Case Files Neurology, (LANGE Case Files) 2nd Ed.

Part 3. Approach to Reading

The clinical problem-oriented approach to reading is different from the classic “systematic” research of a disease. Patients rarely present with a clear diagnosis; hence, the student must become skilled in applying textbook information to the clinical scenario. Since reading with a purpose improves the retention of information, the student should read with the goal of answering specific questions. There are several fundamental questions that facilitate clinical thinking. These are:

1. What is the most likely diagnosis?

2. How would you confirm the diagnosis?

3. What should be your next step?

4. What is the likely neuroanatomical defect?

5. What are the risk factors for this condition?

6. What are the complications associated with the disease process?

7. What is the best therapy?

CLINICAL PEARLS

Images Reading with the purpose of answering the seven fundamental clinical questions improves retention of information and facilitates the application of “book knowledge” to “clinical knowledge.”

1. What Is the Most Likely Diagnosis?

The method of establishing the diagnosis has been covered in the previous section. One way of attacking this problem is to develop standard approaches to common clinical problems. It is helpful to understand the most common causes of various presentations (see the Clinical Pearls at the end of each case), such as “the worst headache of the patient’s life is worrisome for a subarachnoid hemorrhage.”

The clinical scenario would be something such as:

A 38-year-old woman is noted to have a 2-day history of a unilateral, throbbing headache and photophobia. What is the most likely diagnosis?

With no other information to go on, the student would note that this woman has a unilateral headache and photophobia. Using the “most common cause” information, the student would make an educated guess that the patient has a migraine headache. If instead the patient is noted to have “the worst headache of her life,” the student would use the Clinical Pearl: “The worst headache of the patient’s life is worrisome for a subarachnoid hemorrhage.”

CLINICAL PEARLS

Images The more common cause of a unilateral, throbbing headache with photophobia is a migraine, but the main concern is subarachnoid hemorrhage. If the patient describes this as “the worst headache of his or her life,” the concern for a subarachnoid bleed is increased.

2. How Would You Confirm the Diagnosis?

In the scenario above, the woman with “the worst headache” is suspected of having a subarachnoid hemorrhage. This diagnosis could be confirmed by a CT scan of the head and/or lumbar puncture (LP). The student should learn the limitations of various diagnostic tests, especially when used early in a disease process. The LP showing xanthochromia (red blood cells) is the gold standard test for diagnosing subarachnoid hemorrhage, but it can be negative early in the disease course.

3. What Should Be Your Next Step?

This question is difficult because the next step has many possibilities; the answer can be to obtain more diagnostic information, stage the illness, or introduce therapy. It is often a more challenging question than “What is the most likely diagnosis?” because there may be insufficient information to make a diagnosis, and the next step may be to pursue more diagnostic information. Another possibility is that there is enough information for a probable diagnosis, and the next step is to stage the disease. Finally, the most appropriate answer may be to treat. Hence, from clinical data, a judgment needs to be rendered regarding how far along one is on the road of:

1. Make a diagnosis → 2. Stage the disease →

3. Treat based on stage → 4. Follow response

Frequently, the student is taught “to regurgitate” the same information that someone has written about a particular disease but is not skilled at identifying the next step. This talent is learned optimally at the bedside, in a supportive environment, with freedom to take educated guesses and with constructive feedback. A sample scenario can describe a student’s thought process as follows:

1. Make a diagnosis: “Based on the information I have, I believe that Mr. Smith has a left-sided cerebrovascular accident.”

2. Stage the disease: “I don’t believe that this is severe disease because his Glasgow score is 12, and he is alert.”

3. Treat based on stage: “Therefore, my next step is to treat with oxygenation, monitor his mental status and blood pressure, and obtain a CT scan of the head.”

4. Follow response: “I want to follow the treatment by assessing his weakness, mental status, and speech.”

CLINICAL PEARLS

Images Usually, the vague query, “What is your next step?” is the most difficult question because the answer can be diagnostic, staging, or therapeutic.

4. What Is the Likely Neuroanatomical Defect?

Since the field of neurology seeks to correlate the neuroanatomy with the defect in function, the student of neurology should constantly be learning the function of the various brain centers and the neural conduits to the end organ. Conveniently, neurology can be subdivided into compartments such as movement disorders, stroke, tumor, and metabolic disorders for the purpose of reading; yet, the patient can have a disease process that affects more than one central nervous function.

5. What Are the Risk Factors for This Condition?

Understanding the risk factors helps the practitioner to establish a diagnosis and to determine how to interpret tests. For example, understanding risk factor analysis may help in the management of a 55-year-old woman with carotid insufficiency. If the patient has risk factors for a carotid arterial plaque (such as diabetes, hypertension, and hyperlipidemia) and complains of transient episodes of extremity weakness or numbness, she may have either an embolic or thrombotic disease mechanism.

CLINICAL PEARLS

Images Being able to assess risk factors helps to guide testing and develop the differential diagnosis.

6. What Are the Complications Associated with the Disease Process?

Clinicians must be cognizant of the complications of a disease, so that they will understand how to follow and monitor the patient. Sometimes the student will have to make the diagnosis from clinical clues and then apply his or her knowledge of the consequences of the pathologic process. For example, “A 26-year-old man complains of severe throbbing headache with clear nasal drainage.” If the patient has had similar episodes, this is likely a cluster headache. However, if the phrase is added, “The patient is noted to have dilated pupils and tachycardia,” then he is likely a user of cocaine. Understanding the types of consequences also helps the clinician to be aware of the dangers to a patient. Cocaine intoxication has far different consequences such as myocardial infarction, stroke, and malignant hypertension.

7. What Is the Best Therapy?

To answer this question, not only do clinicians need to reach the correct diagnosis and assess the severity of the condition, but they must also weigh the situation to determine the appropriate intervention. For the student, knowing exact dosages is not as important as understanding the best medication, route of delivery, mechanism of action, and possible complications. It is important for the student to be able to verbalize the diagnosis and the rationale for the therapy.

CLINICAL PEARLS

Images Therapy should be logically based on the severity of disease and the specific diagnosis. An exception to this rule is in an emergent situation such as respiratory failure or shock when the patient needs treatment even as the etiology is being investigated.

SUMMARY

1. There is no replacement for a meticulous history and physical examination.

2. There are four steps in the clinical approach to the neurology patient: Making the diagnosis, assessing severity, treating based on severity, and following the response.

3. There are seven questions that help to bridge the gap between the textbook and the clinical arena.

REFERENCES

Folstein MF, Folstein SE, McHugh PR. Mini-mental state: a practical method for grading the state of patients for the clinician. J Psychiatr Res. 1975;12:189-198.

Simon R, Greenberg D, Aminoff M. The neurological examination. In: Simon R, Greenberg D, Aminoff M, eds. Clinical Neurology, 7th ed. New York, NY: McGraw-Hill Publishers; 2009.