The biochemical techniques for detecting and establishing the presence of a pheochromocytoma. A review of ten years' experience

Biochemical Assessment of Pheochromocytoma and Paraganglioma

Pheochromocytoma and paraganglioma (PPGL) require prompt consideration and efficient diagnosis and treatment to minimize associated morbidity and mortality. Once considered, appropriate biochemical testing is key to diagnosis. Advances in understanding catecholamine metabolism have clarified why measurements of the O-methylated catecholamine metabolites rather than the catecholamines themselves are important for effective diagnosis. These metabolites, normetanephrine and metanephrine, produced respectively from norepinephrine and epinephrine, can be measured in plasma or urine, with choice according to available methods or presentation of patients. For patients with signs and symptoms of catecholamine excess, either test will invariably establish the diagnosis, whereas the plasma test provides higher sensitivity than urinary metanephrines for patients screened due to an incidentaloma or genetic predisposition, particularly for small tumors or in patients with an asymptomatic presentation. Additional measurements of plasma methoxytyramine can be important for some tumors, such as paragangliomas, and for surveillance of patients at risk of metastatic disease. Avoidance of false-positive test results is best achieved by plasma measurements with appropriate reference intervals and preanalytical precautions, including sampling blood in the fully supine position. Follow-up of positive results, including optimization of preanalytics for repeat tests or whether to proceed directly to anatomic imaging or confirmatory clonidine tests, depends on the test results, which can also suggest likely size, adrenal vs extra-adrenal location, underlying biology, or even metastatic involvement of a suspected tumor. Modern biochemical testing now makes diagnosis of PPGL relatively simple. Integration of artificial intelligence into the process should make it possible to fine-tune these advances.

Selective nanomolar detection of dopamine using a boron-doped diamond electrode modified with an electropolymerized sulfobutylether-beta-cyclodextrin-doped poly(N-acetyltyramine) and polypyrrole composite film

N-acetyltyramine was synthesized and electropolymerized together with a negatively charged sulfobutylether-beta-cyclodextrin on a boron-doped diamond (BDD) electrode followed by the electropolymerization of pyrrole to form a stable and permselective film for selective dopamine detection. The selectivity and sensitivity of the formed layer-by-layer film was governed by the sequence of deposition and the applied potential. Raman results showed a decrease in the peak intensity at 1329 cm(-1) (sp(3)), the main feature of BDD, upon each electrodeposition step. Such a decrease was correlated well with the change of the charge-transfer resistance derived from impedance data, i.e., reflecting the formation of the layer-by-layer film. The polycrystalline BDD surface became more even with lower surface roughness as revealed by scanning electron and atomic force microscopy. The modified BDD electrode exhibited rapid response to dopamine within 1.5-2 s and a low detection limit of 4-5 nM with excellent reproducibility. Electroactive interferences caused by 4-dihydroxyphenylalanine, 3,4-dihydroxyphenylacetic acid, ascorbic acid, and uric acid were completely eliminated, whereas the signal response of epinephrine and norepinephrine was significantly suppressed by the permselective film.

Excretion of adrenaline, noradrenaline, vanilmandelic acid and metanephrines in 64 patients with pheochromocytoma. Results of repeated analyses in patients with sustained and paroxysmal hypertension

Sixty-four patients with pheochromocytoma were operated upon at Sahlgrenska Hospital during 1956-82. The excretion of adrenaline and/or noradrenaline as well as their metabolites was high at each observation in 28 subjects with sustained hypertension, one patient, however, showing only slightly increased excretion of adrenaline at one observation. Another of the hypertensive patients consistently displayed normal amounts of vanilmandelic acid and metanephrines. Most of 28 patients with paroxysmal hypertension showed similar results. In five subjects with few attacks, however, normal findings were obtained on one or several occasions. Among the remaining patients the excretion of catecholamines was normal in the face of severe hypertension in two, the high blood pressure being probably due to diseases other than pheochromocytoma. Five normotensive subjects without hypertensive attacks presented variable findings. The results from analyses of catecholamines were somewhat more helpful than those from measurements of vanilmandelic acid, which failed completely in one hypertensive patient and in three others with paroxysmal attacks.

Effects of slow-release octreotide on urinary metanephrine excretion and plasma chromogranin A and catecholamine levels in patients with malignant or recurrent phaeochromocytoma

OBJECTIVE

Somatostatin receptors are present on human phaeochromocytomas. Catecholamine concentrations may decrease following short-term administration of somatostatin agonists to patients with phaeochromocytomas. We carried out a prospective study on 10 patients with malignant or recurrent phaeochromocytomas to examine the clinical and hormonal effects of three monthly intramuscular injections of 20 mg slow-release octreotide.

DESIGN AND MEASUREMENTS

Patients underwent somatostatin receptor scintigraphy using 111In-pentetreotide before slow-release octreotide was administered. The patients' symptoms, blood pressure, blood glucose concentrations, glycosylated haemoglobin concentra-tions, plasma insulin and noradrenaline concentrations, and the levels of two putative markers of tumour burden, urinary metanephrine excretion and plasma chromogranin A concentration, were recorded before the first injection and 28 days after the third injection.

RESULTS

Slow-release octreotide did not significantly alter symptoms, blood pressure, blood glucose concentrations, plasma catecholamine and chromogranin A concentrations or metanephrine excretion. Median glycosylated haemoglobin concentrations increased from 5.3% to 6.0% (P = 0.03). Patients whose tumours took up 111In- pentetreotide did not differ from those whose tumours did not after slow-release octreotide treatment in terms of symptoms, blood pressure, blood glucose, plasma catecholamine and chromogranin A concentrations or metanephrine excretion.

CONCLUSION

Our data suggest that slow-release octreotide is of limited value for the long-term treatment of patients with malignant or recurrent benign phaeochromocytomas.

Malignant pheochromocytoma. Chromaffin granule transmitters and response to treatment

Chromaffin granule transmitters such as chromogranin A and catecholamines have been used in the diagnosis of pheochromocytoma, but the diagnostic and prognostic value of chromogranin A have not been explored in malignant pheochromocytoma. We evaluated these transmitters in patients with pheochromocytoma (n=27), both benign (n=13) and malignant (n=14). Patients with benign pheochromocytoma were studied before and after surgical excision (n=6), whereas patients with malignant pheochromocytoma were evaluated before and after combination chemotherapy with regular cycles of cyclophosphamide/dacarbazine/vincristine (nonrandomized trial in n=9). During treatment, patient responses to chemotherapy were divided according to anatomic and clinical criteria: responders (n=5) versus nonresponders (n=4). Plasma chromogranin A rose progressively (P<0.0001) from control subjects (48.0+/-3.0 ng/mL) to benign pheochromocytoma (188+/-40.5 ng/mL) to malignant pheochromocytoma (2932+/-960 ng/mL). Parallel changes were seen for plasma norepinephrine (P<0.0001), though plasma epinephrine was actually lower in malignant than benign pheochromocytoma (P=0.0182). In bivariate analyses, chromogranin A, norepinephrine, and epinephrine discriminated between pheochromocytoma and control subjects (all P<0.0001), whereas in a multivariate analyses, norepinephrine was the best discriminator (P:=0.011). Chromogranin A was significantly different in benign versus malignant pheochromocytoma on both bivariate (P=0.0003) and multivariate (P:=0.011) analyses. After excision of benign pheochromocytoma, chromogranin A (P=0.028), norepinephrine (P=0.047), and epinephrine (P=0.037) all fell to values near normal. During chemotherapy of malignant pheochromocytoma (n=9), plasma chromogranin A (P=0.047) and norepinephrine (P=0.02) fell but not epinephrine. In 5 responders to chemotherapy, there were significant declines in chromogranin A (P=0.03) and norepinephrine (P=0.03) but not epinephrine; in 4 nonresponders, none of the transmitters changed. Plasma chromogranin A varied longitudinally with tumor response and relapse. We conclude that plasma chromogranin A is an effective tool in the diagnosis of pheochromocytoma, and markedly elevated chromogranin A may point to malignant pheochromocytoma. During chemotherapy of malignant pheochromocytoma, chromogranin A can be used to gauge tumor response and relapse.

Pheochromocytoma: clinical observations from a Brooklyn tertiary hospital

OBJECTIVE

To report eight cases of pheochromocytoma, diagnosed and treated at our tertiary hospital during a 42-month period.

METHODS

We review clinical manifestations as well as historical and family data. Biochemical and radiologic methods for diagnosis and tumor localization at our institution were compared with methods at other teaching centers.

RESULTS

Among 4,180 patients with essential hypertension encountered during a 42-month interval, 8 had pheochromocytoma. The most common clinical findings were diaphoresis, chest or abdominal pain, palpitations, headaches, and nausea. Clinical features were remarkable only for the significant correlation between urinary excretion of vanillylmandelic acid and tumor volume (r = 0.925; P<0.01). Only one patient, with a history of medullary thyroid carcinoma, had multiple endocrine neoplasia. No unusual familial concentration of pheochromocytomas was found in our community, and our diagnostic techniques were similar to those reported from other institutions. We calculated an average annual incidence rate of 0.5 per 100,000 person-years, a figure comparable to that reported at the Mayo Clinic in Rochester, Minnesota.

CONCLUSION

Because our institution does not see the volume of referral patients as does the Mayo Clinic, we suggest that the frequency of pheochromocytoma may be underestimated in the patient population that we serve.

[Malignant adrenal pheochromocytoma--problems in evaluating clinical diagnosis and morphologic extent]

Reports on three patients with malignant adrenal phaeochromocytoma are used as a basis for discussion of involved in diagnosing functionally inactive paragangliomas and in discriminating between benign and malignant adrenomedullary tumours. Malignancy can so far only be ascertained in such neoplasms by evidence of metastatic growth. Our findings, however, show that increased tumour weight (more than 200 g), high mitotic activity (more than 5 mitoses per HPF) and loss of S-100 protein-positive subtentacular cells make it possible to distinguish high-risk cases (with increased risk of recurrence and metastasis).

Biochemical tests for pheochromocytoma: strategies in hypertensive patients

OBJECTIVE

To determine the optimal clinical strategy utilizing either 1) serum catecholamines, 2) urinary metanephrines, or 3) urinary vanillylmandelic acid measurements in the evaluation of hypertensive patients with suspected pheochromocytoma.

DESIGN

Prospective clinical determination of test-operating characteristics.

SETTING

Tertiary care university medical center.

PATIENTS/PARTICIPANTS

415 patients referred for evaluation of suspected pheochromocytoma.

INTERVENTIONS

All subjects had measurements of the three above-mentioned biochemical tests with the diagnosis of pheochromocytoma established by tissue confirmation.

RESULTS

All three biochemical tests were similar in sensitivity (0.70-0.75), specificity (0.90-0.95), and receiver operating characteristics. With an estimated disease prevalence of 5.9% in symptomatic hypertensive patients, the predictive value of any single negative test would be 98% in ruling out disease.

CONCLUSIONS

All three biochemical tests have similar performance characteristics and only a single test need be performed to exclude pheochromocytoma in most symptomatic hypertensive patients in a primary care population.

Role of 131I-metaiodobenzylguanidine in the localization of suspected phaeochromocytomas

Iodine-131-metaiodobenzylguanidine is a recently-developed radiopharmaceutical agent for adrenal medullary scintigraphy. Twenty-one scans with 131I-metaiodobenzylguanidine were performed in 20 adults with suspected phaeochromocytomas over a four-year period. All patients previously had undergone computed tomographic scans of the abdomen and pelvis. The computed-tomographic scans were abnormal in 14 patients (16 tumours), eight (nine tumours) of whose 131I-metaiodobenzylguanidine scans gave positive results. Both types of scan gave negative results in the remaining six patients. Among 12 patients who underwent surgery or postmortem examination, the 131I-metaiodobenzylguanidine scan correctly showed eight phaeochromocytomas; six tumours that were found on computed-tomographic scans but not on 131I-metaiodobenzylguanidine scans proved not to be phaeochromocytoma. The 131I-metaiodobenzylguanidine scan probably gave a true-positive result in an additional case (surgical confirmation was not available). None of the remaining seven patients in whom the 131I-metaiodobenzylguanidine scan gave negative results has been shown to harbour a phaeochromocytoma on extended follow-up (2.5 to four years). Iodine-131-metaiodobenzylguanidine is a highly sensitive and specific agent for the localization of phaeochromocytomas. In patients with suspected phaeochromocytomas and abnormal computed-tomographic findings, 131I-metaiodobenzylguanidine permits a non-invasive, functional evaluation of the morphological abnormalities to be made. The importance of making a biochemical diagnosis of a phaeochromocytoma before attempting localization studies is emphasized.

Diagnosis, localization, and management of pheochromocytoma. Pitfalls and follow-up in 41 patients

Forty-one patients who had pheochromocytoma are described. These patients represent the experience of the authors over the last 19 years. The diagnoses, investigations, treatments, and pitfalls of this study and the management of these patients are described. The most sensitive screening test was the urinary measurement of catecholamines, vanillylmandelic acid (VMA), and metanephrines. The most useful localizing procedure was the metaiodobenzylguanidine (MIBG) scintigraphy and computed tomography (CT). After careful alpha and beta adrenergic blockade in 32 patients, no complications occurred during or after tumor resection. When this procedure was ignored even in patients who had normal blood pressure before surgery, severe cardiovascular complications occurred and two patients died. In familial pheochromocytoma, bilateral adrenalectomy with preservation of normal adrenal cortical tissue when possible may be the method of choice, but careful follow-up is warranted.

Improved solid-phase extraction and liquid chromatography with electrochemical detection of urinary catecholamines and 5-S-L-cysteinyl-L-dopa

We describe a rapid, precise, accurate liquid chromatographic procedure for determining urinary catecholamines and 5-S-L-cysteinyl-L-dopa. The catecholamines (norepinephrine, epinephrine, and dopamine) and 5-S-L-cysteinyl-L-dopa are extracted from 1.0 ml of urine together with internal standards, by using a Bond-Elut strong cation-exchange (SCX) and an affinity phenylboronic acid (PBA) extraction column in series. The eluate obtained from PBA column is then chromatographed on a reversed-phase C18 column with a mobile phase containing pentane- and heptanesulfonate as ion-pair reagents. The detection is achieved with an amperometric detector set at an oxidation potential of +0.55 V. The chromatography is complete is less than 8 min for catecholamines and less than 5 min for cysteinyldopa. The method can measure less than 2 micrograms/l for catecholamines and 5 micrograms/l for cysteinyldopa. Analytical recoveries of catecholamines and cysteinyldopa added to urine pool ranged from 90-107%. Between run coefficient of variation ranged from 4.7 to 8%. None of the drugs and catecholamines metabolites tested interfered with the assay.

Automatic determination of urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid by liquid chromatography with electrochemical detection

An automated liquid chromatographic method for the determination of urinary concentrations of 4-hydroxy-3-methoxymandelic acid (VMA) is described. Urine samples are purified by solid-phase extraction on an anion-exchange cartridge and automated on-line chromatographic elution is carried out using a Varian AASP (advanced automated sample processor) system. The column effluent is monitored with an electrochemical detector using a glassy carbon working electrode. The method allows the determination of VMA in 0.05 ml of normal urine with a relative standard deviation of less than 3%. The analysis time can be shortened by use of back-flushing technique, and the correlation with a classical (but non-automated) VMA analysis method is excellent.

A re-evaluation of dopamine excretion in phaeochromocytoma

In a re-evaluation of the use of dopamine as a prognostic factor in phaeochromocytoma, a series of 34 patients was imaged with iodine-131-meta-iodobenzylguanidine, a radiopharmaceutical specifically localized in chromaffin tumours. Fourteen patients were found to have malignant disease. Increased dopamine excretion was found in 9 (64%) of these patients including all four with primary intra-adrenal tumours, and this was associated with a poor prognosis. Of the five patients in the malignant group with normal dopamine excretion on referral, the disease extent was minimal and in four the primary tumour had been resected. Twenty patients appeared to have benign phaeochromocytoma from the imaging results. Of these, 16 were intra-adrenal and four were extra-adrenal. In 19 the dopamine excretion was within the control range but in one it was marginally increased. From these observations it would seem that dopamine excretion may be a useful prognostic factor when combined with imaging to determine the extent of the disease.

Analysis of vanillylmandelic and homovanillic acids in urine using solid phase sample preparation and high pressure liquid chromatography with electrochemical detection

A rapid, simple and specific method for quantification of vanillylmandelic acid (VMA) and homovanillic acid (HVA) in urine is described. The method is suitable for routine use and may include other organic acids in human urine.

Measurement of urinary vanilmandelic acid and homovanillic acid by high-performance liquid chromatography with electrochemical detection following extraction by ion-exchange and ion-moderated partition

An improved protocol has been developed to isolate homovanillic acid (HVA) and vanilmandelic acid (VMA) from urine with strong anion-exchange resin. The sample is diluted with acetate buffer and passed through a disposable column. HVA, uric acid, and many hydrophobic organic acids are removed with 1.0 M acetic acid--ethanol. Then VMA is eluted with 0.5 M phosphoric acid. Two isocratic mobile phases allow rapid high-performance liquid chromatographic measurement of VMA (5 min) and HVA (8 mins) on a 5-micron ODS column. Selective conditions were developed with dual-electrode coulometric detection to permit specific measurement of VMA, HVA, and internal standards, with less than 5% between-run variation.

Malignant phaeochromocytoma: clinical, biochemical and scintigraphic characterization

We have evaluated thirty patients with malignant metastatic phaeochromocytoma with regard to clinical features, indices of catecholamine secretion, histology of lesions and a number of imaging procedures including scintigraphy with the recently developed sympathetic tissue-seeking radiopharmaceutical 131I-metaiodobenzylguanidine (131I-MIBG). The primary tumour was extra-adrenal in 13 cases. The commonest site of metastases was the axial skeleton (20 cases), followed by liver (four cases), lymph nodes (four cases), peritoneum (two cases) and lung (three cases). The malignancies were indolent, the mean time following the initial diagnosis was 9.18 years (range 0 to 33 years) and the mean duration of known metastases 3.71 years (range 0 to 18 years). There was a wide range of abnormalities in plasma and urinary catecholamines which did not correlate with the extent of tumour spread, histological pattern (mitotic index, Zellballen pattern, capsular or vascular invasion pleomorphism or necrosis) or 131I-MIBG uptake by tumour deposits. 131I-MIBG scintigraphy was found to be a useful technique for determining the extent of metastatic disease in most cases (26 of 30) and in some patients (16 of 30) was more sensitive than other radiological procedures. No false positive scans were encountered.

The coexistence of renal artery stenosis and pheochromocytoma

The coexistence of renal artery stenosis and pheochromocytoma has been recognized since 1958 and a total of 36 patients reported. This article provides an additional patient with an extra adrenal pheochromocytoma and fibrous bands constricting the left renal artery. Hypertension was confirmed to occur from both excess catecholamine production and hyperreninemia from the left kidney. Surgical removal of the functioning paraganglioma and correction of the renal artery stenosis restored the postoperative plasma catecholamine, renin, and blood pressure to normal. A literature review confirmed the coexistence of these two lesions but failed to provide a common etiology to explain the pathophysiology encountered. However, when the two diseases occur simultaneously, both must be diagnosed accurately and treated in a definitive manner.

Amine metabolite profile of normal and uremic urine using gas chromatography--mass spectrometry

A method for the simultaneous analysis of phenolic amines and aliphatic amines in human urine is described. The amine metabolites in urine were extracted using Dowex 50W-X8 cationic resin, derivatized and analyzed by a gas chromatographic--mass spectrometric--computer system. The amine metabolites profile of 5 ml of urine was obtained with good gas chromatographic separation. The gas chromatographic method described here separates urinary phenolic amines, di- and polyamines and methylguanidine in a single chromatographic separation. The urinary levels of methylguanidine, putrescine, cadaverine, spermidine, p-tyramine, dopamine, and 3-methoxytyramine were quantitated by using a mass spectrometric technique. In uremic patients, only the urinary excretion of methylguanidine was increased in comparison with normal subjects, although the urinary excretion of other amines was decreased in uremic patients.

Familial hypocalciuric hypercalcemia. Report of a new family

We report a new family with familial hypocalciuric hypercalcemia (FHH) composed by 55 living members. Of 38 studied, 10 have been found to be affected by FHH. Differences between FHH and primary hyperparathyroidism are emphasized; lack of clinical features, relative hypocalciuria for the concomitant hypercalcemia and low phosphate excretion index. The PTH and urinary cAMP are normal. It is noteworthy that the disease is benign. None of our patients have undergone surgery, and all of them are asymptomatic.

[The influence of different diets and smoking on the clinical chemical diagnosis of pheochromocytoma, neuroblastoma, and carcinoid syndrome (author's transl)]

The interference of various foodstuffs on methods to determine epinephrine (E), norepinephrine (NE), vanillylmandelic acid (VMA), metanephrines (MN), homovanillic acid (HVA), and 6-hydroxyindole acetic acid (5-HIA) in the 24 h urine for diagnosis of pheochromocytoma and carcinoid syndrome, respectively, was investigated. The foodstuffs included were: tea, coffee, almonds, pineapples, cheese, walnuts, vanilla pudding, bananas, tomatoes, and chocolate. Further, the interference of cigarette smoking on the determination of E, NE, VMA, and MN was also investigated. Walnuts caused a rather high elevation of 5-HIA in the urine. After eating bananas elevated excretion of E, NE, VMA, MN, and 5-HIA was observed. Small increases of the MN values were noticed after coffee and pineapples. Smoking of 20-30 cigarettes/day had no influence on the variables measured. If the methods described are used, thus, only bananas and walnuts have to be restricted some days before and during urine sampling, but not coffee and pineapples if consumed in the usual small quantities. There is no reason to insist on diet restriction except for bananas and walnuts.

Biochemical tests for diagnosis of phaeochromocytoma: urinary versus plasma determinations

Fifteen patients with hypertension due to phaeochromocytoma and 35 controls with essential hypertension were studied to assess the diagnostic value of urinary and plasma biochemical determinations in phaeochromocytoma. In every case of phaeochromocytoma the urinary concentration of vanillylmandelate, metanephrines, or adrenaline plus noradrenaline was diagnostic of the disease irrespective of whether the patient was normotensive or hypertensive at the time. Plasma determinations of adrenaline and noradrenaline, however, gave falsely negative results on three occasions. These findings suggest that urinary biochemical determinations--particularly of metanephrines--are more reliable than plasma catecholamine measurements as a test for phaeochromocytoma. The test is particularly useful in patients with intermittent hypertension.

Clinical study of pheochromocytoma

Seventeen patients underwent 22 operations for pheochromocytoma over a 26 year period. The patients included 11 in three kindreds of familial pheochromocytoma and 6 with sporadic tumors. The diagnosis was usually suggested by the patient's history. Confirmation of the diagnosis frequently required repeated testing for urinary or plasma catecholamines. Arteriography was the most effective method of preoperative tumor localization. Two tumors were proven nonfunctional. Others secreted either norepinephrine or epinephrine and norepinephrine. The familial patients showed a high incidence of multiple, bilateral and extraadrenal lesions. In contrast to previous reports, the familial tumors were found more often in the right than in the left adrenal gland. HL-A genotyping analysis of the sporadic and familial patients failed to demonstrate any HL-A antigen association or interdependent segregation of tumor and HL-A antigens within kindreds.

Analysis of urinary metanephrines by reversed-phase high-performance liquid chromatography and electrochemical detection

A sensitive and specific direct analysis of urinary normetanephrine (NMN) and metanephrine (MN) was achieved utilizing reversed-phase high performance liquid chromatography and electrochemical detection. Individual specimens from "control" subjects and those with pheochromocytoma were hydrolyzed and the metanephrines separated from other urinary constituents by elution with ammonia from a Dowex CG-50 resin. Chromatographic peaks were identified by retention behavior, co-chromatography with reference compounds, ratio of responses at various oxidation potentials and stopped-flow UV spectra of the collected fractions. The NMN and MN content for the control subjects was between 0.086 and 0.21 (mean - 0.14) microgram/mg creatinine and 0.012 and 0.092 (mean = 0.039) microgram/mg creatinine, respectively. The values for subjects with pheochromocytoma varied from 1.5 to 27.5 (mean = 9.9) microgram/mg creatinine for NMN and 0.10 to 1.60 (mean = 0.86) microgram/mg creatine for MN. The patient with ganglioneuroma had an NMN of 4.1 and an MN of 0.80 microgram/mg creatinine. While this method permits discrimination between those patients with pheochromocytoma and the overwhelming majority of hypertensive patients, it may ultimately be further extended to separate normal subjects from those with more subtle derangements in catecholamine metabolism.

Pheochromocytoma: clinical manifestations and diagnostic tests

Pheochromocytoma accounts for about 0.1 per cent of patients with diastolic hyperstension. It mimics many diseases varying from anxiety psychoneurosis to intracranial tumors. Cardinal symptoms include sevre headache (72 to 92 per cent), sweating (60 tp 70 per cent), palpitations (51 to 73 per cent), and hypertension (> 90 per cent) of which 50 per cent is sustained, 50 per cent paroxysmal. Many drugs (phenothiazines, Saralasin, antiemetics, steroids, etc.) have been reported as precipitating factors. Patients who should be screened for pheochromocytoma include: (1) all symptomatic patients with sustained or paroxysmal hyperstension; (2) asymptomatic hypertension; (3) all patients with MEA 2a,b (hyperparathyroidism, medullary carcinoma of the thyroid, neurocutaneous lesions) and their first degree relatives, even if the latter are asymptomatic and normotensive; (4) hypertension plus diabetes mellitis or hypermetabolism; (5) hypertensive episode during induction of anesthesia or radiologic procedure; and (6) hypertensive response during histamine administration, i.e., gastric analysis. Urinary metanephrine is the single best screening test. Plasma catecholamine determination is particularly helpful when collected before and immediately after an attack. Provacative agents (histamine, glucagon, tyramine) are needed rarely. Preoperative localization of the tumor can be done with nephrotomography IVP, computerized axial tomography, ultrasound, 131-I-19-iodocholesterol scan, arteriography, venography.

High performance liquid chromatographic analysis of urinary catecholamines employing amperometric detection: references values and use in laboratory diagnosis of neural crest tumors

We have developed an high performance liquid chromatographic procedure employing amperometric detection for the measurement of urinary free norepinephrine, epinephrine and dopamine. The between-day precision (C.V.) at various concentrations of the above analytes varied from 4.8-11.6%. There was negligible between-urine difference in the percent recovery of norepinephrine and epinephrine but considerable between-urine difference for dopamine. The procedure has been used to determine reference ranges in infants, children and adults. Its preliminary application to the laboratory detection of neural crest tumors is also described.

A simple chromatographic technique for the estimation of urinary levels of normetadrenaline and metadrenaline

A simple, but effective, procedure is described for the concurrent estimation of normetadrenaline (NMA) and metadrenaline (MA) in urine. The 3-methoxycatecholamines are adsorbed by a cation exchange resin, desorbed, separated by paper chromatography, and finally estimated spectrophotometrically after oxidation to vanillin. The mean (+/- 2 standards deviations) urinary outputs of NMA and MA from 123 normals (80 males, 43 females) in 24 hours was 2.15 +/- 1.04 and 1.79 +/- 0.96 mu mol respectively. There was no significant difference in the 24-hour urinary outputs of NMA between the male and female groups. However, the output of MA from the males was significantly higher than that from the females.

Hypertension: strategies for laboratory diagnosis

Although surgically correctable causes account for relatively few cases of hypertension, laboratory investigation is warranted if clinical clues are present. Pheochromocytoma, which triggers hypertension by producing excess catecholamines, can be identified by detecting metabolites of these substances in urine. An abnormal intravenous pyelogram suggests renovascular hypertension, but for definitive diagnosis, bilateral renal vein renin measurements are necessary. In primary aldosteronism, with its characteristic hypokalemia, serum potassium determination remains the most feasible, if not the most accurate, detection method.

Random one-hour urine catecholamine and 4-hydroxy-3-methoxymandelic acid assays for diagnosis of pheochromocytoma

Using randomly voided 1-h urine samples, levels of excretion of catecholamines (CA) and 4-hydroxy-3-methoxymandelic acid (vanillylmandelic acid; VMA) were determined in order to save time in and simplify the diagnostic work-up of pheochromocytoma, particularly in out-patient hypertension clinics. Twenty-nine patients with surgically verified pheochromocytoma (15 paroxysmal and 14 sustained type), 56 patients with essential hypertension (26 labile and 30 fixed type) and 14 normal volunteers were studied. Abnormally high excretion of CA and VMA was found in all patients with pheochromocytoma when compared to those with essential hypertension or to normal controls after duly considering the influence of external factors such as food and exercise. From these results, we concluded that assays of CA and VMA even in random 1-h urine samples are useful in separating patients with pheochromocytoma from those with other types of hypertension.