A patient presents after head trauma with an initial loss of consciousness, a lucid interval, then deterioration, headache, vomiting, and unilateral pupil dilation. What is the most likely diagnosis?

A patient presents after head trauma with an initial loss of consciousness, a lucid interval, then deterioration, headache, vomiting, and unilateral pupil dilation. What is the most likely diagnosis?

• A. Epidural hematoma
• B. Subarachnoid hemorrhage
• C. Migraine
• D. Meningitis

Answer: (A)

This presentation is most consistent with an epidural hematoma. The sequence of events—head trauma followed by a lucid interval, then rapid deterioration with headache, vomiting, and a new unilateral dilated pupil—points to an arterial bleed into the space between the skull and the dura. The lucid interval happens because an arterial hematoma can accumulate quickly: the patient initially loses consciousness from the impact, then seems to recover, and as blood continues to collect, intracranial pressure rises and neurological status worsens. The dilated pupil on the same side suggests compression of the oculomotor nerve from increasing pressure, a sign of impending herniation. Understanding why this fits better than the other options helps solidify the concept. Subarachnoid hemorrhage typically presents with a sudden, severe thunderclap headache and meningeal signs, not a traumatic lucid interval followed by focal progression. Migraine and meningitis have distinct, non-traumatic or infectious patterns (severe unilateral or throbbing headaches with aura for migraines; fever, neck stiffness, and systemic symptoms for meningitis) and do not usually arise from an acute head trauma with a lucid interval. In real practice, this scenario is a neurosurgical emergency, and imaging (usually a CT scan) would show a lens-shaped (biconvex) hyperdense collection between skull and dura, with urgent management to evacuate the hematoma if indicated.

This presentation is most consistent with an epidural hematoma. The sequence of events—head trauma followed by a lucid interval, then rapid deterioration with headache, vomiting, and a new unilateral dilated pupil—points to an arterial bleed into the space between the skull and the dura. The lucid interval happens because an arterial hematoma can accumulate quickly: the patient initially loses consciousness from the impact, then seems to recover, and as blood continues to collect, intracranial pressure rises and neurological status worsens. The dilated pupil on the same side suggests compression of the oculomotor nerve from increasing pressure, a sign of impending herniation.

Understanding why this fits better than the other options helps solidify the concept. Subarachnoid hemorrhage typically presents with a sudden, severe thunderclap headache and meningeal signs, not a traumatic lucid interval followed by focal progression. Migraine and meningitis have distinct, non-traumatic or infectious patterns (severe unilateral or throbbing headaches with aura for migraines; fever, neck stiffness, and systemic symptoms for meningitis) and do not usually arise from an acute head trauma with a lucid interval.

In real practice, this scenario is a neurosurgical emergency, and imaging (usually a CT scan) would show a lens-shaped (biconvex) hyperdense collection between skull and dura, with urgent management to evacuate the hematoma if indicated.