Makindo Medical Notes

Related Subjects: |Cortical Functions |Motor System |Sensory System |Mental State Examination |Speech and Language Exam |Cranial Nerves Examination |Assessing Cognition

Important: Facial nerve (VII) weakness, such as in Bell's palsy, does not cause ptosis. Instead, the inability to close the eye is observed in such conditions. This is a common point of confusion for medical students and doctors.

About Ptosis

• The eyelids are kept open by the levator palpebrae superioris (oculomotor nerve, III) and superior tarsal muscle (sympathetic fibres).
• The facial nerve (VII) closes the eyes, so damage causes incomplete closure, not ptosis.
• Frontalis weakness can cause eyebrow ptosis, which mimics eyelid drooping but is distinct.

Causes of Ptosis

Clinical Findings in Horner’s Syndrome

• Mild ptosis from sympathetic loss to superior tarsal muscle.
• Miosis from impaired dilator pupillae activity.
• ± Anhidrosis, enophthalmos.
• Always search for underlying cause (lung apex tumour, carotid dissection).

Cases — Ptosis

• Case 1 — Myasthenia Gravis (Fluctuating) ⚡: A 32-year-old woman presents with drooping eyelids that worsen by evening. She also reports intermittent diplopia and difficulty chewing. Exam: fatigable ptosis that improves with rest. Diagnosis: Myasthenia gravis. Management: Acetylcholinesterase inhibitor (pyridostigmine), immunosuppression, thymectomy if indicated.
• Case 2 — Horner’s Syndrome (Sympathetic Lesion) 🦢: A 55-year-old man with a heavy smoking history presents with right-sided mild ptosis, miosis, and anhidrosis. Chest X-ray reveals a right apical lung mass. Diagnosis: Horner’s syndrome due to Pancoast tumour. Management: Urgent oncology referral; treat underlying malignancy.
• Case 3 — Oculomotor Nerve Palsy (III) 🔴: A 60-year-old man with hypertension and diabetes presents with acute onset left ptosis, “down and out” eye position, and diplopia. Pupils are spared. Diagnosis: Microvascular CN III palsy. Management: Optimise vascular risk factors; exclude aneurysm if pupil involvement.
• Case 4 — Congenital Ptosis 👶: A 3-year-old boy is noted to have a drooping right upper eyelid since birth. Vision testing shows risk of amblyopia. Diagnosis: Congenital ptosis (levator maldevelopment). Management: Ophthalmology referral; surgical correction if vision threatened.
• Case 5 — Chronic Progressive External Ophthalmoplegia (CPEO, Mitochondrial) 🧬: A 28-year-old woman presents with slowly progressive bilateral ptosis and ophthalmoplegia. Family history: maternal relatives with similar problems. Diagnosis: CPEO (mitochondrial myopathy). Management: Supportive; genetic counselling; monitor for systemic features (cardiac conduction defects, myopathy).

Teaching Commentary 👁️

Ptosis is drooping of the upper eyelid, caused by: - Neuromuscular junction disease: Myasthenia gravis (fatigable, variable). - Neurological: CN III palsy (marked ptosis, eye deviated down and out), Horner’s syndrome (mild ptosis + miosis + anhidrosis). - Myopathic: CPEO, oculopharyngeal muscular dystrophy. - Mechanical: congenital ptosis, trauma, eyelid tumours. Examining for associated signs (pupil changes, eye movement, fluctuation, family history) helps localise the lesion. Management depends on the cause, ranging from urgent (CN III aneurysm) to supportive/genetic.