Hello, this is attorney Oh Seung-hyun of Cheongchul Law Firm.

A 20-year-old soldier on leave collapsed and was taken to an emergency room. The paramedics' record expressly noted "hemiplegia, dysarthria and altered consciousness". The attending physician nonetheless performed neither a neurological examination nor a brain MRI, prescribed only arthritis medication and discharged him the same day. When he returned the next day with worsening left-side paralysis, the window for thrombolysis had already closed and extensive infarction surgery was required. More strikingly, the hospital later added entries to the medical records stating that "a neurological examination was performed" and that "an MRI was recommended but refused by the guardian". The court treated this as falsification of medical records, held it against the defendant, and awarded KRW 290.11 million (Daejeon High Court, 2021Na10065, 29 September 2021).

In stroke and cerebral infarction, time is brain. A diagnosis missed within the golden hour leads to lifelong disability. This article sets out, through the case law, when medical negligence is found — and when it is not.

The golden hour in stroke and myocardial infarction — time is brain and heart

(1) Cerebral infarction (ischaemic stroke): 4 hours 30 minutes and 24 hours

In cerebral infarction, where a blocked vessel starves brain tissue, intravenous thrombolysis (rt-PA) can be given within 4 hours 30 minutes of symptom onset, and endovascular thrombectomy within 6 to 24 hours. After that, the treatment opportunity is gone. Yet within the first 24 hours a plain brain CT often shows no abnormality. The medical standard is that where symptoms suggestive of infarction such as hemiplegia or dysarthria are present, a brain MRI should be performed even if the CT is negative.

(2) Haemorrhagic stroke and subarachnoid haemorrhage: missing "this headache is different"

A headache that begins suddenly and with extreme severity — described as a "thunderclap headache" or the worst headache of one's life — is the classic presentation of subarachnoid haemorrhage. Where it is mistaken for a tension or migraine headache and the patient is given only analgesics or sent home without a CT, and an aneurysm subsequently re-ruptures or the haemorrhage worsens, that constitutes diagnostic negligence. Omitting a lumbar puncture where subarachnoid haemorrhage remains suspected despite a negative CT can also amount to negligence.

(3) Myocardial infarction: an immediate ECG for chest pain

In acute myocardial infarction, the coronary artery must be reopened within two hours of chest pain onset to minimise damage to the heart muscle. International guidelines (AHA) require an ECG within 10 minutes of a chest pain patient's arrival in the emergency department. Failing to perform the ECG, misreading it, or diagnosing gastric upset or muscle pain and discharging the patient without checking cardiac enzymes (troponin) amounts to negligent delay in diagnosis.

Cases where the courts found negligence

(1) Paramedic record of hemiplegia, no MRI, and falsified records — KRW 290.11 million

A 20-year-old soldier collapsed and was brought to the emergency room, with the ambulance activity log expressly recording "hemiplegia, dysarthria, altered consciousness and a decision to transport urgently". The attending physician performed neither a neurological examination nor a brain MRI, prescribed only arthritis medication and discharged him the same day. When he returned the next day with worsening left-side paralysis, infarction was confirmed and the golden hour had passed. The hospital subsequently added entries stating that "a neurological examination was performed" and that "an MRI was recommended but refused by the guardian"; the court treated this as falsification and as obstruction of proof weighing against the defendant. The Daejeon High Court found the defendant 70% liable and awarded KRW 290.11 million (2021Na10065, 29 September 2021, final). The claimant had lost at first instance, and the decision was reversed on appeal.

(2) Second dose of thrombolytic despite a contraindication — KRW 174.28 million to the patient

Where a thrombolytic (rt-PA) is administered to an infarction patient, imaging to check for intracranial haemorrhage before and after administration is essential, and a stroke within the previous three months is a contraindication. Here the medical team delayed the haemorrhage check after the first dose, pressed ahead with a second dose despite a stroke within the previous three months, and again delayed the follow-up check. Multiple intracranial haemorrhages and a brain lesion disability resulted. Suwon District Court found the team negligent and awarded KRW 174.28 million to the patient and KRW 8 million to the spouse (2021Gahap32107, 20 December 2023).

Cases where the courts rejected the claim

(1) Seizure is not a typical symptom of infarction — no duty of immediate MRI

Where a patient presented with seizures and only a CT (reported as normal) was performed without an immediate MRI, the court found no negligence (Busan High Court (Ulsan), 2023Na11398, 21 August 2024, final). Seizure is not a typical symptom of cerebral infarction, the CT was normal, and in light of the patient's age and comorbidities the court found no duty to proceed immediately to MRI. The typicality of the symptoms, the CT findings and the patient's risk factors are all material.

(2) MRI within 1 hour 22 minutes, thrombectomy within 2 hours — prompt and appropriate care

Hemiplegia and slurred speech appeared in the recovery room immediately after thyroid cancer surgery. A nurse first noticed the symptoms at 14:05, followed by a report to anaesthesia, a neurology consultation, brain CT and brain MRI, with the MRI completed at 16:08 and thrombectomy performed at 17:14. The patient argued that diagnosis and treatment had been delayed, but the court characterised an MRI within 1 hour 22 minutes and thrombectomy within roughly two hours as "prompt and appropriate care" and dismissed the claim (Seoul Central District Court, 2018Gahap574818, 20 July 2021, final). It also held that observing the patient first was within the range of reasonable judgment, given that transient symptoms can follow anaesthesia after surgery.

Falsifying or concealing records backfires

The most striking feature of the Daejeon High Court decision is that the hospital's later alteration of the records made its position considerably worse. The Civil Procedure Act provides that where a party under a duty to produce a document renders it unusable or denies the facts it records, the court may accept the opposing party's assertions as true (obstruction of proof). In other words, if a hospital changes records to hide unfavourable facts, the court may simply accept the patient's account. That is precisely why medical records should be requested immediately after an incident.

Practical checkpoints

• If the "worst headache of your life" begins suddenly, insist on a brain CT or MRI. Before going home with only a diagnosis of "tension headache", confirm that brain imaging was actually performed. Even with a negative CT, you can request a lumbar puncture where subarachnoid haemorrhage is suspected.

• If stroke symptoms such as hemiplegia, slurred speech or sudden visual loss appear in the emergency department, tell the medical team directly that a plain CT within 24 hours of infarction may appear normal, and request a brain MRI. If the paramedics recorded hemiplegia, make sure the team sees that record.

• The ambulance activity log is independent evidence. Where the hospital record and the paramedic record diverge, the paramedic record — created earlier — carries far greater weight. Apply to the ambulance service for a copy immediately after the incident.

• Request a copy of the medical records as soon as you arrive at the emergency department. Even if the hospital later adds to or amends them, an early copy allows falsification to be proved. Korean courts treat falsification as obstruction of proof and decide in the patient's favour.

• If you have had a stroke within the previous three months, tell the medical team before any thrombolytic is given. Administering a thrombolytic despite that contraindication, resulting in intracranial haemorrhage, is negligent medication. Check too whether CT imaging for haemorrhage was carried out before and after administration.

• Do not abandon a claim simply because the golden hour (4.5 hours for infarction, 2 hours for myocardial infarction) has passed. Korean courts presume causation where the claimant establishes the probability that "timely diagnosis would have allowed thrombolysis or thrombectomy and prevented the present disability" (Supreme Court, 17 March 2022). Confirm that probability with a specialist expert opinion before suing.

"I went to the emergency room, they did a CT, said it was normal and sent me home." The next day the patient was carried back in with hemiplegia, and the golden hour had already passed. Delayed diagnosis of stroke and cerebral infarction is the most typical — and the hardest to prove — form of medical negligence. Yet with the paramedic records, the time of symptom onset and the time of imaging interpretation carefully secured, it can be proved. And if the hospital altered the records after the fact, that itself becomes evidence in the patient's favour.

Cheongchul Law Firm handles delayed diagnosis cases involving stroke, cerebral infarction and myocardial infarction end to end: securing the ambulance activity log, analysing medical records and imaging files, reviewing compliance with the golden hour, obtaining independent specialist expert opinions, building the causation strategy and conducting the damages litigation.