Hyperinsulinaemic, hypoglycaemic syndrome due to acquired nesidioblastosis in a cat

Abstract

Case summary A 6-year-old, neutered female British Shorthair cat presented with acute-onset weakness and mental dullness. Initially the cat was mildly hyperglycaemic (9.9 mmol/l; reference interval [RI] 3.3–6.7 mmol/l). Over the following 12 h the cat developed central blindness, tremors, intermittent seizures and opisthotonus. Repeat blood sampling revealed a marked hypoglycaemia (0.8 mmol/l). Insulin level (performed on a serum sample collected while the cat was hypoglycaemic) was inappropriately elevated (1575 mIU/l; RI 10–80 mIU/l). An abdominal ultrasound was unremarkable. An exploratory laparotomy revealed a firm and erythematous left limb of the pancreas. Following surgical resection of the left limb of the pancreas, the cat returned to a euglycaemic state after a brief rebound hyperglycaemia. Histopathology revealed pancreatic fibrosis with marked multifocal micronodular hyperplasia of exocrine and endocrine cells. Synaptophysin immunohistochemistry confirmed nodular β-cell hyperplasia.Relevance and novel information Nesidioblastosis describes a syndrome of acquired hyperinsulinaemia and associated hypoglycaemia secondary to focal or diffuse (non-neoplastic) β-cell hyperplasia within the pancreas. Acquired nesidioblastosis has been reported in humans, where β-cell dysregulation is thought to occur in response to pancreatic injury. This is the first reported case of clinically significant hypoglycaemia due to acquired nesidioblastosis in an adult domestic cat. While this condition is rare, nesidioblastosis is being increasingly recognised in humans and it is an important differential diagnosis to consider when investigating hypoglycaemia as it cannot be distinguished from insulinoma without histopathological evaluation. While recurrence has been occasionally reported in humans, the prognosis is considered good.

Use of contrast-enhanced ultrasonography for the detection of a feline insulinoma

“…1,2 Benign inflammatory pancreatic hyperplasia has also been described in a cat. 3 Insulinomas are uncommon tumours of dogs, 4,5 and only eight cases have been reported in feline medicine (Table 1). In cats, evidence to date indicates an increased incidence in older patients (Table 1), as in the case discussed here.…”

“…Differential diagnoses for hypoglycaemia in adult cats include insulin-secreting neoplasms, hepatic disease, sepsis, hypo-adrenocorticism, storage diseases and, more rarely, beta-cell hyperplasia. 3 Insulin-secreting tumours are most frequently suspected by finding hypoglycaemia with concomitant normal-to-increased serum insulin concentration. 6,15 In our patient, ataxia and seizure-like episodes were reported by the owner and severe hypo-glycaemia with concomitant hyperinsulinaemia were detected at admission.…”

Suspected congenital hyperinsulinism in a Shiba Inu dog

“…Although a relatively novel and extremely rare disease, CHI (of multiple etiologies) is a differential diagnosis for persistently hypoglycemic juvenile dogs, and even may be considered in normoglycemic patients with a history of seizures as evidenced by our dog and the dog of previous case report 19 . Medical management with diazoxide has proven successful thus far, but surgical management and even spontaneous disease remission both remain possibilities.…”

“…Despite a positive response to diazoxide treatment, insufficient evidence was available to confirm an etiology in our case. Two cases termed nesidioblastosis have been reported in the veterinary literature (a 6‐year‐old cat and a 6‐year‐old dog) 19,20 . In these cases, adult‐onset hypoglycemia resolved with partial pancreatectomy in a dog, and pancreatic histopathology disclosed diffusely increased islet area in the pancreas without evidence of malignancy and multifocal micronodular hyperplasia of endocrine and exocrine tissue in a cat.…”

Pathophysiology and aetiology of hypoglycaemic crises

“…A recent report also documents for the first time HHS in a 6‐year‐old female spayed British shorthair cat secondary to suspect nesidioblastosis, a term which describes non‐neoplastic β‐cell hyperplasia within the pancreas (Hambrook et al . ).…”