Sorting Out Possible Diagnoses from the History

ENRIQUE GARCIA-VALENZUELA, MAURICIO E. PONS, AND GARY W. ABRAMS

The approach to successful diagnosis and therapy begins with the clinical history. The medical interview should serve to collect information helpful to detect, treat, and prevent illness.

Many eye diseases are more common in one gender than the other. Multiple facts explain this, including retinal diseases that may be linked to hormonal factors or those that are linked to a gene defect in a sexual chromosome and other less understood reasons. Central serous chorioretinopathy, for example, affects men much more frequently than women. Incontinentia pigmenti, on the other hand, is found almost exclusively in women.

The ethnic background of a patient is very pertinent information when discerning possible retinal diagnoses because many disorders have marked differences in their incidence among various races. These differences are probably due to certain gene defects and other forms of molecular predisposition to disease being found more commonly in one race than in others. For instance, birdshot retinochoroidopathy in white persons has a strong association with antigen human leukocyte antigen (HLA)-A29. Another example is the case of melanin in uveal tissue, a proposed protector against environmental light irradiation. Its relative abundance or scarcity is believed to predispose for different ocular pathology: Vogt–Koyanagi–Harada disease is an autoimmune affliction against melanin in darker-skinned patients, usually Asians, Hispanics, and Native Americans; uveal melanoma has a correlation with sun exposure in less pigmented persons, such as those of Northern European ancestry. Diseases like sickle cell disease retinopathy or sarcoid uveitis occur much more frequently in African Americans. Other disorders, like white-dot syndromes, inflammatory chorioretinopathies, or AMD, have a much higher prevalence in the white population.

A patient’s geographic history holds important in the consideration of retinal conditions, particularly those of an inflammatory nature. Ocular infectious agents and environmental factors that affect them often are limited to certain locations and climates. This is the case for presumed ocular histoplasmosis syndrome or fungal and parasitic diseases, including onchocerciasis. Socioeconomic factors, dietary customs, and hygienic practices may vary in different places, again increasing the risk for infectious retinal diseases such as toxoplasmosis, which is associated with poor sanitation and the practice of eating undercooked meat.

External risk factors for retinal disease may be linked to the type and location of the occupation of a patient. Exposures to potential toxic agents, trauma resulting in a rhegmatogenous retinal detachment, and excessive sun exposure related to uveal melanoma are possible associations between employment and retinal disorders. Patients who work in sewers may be in contact with rodent urine and therefore at risk for leptospirosis, whereas brucellosis is more likely to occur in farmers and veterinarians.

This part of the history is particularly important in considering inheritable retinal diagnoses. Some retinal diseases are autosomal dominant and have a classic mendelian inheritance pattern. A positive family history may orient to conditions such as vitelliform dystrophy or retinitis pigmentosa, for example. Other inheritable retinal disorders are recessively transmitted: The presence of disease in siblings or history of consanguinity may suggest the diagnosis, as it may occur in gyrate atrophy or fundus flavimaculatus.

Of all the mentioned components in the history, prior history of disease, either systemic or ocular, has the highest yield in suggesting the cause of the complaints the patient describes. Complete past medical and surgical history often will unveil systemic illnesses associated with retinal diseases. Many common systemic diseases have a retinal component. The most familiar scenarios are diabetes mellitus, systemic hypertension, and rheumatic diseases. History of previous ocular disease is naturally very relevant to possible retinal complications or new disorders that a person may develop. An example is high myopia in a patient complaining of progressive central loss of vision, in which the suspicion for choroidal neovascularization is very high. Another common situation is endophthalmitis in a patient who recently had intraocular surgery.

Avitaminosis, particularly among children and older persons, may cause retinal disease. Vitamin A deficiency is an example of producing fundus xerophthalmia and nyctalopia. As mentioned earlier, consumption of raw or partly cooked meat can lead to toxoplasmosis or cysticercosis. Individuals who include unpasteurized milk in their diet are at risk of tuberculosis and brucellosis. Important habits to keep in mind are drug use, such as intravenous injection of heroin, which can result in retinal arterial occlusions if the drug is impure or in endogenous endophthalmitis. Sexual promiscuity and sometimes drug use are important risks for human immunodeficiency, herpes viruses, and syphilitic uveitis. A history of contact with unwormed dogs is significant in children with suspected ocular toxocariasis.

For many retinal diseases, a meticulous review of systems is necessary to establish the diagnosis. It serves to recognize relevant symptoms previously unrecognized by the patient to be relevant to his or her eye illness. This is particularly true in uveitic, vascular, or neoplastic retinal disorders. An example is HLA-B27-associated uveitis, which frequently coincides with pathology in the skin, mucosae, joints, and gastrointestinal system. Unless directly asked, patients do not realize that there may be a common source with their uveitic disease, which is why they usually fail to mention complaints affecting other organs. Recognition of systemic symptoms is not only extremely helpful in arriving at the retinal diagnosis, but it can be used to prevent serious progression of disease elsewhere in the body.

These categories of information in the clinical history contain the key facts needed to reach a probable diagnosis. For this reason, the physician seeks these components in the history first in the interrogation. The chief complaint is the main reason the patient has come to the ophthalmologist. Identification of the chief complaint allows the physician to recognize the most relevant symptom of the patient’s disease and immediately raises certain categories of retinal disease versus others. In the history of present illness, the severity, time of onset, course, and other characteristics of the patient’s retinal symptoms, starting with the chief complaint, must be thoroughly described. Blurred or decreased vision is most commonly the symptom for which patients seek care. Other usual symptoms include scotomata, which suggests focal retinal damage; metamorphopsia, which can result from mechanical distortion of macular topography from conditions such as epiretinal membranes or sub-retinal or intraretinal fluid; and flashes and floaters, which are common in vitreoretinal traction syndromes. Pain and photophobia, when associated with retinal disease, are symptoms that most commonly reflect anterior intraocular inflammation affecting the iris or ciliary body or elevated intraocular pressure.

The history of current illness is a chronologic description of the patient’s complaints. Each symptom should be distinguished by its type and quality; its intensity; time of onset, and mode of progression; its duration and frequency of recurrence; the existence of precipitating factors, alleviating factors, or aggravating factors; and associated events that precede, occur simultaneously, or follow the symptom described. Retinal diseases typically present with visual and ocular symptoms, which often can be explained on the basis of the underlying pathophysiologic process. One type of information that is particularly revealing in retinal problems is whether the complaint is monocular or binocular and to what extent symptoms may be asymmetric. Important clues to retinal diagnosis, particularly those of an inflammatory nature, also may lie in systemic complaints, including those that affect the neurologic system, the skin and mucosae, the musculoskeletal system, the respiratory and gastrointestinal systems, and others.

Development of a reasonable suspicion for one or more retinal diagnoses requires an analytic process that resembles the scientific method, in which observation leads to a hypothesis that can be tested with experimentation to refute or confirm the hypothesis. Physicians formulate potential diagnoses based on the clinical observations that will guide diagnostic testing, or experimentation, to hold one possible diagnosis over others.

The collection of clinical information, starting with the history, is essential to problem solving in retinal diagnosis. The application of scientific reasoning becomes a repetitive cycle during the process of sorting out one true clinical conclusion. As data are accumulated regarding a retinal illness, new hypotheses are produced and supported, and others are invalidated. The physician must remain alert for clinical clues that do not fit the current hypothesis and that might make it necessary to consider renewal of the assessment of information.

The diagnostic process in the retina, and in other fields of ophthalmology as well, is a dynamic one that begins with the history. This process is carried out not only as linear thinking, but several lines of evidence are considered in a parallel manner to reach one or more suspect diagnoses that will be investigated during the physical examination, laboratory testing, and other special testing.

Loss of foveal vision, even in small degree, is probably the most commonly reported symptom by patients who consult the ophthalmologist. The impact on the patient varies, depending on the type and degree of vision loss, whether onset is sudden or gradual, and also whether one or both eyes are affected. Many non-retinal causes exist for the loss of central visual acuity, including refractive conditions, diseases of the cornea and lens, glaucoma, and neuroophthalmologic disorders.

Because of the lack of anterior ocular findings, neuroophthalmic diseases often need to be carefully distinguished from retinal conditions. An important question is whether the degree of visual loss is explainable by the retinal findings. For example, a patient with mild epiretinal membrane maculopathy and severe reduction in visual acuity should be further investigated for other possible causes of visual loss. Diseases of the optic nerve, such as optic neuritis, ischemic optic neuropathy, and impinging tumors, are usually unilateral. A characteristically bilateral optic nerve pathological process that may lead to pronounced visual loss is papilledema seen in increased intracranial pressure. Chiasmal lesions can result in a visual loss that exhibits a variety of patterns with bilateral field involvement. Retrochiasmal neurologic disorders affect typically bilateral vision but spare half the macular vision without a decrease in visual acuity.