Question: An internist prescribed increasing doses of cholestyramine for a patient with hypercholesterolemia with resulting constipation. The constipation worsened after codeine was used to relieve abdominal pain. A month later, the patient experienced severe abdominal distress, and a barium enema revealed a perforated sigmoid colon. She underwent emergency surgery, and the colon was found to be distended, with impacted feces the size of tennis balls. She sued the internist, alleging that his negligence in prescribing the various medications led to the intestinal perforation. Which of the following statements best fits the situation?
A. The internist will lose the case because he should have chosen a statin over a bile acid sequestrant.
B. The internist was negligent when he prescribed codeine in combination with cholestyramine.
C. The patient was fully aware that constipation is a side effect of these medications, and so assumed the risk of injury.
D. The patient has not proved that the bowel perforation was caused by the internist's negligence.
E. The barium enema could have caused the perforation, and the proper party to sue is the radiologist.
Answer: D. Choices A and B may reflect the general medical view, but the use of these approved drugs is determined by the individual clinical situation and may not constitute substandard care. Choice C is incorrect, as the patient can hardly be said to have accepted the risk of a bowel perforation. This hypothetical case is adapted from Roskin v. Rosow (#301356, San Mateo Cty Super. Ct. [Cal. 1987]), which illustrates the importance of the causation factor in tort litigation. The defendant contended that the plaintiff reported only mild constipation, and that the bowel was perforated during the barium enema, not from the use of medications. There being no settlement, the case went to trial, and the jury found for the defendant because the plaintiff did not satisfy the causation element. The radiologist was apparently not sued, perhaps because the statute of limitations had lapsed.
In order to prevail in a medical negligence lawsuit, a plaintiff must prove causation even after establishing that the doctor owes a duty of care and that there has been a breach of the standard of care. There are two types of causation, factual cause and proximate cause, and both must be proved. Factual cause is established by the use of the “but-for” test, that is: “The defendant's conduct is a factual cause of plaintiff's injuries if plaintiff's harm would not have occurred but for defendant's conduct,” or “the defendant's conduct is a factual cause of plaintiff's injuries if plaintiff's harm would not have occurred without defendant's conduct” (Steven Finz, 1998, “Sum & Substance Audio on Torts”).
Proximate cause is not as easily ascertained. One Court of Appeals has stated: “A plaintiff proves proximate cause, also referred to as legal cause, by demonstrating a natural and continuous sequence of events stemming from the defendant's act or omission, unbroken by any efficient intervening cause, that produces an injury, in whole or in part, and without which the injury would not have occurred” (Barrett v. Harris, 86 P.3d 954 [Ariz. 2004]).
The key inquiry in proximate cause analysis is whether the injury was foreseeable. If the defendant could not reasonably have foreseen the resulting harm, the defendant escapes liability. Suppose Mr. A negligently broke the leg of a pedestrian as the result of careless driving. Unfortunately, the injury was worsened by a surgeon's intervening negligence. Because surgical malpractice is foreseeable, the surgeon's negligence is said to be a concurring cause, and Mr. A, the original tortfeasor, becomes liable to the pedestrian for both the original and the aggravated injury (the surgeon is of course also liable).
In a recent Florida case, the District Court of Appeals found several doctors liable for missing the diagnosis of tuberculous meningitis. The court held that since there were multiple doctors involved, i.e., concurring causes, the plaintiff was entitled to concurring-cause jury instruction. The purpose of such instruction was to negate the idea that a defendant is excused from the consequences of negligence by reason of some other cause concurring in time and contributing to the same injury (Hadley v. Terwilleger, 873 So.2d 378 [Fl. 2004]).
On the other hand, an event may occur in the interval between the defendant's negligent act and the plaintiff's injury that breaks the chain of causation. The law, for example, does not hold a defendant liable when an unforeseeable intervening factor has led to an unforeseeable injury. Superseding cause is “an act of a third person or other force which by its intervention prevents the actor from being liable for harm to another which his antecedent negligence is a substantial factor in bringing about” (Restatement [Second] of Torts §440).