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Part 2. Approach to Clinical Problem Solving

Part 2. Approach to Clinical Problem Solving

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SECTION I: HOW TO APPROACH CLINICAL PROBLEMS



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Table I–2 • ASSESSMENT OF ABCS

Airway



Breathing



Assessment



Management



Assess oral cavity, patient color

(pink vs cyanotic), patency of

airway (choking, aspiration, compression, foreign body, edema,

blood), stridor, tracheal deviation,

ease of ventilation with bag

and mask



Head-tilt and chin-lift



Look, listen, and feel for air

movement and chest rising



Resuscitation (mouth-to-mouth,

mouth-to-mask, bag and mask)



Respiratory rate and effort

(accessory muscles, diaphoresis,

fatigue)



Supplemental oxygen, chest tube

(pneumothorax or hemothorax)



If cervical spine injury suspected, stabilize neck

and use jaw thrust

If obstruction, Heimlich maneuver, chest thrust,

finger sweep (unconscious patient only)

Temporizing airway (laryngeal mask airway)

Definitive airway (intubation [nasotracheal or

endotracheal], cricothyroidotomy)



Effective ventilation

(bronchospasm, chest wall

deformity, pulmonary embolism)

Circulation



Palpate carotid artery

Cardiac monitor to assess rhythm



If pulseless, chest compressions and determine

cardiac rhythm (consider epinephrine,

defibrillation)



Consider arterial pressure

monitoring



Intravenous access (central line)

Fluids



Assess capillary refill



Consider 5Hs and 5Ts: Hypovolemia, Hypoxia,

Hypothermia, Hyper-/Hypokalemia, Hydrogen

(acidosis); Tension pneumothorax, Tamponade

(cardiac), Thrombosis (massive pulmonary

embolism), Thrombosis (myocardial infarction), Tablets (drug overdose).



Assess pulse and blood pressure



or most serious ones, based on the clinician’s knowledge, experience, and selective

testing. For example, a patient who complains of upper abdominal pain and who

has a history of nonsteroidal anti-inflammatory drug (NSAID) use may have peptic

ulcer disease; another patient who has abdominal pain, fatty food intolerance, and

abdominal bloating may have cholelithiasis. Yet another individual with a 1-day history of periumbilical pain that now localizes to the right lower quadrant may have

acute appendicitis.



CLINICAL PEARL





The second step in clinical problem solving is making the diagnosis.



ASSESSING THE SEVERITY OF THE DISEASE

After establishing the diagnosis, the next step is to characterize the severity of the

disease process; in other words, to describe “how bad” the disease is. This may be as

simple as determining whether a patient is “sick” or “not sick.” Is the patient with a

urinary tract infection septic or stable for outpatient therapy? In other cases, a more



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CASE FILES: EMERGENCY MEDICINE



formal staging may be used. For example, the Glasgow coma scale is used in patients

with head trauma to describe the severity of their injury based on eye-opening, verbal, and motor responses.



CLINICAL PEARL





The third step in clinical problem solving is to establish the severity or

stage of disease. This usually impacts the treatment and/or prognosis.



TREATING BASED ON STAGE

Many illnesses are characterized by stage or severity because this affects prognosis

and treatment. As an example, a formerly healthy young man with pneumonia and

no respiratory distress may be treated with oral antibiotics at home. An older person

with emphysema and pneumonia would probably be admitted to the hospital for IV

antibiotics. A patient with pneumonia and respiratory failure would likely be intubated and admitted to the intensive care unit for further treatment.



CLINICAL PEARL





The fourth step in clinical problem solving is tailoring the treatment to fit

the severity or “stage” of the disease.



FOLLOWING THE RESPONSE TO TREATMENT

The final step in the approach to disease is to follow the patient’s response to the

therapy. Some responses are clinical such as improvement (or lack of improvement)

in a patient’s pain. Other responses may be followed by testing (eg, monitoring the

anion gap in a patient with diabetic ketoacidosis). The clinician must be prepared

to know what to do if the patient does not respond as expected. Is the next step to

treat again, to reassess the diagnosis, or to follow up with another more specific test?



CLINICAL PEARL





The fifth step in clinical problem solving is to monitor treatment response

or efficacy. This may be measured in different ways—symptomatically

or based on physical examination or other testing. For the emergency

physician, the vital signs, oxygenation, urine output, and mental status

are the key parameters.



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.



SECTION I: HOW TO APPROACH CLINICAL PROBLEMS



11



Because reading with a purpose improves the retention of information, the student

should read with the goal of answering specific questions. There are seven fundamental questions that facilitate clinical thinking.

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 most likely mechanism for this process?

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 PEARL





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.”



WHAT IS THE MOST LIKELY DIAGNOSIS?

The method of establishing the diagnosis was 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, such as “the worst headache of the patient’s life is worrisome for a

subarachnoid hemorrhage.” (See the Clinical Pearls at end of each case.)

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 PEARL





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 her life,” the concern for a subarachnoid bleed is increased.



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CASE FILES: EMERGENCY MEDICINE



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. The student should learn the limitations of

various diagnostic tests, especially when used early in a disease process. The lumbar

puncture showing xanthochromia (red blood cells) is the “gold standard” test for

diagnosing subarachnoid hemorrhage, but it may be negative early in the disease

course.



WHAT SHOULD BE YOUR NEXT STEP?

This question is difficult because the next step has many possibilities; the answer

may 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 the 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 might describe a student’s thought process as follows:

1. Make the diagnosis: “Based on the information I have, I believe that Mr. Smith

has a small-bowel obstruction from adhesive disease because he presents with

nausea and vomiting, abdominal distension, high-pitched hyperactive bowel

sounds, and has dilated loops of small bowel on x-ray.”

2. Stage the disease: “I don’t believe that this is severe disease because he does not

have fever, evidence of sepsis, intractable pain, peritoneal signs, or leukocytosis.”

3. Treat based on stage: “Therefore, my next step is to treat with nothing per

mouth, NG (nasogastric) tube drainage, IV fluids, and observation.”

4. Follow response: “I want to follow the treatment by assessing his pain (I will ask

him to rate the pain on a scale of 1 to 10 every day), his bowel function (I will

ask whether he has had nausea or vomiting, or passed flatus), his temperature,

abdominal examination, serum bicarbonate (for metabolic acidemia), and white

blood cell count, and I will reassess him in 48 hours.”

In a similar patient, when the clinical presentation is unclear, perhaps the best

“next step” may be diagnostic, such as an oral contrast radiological study to assess

for bowel obstruction.



SECTION I: HOW TO APPROACH CLINICAL PROBLEMS



13



CLINICAL PEARL





Usually, the vague query, “What is your next step?” is the most difficult

question because the answer may be diagnostic, staging, or therapeutic.



WHAT IS THE LIKELY MECHANISM FOR THIS PROCESS?

This question goes further than making the diagnosis, but also requires the student

to understand the underlying mechanism for the process. For example, a clinical

scenario may describe a 68-year-old man who notes urinary hesitancy and retention, and has a nontender large hard mass in his left supraclavicular region. This

patient has bladder neck obstruction either as a consequence of benign prostatic

hypertrophy or prostatic cancer. However, the indurated mass in the left neck area is

suspicious for cancer. The mechanism is metastasis occurs in the area of the thoracic

duct, because the malignant cells flow in the lymph fluid, which drains into the left

subclavian vein. The student is advised to learn the mechanisms for each disease

process, and not merely memorize a constellation of symptoms. Furthermore, in

emergency medicine, it is crucial for the student to understand the anatomy, function, and how treatment would correct the problem.



WHAT ARE THE RISK FACTORS FOR THIS PROCESS?

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 anemia. If the patient

has risk factors for endometrial cancer (such as diabetes, hypertension, anovulation)

and complains of postmenopausal bleeding, she likely has endometrial carcinoma

and should have an endometrial biopsy. Otherwise, occult colonic bleeding is a common etiology. If she takes NSAIDs or aspirin, then peptic ulcer disease is the most

likely cause.



CLINICAL PEARL





Being able to assess risk factors helps to guide testing and develop the

differential diagnosis.



WHAT ARE THE COMPLICATIONS TO THIS 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 pathological process. For example, “a 26-year-old man complains of right-lower-extremity swelling and pain after a trans-Atlantic flight” and

his Doppler ultrasound reveals a deep vein thrombosis. Complications of this process include pulmonary embolism (PE). Understanding the types of consequences

also helps the clinician to be aware of the dangers to a patient. If the patient has



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CASE FILES: EMERGENCY MEDICINE



any symptoms consistent with a PE, CT angiographic imaging of the chest may be

necessary.



WHAT IS THE BEST THERAPY?

To answer this question, not only does the clinician need to reach the correct diagnosis and assess the severity of the condition, but the clinician 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 PEARL





Therapy should be logical 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. The first and foremost priority in addressing the emergency patient is stabilization, then assessing and treating the ABCs (airway, breathing, circulation).

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

3. There are five steps in the clinical approach to the emergency patient: addressing life-threatening conditions, making the diagnosis, assessing severity, treating

based on severity, and following response.

4. There are seven questions that help to bridge the gap between the textbook and

the clinical arena.



REFERENCES

Hamilton GC. Introduction to emergency medicine. In: Hamilton GC, Sanders AB, Strange GR, Trott

AT, eds. Emergency Medicine: An Approach to Clinical Problem-Solving. Philadelphia, PA: Saunders;

2003:3-16.

Hirshop JM. Basic CPR in adults. In: Tintinalli J, Stapczynski JS, Ma OJ, Cline D, Cydulka R, Meckler

G, eds. Emergency Medicine. 7th ed. New York, NY: McGraw-Hill; 2010.

Ornato JP. Sudden cardiac death. In: Tintinalli J, Stapczynski JS, Ma OJ, Cline D, Cydulka R, Meckler

G, eds. Emergency Medicine. 7th ed. New York, NY: McGraw-Hill; 2004.

Shapiro ML, Angood PB. Patient safety, errors, and complications in surgery. In: Brunicardi FC, Andersen

DK, Billiar TR, et al, eds. Schwartz’s Principles of Surgery. 9th ed., New York, NY: McGraw-Hill; 2009.



SECTION II



Clinical Cases



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CASE 1

A 13-year-old adolescent boy presents to the emergency department with a chief

complaint of sore throat and fever for 2 days. He reports that his younger sister

has been ill for the past week with “the same thing.” The patient has pain with

swallowing, but no change in voice, drooling, or neck stiffness. He denies any

recent history of cough, rash, nausea, vomiting, or diarrhea. He denies any recent

travel and has completed the full series of childhood immunizations. He has no

other medical problems, takes no medications, and has no allergies.

On examination, the patient has a temperature of 38.5°C (101.3°F), a heart

rate of 104 beats per minute, blood pressure 118/64 mm Hg, a respiratory rate of

18 breaths per minute, and an oxygen saturation of 99% on room air. His posterior

oropharynx reveals erythema with tonsillar exudates without uvular deviation, or

significant tonsillar swelling. Neck examination is supple without tenderness of

the anterior lymph nodes. Chest and cardiovascular examination is unremarkable.

His abdomen is soft and nontender with normal bowel sounds and no hepatosplenomegaly. Skin is without rash.











What is the most likely diagnosis?

What are the dangerous causes of sore throat you don’t want to miss?

What is your diagnostic plan?

What is your therapeutic plan?



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CASE FILES: EMERGENCY MEDICINE



ANSWERS TO CASE 1:

Streptococcal Pharyngitis (“Strep Throat”)

Summary: This is a 13-year-old adolescent boy with pharyngitis. He has fever, tonsillar exudate, no cough, and no tender cervical adenopathy. There is no evidence of

airway involvement.

• Most likely diagnosis: Streptococcal pharyngitis.

• Dangerous causes of sore throat: Epiglottitis, peritonsillar abscess, retropharyngeal abscess, Ludwig angina.

• Diagnostic plan: Use Centor criteria to determine probability of bacterial pharyngitis and rapid antigen testing when appropriate.

• Therapeutic plan: Evaluate the patient for need of antibiotics versus supportive

care.



ANALYSIS

Objectives

1. Recognize the different etiologies of pharyngitis, paying close attention to those

that are potentially life-threatening.

2. Be familiar with widely accepted decision-making strategies for the diagnosis and

management of group A β-hemolytic streptococcal (GABS) pharyngitis.

3. Learn the treatment of GABS pharyngitis and understand the sequelae of this

disease.

4. Recognize acute airway emergencies associated with upper airway infections.



Considerations

This 13-year-old patient presents with a common diagnostic dilemma: sore throat

and fever. The first priority for the physician is to assess whether the patient is

more ill than the complaint would indicate: stridorous breathing, air hunger,

toxic appearance, or drooling with inability to swallow would indicate impending

disaster. The ABCs (airway, breathing, circulation) must always be addressed first.

This patient does not have those types of “alarms.” Thus a more relaxed elicitation

of his history can take place, and examination of the head, neck, and throat can

be performed. In instances suggestive of epiglottitis such as stridor, drooling, and

toxic appearance, examination of the throat (especially with a tongue blade) may

cause upper airway obstruction in children, leading to respiratory failure. During the

examination, the clinician should be alert for complications of upper airway infection; however, this patient presents with a simple pharyngitis.

Overall the most common etiology of pharyngitis is viral organisms. This teenager has several features that make group A streptococcus more likely: age less than

15 years, fever, absence of cough, and the presence of tonsillar exudate. Of note,



SECTION II: CLINICAL CASES



19



the patient does not have “tender anterior cervical adenopathy.” The diagnosis of

group A streptococcal pharyngitis can be made clinically or with the aid of rapid

antigen testing. Rapid streptococcal antigen testing can give a fairly accurate result

immediately and treatment or nontreatment with penicillin can be based on this

result. If the rapid streptococcal antigen test is positive, antibiotic therapy should be

given; if the rapid test is negative, throat culture should be performed and antibiotics should be withheld. The gold standard for diagnosis is bacterial culture, and if

positive, the patient should be notified and given penicillin therapy.



APPROACH TO:

Pharyngitis

CLINICAL APPROACH

The differential diagnosis of pharyngitis is broad and includes viral etiologies

(rhinovirus, coronavirus, adenovirus, herpes simplex virus [HSV], influenza, parainfluenza, Epstein-Barr virus [EBV], and CMV [cytomegalovirus] [causing infectious

mononucleosis], coxsackievirus [causing herpangina], and the human immunodeficiency virus [HIV]), bacterial causes (GABS, group C streptococci, Arcanobacterium

haemolyticum, meningococcal, gonococcal, diphteritic, chlamydial, Legionella, and

Mycoplasma species), specific anatomically related conditions caused by bacterial

organisms (peritonsillar abscess, epiglottitis, retropharyngeal abscess, Vincent angina,

and Ludwig angina), candidal pharyngitis, aphthous stomatitis, thyroiditis, and bullous erythema multiforme. Viruses are the most common cause of pharyngitis.

Group A streptococcus causes pharyngitis in 5% to 10% of adults and 15% to 30% of

children who seek medical care with the complaint of sore throat. It is often clinically

indistinguishable from other etiologies, yet it is the major treatable cause of pharyngitis.

Primary HIV infection may also cause acute pharyngitis, and its recognition can be

beneficial because early antiretroviral therapy can be started. Infectious mononucleosis

is also important to exclude because of the risk of splenomegaly and splenic rupture.

Other bacterial etiologies may also be treated with antibiotics. Studies suggest that

certain symptoms and historical features are suggestive of streptococcal pharyngitis and

may help guide the provider in generating a reasonable pretest probability of GABS.

The Centor criteria, modified by age risk, is helpful in assessing for GABS (Table 1–1).

Of note, recent epidemiologic data suggest Fusobacterium necrophorum causes

pharyngitis at a rate similar to GABS in young adults and if not treated is implicated

in causing Lemierre syndrome, a life-threatening suppurative complication.

Throat cultures remain the gold standard for the diagnosis of GABS pharyngitis,

but they have several limitations in use for daily practice. False-negative throat

cultures may occur in patients with few organisms in their pharynx or as a result of

inadequate sampling (improper swabbing method, errors in incubation or reading of

plates). False-positive throat cultures may occur in individuals who are asymptomatic carriers of GABS. Throat cultures are costly and, perhaps more importantly,

require 24 to 48 hours for results. Although it may be reasonable to delay therapy for



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