to multiple myeloma should be confirmed by electrophoretic and immunoelectrophoretic studies.
Preoperative Preparation and Treatment
A comprehensive survey of all systems should be performed, focusing on the most frequently involved organs. Careful evaluation for systemic involvement of amyloidosis or associated disease is important, even in apparently isolated tumorous amyloidosis ( Table 20-3 ).
| System | Assessment |
|---|---|
| Nervous | Peripheral neuropathy: document pre-existing peripheral neurologic symptoms Autonomic neuropathy: orthostatic blood pressure, etc. |
| Airway | Macroglossia |
| Pulmonary | Diffuse dysfunction: pulmonary function studies |
| Cardiac | Arrhythmia, cardiomyopathy, and valvular involvement: cardiac function echocardiogram and electrocardiogram |
| Gastrointestinal | Esophageal motility abnormality, intestinal obstruction |
| Liver | Liver function studies |
| Kidney | Abnormal renal function: electrolytes, renal function studies |
| Hematology | Enlarged spleen; check CBC: RBCs, platelets, coagulation coagulopathy, and factor deficiency |
| Endocrine | Pancreatic or adrenal gland involvement; thyroid function test to rule out hypothyroidism |
Treatment of localized amyloid tumors is surgical excision. However, no effective treatment exists for systemic amyloidosis. Currently, care is generally supportive, and therapy is directed at reducing production of and promoting lysis of amyloid fibrils. Hemodialysis and immunosuppressive therapy may be useful. Current treatment of primary amyloidosis includes a program of prednisone/melphalan or prednisone/melphalan/colchicine. Liver transplantation, kidney transplantation, and stem cell transplants have yielded promising results. In certain familial amyloidoses, genetic counseling is an important aspect of treatment.
Ultimately, some people with amyloidosis continue to deteriorate. The major causes of death are heart disease and renal failure. Sudden death is common, presumably caused by arrhythmias.
Anesthetic considerations
Localized amyloid deposition has been reported at various sites. Amyloid in the tongue can cause macroglossia to a degree requiring glossectomy. In addition, amyloid macroglossia may be associated with coexisting hypothyroidism. Laryngeal amyloidosis is fragile and carries the risk of spontaneous massive hemorrhage, even without manipulation. The airway tumor should be assessed by noninvasive imaging, such as computed tomography (CT) or MRI. Before intubation, preparations should be made for both difficult airway and massive hemorrhage.
A smaller endotracheal tube (ETT) may be considered. In addition, direct laryngoscopy monitored by a fiberscope-video system, rather than blind insertion of the ETT through vocal cords over a fiberoptic bronchoscope, has been advocated.
It is controversial whether depolarizing muscle relaxants should be administered to patients with amyloidosis, especially those with cardiac involvement. Patients with familial amyloid polyneuropathy have a high incidence of cardiac arrhythmias during anesthesia. Exaggerated elevations in potassium concentration may occur after succinylcholine administration and may be a contributing factor. However, Viana et al. reported that the average increase in plasma potassium concentrations after succinylcholine administration in patients with familial amyloid polyneuropathy was similar to the increase observed in a normal population. However, they could not exclude that a dangerous rise in serum potassium concentration might not occur in a certain percentage of patients with familial amyloid after administration of succinylcholine. This may also be true in patients with amyloidosis who also have long-standing polyneuropathy. Thus, it may be prudent to avoid administration of depolarizing muscle relaxants in patients with amyloidosis, especially in the presence of coexisting polyneuropathy or cardiac disease.
Autonomic dysfunction secondary to amyloidosis has dramatic perioperative ramifications. In particular, the administration of anesthetic drugs to patients with amyloidotic polyneuropathy presents a risk of significant hypotension (even use of ketamine does not prevent hypotension). Patients with decreased preload are especially sensitive. In addition, hypotension is frequent even in patients with adequate preload as a result of low systemic vascular resistance. Given these observations, the anesthesiologist should consider using invasive blood pressure monitoring and preparation of a vasoconstrictor infusion for effective anesthetic management of these patients.
Idiopathic pulmonary fibrosis
The pathophysiology of idiopathic pulmonary fibrosis (IPF) is not currently understood. IPF may represent a model of chronic dysregulated repair and lung remodeling, resulting from an epithelial/endothelial insult and persistent inflammatory cell activation. The initial injury event remains undefined. However, evidence suggests that viral infections or environmental factors may provide mediating events. Interestingly, a majority of patients with IPF have a smoking history.
Symptoms associated with IPF include breathlessness, fatigue, weight loss, and a chronic dry cough. On physical examination, dry “Velcro” crackles may be heard throughout the lung fields. Cyanosis and clubbing may also be observed. As the disease progresses, signs of pulmonary hypertension and right-sided heart failure (loud S 2 heart sound, right ventricular heave, or pedal edema) may be present.
A chest radiograph may show interstitial infiltrates in the lung bases. CT is more sensitive than a chest radiograph for detecting disease early. Typically, CT shows a pattern of patchy white lines in the lower lungs. In areas of more severe involvement, the thick scarring often creates a honeycomb appearance. Pulmonary function studies show a restrictive pattern. Arterial blood gas (ABG) analysis may show hypoxemia with minimal exercise and, as the disease progresses, even at rest. However, the definitive test to confirm diagnosis of IPF is lung biopsy.
The diagnosis of idiopathic pulmonary fibrosis should be reserved for patients with a specific type of fibrosing interstitial pneumonia known as usual interstitial pneumonia. Foremost in the differential diagnosis is to distinguish usual interstitial pneumonia from other idiopathic interstitial pneumonias. This distinction is made on a pathologic basis.
Numerous other disease processes may lead to IPF and should be ruled out as diagnoses ( Box 20-1 ). Fibroses may occur as a result of occupational or environmental exposure to toxic substances, lung infection, drug exposure, connective tissue disease, and sarcoidosis.
Symptoms: Breathlessness; dry cough; weight loss; fatigue
Physical findings: Change in shape of fingers and toenails (clubbing); cyanosis (late stages of disease); dry “Velcro” crackles throughout lung fields on auscultation
Differential Diagnosis
Pathologic distinction from other types of fibrosing interstitial pneumonia:
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Desquamative interstitial pneumonia (respiratory bronchitis, interstitial lung disease)
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Acute interstitial pneumonia
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Nonspecific interstitial pneumonia
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Cryptogenic organizing pneumonia (bronchiolitis obliterans, organizing pneumonia)
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Pulmonary fibrosis resulting from occupational or environmental exposure: asbestosis, silicosis, farmer’s lung, bird breeder’s lung; exposure to metal dust, bacteria, fumes, animals, other dusts, or gases
Fibrosis resulting from infection: tuberculosis; pneumococci; Pneumocystis jiroveci (P. carinii); bacterial, fungal, viral pneumonia
Drug exposure: bleomycin
Connective tissue disease: rheumatoid arthritis, systemic sclerosis
Sarcoidosis
Comorbidities: Respiratory failure, chronic hypoxemia, cor pulmonale, polycythemia, increased incidence of lung cancer
Critical Questions
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Is the patient approaching end-stage disease?
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Is there a history of respiratory failure?
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Is there a need for home oxygen?
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Are there any signs and symptoms of chronic hypoxemia?
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Is there any evidence of cor pulmonale?
Chronic medications: Corticosteroids, cyclophosphamide (Cytoxan), oxygen, colchicine
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