Kay's Tutor v Ayrshire and Arran Health Board

Factual and Procedural Background

A young child (“Plaintiff”) was admitted to The Hospital in November 1975 suffering from pneumococcal meningitis. During treatment a senior house officer mistakenly administered an intrathecal overdose of penicillin (approximately 300,000 units instead of 10,000 units). The overdose caused immediate seizures, respiratory distress, temporary hemiparesis and a brief coma, all of which resolved within days. Some weeks later the child was found to be profoundly and permanently deaf in both ears.

The child’s father (“Plaintiff”) raised an action for damages against the regional health authority (“Defendant”), which admitted negligence for the overdose but disputed any causal link between the overdose and the deafness. After an extended proof, the trial judge (“Lord Ordinary”) accepted the Plaintiff’s case, holding that the overdose had materially contributed to the deafness and awarding £102,000.

The Defendant reclaimed to the Inner House, First Division, which on 18 December 1985 allowed the reclaiming motion, overturned the finding on causation, and substituted an award of £3,000 plus interest (£7,275 in total) for the transient injuries alone.

The Plaintiff appealed further to the appellate court (“the House of Lords”). The present opinion, delivered on 14 May 1987, addresses that final appeal.

Legal Issues Presented

1. Whether, on the evidence led, the intrathecal overdose of penicillin caused or materially contributed to the Plaintiff’s permanent bilateral deafness.
2. Whether a trial judge may found liability on a scientific theory not advanced by either party, not explored with expert witnesses, and unsupported by the evidence.
3. If causation were established, the appropriate measure of damages.

Arguments of the Parties

Plaintiff's Arguments

• The overdose weakened the child’s physiological defences, thereby increasing the risk that pneumococcal toxins would damage the auditory nerve.
• Even if the precise mechanism was unclear, the overdose at least materially increased the risk of deafness; relying on McGhee v N.C.B., that increased risk should satisfy legal causation.
• The trial judge correctly assessed damages on the basis that the deafness and other residual problems were attributable to the overdose.

Defendant's Arguments

• Medical literature and expert testimony unanimously show no recorded instance of penicillin, in overdose or otherwise, causing sensorineural deafness.
• The theory adopted by the Lord Ordinary (that neuron firing diverted oxygenated blood from defensive mechanisms) was never put to any expert and had no evidential support; judgment based on that theory is unsustainable.
• The only proven consequences of the overdose were transient seizures and temporary neurological symptoms, warranting modest damages only.

Table of Precedents Cited

Court's Reasoning and Analysis

The appellate court agreed with the Inner House that the Lord Ordinary’s causal finding was unsound. Key steps in its analysis included:

• Lack of evidential support: All qualified experts, save one, testified that penicillin has never been shown to cause deafness. The lone contrary opinion (from “Expert Witness A”) was rejected by the trial judge on other grounds and could not sustain liability.
• Judicial overreach: The Lord Ordinary devised his own physiological theory after the proof, never ventilated with witnesses. Deciding on that basis denied the Defendant a fair opportunity to rebut and contravened basic procedural fairness.
• Failure to establish pre-overdose hearing status: Evidence did not prove whether the child was deaf before the overdose. At best the fact was neutral, leaving the burden of proving causation unmet.
• Statistical and clinical evidence of meningitis: Deafness is a common sequela of pneumococcal meningitis (about one-third of cases). Rapid recovery post-overdose and absence of recognised ototoxicity from penicillin pointed strongly to meningitis as the sole cause.
• Inapplicability of McGhee: Because no evidence demonstrated that a penicillin overdose increases the risk of deafness, the Plaintiff could not invoke the risk-based causation doctrine.

Holding and Implications

HOLDING: Appeal dismissed; the Inner House’s interlocutor is affirmed.

Consequently, the Plaintiff recovers only £3,000 in general damages plus agreed interest (£7,275 total) for the short-lived seizures, respiratory distress and temporary hemiparesis immediately following the overdose. No compensation is payable for the deafness or other alleged residual conditions.

Implications: The decision reinforces two principles: (1) a court must base findings of scientific causation on evidence tested in adversarial proceedings, not on an unexamined theory of its own; and (2) the McGhee risk-increase doctrine applies only where reliable evidence shows that the defendant’s breach actually elevates the relevant risk. The ruling sets no new precedent but underscores rigorous evidential standards in medical-causation litigation.