What is Endogenous Endophthalmitis?
Endophthalmitis is a serious eye emergency. In simple terms, it’s an infection that affects the layers of the eyeball, causing inflammation inside the eye’s jelly-like center known as the vitreous. This condition can lead to important eye and overall health complications.
The infection can enter the eye from outside (exogenous) or from within the body (endogenous). External sources of infection can be a physical injury to the eye, after-surgery complications, or due to keratitis, a disease that causes inflammation of the eye’s outer layer. On the other hand, endogenous endophthalmitis, also known as metastatic endophthalmitis, can result from the spread of bacteria through the bloodstream because of other problems in the body, like diabetes, weak immune system, kidney disease, and so on.
Doctors may use different tests, such as an ultrasound of the eye or acquire fluid samples for culture and sensitivity testing, to diagnose this condition quickly. They might also take a sample of the vitreous in some cases.
It’s extremely important to diagnose endophthalmitis as soon as possible, conduct tests to understand it better, manage the condition meticulously, and check on the patient regularly to protect their vision. Treatment usually involves eye drops or systemic antibiotics or antifungals to fight off the infection, direct injections of antibiotics or antifungals into the eyeball, and sometimes surgery, specifically a procedure called “pars plana vitrectomy,” which removes the vitreous gel from the middle of the eye to clear out infection.
In treating this serious condition, the coordination between the eye surgeon, microbiologists (scientists who study microorganisms that cause diseases), pathologists (doctors who analyze disease patterns), and critical care physician is key in ensuring the overall and eye-related prognosis of the patient.
What Causes Endogenous Endophthalmitis?
Endogenous endophthalmitis (EE) is a type of eye infection that can be caused by bacteria or fungi, and the specific causes can vary in different parts of the world. In many cases, the culprits are various kinds of fungi, which make up a large portion of cases. In parts of Asia, for example, fungal EE is seen in about 11.1-17.54% of all instances.
The most common type of bacteria causing EE are Streptococcus and Staphylococcus, which are a type of bacteria mostly found on the skin. However, in Asian countries, cases involving bacteria that are negative in a test called gram stain are more common. Among the fungi causing EE, ailment is frequently seen due to yeast known as Candida albicans, and a type of mold called Aspergillus flavus.
Klebsiella pneumonia, a certain type of bacteria, can also cause EE. This bacteria is usually found in patients with conditions like liver abscess, diabetes, heart infection, or even after undergoing routine procedures like colonoscopy.
Fungal EE is typically seen after chemotherapy, or in patients who have undergone liver and heart transplants or stem cell transplants. Candida EE is also common in patients on ventilators or in newborn babies.
There are several risk factors that can contribute to an increased chance of EE. These include diabetes, weakened immune system, being on long-term steroid medication, recent hospitalization, pneumonia associated with ventilators, urinary tract infection, immune deficiencies, chemotherapy, liver abscess, alcoholism, certain cancers such as lymphoma and leukemia, and drug abuse.
Neonatal EE, an eye infection occurring in newborn children, can be alarming and it is often linked with bacterial infections, yeast infections, malnourishment, low birth weight, and bloodstream infection. The most common bacteria involved in neonatal EE are Streptococci, S. agalactiae, Pseudomonas, and Klebsiella.
Some EE cases are also related to less obvious body-wide infections which do not show up in cultures. Recently, there have been a few reported cases of EE in patients with COVID-19, possibly due to weakened immune systems.
Risk Factors and Frequency for Endogenous Endophthalmitis
Endophthalmitis, also known as EE, is a type of eye infection. It’s not very common, with only 2 to 8% of people being affected. The first known case of this disease was recorded in 1856 and was associated with a repeated Klebsiella bacteria infection. Until 2003, approximately 335 cases of bacterial EE had been reported.
- EE can affect anyone, regardless of age or gender.
- In a study involving 27 people, the average age of those affected was 63.
- The infection is more common in the right eye. For every one left eye affected, two right eyes are affected because the blood flow from the right carotid artery is more direct.
- About 25% of people with EE have the infection in both eyes.
Signs and Symptoms of Endogenous Endophthalmitis
Endogenous endophthalmitis is a condition that affects the eye, causing symptoms such as pain, redness, irritation, swelling, sensitivity to light, changes in vision, and seeing floaters or flashes. Bacterial endogenous endophthalmitis generally causes inflammation in the front of the eye, and it is often seen on both sides with Mycobacterium tuberculosis.
The condition can exhibit various signs, ranging from swelling around the eyes, inflammation of the white part of the eye, bulging of the eyes, red eyes, hazy cornea, accumulation of water in the cornea, reaction in the anterior chamber (the front part of the eye), presence of whitish-yellow pus called ‘hypopyon’, fibrinous membrane (a kind of tissue), excretion in the iris, nodules in the iris, unresponsive pupil, a defect in the pupil causing it to not correctly respond to light, adhesion of the iris, cataract, absence of red reflex, hazy vitreous (the clear gel filling the eyeball), cells in the vitreous, floaters in the vitreous, membranes, and exudates.
The most vital diagnostic sign of this condition is the involvement of the vitreous. For instance, the fungus Aspergillus flavus can cause yellow or white exudates in the vitreous. Candida endogenous endophthalmitis often presents as fluffy, cotton wool-like white exudates in the retina alongside vitritis or inflammation of the vitreous. Additionally, there can be subretinal and choroidal abscesses in cases of bacterial endophthalmitis.
Endogenous endophthalmitis can be divided into three categories based on the ocular signs and symptoms:
- Probable, where the condition is likely but not confirmed
- Possible, where the condition may exist but needs further investigation
- Positive, where the condition has been confirmed
Some of these signs may include congestion of the conjunctiva and cornea, changes in the anterior chamber such as the appearance of hypopyon, abscess or exudates in the iris and uveal tissue, vitreous haze, changes in the retina and choroid, and scleritis or inflammation of the white part of the eye.
Certain additional symptoms, such as fever and panophthalmitis, which is inflammation involving the whole eyeball, may also be present. When the condition is presented with symptoms two weeks after their onset, it might be linked to an increased risk of retinal detachment, especially in MRSA-associated cases.
Testing for Endogenous Endophthalmitis
Determining whether a patient has endogenous endophthalmitis (EE), a type of eye infection, involves several steps. Sometimes, figuring out whether someone has this infection can take a while because the signs of the infection can resemble many other conditions. If a doctor suspects that a patient might have this infection, they will likely need to perform a close examination of the patient’s eye using a slit lamp, which is a special microscope that allows them to see the structures at the front of the eye in detail, and dilated fundus evaluation, a procedure that allows the doctor to see inside the back of your eye. They will also want to conduct a general assessment to understand the patient’s overall health.
Imaging Tests
B Scan Ultrasound
An B scan ultrasound is a kind of imaging test that can help identify certain features of EE. This includes increased cells in the vitreous humor (a gel-like substance in the back of the eye), membranes, discharge in the vitreous humor, retinal detachment, and a choroidal abscess (a pocket of pus in the choroid layer of the eye). These findings can appear as echoes on the ultrasound image.
Optical Coherence Tomography (OCT)
OCT is an imaging test that lets the doctor see the different layers of the retina, a tissue at the back of the eye that senses light, and underneath it. It can help point out areas with discharge, lesions on the pigmented layer of the retina, swelling of the retina, additional cells and discharge in the vitreous humor, and involvement of the choroid layer.
Anterior Chamber and Vitreous Tap
During these procedures, the doctor takes a tiny amount of fluid from either the anterior chamber (the space between the cornea and the iris) or the vitreous humor for examination. This fluid is then sent off for further testing, such as a culture and sensitivity test (which determines what kind of microbe is causing the infection and which antibiotics it would respond to) and histopathological examination (which examines the structure of the cells).
Polymerase Chain Reaction (PCR)
The fluid samples can also be subjected to a PCR test. This is a test that can detect very small amounts of specific genetic material, making it very accurate. While PCR can’t tell you what kinds of antibiotics the infection would respond to, it’s a good way to identify the organism causing the infection. The results can typically be available in 90 minutes, making it a quicker test than waiting for results of a culture.
Blood Culture
A blood culture can help determine if the infection has spread elsewhere in the body. Typically, three samples are taken over three days under clean conditions to get the best results. It is also important to get a urine culture to identify any hidden microorganisms. According to some studies, blood culture has a higher success rate than vitreous sample in detecting organisms.
Next Generation Tools
2-Deoxy-2-[18F] Fluoro-Dglucose Positron Emission Tomography/Computed Tomography Scan
This is a newer test that might be used to evaluate patients with EE, especially those with a COVID-19 infection. This imaging test uses a radioactive drug to show activity in the body on a cellular level.
Treatment Options for Endogenous Endophthalmitis
Endogenous endophthalmitis is a medical emergency that can threaten your vision. It requires quick and careful treatment, determined by the stage of the disease, the bacteria or fungus causing the infection, how the infection got into your body, and your overall health.
A general plan for managing endogenous endophthalmitis involving a bacterial infection begins with treating the infection throughout your body with antibiotics. If the results of blood tests reveal the type of bacteria causing the infection, tailored antibiotic treatment can begin. If the eye infection is severe, additional medication may be injected directly into the eye. In extreme cases, where the infection is advancing quickly and not responding to medication, a surgical procedure known as a pars plana vitrectomy may be needed.
If endogenous endophthalmitis is suspected, doctors will take a sample from your eye for testing and promptly start antibiotic treatment in the eye. Getting antibiotics in the eye within 24 hours of first symptoms often leads to better results. Broad-spectrum antibiotics, which work against many types of bacteria, are used at the start. If tests show a specific bacteria is causing the infection, then doctors can switch to a targeted antibiotic for best results. Pregnant or breast-feeding women may need to be treated carefully to avoid potential harm to the baby.
For endogenous endophthalmitis caused by fungus, particularly Candida, antifungal medications like Amphotericin and Voriconazole can be injected into the eye. This treatment may have some side effects like damage to the kidneys, low blood pressure, and irregular heart rhythms, so patients need to be closely monitored. Other fungi like Aspergillus, Paecilomyces, and Fusarium also respond to these types of medication, but in severe cases, surgery may be required.
The process of pars plana vitrectomy, or removing the vitreous jelly from inside the eye, can be needed for severe cases of either bacterial or fungal endogenous endophthalmitis that are not improving with medication alone. This procedure can serve the dual purpose of helping to diagnose the exact infectious agent and treating the condition by reducing the load of infectious organisms inside the eye. This does not only speed up recovery but also prevents further complications like retinal detachment. Corticosteroid treatment, either systemically or directly in the eye, may also be considered to reduce inflammation, although the evidence for this approach is mixed.
In end, the approach to treating endogenous endophthalmitis is tailored to the specific characteristics of the disease and the patient, aiming for the best possible outcome.
What else can Endogenous Endophthalmitis be?
The causes of eye inflammation, also known as uveitis, can be classified into various categories. These include:
Infectious causes such as:
- Cytomegalovirus
- Herpes simplex virus
- Varicella-zoster virus
- Epstein bar virus
- Disseminated toxoplasmosis
- Disseminated viral retinitis
- Tuberculosis
- Lyme’s disease
- Pythium
Non-infectious causes like:
- Vogt-Koyanagi-Harada syndrome
- Sarcoidosis
- Behcet syndrome
- Unexplained cause (Idiopathic)
- Toxic anterior segment syndrome
- Sympathetic ophthalmia
- Juvenile idiopathic arthritis
- Posterior scleritis
There are certain conditions that may appear after any surface or intraocular surgery such as postoperative endophthalmitis.
A few conditions may mimic eye inflammation symptoms, these are known as Masquerade and include:
- Leukemia
- Lymphoma
- Retinoblastoma
- Choroidal melanoma
- Tumour necrosis with inflammation
Sometimes, inflammation can also be caused by an intraocular foreign body or variety of other conditions explained as White dot syndromes:
- Punctate inner choroidopathy
- Serpiginous choroidopathy
- Multifocal choroiditis and panuveitis
- Subretinal fibrosis and uveitis
- Multiple evanescent white dot syndrome
- Acute posterior multifocal placoid pigment epitheliopathy
- Birdshot chorioretinopathy
In rare cases, eye inflammation might occur due to Asteroid Hyalosis, Disseminated Intravascular Coagulation or Thrombotic Thrombocytopenic Purpura.
What to expect with Endogenous Endophthalmitis
The future health of someone with endogenous endophthalmitis – a serious, internal eye infection – can depend on several factors. These include how quickly the condition was discovered and treated, the symptoms they experienced, how much of the jelly-like substance in the eye (or vitreous) has been affected, and how potent the germ causing the infection is. Endogenous endophthalmitis is challenging to diagnose, and because it’s often linked with other medical conditions, it can sometimes go undetected for too long.
Studies show that patients tend to have the best outcomes when the infection is caused by yeast. Bacteria are next, but the prognosis is not as hopeful when the infection is caused by molds.
Unfortunately, patients who come in for treatment later, or when their diagnosis and treatment are delayed, often completely lose their sight, and have a much poorer outlook. Patients needing a vitreous tap, a procedure to remove some of the infected vitreous jelly, have a risk of retinal detachment, which can threaten vision, so their outlook is uncertain.
Various studies point to different aspects of this condition. For example, one study revealed the outlook is generally poor when the infection is bacterial. Typically, the infected eye needs to be removed or emptied out. However, if the condition was promptly diagnosed and treated, there’s a greater likelihood (64%) that the patient will have a better visual outcome.
Early and aggressive treatment, such as vitrectomy (i.e., removing the vitreous, the clear gel that fills the inside of your eye) within two weeks of diagnosis, can lead to good results and a better prognosis.
Interestingly, when it comes to the various germs causing the infection, those with an infection caused by MRSA (a type of antibiotic-resistant bacteria) tend to fare worse and face higher death rates. Although some research also points to different infection outcomes, depending on the germ. For instance, many patients with an infection caused by a type of germ called Klebsiella needed a vitrectomy according to one study.
Lastly, another study found that the presence of hypopyon (a layer of white blood cells in the front of the eye) in a Klebsiella infection could predict the future health outcomes for the patient.
Possible Complications When Diagnosed with Endogenous Endophthalmitis
These are some side effects and complications that can happen:
- Keratitis or inflammation of the cornea
- Hypopyon uveitis that doesn’t resolve or improve
- Secondary glaucoma, an eye condition causing increased pressure
- Cataract, cloudy lens in the eyes
- Lens abscess or infected eye lens
- Panophthalmitis or eye inflammation
- Retinal detachment, where light-sensitive layer in the eye pulls away from its normal position
- Choroidal detachment that involves separation from the vascular layer of the eye
- Hypotony or low eye pressure
- Phthisis bulbi, a shrunken and non-functional eye
- Atrophic bulbi, which is an eye that has become small and without function
- A painful blind eye
Recovery from Endogenous Endophthalmitis
People diagnosed with EE (Endophthalmitis) must be hospitalized so doctors can closely observe them. This disease affects both the body and eye, requiring constant monitoring. If patients need injections directly into the eye (intravitreal injections), the medical team will want to check on them every day to see if their condition is improving and if more injections are needed.
If EE gets worse, the surgeon will decide whether the patient needs a surgery called a pars plana vitrectomy where some of the jelly-like substance in the back of the eye is removed. After this surgery, the patient will start a treatment that includes eye drops that contain steroids (like prednisolone or dexamethasone), decreasing the number of drops each week. They’ll also use two other types of eye drops, homatropine and timolol, twice daily, along with oral antibiotics and anti-inflammatory medications.
The patient will need regular appointments so doctors can check if their condition is getting better and to make sure there aren’t any complications from the treatment or disease.
Preventing Endogenous Endophthalmitis
The patients should be clearly informed about the severity of their condition, including warning signs and symptoms such as pain, redness, swelling, sudden decrease in clarity of vision, and sensitivity to light. They should understand that their ailment will necessitate a stay in the hospital and intense treatment that involves both medication applied directly to the eye and pills to swallow, injections into the eyeball, and potentially even surgery. Further, the patients should be briefed about the expected outcomes for their vision and be encouraged to have realistic expectations.