Endocrinology Made Simple : Hyperglycemic Non Ketotic State / Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS)

Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS)

Hyperosmolar Hyperglycemic Nonketotic Syndrome, or HHNS, is a life threatening pathology  most frequently seen in patients with type 2  Diabetes Mellitus with poorly controlled blood sugar levels.

Pathophysiology

High blood sugars cause severe dehydration, increases in osmolarity (relative concentration of solute) and a high risk of complications, coma and death.

It is related to diabetic ketoacidosis (DKA), another complication of diabetes more often (but not exclusively) encountered in people with type 1 diabetes; they are differentiated with measurement of ketone bodies, organic molecules that are the underlying driver for DKA but are usually not detectable in HHS.

Predisposing factors:

It usually occurs by a stress to body such as  illness or infection.

Clinical Features:

In HHNS, blood sugar levels rise, and body tries to get rid of the excess sugar by passing it into urine. Initial symptoms include polyuria in the beginning followed by dark urine.

The patients will feel  very thirsty.

Fluid replacement if not adequately done will lead to dehydration

If HHNS continues, the severe dehydration will lead to seizures, coma and eventually death.

HHNS may take days or even weeks to develop.

Warning Signs

Blood sugar level over 600 mg/dl

Dry, parched mouth

Extreme thirst (although this may gradually disappear)

Warm, dry skin that does not sweat

High fever (over 101 degrees Fahrenheit, for example)

Sleepiness or confusion

Loss of vision

Hallucinations (seeing or hearing things that are not there)

Weakness on one side of the body

Serum osmolality >320 mOsm/kg

Profound dehydration, up to an average of 9L (and therefore substantial thirst (polydipsia))

Small ketonuria (~+ on dipstick) and absent-to-low ketonemia (<3 mmol/L)

Hyperviscosity and increased risk of blood clot formation

Serum glucose levels in HHS are extremely high, usually greater than 40-50 mmol/L, but an anion-gap metabolic acidosis is absent or mild unlike in DKA where these are present.

Altered mental status is also more common in HHS than DKA.

DKA is usuaully associated with Type I Diabetes, whereas HHS has been associated with Type II,However HHS can be seen in patients of both types.

HHS also tends to have an elderly preponderance.

Prevention

HHNS only occurs when diabetes is uncontrolled.

The best way to avoid HHNS is to check  blood sugar regularly especially before or after meals.

Management :

The treatment of HHS consists of correction of the dehydration with intravenous fluids, reduction of the 

blood sugar levels with insulin, and management of any underlying conditions that might have precipitated the illness, such as an acute infection.

Intravenous fluids

Treatment of HHS begins with re-establishing tissue perfusion using intravenous fluids. People with HHS can be dehydrated by 8 to 12  liters. Attempts to correct this usually take place over 24 hours with initial rates of normal saline often in the range of 1 L/h for the first few hours

Electrolyte replacement

Severe potassium deficits often occur in HHS. They usually range around 350 mEq in a 70 kg person. This is generally replaced at a rate 10 mEq per hour as long as there is urinary output.

Insulin

Insulin is given to reduce blood glucose concentration; however, as it also causes the movement of potassium into cells.

Serum potassium levels must be sufficiently high or dangerously low blood potassium levels may result.

Once potassium levels have been verified to be greater than 3.3 mEq/l, then an insulin infusion of 0.1 units/kg is begun.