Monitored anesthesia care in a case of pheochromocytoma and atrial myxoma.

Anesthesia for a patient with pheochromocytoma is challenging; irrespective of whether it is a diagnosed case for planned surgery or an occult case, it can be a nightmare. The patient may be given anesthesia for removal of the primary tumor or for surgery other than for the removal of the primary tumor. Hemodynamic derangements like hypertension and arrhythmia can be catastrophic. Monitored anesthesia care, though used for many cases, is unusual for a patient with diagnosed pheochromocytoma, with vertebral metastasis leading to paraplegia and atrial myxoma. In the case described below, the patient was operated for closed reduction, internal fixation with interlock nail femur, for pathological fracture. Surgery was done under monitored anesthesia care as there was no need for regional, spinal, or general anesthesia because of coexisting paraplegia. Surgery was uneventful and the postoperative period was smooth. This case is presented for its uniqueness of multiple diseases and uneventful recovery without any complications of anesthesia. The nightmare of pheochromocytoma eased without any morbidity for the patient, but this may not always be the case.

INTRODUCTION

Anesthetic management of a surgical patient with pheochromocytoma is challenging in either diagnosed or undiagnosed situations. The incidence of pheochromocytoma is said to be very low (2 people/million/year) (Duane JM).[1] A proportion of patients are diagnosed at the time of incidental surgery when induction of anesthesia may precipitate a hypertensive crisis. In such situation, mortality is close to 80% (Duane JM).[1] The relatively high prevalence of pheochromocytoma in autopsy studies (0.05%) indicates that the diagnosis is often missed and the overall incidence is estimated to be 1.6-8 cases per million inhabitants per year (van der Heide et al.).[2] Pheochromocytoma can become a potential life-threatening disease with cardiovascular complications such as myocardial infarction, arrhythmias, cardiomyopathy, stroke, and pulmonary edema. We encountered a patient with a pheochromocytoma with vertebral and brain metastasis with paraplegia posted for surgery for fractured neck of femur.

Monitored anesthesia care (MAC) has been in vogue since 1990 and is given for a variety of cases (Rii A et al.).[3] MAC gives a tremendous morale boost to the operating surgeon and the anesthetist is prepared to combat any complicationencountered, though he or she may not actively intervene. In the present case, MAC was given to a patient with pheochromocytoma with paraplegia and associated with a benign cardiac tumor. It was a potentially scary venture but the disease itself blessed the anesthetist and patient with an uneventful recovery. Such an incidence is rare, and hence the case is presented.

CASE REPORT

An elderly male, 62 years old, was posted for pathological fractured neck of femur on the right side. The patient had a past history of hospitalization due to cough and breathlessness about a year and a half ago. On physical examination, systolic murmur and loud P2 in the pulmonary area were seen.Chest radiograph showed cardiomegaly. A two-dimensional (2D) echo showed left atrial mass suspected to be myxoma, with left ventricular (LV) concentric hypertrophy, diastolic dysfunction, and normal LV systolic function with an ejection fraction of 60%. Abdominal ultrasonography (USG) revealed an abdominal mass suspected to be pheochromocytoma. Positron emission tomography (PET scan), after the administration of 18F-fluorodeoxyglucose, showed a large mass in the left hyppchondriac and lumbar region, metabolically active, retroperitoneal with large central cystic component [Figure 1]. The mass crossed the midline, had uneven wall thickness with a central cystic or necrotic component measuring 19.2 × 14.3 cm with a standardized uptake value (SUV) maximum of 21.04 likely to be of adrenal origin with para-aortic lymph node and skeletal metastasis. Atrial mass was also seen in computed tomography (CT) but was reported that it was unlikely to be related to the retroperitoneal mass. For one year, the patient went about his routine activities after having been diagnosed with pheochromocytoma. Subsequently, the patient developed paraparesis leading to total paraplegia. Within a span of two months, bladder and bowel control were lost. Magnetic resonance imaging (MRI) of the brain showed metastasis. MRI of the spine using metaiodobenzylguanidine (MIBG) done a week before surgery further revealed epidural soft tissue component edema at T7 level, and canal stenosis and cord edema [Figure 2]. The findings were suggestive of metastasis secondary to neoplastic etiology.

Figure 1

PET CT scan (18F-fluorodeoxyglucose) showing pheochromocytoma with metastasis

Figure 2

MRI of spine (MIBG) showing lesion at T7

The cause for paraplegia was cord compression due to edema secondary to metastasis. The patient had a pathological fracture neck of femur, following which he was posted for surgery.

Preanesthetic evaluation

Routine investigations were done. In view of the presence of atrial myxoma, the opinion of the cardiologist was sought. Preoperative 2D echo showed mild LV hypertrophy (LVH) and ejection fraction of 53% and pulmonary hypertension.The patient was put on sequential α- and β-blockers, prazosin and propanalol, respectively (α-blocker for 48 hours followed by α- and β-blockers).

On clinical examination, the patient was normotensive andnondiabetic. There was no evidence of pulmonary embolism. Sensory level was up to T10. The patient was posted for interlock nailing under MAC.

Intraoperative management

As hemoglobin was 7.2 g%, one pint of whole blood was kept ready. Two goodintravenous (IV) lines were secured. A urometer was connected to measure hourly urine output. The left lateral position of the patient was used for surgery;direct pressure on the abdomen was avoided by adjusting the side support adequately. This step was crucial as it avoided direct pressure over the mass which was in the left hypochondriac region that had become dependent in the left lateral position. Maximum care was taken to avoid external pressure on the abdomen from the sides and above. An emergency trolley with all essential and emergency drugs were kept ready.

Intraoperative monitoring

Pulse, noninvasive blood pressure (NIBP), oxygen saturation (SpO2), electrocardiogram (ECG) and urine output were monitored. Infusions of 1000 mL of crysralloids and one unit of whole blood were given. Oxygen was given by oxygen mask at the rate of 4 L per minute. After positioning, midazolam 1 mg was given to allay anxiety. A second dose of midazolam was given when the systolic blood pressure shot up to 150 mm systolic and heart rate reached 82 per minute. The patient had mild shivering and then the third dose of midozolam was given along with 50 mg of tremadol. Total surgical period was two and a half hours and was uneventful. Postoperative hemoglobin (Hb) was 8.5 g%.

Postoperative

Recovery was smooth and totally unefventful. ECG and O2 saturation was normal. Urine output was 1300 mL. Although labetelol IV was kept ready to use in case of intraoperative surge in blood pressure, it was not needed.

DISCUSSION

As there was already existing paraplegia with loss of a sensory modality up to the level of T10, no anesthesia was necessary. Surgery was carried out without any anesthesia, either regional or general. Practically no anesthetic drugs of any kind were given. No hemodynamic disasters like hypertensive crisis (Sushil PA,[3] Steve Z et al.[4]) or arrhythmia were encountered either. The presence of arterial myxoma was another impediment in the present case. Metastasic involvement of the spine with paraplegia was a blessing in disguise. Had there been need for any anestheisa, it would have been very challenging for the anesthesiologist, because in addition to pheochromocytoma there was coexisting heart disease and pulmonary hypertension. It is very rare for the anesthetist to be lucky to handle such a unique case.

It appears that adequate preoperative assessment, involving the physician and cardiologist, and preoperative preparation of the patient with α- and β-blockers did make a difference for a smooth intraoperative phase. The absence of autonomic reflexes because of cord compression by metastatic lesion leading to paraplegia, optimization of the patient with sedation, crystalloid infusion, and blood transfusion probably averted a hemodynamic crisis.

According to the American Society of Anesthesiologists, MAC is a planned procedure in which a combination of local anesthesia, sedation, and analgesia are administered. MAC is said to be the first choice of anesthesia in 10-30% of cases (Ghisi D et al.[5]). Advantages of MAC are minimal intervention with the patients’ milieu interieur, protection of the airway, controlled sedation, and faster recovery. Rii et al.[6] have reported a similar incident wherein a 63-year-old male with a pheochromocytoma and metastasis was taken for transarterial embolization (TAE) under MAC in the angiography room. The patient had hypertension and ventricular arrhythmia, which were successfully controlled. Postoperatively, the patient had transient hypotension, which was controlled with norephinephrine infusion. However, the authors did not come across any reported literature of MAC for a case of pheochromocytoma, operated for some other surgical condition without touching the primary tumor. Hence, this case was unique by itself. This experience encourages the idea to undertake patients with diagnosed pheochromocytoma for surgeries other than resection of the tumor per se under monitored anesthesia. Combinations of regional and/or local anesthesia along with stringent hemodynamic monitoring are worth trying.

Diagnosed, undiagnosed, or occult pheochromocytoma continues to be an anesthesiologist's nightmare. Occasionally, the nightmare recedes, although that may not be so always.