When a COPD patient has diabetes as well, the doctor must consider two essential issues when choosing an appropriate bronchodilator medicine. For all such patients, the doctor must know which drugs affect the body's release of stored sugar and its metabolism of sugar in general. For diabetics whose disease has affected their autonomic nervous system, the doctor must know what the implications of this are for COPD, and which COPD drugs may worsen this impairment.

Also, diabetics are much more susceptible to all sorts of infections. The diabetic chronic bronchitic in particularbecause his lungs become a fertile breeding ground for infectionsneeds aggressive surveillance by clinical exam, laboratory tests, and X-rays. Intervention should begin immediately when a beginning infection is indicated.

Creating a glucose (sugar) imbalance in the diabetic COPD patient is a particular worry when steroids must be used to treat the COPD. Glucose is the body's primary energy source. The presence of insulin allows cells to take in the glucose they need. Then the cells use oxygen to burnor "metabolize"this sugar to produce their energy. Since the diabetic does not produce the amount of insulin needed to allow his cells to take in enough glucose, he must take supplemental insulin (or a related drug).

One effect of glucocorticoidsthe group of steroids given COPD patientsis to increase the amount of glucose in the blood while also disrupting the cells' ability to take in sugar. In addition, steroids promote the breakdown of proteins within each cell as a substitute energy fuel. So the blood is flooded with excess sugar, while the cells are burning protein for energy because so little of this sugar is available to them.

When steroids are indicated for a diabetic COPD, these side effects can be somewhat reduced by using large doses of aerosolized steroids instead of smaller oral doses. This, though, produces its own set of problems. Oral yeast infections and loss of voice are frequently troublesome with high inhaled doses. The use of a spacer between canister and mouth, though, can reduce the amount of steroid deposited in the mouth, which may diminish these difficulties. Also helpful are the prophylactic use of antifungal medication (such as oral nystatin), plus fastidious oral hygiene. Although inhaled steroids reduce the diabetes-promoting problem somewhat, they by no means make it disappear. So the primary countermeasure may be an increase in antidiabetic medication.

Adrenergic beta-2 selective drugs also increase the amount of glucose in the blood, especially when they are given orally. Even when these drugs are used in aerosolized form, the diabetic must pay greater attention to monitoring his glucose level.

The autonomic nervous system in diabetics can develop problems related to heart rate, blood pressure regulation, urination, and male sexual function. In theory, vagal nerve (part of the autonomic nervous system, and a bronchoconstricting pathway) dysfunction should improve COPD symptoms by removing this pathway. In reality, COPD patients with this loss of autonomic control appear to have a greater chance of respiratory failure. Laboratory studies have shown that when their oxygen level falls, they fail to increase their rate and/or depth of breathing to compensate. This becomes a critical concern during an acute episode. That is why diabetic COPD patients with autonomic nervous system impairmentwhen they develop an infectionusually get supplemental oxygen and have their blood gases monitored without delay.

Both the beta-2 stimulators and the theophyllines improve the ventilatory response of falling oxygen and increasing carbon dioxide. In theory, then, these drugs would appear to be especially appropriate for this subgroup of diabetic COPD patients. However, it is known that beta-2 stimulators must be given cautiously with these patients to prevent a rapid, uncontrolled drop in blood pressure.

So, the order of medication preference for the diabetic COPD patient is the same as when COPD coexists with cardiovascular disease. First choice is typically ipratropium bromide, second is inhaled beta-2 stimulators. Next in line are aerosol steroids andonly if they cannot be avoidedoral steroids.