Eric P. Pourmand, MD CA‐2 Resident Jake H. Abernathy III, MD, MPH Faculty Advisor MUSC Anesthesia Resident Research Night February 20, 2008 Background Pathophysiology Pre‐operative Management Intra‐operative Management Post‐operative Management Carcinoid tumors are the most common of the neuroendocrine tumors Estimated prevalence is 1.5 clinical cases per 100,000 population, however, autopsy data shows the prevalence to be roughly 650 cases per 100,000 population. Most of these tumors occur in adults and are extremely rare in children Carcinoid tumors are derivatives of primitive stem cells in the gut wall but can be seen in many other organs Metastatic disease can occur, which can cause a variety of symptoms, known collectively as the carcinoid syndrome Midgut tumors are by far the most common (60‐80%) location for carcinoid tumors Depending on the location of the tumor, different secretory features can be seen Foregut tumors secrete 5‐HTP, histamine, and several polypeptide hormones. Midgut tumors secrete high levels of serotonin, kinins, prostaglandins, substance P, and other vasoactive peptides Hindgut tumors produce very low levels of any of these substances and consequently rarely have any symptomotology Acid phosphatase Alpha‐1‐antitrypsin Amylin ANP Catecholamines Dopamine FGF Gastrin Glucagon …and many more 5‐HIAA 5‐HT Histamine Insulin Kallikrein Motilin PDGF Prostaglandins VIP Patient history can be somewhat vague in early stages of the disease process The most common complaint is periodic abdominal pain while the earliest manifestation is cutaneous flushing particularly of the head and neck Patients with carcinoid syndrome present with more dramatic symptoms such as: intense flushing, diarrhea, tachycardia, hemodynamic lability, and altered mental status Involvement of the lungs can produce wheezing and asthma‐like symptoms One of the most troublesome sequela is cardiac involvement leading primarily to fibrosis of the tricuspid valve and eventually heart failure Laboratory testing relies on identifying the various biomarkers that are hallmarks of the disease Urinary 5‐HIAA levels will usually be elevated and is the single best screening method. Alternatively, plasma levels of the various secretory products can be obtained to aid in the diagnosis Imaging studies from conventional radiology applications to endoscopy can also be used to aid in diagnosis Electrolyte abnormalities pre‐operatively are to be expected and treated Anesthetics known to trigger 5‐HT release should be avoided (e.g., morphine) Both hypotension and hypertension can occur from the release of vasoactive peptides from the tumor and therefore mandate that all patients have invasive BP monitoring Catecholamines generally should be avoided as first line treatments for hypotension and instead agents such as vasopressin and alpha‐adrenergic agents used first Steroids have been shown to be beneficial in the management of bronchial symptoms (mainly bronchoconstriction) Because of the potential for histamine release, H2 antagonism has also been used to prevent the flushing and subsequent hypotension that can occur The single most beneficial agent to use has now become somatostatin. It can be used peri‐ operatively for symptom management and works by decreasing release of peptides from the tumor Ideally, somatostatin infusion used intra‐ operatively should be continued in the post‐ operative period for patients who underwent surgery not involving tumor removal Careful monitoring of the patient’s hemodynamic and oxygenation status is warranted and triggering mechanisms for tumor secretion should be avoided References: Miller’s Anesthesia, 6th Edition, 2005 Barash’s Clinical Anesthesia, 5th Edition, 2006 Some pictures taken from carcinoid.com