Also see Pharmacy Profession Forum for the thread "[Diagnosis] Diagnostic Series" at http://forum.tomhsiung.com/pharmacy-students-and-residents/clinical-skills/817-diagnosis-diagnostic-series.html

Identify the Problems

Step 1 Obtain Patient Data

Consider all available patient data. Review all previously charted data (history, physical examination findings, results of laboratory and diagnostic tests) and interview the patient for the patient's medication history. Reviewall relevant data resources, including data from the current patient chart, data from past charts, data obtained from patient interviews or interviews with relatives or significant others if the patient is not capable of providing information, and uncharted data available from team members. Seeking out and then identifying relevant data requires patience and methodical scrutiny. Note that the patient's story may vary depending on who interviewed the patient and when the patient was interviewed. Some data may be contradictory. But it is important to gather and then consider all available data.

Patient factors that by themselves appear unimportant may be important when considered in the context of other patient data. Pertinent positive data (abnormal findings) include abnormal laboratory results such as a serum potassium level that exceeds the upper limit of the reference range, abnormal signs and symptoms described by the patient, and abnormalities noted on physical examination, and are easy to identify. Pertinent negative data (findings that are normal but, given the patient's disease or condition, would have been expected to be abnormal) are more difficult to recognize, and identifying them requires a good understanding of human disease and pharmacotherapeutics.

Create a working list of the data. Subdivide the data into lists of subjective data and objective data. Subjective data, such as coughing, pain, and itching, are describable but cannot be precisely measured or quantified. Some clinicians view all data obtained directly from the patient to be subjective data, because the data are not verifiable by an independent observer and must be considered just a story. Objective data, such as blood pressure, heart rate, and temperature, are data that can be precisely measured or quantified. By convention, data that are obtained by the health care professional by direct observation of the patient or are obtained during the physical examination but that cannot be precisely quantified are considered objective data because the data were obtained by an objective, trained clinician. Data documented by other health care professionals are considered objective data.

Step 2 Group Related Data

Evaluate the list of objective and subjective data for possible relationships among the data. This step requires comprehensive knowledge of the signs and symptoms of disease and pharmacotherapy and becomes easier with experience. For example, subjective complaints of fever, one episode of chills, and productive cough combined with objective data of leukocytosis with an increased percentage of bands, a chest radiograph showing right middle lobe consolidation, and sputum positive for gram-positive encapsulated cocci in pairs are related. A less experienced clinician should be able to recognize that the patient has some kind of lower respiratory tract bacterial infection.

Work through the list of patient data making sure that every piece of patient data is considered. Note that it only takes one piece of data to identify a patient problem. For example, a patient may smoke tobacco but have normal physical examination findings and normal laboratory results. The patient's self-identification of the smoking history is enough to categorize the patient as a smoker (the problem). Some data may belong with more than one group of data. For example, a blood pressure of 160/110 mm Hg belongs with data related to the patient's diagnosis of hypertension, but if the patient had been prescribed antihypertensive drug therapy but missed many doses, the blood pressure of 160/110 mm Hg also belongs with data related to patient nonadherence.

Step 3 Determine Each Problem

Evaluate each group of related subjective and objective data items to determine the specific patient problem or issue. The problem is not always a specific diagnosis but may be a preliminary identification of the issue pending acquistition of additional data (e.g., acute diarrhea, not shigellosis). The problem list is refined as more data become available. Patient problems include current medical problems such as hypertension, pneumonia, asthma, diabetes, and gastrointestinal bleeding; past medical problems such as history of migraine headache, hip fracture, deep vein thrombosis, and myocardial infarction; past surgeries such as appendectomy, tonsillectomy, coronary artery bypass grafts, and transurethral resection of the prostate; and issue such as nonadherence, obesity, illicit drug abuse, alcohol use, tobacco use, and allergies.

Step 4 Assess Each Problem

  • Each problem is then assessed in terms of each of the following characteristics:
  • Acuity (acute or chronic)
  • Severity (mild, moderate, or severe)
  • Symptom level (symptomatic or asymptomatic)
  • Treatment status (treated or untreated)
  • Degree of control (controlled or uncontrolled)
  • Classification (staging of disease)

Knowing these characteristics is useful when prioritizing patient problems and when planning patient-specific drug and nondrug interventions. Management of a patient's acute, severe, uncontrolled, untreated asthma exacerbation will take precedence over treatment of any of the patient's other chronic and controlled problems. Because historical problems cannot be assessed for these characteristics, by convention these problems are simply documented as "S/P" (meaning "status post" or "a history of").


Prioritize The Problems

Prioritization means ranking the patient problems with the most urgent problems at the top of the list and the least urgent problems at the bottom of the list. Prioritization is a way of ordering the relative need for intervention and is not meant to imply a rank ordering of importance or significance to the patient's overall health care needs. Problems of equal urgency are still listed in a rank order although the plans document the need to address each problem simultaneously. Historical (inactive) problems are not ranked but are simply listed at the bottom of the problem list. Problem lists are dynamic lists that evolve and are modified as new data become available.

Step 1 Identify the Active Problems

Active problems are problems that require some kind of drug or nondrug intervention to resolve and/or manage the problem.

Step 2 Identify the Inactive Problems

Inactive problems are problems that do not require any kind of drug or nondrug intervention and are of historical interest only. Examples of inactive problems include a history of an appendectomy at age 12, a history of pneumonia 2 years ago, a history of smoking two packs of cigarettes per day until quitting 10 years ago, etc. Although inactive problems do not require planning for current drug or nondrug therapy interventions, inactive problems are still identified and listed on the patient problem list so that they can be considered when planning drug and nondrug interventions for active problems. For example, a patient with a history of splenectomy is at increased risk of infection with some pathogens. Knowledge of this risk will help in planning patient-specific antibiotic therapy in the event that the patient has signs and symptoms consistent with infection.

Step 3 Rank the Problems

Rank-order the active patient problems. One approach to ranking patient problems is to identify the problem that needs the most immediate attention and then rank the remaining active problems in order of need for intervention. The number one problem is the problem that if left untreated will cause the most harm to the patient in the shortest amount of time. Another approach is to work from the bottom of the list up by determining the problem requiring the lest attention. This problem is ranked as the least important problem. The pharmacist repeats the ranking process with the remaining problems until all are ranked. Regardless of the approach, the active problems are placed at the top of the list, inactive problems are at the botton of the list, and active but less acute problems are in the middle. As noted previously, the rank ordering is rather arbitrary if the the problems all have relatively equal need for intervention.

Clinicians given the same list of patient data may develop different prioritized lists. This is not unexpected; no one list is correct. Lists are developed based on the clinical judgment and experience of the practitioner. In addition, because the focus of the pharmacist is on therapeutic issues rather than on differential diagnosis, the pharmacist-generated patient problem list may be similar although not necessarily identical to the problem list generated by physicians, nurses, or other health care professionals.


Select Patient-Specific Drug and Nondrug Interventions

Once the prioritized patient problem list is developed, the next step is to select patient-specific drug and nondrug interventions for each and nondrug interventions.

Determine appropriate nondrug interventions, including patient eduation. For example, an important part of the management of allergic rhinitis is avoidance of allergens; patients may benefit from education regarding allergen avoidance.

Determine an appropriate medication regimen for each patient problem that can be treated and/or managed with medications. For each medication selected, include the dosage, the dosage formulation, the route of administration, dosing interval, duration of therapy, and rationale (the evidence-based reason for selecting the patient-specific therapeutic intervention). The general approach is to develop the therapeutic plan for each problem and then integrate the individual plans, with care taken to ensure that each component of the plan is appropriate given the other plans and that the overall integrated plan is achievable for the pateint. For example, when considered individually plans for therapeutic interventions for a patient with multiple chronic medical conditions may seem reasonable and appropriate, but when considered together they may not be doable if the multiple medication regimens require the patient to adhere to multiple sets of complicated instructions (e.g., take with food, take 2 hours before eating, take every 4 hours around the clock, take every 8 hours around the clock, do not take within 2 hours of taking another medication, etc.).

Selection of a specific regimen requires assessment of each patient problem in the context of everything that is known about the patient such as other patient problems and medications, social habits, cultural beliefs, and willingness to commit to a course of therapy, as well as external factors such as insurance coverage and access to refrigeration for storage of refrigerated medications. See below,

Patient-specific factors

  • What regimens have effectively managed the problem in the past?
  • What regimens have not effectively managed the problem in the past?
  • How might other patient problems influence the proposed regimen?
  • How might the proposed regimen influence other patient problem´╝č
  • Does the patient have any culturally based needs?

External factors

  • State-of-the-art therapeutics (e.g., current guidelines)
  • Cost of the proposed therapy
  • Formulary limitations

For example, a patient who has responded well to a specific decongestant in the past will most likely respond well to the same decongestant in the future. A patient with renal insufficiency is at risk of developing seizures from the accumulation of normeperidine, a renally eliminated metabolite of meperidine. A drug with negative inotropic effects may worsen a patient's congestive heart failure.

Step 1 Determine Short-Term and Long-Term Goals of Therapy

All drug and nondrug interventions should be in the context of the specific short-term and long-term goals of therapy, which may or may not be the same depending on the specific patient problem. For example, the short-term goal for patient being treated for a hypertensive emergency is to reduce the diastolic blood pressure to 100 to 105 mm Hg within 2 to 6 hours of presentation with a maximum reduction of 25% or less of the initial diastolic blood pressure. The long-term goal is to reduce the diastolic blood pressure to 85 to 90 mm Hg over the next 2 to 3 months to reduce the long-term morbidity and mortality associated with the elevated diastolic blood pressure.

Determine specific goals and outcomes of therapy before doing any other planning. Set specific goals for each patient problem and for the overall therapeutic outcome in general. When setting therapeutic goals, consider long-term factors such as the impact of the therapeutic regimen on the patient's quality of life and survival. For example, a long-term weight reduction plan is not appropriate for a patient with a short life expectancy. Select target therapeutic ranges for all objective parameters (e.g., systolic blood pressure between 110 and 130 mm Hg; serum potassium level between 3.5 and 4.5 mEq/L, etc.)

Consider the severity of disease and the short-term or long-term nature of therapy when setting therapeutic goals. For example, consider the differences in the goals of insulin therapy for a young patient with newly diagnosed type 1 diabetes mellitus and significant cardiovascular and peripheral vascular disease. Evidence suggests that tight control of blood glucose levels may delay the onset and decrease the severity of the complications of diabetes. Therefore the target blood glucose level for the young patient with newly diagnosed daibetes is lower and has a narrower acceptable range than that for the elderly patient with diabetes and longstanding disease who has already developed complications from the disease and is at risk of hypoglycemia-related falls.

Step 2 Create A List of Options

Identify all classes of drugs and possible therapeutic approaches for each problem; do not eliminate any option at this stage of planning. The options list is usually a mental list, although students and inexperienced clinicians may find it helpful to create and then work from a written list. Depending on how familiar the pharmacist is with the management of the medical condition, this step may require review of current pharmacotherapeutics and human disease textbooks, literature searches of the current pharmacy and medical literature, review of current treatment guidelines, or consultation with colleagues. This step becomes easier and more time efficient with practice and experience. As the member of the heath care team with the most knowledge of pharmacotherapy, it is the pharmacist's responsibility to identify all possible drug therapy options.

Step 3 Eliminate Options Based on Patient-Specific and External Factors

Once all therapeutic options are identified, eliminate options based on the comparative effectiveness of the drugs; the suitability of the drug for the patient given the other patient medical conditions and drug therapies; the ability of the patient to adhere to the proposed regimen; and other factors such as the effectiveness of previous treatment regiments, cost, and formulary restrictions. Consider the impact of the therapeutic option on other patient problems and the influence of other patient problems on the therapeutic option.

Drug-specific factors

  • Effectiveness of the clinical outcome (e.g., evidence-based benefit)
  • Pharmacologic mechanisms
  • Effectiveness of the drugs (e.g., physiologic effect, potency, maximum effect, slope of effect-concentration curve)
  • Evidence-based toxicity of the drug
  • Toxicity of the drugs (e.g., therapeutic index/window)
  • Drug delivery systems (e.g., inhalant, sublingual, oral)
  • How drug get active in the body (e.g., prodrug)
  • In-body drug process/pharmacokinetics (e.g., absorption, distribution, metabolism, excretion)
  • Drug interactions

Patient-specific factors

  • What regimens have effectively managed the problem in the past?
  • What regimens have not effectively managed the problem in the past?
  • How might other patient problems influence the proposed regimen? (e.g., renal failure, hepatic failure, genetic variability/mutation, etc.)
  • How might the proposed regimen influence other patient problem?
  • Does the patient have any culturally based needs?
  • The severity of the problem
  • How the patient's life style affect the proposed regimen?
  • The past patient experiences
  • The patient's ability to adhere to the proposed regimen

External factors

  • State-of-the-art therapeutics (e.g., current guidelines)
  • Cost of the proposed therapy
  • Formulary limitations
  • Risk of medication errors

Step 4 Select Appropriate Drug and Nondrug Interventions

Decisions about appropriate drug and nondrug interventions are based on past patient experiences, assessment of the severity of the problem, drug-specific factors such as the therapeutic index of the drug, and specific patient factors such as the presence of chronic renal or hepatic disease that may influence the elimination or metabolism of the drug. Determine the best drug and nondrug regimen, including each specific drug to be used, dosage, route, duration of therapy, and rationle for the selection of each drug and nondrug component of the regimen. For example, if a patient failed to stop smoking because the patient developed varenicline-associated side effects and stopped taking the medication, then the patient should not be prescribed varenicline the next time the patient attempts to quite smoking. If a patient's prescription medication insurance no longer covers a specific branded product, then every effort should be made to find an equivalent medication, generic or otherwise, that is paid for by the prescription medication insurance plan.

The rationale, the reason why the specific intervention was selected, should be patient specific and based on current published evidence. The rationale should be documented in the SOAP note in the patient chart even if verbally discussed with the prescriber. For example, the recommendation to initiate antihypertensive drug therapy with hydrochlorothiazide 12.5 mg daily for a patient with newly diagnosed uncomplicated hypertension is based on the recommendations of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The recommendation to vaccinate or note vaccinate a person with the influenza vaccine is based on current Centers for Disease Control and Prevention recommendations.

Step 5 Identify Alternative Interventions

An important part of the planning process is anticipation of potential patient problems with the prescribed and/or recommended drug and nondrug interventions ("what if"). A well-though-out plan includes alternative medication regimens for common potential problems, such as the development of an allergy or adverse reaction to the initial therapeutic regimen, lack of desired therapeutic response to the initial therapeutic regimen, and identification of additional patient problems that may influence the effectiveness or pharmacokinetic profile of the initial therapeutic regimen. Anticipation of these potential issues allows the creation of well-thought-out alternative therapeutic plans instead of therapeutic plans hastily chosen when unanticipated patient problems suddenly appear. For example, therapeutic planning for a patient with newly diagnosed hypertension should include plans for what to do if the initial treatment fails to lower the blood pressure or has to be discontinued because of the development of intolerable side effects (both very common issues).

(The End)