Conjunctivitis diagnosis

The direct and immediate use of laboratory data in medical diagnostic decision making is unique, so the proper use of reference materials in conjunction proficiency testing clinical chemistry is vital if false and mis diagnosis is to be avoided. 

While no exact numbers are available, conjunctivitis, which is also known as red eye, is one of the most common ophthalmic complaints seen by general clinicians. An inflamed conjunctiva is the most common cause of red eye.10 Use the differential diagnosis algorithm shown in Fig. 60-1 to determine the proper treatment or need for referral. 

Imaging studies also may help to identify anatomic localization of the infection. These studies usually are performed in conjunction with other tests to establish or rule out the presence of an infection. X-rays are performed commonly to establish the diagnosis of pneumonia, as well as the severity of disease (single versus multilobe involvement). CT scans are a type of x-ray that produces a three-dimensional image of the combination of soft tissue, bone, and blood vessels. In contrast, MRI use electromagnetic radio waves to produce two- or three-dimensional images of soft tissue and blood vessels with... 

A history of urethritis and prostatitis in men or of cervicitis and cystitis in women is common in patients with ReA. The disease has been called HLA-B27 associated ReA and includes classical Reiter s disease with arthritis, urethritis and conjunctivitis. Presenting symptoms and signs are mostly asymmetrical axial and/or peripheral arthritis. Determining the B27 status of an individual patient with ReA is irrelevant to therapy. Diagnosis usually can be made by clinical examination and history. 

Pediatric PTSD is a psychiatric disorder that is prone to both under- and overdiagnosis, especially when assessments are superficially or inexpertly conducted. For example, a traumatic exposure history in combination with current externalizing behavioral symptoms does not necessarily imply a diagnosis of PTSD. Conversely, children who present with an externalizing behavioral disorder in conjunction with anxiety symptoms and aggression are often not fully evaluated for PTSD. 

A normal response is an increase in plasma TSH of 5 to 15 pU/mL above baseline. A response of less than 5 pU/mL above baseline is generally considered to be blunted (some laboratories consider a response below 7 pU/mL to be blunted) and may be consistent with a major depression. An abnormal test is found in approximately 25% of patients with depression. A blunted TSH response (especially in conjunction with an abnormal DST) may help in confirming the differential diagnosis of a major depressive episode and support continued antidepressant treatment. An increased baseline TSH or an augmented TSH response (higher than 30 pU/mL), in conjunction with other thyroid indices, might identify patients with hypothyroidism, mimicking a depressive disorder. These patients may benefit most from thyroid replacement therapy. 

Gas chromatography permits the determination of these meta-r bolites simultaneously, and in conjunction with some clinical background, can make diagnosis much easier. Colorimetric methods lack adequate selectivity for differentiation. 

The measurement of serum cholesterol is one of the most common tests performed in the clinical laboratory. Hypercholesterolemia (high blood cholesterol levels) can be the result of a variety of medical conditions. Among the conditions implicated are diabetes mellitus, atherosclerosis, and diseases of the endocrine system, liver, or kidney. High blood cholesterol levels do not point to a specific disease determination of cholesterol is used in conjunction with other clinical measurements mainly for confirmation of a particular diseased condition, rather than for diagnosis of a specific ailment. 

In its mild form ocular surfece disease (OSD) may cause intermittent patient discomfort with symptoms of burning, itching, and blurring of vision. At its most severe the condition may precipitate secondary keratitis and conjunctivitis, corneal ulceration and scarring, and permanent vision loss. Up to one-fourth of all adults in the United States are affected by OSD. Fortunately, in most the condition is mild to moderate, and with proper diagnosis and treatment these patients can maintain comfortable clear vision and good ocular health. 

Diagnosis. In the classic form, vesicles form along the eyelid margin and/or periocular skin (Figure 23-16). The lesions are clear, pinhead in size, and have an inflamed erythematous base.Typically, within 1 week of presentation the vesicles break and ulcerate, resulting in a painful edematous blepharitis or dermatitis.The involved portion of the lid usually demonstrates mild swelling and tenderness. Pronounced conjunctival injection, a secondary follicular conjunctivitis, a weepy wet eye, and a regional lymphadenopathy may all be present. 

Systemic disorders may also manifest with conjunctival inflammation. Acute or chronic conjunctivitis may present with any of five signs of conjunctival inflammation chemosis, hyperemia, discharge or exudate, follicles, and papillae (Table 25-1). Specific patterns of inflammation may be helpful in diagnosis of the underlying cause. 

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