HONK and Lactic Acidosis

Diabetic Hyperosmolar Non-ketotic Syndrome (HONK)

HONK has some similarities to DKA but there are also significant differences - in its development, the people affected, physiology, symptoms and rate of mortality. HONK usually develops over a period of several weeks, instead of days which is the usual case with DKA. It is characterized by very high blood glucose levels, usually greater than 50 mmol/1 and often in excess of 60 mmol/1. In DKA hyperglycaemia is not so high and blood glucose levels are usually less than 40 mmol/1. In HONK there is no ketosis or acidosis, ketonuria or hyperketonaemia. Ketones are either absent from blood and urine or only present at a minimal level.

This is in marked contrast to the situation in DKA. In HONK there is a high level of bicarbonate in blood plasma, usually exceeding 18 mmol/1 (plasma osmolarity), whereas in DKA the level is usually below 15 mmol/1. HONK produces profound dehydration, intense thirst, polyuria, drowsiness and eventual loss of consciousness, similar signs to those of DKA. The person with HONK often responds to their intense thirst by drinking large quantities of sweet, fizzy drinks which only makes the situation worse as this contributes to hyperglycaemia and dehydration. HONK does not produce symptoms of vomiting or abnormal, Kussmaul breathing, but affected people are often admitted to hospital in an unconscious state as medical emergencies.

HONK occurs less frequently than DKA and it usually affects people with Type 2 diabetes. It is most commonly encountered in middle-aged or elderly people, and in 60 per cent of cases it occurs in those with previously undiagnosed diabetes. The mortality rate, at 30 per cent, is much higher than in DKA, and death often results from thromboembolic complications such as pulmonary embolism or stroke. As with DKA, there are a number of well-recognized precipitating causes. These include infection, treatment with certain antihypertensive drugs (used to bring down high blood pressure, especially thiazide diuretics), and a high consumption of sweet drinks (understandable in those who do not know that they have diabetes).

As with DKA, a person with HONK requires specialized treatment and monitoring in hospital in an intensive care unit. The condition is managed in a similar way to DKA by reversing dehydration and loss of electrolytes and initiating insulin treatment, all by means of intravenous infusion. Once the person has recovered and is able to eat, insulin is usually given by means of subcutaneous injection. Eventually, most people who recover from HONK are able to transfer to oral antidiabetic drugs to manage their diabetes. After recovery, an attempt is made to discover the underlying cause so that a recurrence can be avoided in the future.

Lactic Acidosis

This is another rare acute complication which can arise in diabetes as a result of faulty lactate metabolism. It was particularly associated with the use of a certain type of biguanide called phenformin, but has become extremely rare since this drug was withdrawn. Its occurrence now is confined to those being treated with metformin and almost all of those affected have undiagnosed kidney impairment and hence are, in fact, unsuitable for biguanide therapy.

See more diabetic complications information.