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Paediatric

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Endocrinology

Question
35 out of 35
 

The following is true about Nesidioblastosis except? (AIPG 2011)



A Presents with hypoglycemic attacks

B More common in adults than in children

C Histopathology shows hyperplasia of islet cells

D Diazoxide is used for treatment

Ans. B

More common in adults than in children.

(Ref. Nelson essentials of pediatrics 18th/pg. 786)

Nesidioblastosis

1.

a. Nesidioblastosis is a controversial medical term for hyperinsulinemic hypoglycemia attributed to excessive function of pancreatic beta cells with an abnormal microscopic appearance.

b. The term ‘nesidioblastosis’ was originally conceived by Laidlaw (1938) who described the neoformation of islets of Langerhans from pancreatic duct epithelium whereas ‘nesidioblastoma’ was proposed for an adenoma com- posed of islet cells.

c. The term is derived from the Greek words nesidion, for islet, and blastos, for germ.

d. However, only three decades later, severe infantile hypoglycaemia was first associated with nesidioblastosis by Brown & Young (1970).

e. Then, Yakovac et al. (1971) demonstrated the presence of both single islet cells and clusters of islet cells that were separate from the islets of Langerhans in nesidioblastosis.

f. Subsequently, it was suggested that nesidioblastosis may be the result of im-proper develop- ment of the endo.

g. The abnormal histologic aspects of the tissue included the presence of islet cell enlargement, islet cell dysplasia, beta cells budding from ductal epithelium, and islets in apposition to ducts.

2.

a. Hyperinsulinism is the most common cause of persistent neonatal hypoglycaemia.

b. The underlying genetic defects of cell regulation include a severe recessive disorder of the sulphonylurea receptor, a milder dominant form of hyperinsulinism, and a syndrome of hyperinsulinism plus hyperammonaemia.

c. This condition requires prompt medical and surgical therapy in order to prevent permanent brain damage.

d. Nesidioblastosis may also occur in adults and it has also been described as a result of covert sulphonylurea administration.

3. Persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI), congenital hyperinsulinism, nesidiodys-plasia and islet-cell dysmaturation syndrome are syno-nyms in use for nesidioblastosis.

Histopathology

1.

a. The morphologic features characteristic for nesidio-blas-tosis are ductoendocrine proliferation, numerous small endocrine cell groups and large endocrine areas.

b. Nesidioblastosis is classified into a focal and a diffuse type which are characterized by different clinical outcomes.

c. Focal nesidioblastosis exhibits nodular hyperplasia of islet-like cell clusters, including ductuloinsular complexes and hypertrophied insulin cells with giant nuclei.

d. In contrast, diffuse nesidioblastosis involves the entire pancreas with irregularly sized islets.

e. It was concluded that de novo formation of intermediate cells (acinar-islet cells) is a phenomenon which is clearly associated with nesidioblastosis.

f. The term ‘nesidiodysplasia’ has been proposed to include the apparently increased and possibly maldistributed and/or malregulated endocrine cells associated with hyper- insulinaemic hypoglycaemia.

g. Future classifications will be related to the underlying genetic defects and may thus result in appropriate modification of the existing nomenclature.

Symptomatology

1. Sporadic persistent hyperinsulinaemic hypoglycaemia is a common feature of nesidioblastosis. An inappropriately elevated serum insulin level and low serum ketone and free fatty acid concentrations associated with hypoglycaemia deter- mines the diagnosis. Arterial calcium injection and subsequent venous sampling reveals a brisk response of the plasma insulin level, indicating that this may be a valuable method for the diagnosis of nesidioblastosis in both children and adults. Ultimately, only histological analysis is a valuable tool for the diagnosis of nesidio- blastosis.

Rx:

Treatment

1. Somatostatin (octreotide) and diazoxide, which is a specific ATP-sensitive potassium channel agonist in normal cells, are key therapeutics for the treatment of PHHI.

2. Sulphonylurea drugs are used in diabetes mellitus in order to increase levels of insulin secretion through inhibition of pancreatic -cell KATP channels.

3. Diazoxide may also modulate a novel ion channel in PHHI cells as they lack KATP currents.

4. Persistent post- operative hyperinsulinaemic hypoglycaemia was success- fully treated with the calcium channel blocking agent nifedipine, indicating that ionic control of insulin release in nesidioblastosis may represent a new approach to achieve normoglycaemia.

Endocrinology Flashcard List

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