Diagnostic Challenge of Glucagonoma: Case Report and Literature Review

OBJECTIVE

To report the diagnostic difficulties encountered in a case of glucagonoma.

METHODS

We provide a literature review and present the clinical findings, pertinent laboratory data, and results of related studies in a patient with a glucagonoma.

RESULTS

A 54-year-old-man, with no relevant history of endocrine disorders, presented to the hospital with a 5-year history of recurrent stomatitis and glossitis, a more recent weight loss of 11.5 kg, and recurrent pruritic maculae on the scalp in conjunction with raised erythematous maculae in the scrotal region and perineum that gradually migrated to the distal extremities, becoming bullous and painful. The patient was hospitalized, and because of the dermatologic findings suggestive of necrolytic migratory erythema, the presence of a glucagonoma was suspected. His blood glucose levels were in the normal range. Glucagon levels were found to be elevated, and imaging studies confirmed the presence of an enlarged mass in the pancreatic tail, without evidence of extension to surrounding structures. Liver metastatic lesions were also excluded. After surgical removal of the tumor, the skin and oral mucosal lesions disappeared spontaneously. The histologic appearance and immunohistochemical staining results confirmed the diagnosis of a glucagonoma. Subsequently, all related symptoms resolved, and the glucagon levels normalized.

CONCLUSION

The diagnosis of glucagonoma is often delayed. Clinicians should be aware of the unusual initial manifestations of this tumor and the potential for less than a full spectrum of the characteristic features of the glucagonoma syndrome.

Effectiveness of a gentamicin dosing protocol based on postconceptional age: comparison to published neonatal guidelines

OBJECTIVE

To evaluate the effectiveness of a gentamicin dosing protocol based on postconceptional age in producing therapeutic serum concentrations and to compare the protocol with commonly used gentamicin dosing guidelines.

DESIGN

During the initial three months of this study infants were dosed according to physician discretion (group I). In the subsequent three-month period patients were dosed according to a postconceptional age dosing schedule (group II).

SETTING

Infants were enrolled after being admitted to the Newborn Intensive Care Unit at the University of Miami/Jackson Memorial Medical Center.

PATIENTS

Infants less than 37 weeks gestational age with normal renal function, not receiving indomethacin, and requiring gentamicin treatment were enrolled. Fifty-nine infants were enrolled into group I (median weight 1300 g [range 720-3300]), postconceptional age 29 weeks [26-37]); and 68 infants were enrolled into group II (weight 970 g [530-3000], postconceptional age 29 weeks [24-36]).

INTERVENTION

Patients in group II were dosed according to the following protocol: postconceptional age less than 30 weeks, 3.0 mg/kg q24h, and postconceptional age 30-37 weeks, 2.5 mg/kg q18h. Peak and trough serum gentamicin concentrations were obtained in all study patients. Pharmacokinetic parameters were calculated from measured serum concentrations. Using the calculated pharmacokinetic data, peak and trough serum concentrations were simulated for five published neonatal dosing guidelines and the proposed postconceptional age protocol.

MAIN OUTCOME MEASURES

The number of therapeutic serum gentamicin concentrations resulting from the dosing guidelines studied were compared.

RESULTS

Measured trough concentrations differed significantly between the two groups with 35 percent of patients in group I and 90 percent of patients in group II having trough values less than 2 mg/L (p less than 0.001). There was no significant difference in measured peak concentrations between groups. Simulated trough concentrations were significantly different when postconceptional age dosing was compared with commonly used protocols (p less than 0.0001) with the highest percentage of concentrations less than 2 mg/L (89 percent) resulting from the proposed postconceptional age guidelines.

CONCLUSIONS

These data suggest that the proposed postconceptional age protocol is reproducible and reliable in achieving therapeutic gentamicin serum concentrations in neonates.