Silver

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:

direct observations: clinical cases, poisoning incidents and other

Type of information:

other: human data

Adequacy of study:

supporting study

Reliability:

other: not rated acc. to Klimisch

Rationale for reliability incl. deficiencies:

other: Well-documented case report

Data source

Reference

Reference Type:

publication

Title:

Ocular argyrosis secondary to long-term ingestion of silver nitrate salts

Author:

Stafeeva, K. et al.

Year:

2012

Bibliographic source:

Clinical Ophthalmology 6, 2033-2036

Materials and methods

Study type:

clinical case study

Endpoint addressed:

repeated dose toxicity: oral

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The case report describes the clinical, autofluorescence, and optical coherent tomography findings in a 86-year old Caucasian male with panocular argyrosis secondary to chronic intake of diluted silver nitrate salts in his water supply.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Silver nitrate

EC Number:

231-853-9

EC Name:

Silver nitrate

Cas Number:

7761-88-8

Molecular formula:

AgNO3

IUPAC Name:

Silver nitrate

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): silver nitrate

Method

Type of population:

general

Subjects:

- Number of subjects exposed: one subject
- Sex: male
- Age: 86 year old
- Race: Caucasian

Subject with a previous medical history remarkable for normal pressure hydrocephalus after ventricular shunt placement, early dementia, and skin argyria (2 years) was seen at the ophthalmology clinic, complaining of slowly decreasing visual acuity and nyctalopia in both eyes.

Ethical approval:

not specified

Route of exposure:

oral

Reason of exposure:

intentional

Exposure assessment:

not specified

Details on exposure:

The patient had been drinking water from a well and purifying it with silver nitrate compounds for a period of at least 13 years. The patient was subsequently advised to suspend the silver nitrate intake 2 years prior to presentation to the authors.

Examinations:

The patient was investigated using fundus autofluorescence and optical coherent tomography findings. In addition, clinical findings were described.

Medical treatment:

no data

Results and discussion

Clinical signs:

During the initial consultation, the patient’s appearance was remarkable for a generalized gray-bluish hue of the skin and fingernails, more pronounced on the face, periorbital area, and forearms. Best corrected visual acuity was right eye (OD) 20/40 and left eye (OS) 20/50. Intraocular pressure OU was 14 mmHg. There was no afferent pupillary defect and confrontational vision fields were full in both eyes. Color vision was 8/8 on the Ishihara color plate test. Both palpebral and bulbar conjunctiva had a purple-blue hue, but were normally vascularized and showed no epithelial defect. The palpebral portion of the main lacrimal gland also had a purple-bluish hue. The lacrimal punctum was permeable. Both corneas were clear and mild bilateral nuclear sclerotic cataracts were present.

Results of examinations:

Fundus examination was remarkable for retinal pigment epithelium (RPE) changes and drusen formation on macula OU, consistent with age-related macular degeneration.
Fluorescein angiography showed choroidal blockage with completely dark choroid in later phases in both eyes. Areas of dot hyperfluorescence in the macula were present, in both eyes, most likely representing drusen from age-related macular degeneration. An electroretinogram was obtained because of the patient’s symptoms of nyctalopia, and revealed normal scotopic and photopic amplitudes and latency, as well as normal oscillatory potentials and 30 Hz flicker testing

Effectivity of medical treatment:

no data

Outcome of incidence:

no data

Applicant's summary and conclusion

Conclusions:

Fluorescein angiography showed choroidal blockage with a completely dark choroid. Fundus autofluorescence was within normal limits. Optical coherent tomography showed multiple excrescences of retinal pigment epithelium in both eyes. According to the authors, although the drusen-like changes on fundus examination and retinal pigment epithelium changes may account for the diminished vision, the presence of concomitant nyctalopia suggests underlying damage of the photoreceptors.