Journal of Postgraduate Medicine
 Open access journal indexed with Index Medicus & ISI's SCI  
Users online: 2290  
Home | Subscribe | Feedback | Login 
About Latest Articles Back-Issues Article Submission Resources Sections Etcetera Contact
 
  NAVIGATE Here 
  Search
 
  
 RESOURCE Links
 ::  Similar in PUBMED
 ::  Search Pubmed for
 ::  Search in Google Scholar for
 ::  Article in PDF (1,250 KB)
 ::  Citation Manager
 ::  Access Statistics
 ::  Reader Comments
 ::  Email Alert *
 ::  Add to My List *
* Registration required (free) 

  IN THIS Article
 ::  References
 ::  Article Figures

 Article Access Statistics
    Viewed3296    
    Printed36    
    Emailed0    
    PDF Downloaded15    
    Comments [Add]    

Recommend this journal


 


 
  Table of Contents     
CASE SNIPPET
Year : 2013  |  Volume : 59  |  Issue : 1  |  Page : 61-62

An unusual cause of hypokalemic paralysis


1 Department of Medical Gastroenterology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
2 Department of Surgical Gastroenterology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
3 Department of Endocrinology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
4 Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India

Date of Web Publication22-Mar-2013

Correspondence Address:
R Vijayahari
Department of Surgical Gastroenterology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0022-3859.109501

Rights and Permissions




How to cite this article:
Lakshmi C P, Vijayahari R, Kamalanathan S K, Rajesh G N, Verma S K. An unusual cause of hypokalemic paralysis. J Postgrad Med 2013;59:61-2

How to cite this URL:
Lakshmi C P, Vijayahari R, Kamalanathan S K, Rajesh G N, Verma S K. An unusual cause of hypokalemic paralysis. J Postgrad Med [serial online] 2013 [cited 2019 Sep 21];59:61-2. Available from: http://www.jpgmonline.com/text.asp?2013/59/1/61/109501


Vasoactive intestinal polypeptide (VIP) secreting tumors (VIPomas) are rare tumors of the islet cells of pancreas, with an estimated annual incidence of 1 per 10,000,000 individuals in the general population. [1] It classically presents with severe watery diarrhea with hypokalemia and hypochlorhydria. More than two-thirds of these tumors are malignant, with evidence of lymph nodal or liver metastasis at presentation. [2] and more than 90% arise from pancreas. The management is usually surgical. [3] We present in this paper, a case of VIPoma which presented with acute flaccid paralysis, highlighting the fact that VIPoma should also be included in the differential diagnosis of a case of hypokalemic paralysis.

A 39-year-old female, a known diabetic, presented to the emergency department with acute flaccid bilateral lower limb weakness. She was found to have a serum potassium level of 2 meq/L (3.5-5 meq/L) and improved with intravenous potassium supplementation. She gave a history of recurrent episodes of severe watery diarrhea since the past 2 years. Diarrhea was large volume, with no blood or mucus, with mild crampy periumbilical pain during episodes. Each episode lasted a roughly a week and episodes recurred monthly. She remained fully asymptomatic between episodes. She gave a history of diabetes mellitus since 2 years and was on insulin. She had no clinical and biochemical features suggestive of multiple endocrine neoplasia (MEN) syndrome and an ultrasound abdomen showed a small mass lesion in head of pancreas.

In view of typical episodic diarrhea with hypokalemia and a pancreatic mass, a potential diagnosis of VIPoma was reached. A contrast enhanced computed tomogram (CECT) abdomen showed a 3-cm-mass lesion in uncinate process of pancreas, with no significant enhancement in early arterial phase, appearing isodense to pancreatic parenchyma in portal phase [Figure 1]a and b.
Figure 1: (a) Arterial phase of computed tomography (CT) scan showing mass lesion in uncinate process of pancreas with no significant arterial enhancement. (b) Portal venous phase of CT scan showing mass lesion in uncinate process, appearing isodense to pancreatic parenchyma, with dilated main pancreatic duct. (c) Pancreatico‑duodenectomy specimen of the patient. (d) Cut section of tumor in uncinate process of pancreas, showing homogenous lesion with no hemorrhage or necrosis

Click here to view


She was taken up for Whipple's pancreatico-duodenectomy, where a well-circumscribed tumor measuring 3.2 × 3 × 2 cm was observed in uncinate process [Figure 1]c. Cut surface of the tumor was homogeneously gray brown with no evidence of hemorrhage or necrosis [Figure 1]d. Microscopic sections showed an encapsulated tumor comprising of small round tumor cells arranged in trabecular and acinar pattern [Figure 2]a. Nuclei had stippled chromatin pattern [Figure 2]b and there was no evidence of mitosis or necrosis. Immunohistochemistry for chromogranin, synaptophysin, and neuron-specific enolase were positive in 40%, 20%, and 10% tumor cells, respectively. Subsequently, immunohistochemistry performed with antibodies for VIP showed strong cytoplasmic expression in 70% of the tumor cells [Figure 2]c and d. The patient had an uneventful post-operative course and is now asymptomatic, and free of diarrhea at 8 months of follow-up.
Figure 2: (a) Section shows an encapsulated tumor arising from pancreas comprised of small round tumor cells arranged in acinar and lobular pattern (H and E, ×20). (b) Section shows uniform small round tumor cells with stippled chromatin. There is no evidence of mitotic activity (H and E, ×400). (c) Section shows cytoplasmic expression of VIP in tumor cells, immunohistochemistry with DAKO antibody (DAB, ×40). (d) Section shows cytoplasmic expression of VIP in tumor cells, immunohistochemistry with DAKO antibody (DAB, ×400)

Click here to view


VIPomas are rare islet cell tumors of pancreas that secrete VIP, a structural homolog of secretin. Elevated serum VIP levels cause increased intestinal secretion of Na + , K + , HCO3 , and Cl , as well as bone resorption, vasodilation, and inhibition of gastric acid secretion. [4] These effects lead to a well-defined clinical syndrome, characterized by watery diarrhea, hypokalemia, and hypochlorhydria. This syndrome is commonly known as Watery diarrhea hypokalemia achlorhydria (WDHA) syndrome, other acronyms being pancreatic cholera syndrome, endocrine cholera, and the Verner-Morrison syndrome. In 1968, Verner and Morrison described this clinical syndrome in two male patients, who had pancreatic tumors at autopsy which were considered to be responsible for their clinical manifestations. [5]

VIPomas are most commonly found in the pancreas, other sites being colon, bronchus, adrenals, liver, and sympathetic ganglia. In pancreas, about 72% are located in the tail of pancreas with the rest being observed on the head of pancreas. The mean tumor size as described in various case series is about 5 cm, with the majority having evidence of locoregional spread or liver metastasis. In a review of 35 cases, 59% had evidence of metastasis at presentation. [4]

The diagnosis is usually suspected when a cross-sectional imaging, either computed tomography (CT) or magnetic resonance imaging (MRI) shows a pancreatic mass lesion in a patient with typical clinical features. The CT scan is quite sensitive in making a diagnosis as majority of VIPomas are more than 3 cm in size at presentation. Somatostatin receptor positivity is seen in 80-90% of VIPomas, making somatostatin receptor scintigraphy, an useful adjunct in the diagnosis. A serum radioimmunoassay for VIP aids diagnosis, especially at the time of a diarrheal episode. In a review of 35 cases, the serum VIP values ranged from 100 to 7200 pg/ml (mean 1209 pg/ml, median 632 pg/ml). [4] In our patient, the estimation was not done for want of funds, and also due to the fact that she did not have a diarrheal episode during stay in our hospital. Moreover, a low or normal value of VIP in non-diarrheal state does not rule out VIPoma.

Histologically, the cellular patterns of VIPomas can be either solid, acinar, or trabecular with scant mitoses. [6] Malignancy is confirmed by the evidence of disease in lymph nodes or distant sites such as liver. Immunohistochemical staining showing positivity for VIP usually confirms the diagnosis, as in our patient.

Aggressive surgical intervention is the main-stay of treatment in most cases, procedures described being distal pancreatectomy, pancreatico-duodenectomy, splenectomy, hemi-gastrectomy, liver resection, and tumor enucleation. [7] In patients with advanced disease, palliative treatment with octreotide shows improvement in clinical features. Other palliative therapeutic modalities include hepatic artery embolization, radiofrequency ablation, hepatic transplantation, and radioactive octreotide. [4] With such multimodality management, the largest case series on VIPomas reports a 5-year actuarial survival rate of 69%. [8]

Literature on VIPoma is limited to case reports and small case series from major pancreatobiliary centers from across the globe. [3],[4],[8],[9] There has only been one pediatric case of VIPoma reported from India so far. [10] We now probably report the first adult case of VIPoma from India. Our patient presented with all typical clinical features of this syndrome and the diagnosis was conclusively proven on immunohistochemistry. We would like to highlight that VIPoma should also be kept in mind during the workup of unexplained episodic diarrheas, especially those with severe hypokalemia.

 
 :: References Top

1.Friesen SR. Update on the diagnosis and treatment of rare neuroendocrine tumors. Surg Clin North Am 1987;67:379-93.  Back to cited text no. 1
[PUBMED]    
2.Mekhjian HS, O'Dorisio TM. VIPoma syndrome. Semin Oncol 1987;14:282-91.  Back to cited text no. 2
[PUBMED]    
3.Joyce DL, Hong K, Fishman EK, Wisell J, Pawlik TM. Multi-visceral resection of pancreatic VIPoma in a patient with sinistral portal hypertension. World J Surg Oncol 2008;6:80.  Back to cited text no. 3
[PUBMED]    
4.Ghaferi AA, Chojnacki KA, Long WD, Cameron JL, Yeo CJ. Pancreatic VIPomas: Subject review and one institutional experience. J Gastrointest Surg 2008;12:382-93.  Back to cited text no. 4
[PUBMED]    
5.Verner JV, Morrison AB. Islet cell tumor and a syndrome of refractory watery diarrhea and hypokalemia. Am J Med 1958;25:374-80.  Back to cited text no. 5
[PUBMED]    
6.Capella C, Polak JM, Buffa R, Tapia FJ, Heitz P, Usellini L, et al. Morphologic patterns and diagnostic criteria of VIP-producing endocrine tumors. A histologic, histochemical, ultrastructural, and biochemical study of 32 cases. Cancer 1983;52:1860-74.  Back to cited text no. 6
[PUBMED]    
7.Norton JA, Kivlen M, Li M, Schneider D, Chuter T, Jensen RT. Morbidity and mortality of aggressive resection in patients with advanced neuroendocrine tumors. Arch Surg 2003;138:859-66.  Back to cited text no. 7
[PUBMED]    
8.Soga J, Yakuwa Y. Vipoma/diarrheogenic syndrome: A statistical evaluation of 241 reported cases. J Exp Clin Cancer Res 1998;17:389-400.  Back to cited text no. 8
[PUBMED]    
9.Smith SL, Branton SA, Avino AJ, Martin JK, Klingler PJ, Thompson GB, et al. Vasoactive intestinal polypeptide secreting islet cell tumors: A 15-year experience and review of the literature. Surgery 1998;124:1050-5.  Back to cited text no. 9
[PUBMED]    
10.Samal SC, Paul AC, Venkateswari S, Nair S, Venkatramani S, Perakath B, et al. VIPoma of pancreas in a child. Indian J Gastroenterol 2000;19:194-5.  Back to cited text no. 10
[PUBMED]    


    Figures

  [Figure 1], [Figure 2]



 

Top
Print this article  Email this article
 
Online since 12th February '04
2004 - Journal of Postgraduate Medicine
Official Publication of the Staff Society of the Seth GS Medical College and KEM Hospital, Mumbai, India
Published by Wolters Kluwer - Medknow