A VIPER IN THE COURTYARD L A I L A ABUZA I D, M D

Transcription

1 A VIPER IN THE COURTYARD L A I L A ABUZA I D, M D E N D O C R I N O L O G Y FELLOW

2 NO DISCOLSURES

3 OBJECTIVES: Recognize signs and symptoms of hyperthyroidism Develop a differential diagnosis for a patient with chronic diarrhea (secretory) Describe anchoring heuristic/premature closure

4 CASE PRESENTATION A 55 year old man presents to the hospital multiple times in two months for uncontrolled watery diarrhea. Onset: 5 months, on-off Non-bloody Associated with nausea and vomiting No abdominal pain Patient had lost 20 pounds/6 months

5 MEDICAL HISTORY OSA on CPAP Grave s disease TSH < 0.02 Free T Radioactive iodine uptake scan: 24-hour uptake of 53% Diarrhea was attributed to hyperthyroidism from Grave s disease. He was started on methimazole 10 mg daily.

6 Past surgical history: Right total hip arthroplasty Family History: Father with DM Medications: Methimazole Immodium Social History: Lives with wife No smoking Occasional alcohol No illicit drug use

7 RECURRENT ADMISSIONS Despite optimal anti-diarrheal therapy and methimazole, he continued to have watery diarrhea, causing acute kidney injury and severe hypokalemia, and required several inpatient admissions for intravenous fluid resuscitation.

8 FIRST ADMISSION: (JAN 3-4 TH, 2016) Diarrhea, nausea and vomiting C. diff: negative TSH <0.02 Free T Managed with IV fluids and loperamide. Diarrhea was thought to be due to viral gastroenteritis + hyperthyroidism

9 SECOND ADMISSION: (FEB 4-7 TH, 2016) Had been holding methimazole for a week for RIA Diarrhea, nausea and vomiting C. diff: negative TSH <0.02 Free T Potassium 2.8 Improved quickly with IV fluids and loperamide. Methimazole restarted.

10 THIRD ADMISSION (FEB TH, 2016) Again, watery diarrhea associated with nausea and vomiting. TSH <0.02 Free T Potassium 2.5 On methimazole. 1. Free T4 is He is ON Methimazole 3. Hyperthyroidism doesn t usually cause watery diarrhea but rather hyper defecation

11 WORK UP FOR SECRETORY DIARRHEA Stool studies for Clostridium difficile and other infectious organisms (including ova and parasites): negative. HIV and hepatitis serologies: negative. Celiac antibody: negative. Autoimmune workup: non-revealing.

12 Fig 1. Coronal (left) and Axial (right) views on CT of abdomen/pelvis showed a large mass in pancreatic body, measuring 8 x 6 cm.

13 VIPoma Plasma metanephrines: not elevated Gastrin level: normal Vasoactive intestinal peptide level: 1065 ng/ml (normal < 75 ng/ml)

14 Fig 2. Octreotide scan showing localized lesion in the pancreas.

15 VIPOMAS Rare endocrine tumors that secrete vasoactive intestinal peptide (VIP), causing secretory diarrhea. Age of onset: Prevalence is 1 in 10 million per year. Pancreatic in origin in 95% of cases The secretory diarrhea is high volume (700 ml/day-3 L/day). Less than 5% of patients will have multiple endocrine neoplasia syndrome type 1 (MEN 1), 3P s PTH 52 pg/ml Normal Calcium Prolactin 14.9 ng/ml

16 VIPOMAS Elevated VIP levels over 75 pg/ml raises suspicion for VIPoma, and should be further worked up with an imaging (either a CT or MRI) to localize as well as stage the tumor. Most VIPomas are greater than 3 cm. Sensitivity of a CT scan to detect a VIPoma larger than 3 cm in size is close to 100%. Octreotide scan localizes tumor metastases outside the abdominal wall. Tissue biopsy is rarely needed if hormonal and imaging findings are unequivocal.

17 VIPOMAS Median survival for VIPoma is 96 months. More than half of patients have metastases at the time of diagnosis, which makes a worse prognosis. Long term follow-up is done with serial VIP levels and crosssectional imaging studies.

18 MANAGEMENT Somatostatin analogs (e.g octreotide). Octreotide has been shown to reduce the frequency and amount of diarrhea, and improve quality of life. Anti-diarrheal agents and repletion of electrolytes. Surgical resection of the tumor is indicated if the tumor is localized to pancreas or has limited hepatic involvement. Advanced disease: hepatic artery chemoembolization or ablation.

19 CASE OUTCOME Patient was discharged from hospital after his diarrhea was well-controlled with octreotide, and his electrolytes were adequately replaced. After 1 week of therapy with octreotide, his diarrhea continues to improve, with 3-4 formed to loose stools per day. Staging: TNM classification from the American Joint Committee on Cancer (AJCC)= T 2 N 0 M 0 = stage IB

20 CASE OUTCOME Underwent central pancreatectomy with removal of 12 * 12 cm encapulated tumor in the neck of the pancreas. Normal Portal and peripancreatic LNs. Currently following with surgical oncology for serial imaging/labs.

21 CONCLUSIONS Hyperthyroidism usually causes hyper defecation rather than watery diarrhea. VIPomas are rare neuroendocrine tumors, require high index of suspicion. Anchoring heuristic: Settling on a diagnosis early in the diagnostic process despite data that refute the diagnosis or support another diagnosis (premature closure).

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