There are two major types of diabetes, called type 1 and type 2. Type 1 diabetes was also formerly called insulin dependent diabetes mellitus (IDDM), or juvenile-onset diabetes mellitus. In type 1 diabetes, the pancreas undergoes an autoimmune attack by the body itself, and is rendered incapable of making insulin. Abnormal antibodies have been found in the majority of patients with type 1 diabetes. Antibodies are proteins in the blood that are part of the body's immune system. The patient with type 1 diabetes must rely on insulin medication for survival.
Findings from the Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) have clearly shown that aggressive and intensive control of elevated levels of blood sugar in patients with type 1 and type 2 diabetes decreases the complications of nephropathy, neuropathy, retinopathy, and may reduce the occurrence and severity of large blood vessel diseases. Aggressive control with intensive therapy means achieving fasting glucose levels between 70-120 mg/dl; glucose levels of less than 160 mg/dl after meals; and a near normal hemoglobin A1c levels (see below).
While the lipid abnormalities seen with metabolic syndrome (low HDL, high LDL, and high triglycerides) respond nicely to weight loss and exercise, drug therapy is often required. Treatment should be aimed primarily at reducing LDL levels according to specific recommendations. Once reduced LDL targets are reached, efforts at reducing triglyceride levels and raising HDL levels should be made. Successful drug treatment usually requires treatment with a statin, a fibrate drug, or a combination of a statin with either niacin or a fibrate.
Epigenetic phenomena, such as DNA methylation and histone modification, have also been implicated in the pathogenesis of hypertension. For example, a high-salt diet appears to unmask nephron development caused by methylation. Maternal water deprivation and protein restriction during pregnancy increase renin-angiotensin expression in the fetus. Mental stress induces a DNA methylase, which enhances autonomic responsiveness. The pattern of serine protease inhibitor gene methylation predicts preeclampsia in pregnant women. 
Renovascular hypertension (RVHT) causes 0.2-4% of cases. Since the seminal experiment in 1934 by Goldblatt et al,  RVHT has become increasingly recognized as an important cause of clinically atypical hypertension and chronic kidney disease—the latter by virtue of renal ischemia. The coexistence of renal arterial vascular (ie, renovascular) disease and hypertension roughly defines this type of nonessential hypertension. More specific diagnoses are made retrospectively when hypertension is improved after intravascular intervention.
^ Grundy SM, Cleeman JI, Daniels SR, Donato KA, Eckel RH, Franklin BA, Gordon DJ, Krauss RM, Savage PJ, Smith SC, Spertus JA, Costa F (October 2005). "Diagnosis and management of the metabolic syndrome: an American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement". Circulation. 112 (17): 2735–52. doi:10.1161/CIRCULATIONAHA.105.169404. PMID 16157765.
Moreover, it is estimated that 1 death is prevented per 11 patients treated for stage 1 hypertension and other cardiovascular risk factors when a sustained reduction of 12 mm Hg in systolic BP over 10 years is achieved.  However, for the same reduction is systolic BP reduction, it is estimated that 1 death is prevented per 9 patients treated when cardiovascular disease or end-organ damage is present. 
Diabetic ketoacidosis can be caused by infections, stress, or trauma, all of which may increase insulin requirements. In addition, missing doses of insulin is also an obvious risk factor for developing diabetic ketoacidosis. Urgent treatment of diabetic ketoacidosis involves the intravenous administration of fluid, electrolytes, and insulin, usually in a hospital intensive care unit. Dehydration can be very severe, and it is not unusual to need to replace 6-7 liters of fluid when a person presents in diabetic ketoacidosis. Antibiotics are given for infections. With treatment, abnormal blood sugar levels, ketone production, acidosis, and dehydration can be reversed rapidly, and patients can recover remarkably well.
The symptoms may relate to fluid loss and polyuria, but the course may also be insidious. Diabetic animals are more prone to infections. The long-term complications recognized in humans are much rarer in animals. The principles of treatment (weight loss, oral antidiabetics, subcutaneous insulin) and management of emergencies (e.g. ketoacidosis) are similar to those in humans.
To measure your blood pressure, a specialist places an inflatable cuff around your arm and measures your blood pressure using a pressure-measuring gauge. A blood pressure reading, as shown in the blood pressure monitor in the image, measures the pressure in your arteries when your heart beats (systolic pressure) in the first number, and the pressure in your arteries between heartbeats (diastolic pressure) in the second number.
Metabolic syndrome is thought to be caused by adipose tissue dysfunction and insulin resistance. Dysfunctional adipose tissue also plays an important role in the pathogenesis of obesity-related insulin resistance.  Both adipose cell enlargement and infiltration of macrophages into adipose tissue result in the release of proinflammatory cytokines and promote insulin resistance. 
^ Ahlqvist, Emma; Storm, Petter; Käräjämäki, Annemari; Martinell, Mats; Dorkhan, Mozhgan; Carlsson, Annelie; Vikman, Petter; Prasad, Rashmi B; Aly, Dina Mansour (2018). "Novel subgroups of adult-onset diabetes and their association with outcomes: a data-driven cluster analysis of six variables". The Lancet Diabetes & Endocrinology. 0 (5): 361–69. doi:10.1016/S2213-8587(18)30051-2. ISSN 2213-8587. PMID 29503172.
A positive result, in the absence of unequivocal high blood sugar, should be confirmed by a repeat of any of the above methods on a different day. It is preferable to measure a fasting glucose level because of the ease of measurement and the considerable time commitment of formal glucose tolerance testing, which takes two hours to complete and offers no prognostic advantage over the fasting test. According to the current definition, two fasting glucose measurements above 7.0 mmol/l (126 mg/dl) is considered diagnostic for diabetes mellitus.
Cataracts and glaucoma are also more common among diabetics. It is also important to note that since the lens of the eye lets water through, if blood sugar concentrations vary a lot, the lens of the eye will shrink and swell with fluid accordingly. As a result, blurry vision is very common in poorly controlled diabetes. Patients are usually discouraged from getting a new eyeglass prescription until their blood sugar is controlled. This allows for a more accurate assessment of what kind of glasses prescription is required.
[Guideline] Skyler JS, Bergenstal R, Bonow RO, et al. Intensive glycemic control and the prevention of cardiovascular events: implications of the ACCORD, ADVANCE, and VA Diabetes Trials: a position statement of the American Diabetes Association and a Scientific Statement of the American College of Cardiology Foundation and the American Heart Association. J Am Coll Cardiol. 2009 Jan 20. 53(3):298-304. [Medline].