As a rule, every medical malpractice claim must have four elements -- duty, breach, causation and damages -- and, at least as a general rule, you need all of them to have a cognizable claim. Sometimes, however, there can be an issue as to when a claim is "mature," i.e., complete or ripe.

Take, for example, a person who has an increased risk of disease because he has been exposed to a defective product, but no illness has manifested. In this situation, many courts have held that the person has no cause of action, but the issue is far from settled.

It is my view that a recovery should be allowed for the increased risk of future disease or for emotional distress as a result of the increased risk. Under these circumstances, it is also logical that a tortfeasor should be responsible for medical expenses necessary to monitor the person's health.

Take,for example, Sinclair v. Merck, 913 A.2d 832 (2007), where the plaintiffs contended they had an increased risk of myocardial infarction due to use of Vioxx, but admitted no present infections. While the trial court dismissed the lawsuit, the appellate court reversed.

The court acknowledged that evidence of current injury is required in some circumstances under New Jersey law, but suggested that this requirement did not necessarily apply where the plaintiff claimed direct exposure to the product and it was possible to assess the existence, dose and duration of the exposure.

The court refused to adopt a bright-line rule requiring the existence of a manifested disease for the maintenance of such claims. Rather, the court said it was necessary to determine what relief "is reasonable and necessary in the circumstances, bearing in mind that the remedy sought by plaintiffs cannot be 'easily invoked.'" That determination could not be made, the court said, on "bare pleadings." The court remanded the matter for discovery and an evidentiary hearing.

Notwithstanding the foregoing, courts have taken a variety of approaches to the requirement that a plaintiff must exhibit an actual injury to recover on a tort claim. In some cases the requirement has been strictly applied, and in other cases courts have shown a willingness to overlook the requirement, depending on the nature of the particular case.

It is unclear what Arizona would do in this circumstance. Consider Kenyon v. Hammer, 142 Ariz. 69, 688 P.2d 961 (1984). In Kenyon, the plaintiff brought a claim for bodily injury and wrongful death claim, based upon a doctor's nurse incorrectly recording a pregnant mother's Rh factor during pregnancy.

During the course of the pregnancy, a routine blood test revealed that Ms. Kenyon had Rh negative blood, but one of the doctor's nurses erroneously marked her chart to indicate that her blood type was Rh positive. A normal, healthy child with Rh positive blood was delivered on July 10, 1972. If the doctor had be aware that Ms. Kenyon had Rh negative blood, however, he would have administered RhoGAM, a drug which suppresses the immune response which Rh negative mothers may develop to the Rh positive blood cells of their child.

To be effective, the drug must be administered within seventy-two hours after delivery of an infant with Rh positive blood. Failure to administer the drug increases the risk of the immune response and the consequent risk to subsequent pregnancy by approximately ten times. The drug, however, was not administered and Ms. Kenyon developed the immune response and her ability to bear additional children was, therefore, substantially impaired.

Ms. Kenyon was unaware of this development.

Over five years after the birth of her first child, Ms. Kenyon again became pregnant. She was delivered of a second child on April 26, 1978. The second baby was stillborn as a result of the destruction of its blood cells by the mother's Rh antibodies.

Ms. Kenyon filed suit for bodily injury and wrongful death of the stillborn child. The doctor argued the claim was barred by the (then-applicable) three-year statute of limitations since the lawsuit was not filed within three years of the medical mistake -- i.e., the failure to administer RhoGAM at the time Ms. Kenyon's first child was born. The doctor also argued that there could not be a claim for injuries to a child that was not even conceived at the time of the medical mistake.

The Arizona Supreme Court disagreed. The Court held that Ms. Kenyon's claims were not barred and that the statute date began to run on the date on which second child suffered some injury and because the action was filed within two years from the date the second child was conceived. Thus, since the Arizona Supreme Court was willing to recognize a cause of action for damages from a medical mistake that led to a decreased ability to have children not yet even conceived, the Court might also be willing to recognize a claim based upon the increased risk of future disease or injury or for emotional distress as a result of the increased risk.

Then again, there's Transamerica Ins. Co. v. Doe, 173 Ariz. 112, 115, 840 P.2d 288, 291 (App. 1992), a Court of Appeals decision holding that being exposed to HIV-infected blood without showing any physical signs of being infected with the virus did not constitute a compensable bodily injury within the meaning of Transamerica uninsured motorist policy. So, who knows!