## Facts

- Diane Dillon received breast-cancer treatment requiring surgical insertion of a chemotherapy catheter into a vein in her upper chest.
- After treatment ended, Dr. Stephen Sener attempted to remove the catheter but removed only part of it; a fragment remained in Dillon’s body.
- A later chest X-ray at Evanston Hospital did not result in disclosure to Dillon of the retained fragment.
- A subsequent routine chest X-ray at another hospital revealed that the fragment had migrated into Dillon’s heart, with the tip embedded in the heart wall and the remainder floating free.
- Physicians advised that surgical removal posed significant risks, so the fragment was left in place.
- Expert testimony described potential future complications (e.g., infection, perforation, arrhythmia, embolization, further migration), but none had occurred by trial and the estimated probabilities were generally low (below 50%).
- Dillon sued Evanston Hospital and Dr. Sener for negligence in catheter insertion/removal and for failure to discover and disclose the retained fragment.
- A jury found for Dillon and awarded damages including past pain and suffering, future pain and suffering, and \$500,000 for “increased risk of future injuries.”

## Issues

1. Whether Illinois law permits recovery of damages for an increased risk of future injury caused by medical negligence when the probability of the future injury is less than 50%.
2. Whether the jury was properly instructed on how to determine and quantify damages for “increased risk of future injuries” without speculation.

## Decision

- The Illinois Supreme Court held that increased-risk-of-future-injury damages are recoverable in Illinois if proven with competent evidence and framed to avoid speculation.
- The court rejected an “all-or-nothing” rule limiting recovery to future harms that are more likely than not to occur.
- The court required that damages for increased risk be valued by determining the loss associated with the feared injury and discounting that amount by the proven probability of its occurrence.
- The court ruled the jury instructions on increased-risk damages were inadequate because they did not direct a probability-based valuation method and risked an undisciplined, speculative award.
- The court affirmed liability and the other damages awards but reversed the increased-risk damages award and remanded for a new trial limited to the amount of increased-risk damages.

## Legal Principles

- Under Illinois’s single-recovery rule, a plaintiff must recover in one action all damages proximately caused by the tort, including future consequences, which supports present compensation for increased future risk when later suit would be barred.
- A plaintiff may recover for an increased risk of future injury even if the likelihood of the injury is less than 50%, so long as the damages are not speculative.
- The proper measure of increased-risk damages is probability-weighted: the fact-finder values the potential future injury and reduces the award according to the evidence-based probability that the injury will occur.
- Jury instructions must clearly guide the fact-finder to tie any increased-risk award to credible expert probability evidence and to avoid guesswork, duplication, or conjecture.

## Conclusion

Illinois permits recovery for increased risk of future injury in medical negligence cases, but the award must reflect a probability-discounted valuation supported by expert evidence; because the jury was not properly instructed on that method, a new trial was required solely to determine the amount of increased-risk damages.


Dillon v. Evanston Hosp., 199 Ill. 2d 483, 771 N.E.2d 357 (Ill. 2002)