A VIPER IN THE

COURTYARDLA ILA ABUZAID , MD

ENDOCR INOLOGY FELLOW

•NO DISCOLSURES

OBJECTIVES:

• Recognize signs and symptoms of

hyperthyroidism

• Develop a differential diagnosis for a patient

with chronic diarrhea (secretory)

• Describe anchoring heuristic/premature

closure

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

MEDICAL HISTORY

• OSA on CPAP

• Grave’s disease

• TSH < 0.02 Free T4 1.37

• 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.

• Past surgical history:

• Right total hip

arthroplasty

• Medications:

• Methimazole

• Immodium

• Family History:

• Father with DM

• Social History:

• Lives with wife

• No smoking

• Occasional alcohol

• No illicit drug use

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.

FIRST ADMISSION: (JAN 3-4TH, 2016)

• Diarrhea, nausea and vomiting

• C. diff: negative

• TSH <0.02 Free T4 1.32

• Managed with IV fluids and loperamide.

• Diarrhea was thought to be due to viral gastroenteritis +

hyperthyroidism

SECOND ADMISSION: (FEB 4-7TH, 2016)

• Had been holding methimazole for a week for RIA

• Diarrhea, nausea and vomiting

• C. diff: negative

• TSH <0.02 Free T4 1.61 Potassium

2.8

• Improved quickly with IV fluids and loperamide.

Methimazole restarted.

THIRD ADMISSION (FEB 16-19TH, 2016)

• Again, watery diarrhea associated with nausea and vomiting.

• TSH <0.02 Free T4 1.44 Potassium 2.5

• On methimazole.

1. Free T4 is 1.44

2. He is ON Methimazole

3. Hyperthyroidism doesn’t usually

cause watery diarrhea but

rather hyper defecation

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.

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.

• Plasma

metanephrines: not

elevated

• Gastrin level: normal

• Vasoactive intestinal

peptide level: 1065

ng/mL (normal < 75

ng/mL)

VIPoma

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

VIPOMAS

• Rare endocrine tumors that secrete vasoactive intestinal

peptide (VIP), causing secretory diarrhea.

• Age of onset: 30-50.

• 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

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.

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 cross-

sectional imaging studies.

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.

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)= T2N0M0 = stage IB

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.

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).