With the popularization of systemic drugs that may affect eye health, it is particularly important to identify the eye side effects caused by drugs. In this medical case analysis, we delved into the diagnosis and treatment process of a 55 year old male patient with toxic optic neuropathy (TON) caused by long-term use of ciprofloxacin. This case provides us with an important warning about the potential impact of drug side effects on the visual system, while also emphasizing the necessity of carefully evaluating drug use history in clinical practice.

Medical history summary

The patient, male, 55 years old, complained of facial recognition difficulties and decreased reading ability for more than 2 months. Upon examination, it was found that there was a decrease in symmetrical visual acuity, visual field defects, and color vision abnormalities in both eyes. He was diagnosed with TON (usually selectively affecting the optic disc macular bundle). Medical history: Chronic osteomyelitis, with a history of long-term use of ciprofloxacin 1500mg/day (oral medication for 6 years) and opioid analgesics; Recurrent urinary tract infection with a history of intermittent use of cephalosporin drugs. Personal history: Has a history of drinking alcohol, but denies drinking in the past four months.

Ophthalmic examination

Vision examination: The best corrected visual acuity (BCVA) of both eyes (OU) decreased to 6/60 (20/200); The patient's OU visual acuity was 6/6 (20/20) one year ago;

IHP detection: Color vision (CV) of both eyes (OU) was 3/15;

Pupil light reflex examination: Bilateral pupils are equally round, with good light response and no relative afferent pupillary dysfunction (RAPD);

Fundus examination: indicates no signs of edema or pallor in the optic nerve;

HVF test: indicates the presence of a central dark spot in the central area of both visual fields.

Other auxiliary inspections

Brain CT, OCT, and gadolinium enhanced MRI examinations: No compressive lesions were found and no significant abnormalities were observed;

Laboratory examination: Inflammation, infection, vascular and genetic causes were excluded, and no significant abnormalities were found in the results; But the level of gamma glutamyltransferase increases, leading to large cell anemia, while the levels of vitamin B12, folate, and thiamine are normal.

Diagnosis and Management

Diagnosis: Enrofloxacin induced TON

Management: Replace oral medication with 500mg ceftriaxone (4 times/day) for the treatment of chronic osteomyelitis, and discontinue oral ciprofloxacin.

prognosis

During the 3-month follow-up examination after discontinuing oral ciprofloxacin, the patient's vision improved to 6/30 per eye (20/100). During the 36 month follow-up examination, visual acuity further improved, with the right eye (OD) reaching 6/6 (20/20) and the left eye (OS) reaching 6/12 (20/40). Visual field examination showed improvement in both eyes (OU), with only a shallow central dark spot visible in the left eye field of view. Although the patient's vision and field of view improved after discontinuing oral ciprofloxacin, color vision was still affected. According to the IHP test, the color vision (CV) of both eyes (OU) was 3/15, and the patient developed segmental optic disc paleness and optic nerve atrophy in both eyes.

enlightenment

As a clinical ophthalmologist, rapid assessment of a patient's visual acuity is crucial for diagnosis. When a patient experiences sudden visual loss without subsequent changes, it is likely due to ischemic injury such as arterial occlusion. Patients with ischemic optic neuropathy may complain of sudden visual loss and further decline in vision in the following days to weeks. If visual impairment gradually occurs within a few days to weeks, it may be caused by inflammation, infection, or demyelination; If the gradual decline in vision continues to progress over several months or even years, it may be due to compressive lesions, nutritional/toxic optic neuropathy, or glaucoma optic neuropathy (GON). The possibility of atypical macular degeneration should not be ignored in differential diagnosis. The typical features of TON are gradually appearing bilateral symmetrical painless visual impairment, color vision abnormalities, and visual field defects. After discontinuing ciprofloxacin, visual function may improve, but structural changes such as thinning of the retinal nerve fiber layer (RNFL), ganglion cell inner plexiform layer (GCIPL), and pale optic nerve are usually not reversed, which is a common characteristic of TON.