Chorioretinitis: A Comprehensive Overview

Introduction

Chorioretinitis is an inflammatory disease affecting the choroid and retina, two critical layers of the eye responsible for vision. This condition manifests as a result of various infectious and non-infectious processes, leading to significant morbidity and visual impairment if not promptly diagnosed and managed. The epidemiological burden of chorioretinitis varies across populations, correlating with underlying systemic diseases, geographical factors, and healthcare access.

Definition

Chorioretinitis is defined as an inflammatory process involving both the choroid, the vascular layer supplying the outer retina, and the retina itself. It may present as a focal or diffuse condition, often leading to exudation, cellular infiltration, and tissue destruction. The term is frequently used interchangeably with retinochoroiditis, though subtle anatomical distinctions exist based on the predominant site of inflammation.

Epidemiology

The prevalence of chorioretinitis is difficult to ascertain owing to its multifactorial aetiology. It is more commonly observed in immunocompromised individuals, neonates, and patients with certain systemic infections. The disease affects all age groups but has higher incidence rates in regions endemic for specific infectious agents, such as Toxoplasma gondii. Epidemiological studies suggest a global distribution, with sporadic outbreaks linked to environmental and sociodemographic factors.

Significance

Chorioretinitis is a major cause of acquired visual impairment and blindness worldwide. Its impact extends beyond ocular morbidity, as it may reflect or complicate underlying systemic illnesses. Early recognition and intervention are critical to mitigate vision loss and systemic complications.

Etiology and Risk Factors

Infectious Causes

The majority of chorioretinitis cases are attributable to infectious agents, with protozoal, viral, bacterial, and fungal pathogens implicated. The most common infectious causes include:

• Toxoplasma gondii: The leading cause globally, particularly in congenital and immunocompromised cases.
• Cytomegalovirus (CMV): Frequently seen in AIDS patients and transplant recipients.
• Herpes simplex virus (HSV) and Varicella-zoster virus (VZV): Cause severe necrotising retinitis.
• Syphilis (Treponema pallidum): Ocular involvement is a recognised manifestation of secondary and tertiary syphilis.
• Tuberculosis (Mycobacterium tuberculosis): Can present as multifocal chorioretinitis, especially in endemic areas.
• Fungal agents: Candida, Aspergillus, and others, particularly in immunosuppressed hosts.

Non-Infectious Causes

Non-infectious chorioretinitis may result from autoimmune processes, systemic inflammatory diseases, and idiopathic mechanisms. Notable non-infectious causes include:

• Autoimmune uveitis syndromes: Behçet’s disease, sarcoidosis, Vogt-Koyanagi-Harada (VKH) syndrome.
• Idiopathic: No identifiable underlying cause, often presenting as isolated ocular inflammation.
• Drug-induced: Certain medications, such as bisphosphonates and immunomodulatory agents.

Predisposing Conditions

Several factors contribute to increased susceptibility:

• Immunosuppression (HIV/AIDS, organ transplantation)
• Congenital immunodeficiencies
• Neonatal exposure to infectious agents
• Systemic diseases (diabetes mellitus, malignancies)
• Environmental exposures (contaminated water, undercooked meat)

Pathophysiology

The pathogenesis of chorioretinitis involves a complex interplay of infectious invasion, immune response, and tissue destruction. Upon entry of the causative agent, the choroid and retina are infiltrated by inflammatory cells, leading to the release of cytokines, chemokines, and other mediators. This results in breakdown of the blood-retinal barrier, exudation, and necrosis of retinal tissue. Chronic inflammation may cause scarring, pigmentary changes, and vascular occlusion, culminating in permanent visual deficits.

In infectious chorioretinitis, the pathophysiology is shaped by the organism’s virulence, route of entry, and host immune status. Non-infectious forms are primarily mediated by autoimmune mechanisms, where molecular mimicry and aberrant immune activation target ocular antigens.

Clinical Presentation

Signs and Symptoms

Chorioretinitis presents with a spectrum of ocular and systemic symptoms, varying with the underlying aetiology and severity. The most common clinical features include:

• Blurred vision or visual field defects
• Floaters
• Photophobia (light sensitivity)
• Pain (variable, more prominent in infectious cases)
• Redness of the eye
• Decreased visual acuity
• Scotomas (blind spots)
• Metamorphopsia (distorted vision)

On examination, key findings may include:

• White or yellowish retinal lesions
• Retinal haemorrhages
• Vitreous haze (indicative of active inflammation)
• Choroidal thickening
• Optic nerve involvement (papillitis, oedema)

Patient History

A thorough history is essential, focusing on:

• Recent infections or systemic illnesses
• Immunosuppressive therapy
• Exposure to risk factors (travel, animal contact, dietary habits)
• Family history of autoimmune diseases
• Previous ocular surgeries or trauma

Diagnostic Approaches

Clinical Examination

Ophthalmic evaluation remains the cornerstone of diagnosis. Key components include:

• Visual acuity testing
• Slit lamp biomicroscopy (anterior segment and vitreous assessment)
• Indirect ophthalmoscopy (retinal and choroidal lesion identification)

Imaging Modalities

Several imaging techniques aid in diagnosis and monitoring:

• Fundus photography: Documents lesion morphology and progression.
• Optical coherence tomography (OCT): Provides cross-sectional images of retinal and choroidal architecture, revealing oedema, disruption, and scarring.
• Fluorescein angiography (FA): Assesses retinal vascular leakage, non-perfusion, and choroidal involvement.
• Indocyanine green angiography (ICGA): Especially useful for choroidal lesions and vascular mapping.
• B-scan ultrasonography: Useful in cases with media opacities.

Laboratory Tests

Laboratory investigations are tailored to suspected aetiology:

• Serology: Detection of antibodies to Toxoplasma, CMV, HSV, VZV, syphilis, and others.
• Polymerase chain reaction (PCR): Identification of microbial DNA in ocular fluids.
• Complete blood count (CBC): Evaluates systemic inflammatory response.
• Autoimmune panels: ANA, ACE, HLA typing for suspected non-infectious causes.
• Chest X-ray/CT scan: Assesses for underlying systemic diseases (e.g., sarcoidosis, tuberculosis).

Differential Diagnosis

Chorioretinitis must be differentiated from other posterior segment pathologies, including:

• Retinitis (isolated retinal inflammation)
• Choroiditis (isolated choroidal inflammation)
• Central serous chorioretinopathy
• Age-related macular degeneration
• Ocular lymphoma
• Vitreoretinal infections (endophthalmitis)

Treatment Strategies

Medical Management

The therapeutic approach is dictated by the underlying cause:

Infectious Chorioretinitis

• Antimicrobial therapy: Targeted agents based on organism (e.g., pyrimethamine and sulfadiazine for toxoplasmosis; ganciclovir or foscarnet for CMV; penicillin for syphilis; anti-tubercular drugs for tuberculosis).
• Adjunctive corticosteroids: To control inflammation, administered only after initiation of appropriate antimicrobials.
• Antifungal drugs: Amphotericin B, voriconazole for fungal aetiologies.

Non-Infectious Chorioretinitis

• Systemic corticosteroids: Mainstay for autoimmune and idiopathic cases.
• Immunosuppressive agents: Methotrexate, azathioprine, mycophenolate mofetil, cyclosporine as steroid-sparing agents.
• Biologics: Anti-TNF agents, monoclonal antibodies for refractory cases.

Surgical Interventions

Surgery is rarely required but may be indicated in cases of complications, such as:

• Retinal detachment repair
• Vitrectomy for non-resolving vitreous opacities or diagnostic sampling
• Laser photocoagulation for neovascular complications

Supportive Care

• Topical steroids and cycloplegics for anterior segment inflammation
• Management of intraocular pressure if elevated
• Low-vision aids and rehabilitation
• Psychological support for patients with vision loss

Prognosis and Complications

Outcomes

The prognosis of chorioretinitis depends on the underlying cause, timeliness of intervention, and extent of ocular involvement. Infectious cases treated early generally have good outcomes, while delayed or inadequate therapy may result in permanent visual impairment. Non-infectious forms may be chronic and relapsing, requiring long-term immunosuppression and monitoring.

Potential Complications

• Permanent vision loss
• Retinal scarring and pigmentary changes
• Secondary glaucoma
• Retinal detachment
• Macular oedema
• Cataract formation (due to chronic inflammation or steroid use)
• Optic atrophy
• Recurrence of inflammation

Factors Influencing Prognosis

• Patient age and immune status
• Virulence and type of causative agent
• Extent of ocular involvement at presentation
• Promptness and appropriateness of treatment
• Presence of systemic comorbidities
• Compliance with follow-up and therapy

Prevention and Patient Education

Preventive Measures

• Screening and treatment of maternal infections during pregnancy to prevent congenital chorioretinitis
• Safe food practices (avoiding undercooked meat, washing fruits and vegetables) to reduce risk of toxoplasmosis
• Use of personal protective equipment for immunocompromised individuals
• Vaccination where applicable (e.g., VZV)
• Early detection and treatment of systemic infections

Patient Counseling

• Importance of regular ophthalmic follow-up
• Adherence to prescribed therapy
• Recognising early symptoms of recurrence
• Managing associated systemic conditions
• Support for vision rehabilitation and psychological well-being

Nursing Care of a Patient with Chorioretinitis

Goals of Nursing Care

• Prevent progression of vision loss
• Alleviate symptoms and discomfort
• Support medical treatment and promote adherence
• Monitor for complications
• Provide education and emotional support to the patient and family

Nursing Assessment

A thorough assessment is crucial for developing an individualized care plan. The nurse should:

• Obtain a detailed history of the present illness (onset, duration, and progression of symptoms)
• Assess for risk factors (recent infections, immunosuppression, autoimmune diseases, trauma, or systemic symptoms)
• Monitor visual acuity using standardized charts
• Observe for signs and symptoms such as blurred vision, eye pain, redness, photophobia, and floaters
• Assess the patient’s coping mechanisms and emotional status, given the risk of vision loss
• Review current medications and allergies

Nursing Diagnoses

Common nursing diagnoses for patients with chorioretinitis may include:

• Disturbed sensory perception (visual) related to retinal inflammation
• Acute pain related to ocular inflammation
• Risk for injury related to decreased vision
• Knowledge deficit regarding disease process and treatment regimen
• Anxiety related to potential vision loss and uncertainty of prognosis

Planning and Expected Outcomes

The expected outcomes are:

• Patient will report decreased eye discomfort and photophobia
• Patient will demonstrate understanding of prescribed medications and follow-up care
• Patient will maintain optimal safety in the environment due to impaired vision
• Patient will exhibit coping strategies for anxiety and emotional distress
• Patient will recognize symptoms requiring immediate medical attention

Nursing Interventions

1. Symptom Management

• Administer prescribed medications—these may include corticosteroids (oral, topical, or periocular), antibiotics, antivirals, or antifungals depending on the etiology.
• Monitor for side effects of medications, especially corticosteroids (e.g., increased intraocular pressure, systemic effects).
• Provide a quiet, dimly lit room to reduce photophobia and discomfort.
• Encourage the use of sunglasses indoors and outdoors to alleviate light sensitivity.
• Apply warm compresses to the eyes if recommended, to relieve discomfort.

2. Vision Support and Safety

• Assess and document changes in visual acuity regularly.
• Ensure the patient’s immediate environment is safe and free from hazards (remove rugs, ensure adequate lighting at night, use non-slip mats).
• Instruct the patient to move slowly and use handrails if available.
• Provide assistive devices as indicated (magnifiers, talking clocks, etc.).
• Encourage call bell use for assistance and explain location of necessary items.

3. Infection Control and Prevention

• Practice proper hand hygiene before and after eye care procedures.
• Educate the patient on avoiding touching or rubbing the eyes.
• If the chorioretinitis is infectious (e.g., due to toxoplasmosis or CMV), instruct on proper disposal of tissues and other contaminated items.
• Monitor for signs of secondary infection or complications, such as endophthalmitis.

4. Patient and Family Education

• Explain the nature of the disease, its possible causes, and the need for prompt treatment to prevent vision loss.
• Demonstrate correct technique for eye drop or ointment administration.
• Provide written instructions about the medication schedule and possible side effects.
• Emphasize the importance of adherence to medication and follow-up appointments with ophthalmology.
• Inform about warning signs that require immediate medical attention: sudden vision loss, severe pain, increased redness or discharge, or visual field changes.
• Discuss the potential long-term prognosis and rehabilitation options if vision loss occurs.

5. Emotional and Psychological Support

• Assess the patient’s emotional response to vision changes and offer reassurance.
• Offer opportunities for the patient to express feelings and fears about vision loss.
• Refer to counseling or support groups if the patient expresses significant anxiety or depression.
• Involve family members in care planning and education to promote a supportive environment at home.

6. Coordination of Care

• Collaborate with ophthalmologists and infectious disease specialists to ensure comprehensive care.
• Arrange for low vision services or occupational therapy if visual impairment persists.
• Coordinate with social workers or community resources to address financial, transportation, or home safety needs.
• Arrange for home health nursing if ongoing support is required post-discharge.

Monitoring and Evaluation

Continual monitoring is essential for timely identification of complications and effectiveness of interventions. Nurses should:

• Document changes in vision and ocular symptoms at each shift.
• Monitor for adverse effects of medications and report to the healthcare provider promptly.
• Assess the patient’s understanding of their condition and treatment, providing clarification as needed.
• Evaluate the patient’s emotional status and coping mechanisms on an ongoing basis.
• Review and reinforce safety measures regularly.

Potential Complications to Watch For

• Progression to retinal detachment
• Development of glaucoma due to steroid treatment
• Optic nerve damage and permanent vision loss
• Secondary infections or systemic spread (especially in immunocompromised patients)

Discharge Planning

Effective discharge planning is vital for continuity of care. Nurses should:

• Ensure the patient and family are comfortable with medication administration and understand the importance of adherence.
• Provide information on follow-up visit schedules and laboratory monitoring (if on systemic therapy).
• Arrange for home modifications if needed due to visual impairment.
• Give contact information for emergency consultation in case of sudden changes in vision or increased eye pain.

REFERENCES

1. American Academy of Ophthalmology. Relentless Placoid Chorioretinitis. https://eyewiki.aao.org/Relentless_Placoid_Chorioretinitis. Last updated 5/9/2023.
2. Geetha R, Tripathy K. Chorioretinitis. https://www.ncbi.nlm.nih.gov/books/NBK551705/. [Updated 2023 Feb 22]. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2023 Jan-.
3. Neri P, Pichi F. Acute syphilitic posterior placoid chorioretinitis: when the great mimicker cannot pretend any more; new insight of an old acquaintance. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8864036/. J Ophthalmic Inflamm Infect. 2022;12(1):9.
4. Crawford CM, Igboeli O. A review of the inflammatory chorioretinopathies: the white dot syndromes. ISRN Inflamm. 2013 Oct 31;2013:783190. doi: 10.1155/2013/783190. PMID: 24294536; PMCID: PMC3833360.
5. Venema WJ, Hiddingh S, Janssen GMC, et al. Retina-arrestin specific CD8+ T cells are not implicated in HLA-A29-positive birdshot chorioretinitis. https://pubmed.ncbi.nlm.nih.gov/36581221/. Clin Immunol. 2023;247:109219.

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