Metabolic syndrome or Syndrome X | Renal, endocrine and reproductive system | Pathology

Metabolic syndrome or Syndrome X

The WHO defines metabolic syndrome as high insulin levels along with any two of the following:

Abdominal obesity (increased waist circumference, BMI > 30)
Dyslipidemia (triglycerides > 150 mg/dl, HDL < 35 mg/dl in males and < 39 mg/dl in females)
Hypertension
Microalbuminuria

Some organizations also use the following as criteria:

Fasting plasma glucose > or = 110 mg/dl
Insulin resistance
Impaired glucose tolerance

Metabolic syndrome is associated with an increased risk of type 2 DM, cardiovascular disease, and mortality.

Risk factors include:

Physical inactivity
Cigarette smoking
Family history of premature CAD
Obesity
Diets high in carbohydrates and fats

It is a proinflammatory and prothrombotic condition. CRP (C-reactive protein) may be elevated.

Recommended management includes:

Weight reduction
Increasing physical activity
Drugs that increase insulin sensitivity (e.g., metformin or thiazolidinediones)
Low-dose aspirin
Optimal management of dyslipidemias and HT

Islet cell tumors: Islet cell tumors are neuroendocrine tumors and may be functional or non-functional.

Functional tumors cause symptoms due to hormone production (e.g., insulin, glucagon, somatostatin).
Non-functional tumors do not produce hormones and therefore often present at a later stage.

Cushing’s syndrome due to increased ACTH secretion may be seen.

Common islet cell tumors

Type	Characteristics
Insulinoma	Most common, present with hypoglycemia, high levels of insulin and C peptide, 10% are malignant, 10% aremultiple, associated with MEN 1
Gastrinoma	Cause Zollinger Ellison syndrome with multiple peptic ulcers, diarrhea, increased gastric acid secretion, raised serum gastrin levels, high basal gastric output, most found in gastrinoma triangle bounded by third part of the duodenum, neck of the pancreas and porta hepatis. Some are extra-pancreatic, in duodenum e.g., mostare malignant, associated with MEN 1.
Glucagonoma	Most are malignant, causenon-ketogenic DM, migrating, necrolytic rash, stomatitis, diarrhea, venous thrombosis
VIPomas	Cause waterydiarrhea, hypokalemia, achlorhydria (Verner-Morrison syndrome), most are intrapancreatic, others are found in adrenal medulla or sympathetic chain, can be benign or malignant
Somatostatinoma	Rare, slow-growing, cause gallstones, DM and steatorrhea, may occur in pancreas or duodenum, maybe seen in neurofibromatosis

Transabdominal ultrasound is less sensitive for detecting islet cell tumors. Endoscopic and intraoperative ultrasound provide better results.

CT scan with contrast is the preferred investigation for diagnosing islet cell tumors. MRI can detect very small tumors as well. ERCP helps to detect tumors blocking the pancreatic ducts.

Somatostatin receptor-positive tumors can be detected by scintigraphy using a radiolabeled somatostatin analogue such as pentetreotide. Chromogranin A may be elevated in some tumors.

Treatment options include enucleation (if the tumor is located in the pancreas), pancreatoduodenectomy (Whipple procedure), distal pancreatectomy, gastrectomy, radiofrequency ablation, cryosurgical ablation, chemotherapy, and chemoembolization.

Somatostatin analogues such as octreotide and lanreotide can control tumor growth. Interferon alpha, everolimus, and sunitinib are other agents used in therapy.