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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3063_Библиотеки_им_академика_М_И_Перельмана
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241
Case 3
Chief Complaint
Nausea and vomiting
History and Physical Examination
A 21-year-old college student is brought to the emergency department with nausea and
vomiting. Her roommate states that she has been depressed lately and is sleeping more
than usual. Things got worse after she failed 2 final exams last week. Since the day
before, she has not seemed herself. She started complaining of nausea this morning and
has been vomiting for the past 6 hrs. She has no other medical problems and denies daily
use of medicines. Her roommate is worried that she took some pills.
She is awake but appears somnolent and in mild respiratory distress. Vital signs are T
38.3° C (101° F), BP 110/60 mm Hg, pulse 130/min, and respirations 26/min.
Cardiovascular exam shows a regular rhythm and hyperdynamic precordium. Lungs are
clear and the abdomen has normal bowel sounds with slight tenderness. There is no
evidence of edema in her extremities.
Differential Diagnosis
Drug overdose, unspecified
1.
Acetaminophen overdose
2.
Salicylate (aspirin) overdose
3.
Alcohol intoxication
4.
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Initial Management Plan Results
WBC 12,000/mm
3
; platelets and hemoglobin WNL
Sodium 146 mEq/L, potassium 5 mEq/L, chloride 108 mEq/L,
bicarbonate 17 mEq/L, glucose 110 mg/dL
BUN 28 mg/dL, creatinine 2.1 U/L
21 mEq/L
pH 7.46/pCO
2
23 mm Hg/pO
2
90 mm Hg/HCO
3
17 mm Hg;
0 mg/dL
CCS NOTE
All patients with acute altered mental status of unclear etiology can receive naloxone,
thiamine, and dextrose as part of their initial set of orders.
Assessment
Gastroenteritis5.
CBC
Serum electrolytes
BUN, creatinine
Anion gap
ABG
Serum ethanol level
243
The presentation of an acute change in mental status in a depressed patient should lead you to
suspect a possible drug overdose. A respiratory alkalosis and metabolic acidosis should
prompt you to suspect salicylate intoxication. A blood alcohol level can help to rule out this
ingestion. The management approach should take into account the patient’s altered mental
status. Other complications of aspirin overdose (not present in this patient) are tinnitus,
pulmonary edema, and coma (resulting from edema).
Aspirin is a very complex metabolic poison. It causes an acute respiratory alkalosis at first by
central brainstem stimulation. Later, there is predominant metabolic acidosis. The acidosis is
actually a lactic acidosis because aspirin poisons the mitochondria, leading to anaerobic
metabolism and the production of lactate. Aspirin is directly toxic to the kidney tubules and
lung parenchyma and may give acute tubular necrosis and acute respiratory distress syndrome.
The direct effect of aspirin on the brain leads to encephalopathy.
Further management plan Results
CCS NOTE
For patients with potential overdose, it is acceptable to order activated charcoal before
obtaining the results of specific diagnostic tests. Although charcoal may not help every
overdose, it has no adverse effects.
Plasma salicylate level
1.
Salicylate level 100 mg/dL (elevated)
1.
Urine or blood toxicology screen
2.
Negative for all but salicylate
2.
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Treatment plan
Discussion
Salicylates (aspirin) have great potential for both accidental ingestion by children and as a
suicide substance for adults. Acute ingestion of >100 mg/kg leads to an initial respiratory
alkalosis and later may cause a mixed respiratory alkalosis and metabolic acidosis. Acute
ingestion invariably presents with vomiting, and this often aids in distinguishing aspirin from
acetaminophen overdose.
Winter’s formula is helpful in evaluating acid-base disorders associated with metabolic
acidosis. It tells you the expected (corrected) pCO
2
in a patient with a metabolic acidosis.
pCO
2
= 1.5(HCO3) + 8 (+/−2)
For example, if bicarbonate is 10 mm/L, the expected pCO
2
is 1.5(10) + 8 = 23 mm Hg.
If the pCO
2
is lower than this, the patient has an additional respiratory alkalosis. This is not
respiratory compensation for a metabolic acidosis. Overcompensation is impossible.
The initial management calls for the prevention of absorption. This is best accomplished at
home by induced emesis (with an agent like ipecac syrup) and should be considered for all
patients without altered mental status. Gastric lavage, used more often in the emergency
department, is used on patients who present within 1 hour of ingestion as another method to
empty the gastric contents. Activated charcoal is administered to absorb the ingested toxin,
Activated charcoal to block further absorption of the drug1.
IV fluids to help restore volume status2.
IV bicarbonate for urine alkalinization, which aids drug excretion3.
Psychiatric consultation when patient is stable4.
245
thereby blocking further systemic absorption. Following these initial measures, alkalinization
of the urine should be performed to promote ionization of the salicylate and to thus reduce
further reabsorption. For this purpose, IV bicarbonate is given. Effectiveness is monitored by
measuring the pH of the urine, not serum.
CCS NOTE
Consultations should rarely, if ever, be ordered for single-best answer questions.
However, you are expected to ask for them much more often on the CCS.
Lastly, hemodialysis would be indicated for:
Final Diagnosis
Salicylate intoxication
Persistent acidosis with pH <7.1
1.
Initial salicylate levels >160 mg/dL or >130 mg/dL after 6 hrs
2.
Coma/seizures
3.
Renal failure
4.
Congestive heart failure
5.
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Case 4
Chief Complaint
“I have blood in my stool.”
History and Physical Examination
A 76-year-old white man comes to the emergency department after passing stool
surrounded by a large volume of blood. The patient states he had 2 similar episodes 7
months ago but did not seek medical attention. He denies abdominal pain, fever, and
diarrhea. He has a history of a myocardial infarction and valvular disease. He takes no
medications.
Vital signs are T 37.0° C (98.6° F), BP 90/70 mm Hg, pulse 100/min, and respirations
16/min. There are orthostatic changes. The abdomen is soft and nontender. Rectal exam
shows no hemorrhoids or stool, but there is bright red blood in rectum. Cardiovascular
exam shows a 3/6 systolic ejection murmur radiating to carotids.
CCS NOTE
On the CCS in GI bleed, the most important initial consideration is hemodynamic
stability. If the patient is hypotensive or tachycardic, a bolus of IV normal saline or
Ringer’s lactate should be ordered with the first set of orders.
247
Differential Diagnosis
CCS NOTE
Specific endoscopy is not as important as fluid resuscitation and correction of
coagulopathy. Order fluids, CBC, type and cross first, then do endoscopy or other
procedures later.
Initial Management Plan Results
Hematocrit 29% (normal 39-49%)
32 mg/dL (normal 8-18 mg/dL)
0.9 mg/dL (0.6-1.3 mg/dL)
Normal
Hemorrhoids
1.
Angiodysplasia
2.
Colonic polyps
3.
Ulcerative colitis
4.
Crohn’s disease
5.
Diverticulosis with diverticular bleeding
6.
Rectal ulcer
7.
CBC
BUN
Creatinine
PT/PTT
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Normal
Setting: emergency department
CLINICAL PEARL
Upper endoscopy should be done before colonoscopy in a patient with hematochezia if
he has hypotension and elevated BUN. That is because 10% of patients presenting with
hematochezia will have an upper GI bleed, and if the patient is unstable, it is more
likely to be an upper bleed which should be addressed immediately.
Assessment
Large volume bleeding from the colon in adults is usually caused by diverticular disease,
angiodysplasia, or ulcerative colitis. Benign or malignant neoplasms and ischemic colitis
rarely cause massive bleeding. The site of bleeding in the colon can be identified in 70-80% of
patients. Massive bleeding originates in the right as often as in the left colon. Diverticulosis is
most often left-sided. Bleeding diverticula and angiodysplasia are common in the right colon.
When active hemorrhage is occurring, radionuclide scintigraphy or angiography can be
performed to identify the site of hemorrhage.
Colonoscopy will show lesions in the colon also, but they are harder to see during large-
volume bleeding. Colonoscopy is the primary method of identifying angiodysplasia.
Nasogastric tube placement is occasionally useful because 10% of cases of hematochezia
originate from the upper GI tract. BUN characteristically rises because of absorption of
nitrogenous breakdown products of blood from the GI tract.
Electrocardiogram
249
Further management plan Results
Treatment plan
CCS NOTE
Nasogastric tube placement is one of the least useful tasks in GI bleeding. Lavaging the
stomach with saline or ice has no efficacy in stopping the bleeding. The nasogastric
tube is useful in guiding the site of the initial endoscopy.
Discussion
Colonoscopy
1.
Spider angioma-like lesions
in right colon
1.
Radionuclide scintigraphy (RBC scan), if bleeding is too rapid
to make colonoscopy effective
2.
Negative
2.
Nasogastric tube placement (if uncertain whether upper or
lower GI source of bleed)
3.
Negative
3.
Normal saline infusion until blood is available for transfusion
1.
Endoscopic electrocoagulation
2.
Blood transfusion if patient symptomatic from anemia or if active ongoing bleed
3.
Surgical consult for possible colonic resection if bleeding is persistent and massive
(>4–6 units of blood in <24 hrs)
4.
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