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Surgery Case Files
Cases 21-25
122
Medical
Professional
08/31/2012

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Cards

Term
What problems are associated with MEN2a?
Definition
medullary thyroid cancer, pheochromocytoma, hyperparathyrodism, lichen planus amyloidosis, Hirschsprungs
Term
What problems are associated with MEN2b?
Definition
medullary thyroid cancer, pheochromocytoma, marfanoidhabitus, mucosal neuromas, ganglioneuromatosis of the GI tract
Term
What is a follicular thyroid adenoma?
Definition
benign thyroid nodule noted to be fairly common in adults; usually takes up radioactive iodine
Term
What is the prevalence of thyroid nodules?
Definition
detected by PE= 4-7%
detected by U/S or autopsy= 19%-67%
Term
At what size are thyroid nodules considered clinically significant and require further evaluation?
Definition
more than 1 cm
Term
What should you ask a pts with a thyroid nodule?
Definition
hyper/hypo thyroidism, compressive sy,mptoms, prior history of head/neck irradiation/thyroid cancer, family history of thyroid cancer, hyperparathyroidism, pheochromocytoma
Term
THyroid nodules commonly compress structures such as...
Definition
trachea, esophagus, recurrent laryngeal nerve
Term
If a pt with a solitary thyroid nodule says they have a history of neck/head irradiaiton, then you should think....
Definition
they have a 40% chance of this nodule being cancer
Term
What percent of thyroid cancers are familial?
Definition
5% of papillary cancers are familial; 20-30% of medullary thyroid cancers occur as part of a familial syndrome
Term
Adenopathy + thyroid nodule=
Definition
increased suspicion of cancer
Term
What is the initial and most important step in diagnostic evaluation of a dominant thyroid nodule?
Definition
fine needle aspiration
Term
How reliable is FNAB of a thyroid nodule?
Definition
1-2% false positive; 2-5% false negative
Term
What do you do if pt with solitary thyroid nodule ahs a benign FNAB and normal TSH?
Definition
yearly physical examination of the neck
Term
What is a cellular FNAB of a thyroid nodule?
Definition
specimen with cytologic features consistent with either a follicular or a Hurthle cell neoplasm but you can't tell if its an adenoma or adenocarcinoma using cytologic criteria alone; made on the presence of capsular or vascular invasion
Term
What percent of pts with a hyperfunctioning nodule have a low TSH?
Definition
90%
Term
What percent of pts with hyperfunctioning nodules have cancer? hypofunctioning?
Definition
hyper= 1%; hypo= 10-20%
Term
PT with a solitary hypofunctioning nodule and a cellular FNAB have a ___ incidence of carcinoma?
Definition
20-30%
Term
If a pt has a nondiagnosted FNAB of a thyroid nodule what is the next step?
Definition
repeat biopsy (50% chance of getting a good specimen)
Term
In a pt with a persistently nondiagnostic FNAB what is the next step?
Definition
if the serum TSH is normal or high, operate to remove it; if TSH is low, perform an iodine-123 scintigraphy
Term
T/F Surgery is recommended for patients with persistently nondiagnostic FNAB results of a hypofunctioning thyroid nodule.
Definition
true; can do a partial thyroidectomy
Term
What is the incidence of carcinoma in patients with a persistenlty nondiagnostic FNAB and a hypofunctioning thyroid nodule?
Definition
9%
Term
What should you do if a pt has incidental finding of multiple subcentimeter thyroid nodules on U/S?
Definition
low probability of cancer so just observe with repeat ultrasound
Term
What is a primary spontaneous pneumothorax?
Definition
caused by rupture of subpleural blebs
Term
What are the causes of a secondary spontaneous pneumothorax?
Definition
bullous emphysematous disease, COPD, cystic fibrosis, primary and secondary cancers, and necrotizing infections with organisms such as Pneumocystis carinii, TB, catamenial, asthma
Term
What is an open pneumothorax?
Definition
injury to the full thickness of the chest wall such that the negative intrapleural pressure results in air being sucked directly through the chest wall defect, preventing air from being taken in through the trachea; it requires a mechanical covering over the chest wound
Term
What is the treatment for pneumothoraxes?
Definition
less than 15% the width of the hemithorax deflated without symptoms can be initially observed with serial CXRs; from 15-30% can use thoracentesis or pleural catheter drainage; over 30% can use tube thoracostomy; if complicated may require surgery
Term
What should you do if a patient's pneumothorax doesn't improve with observation or thoracentesis or the patient develops symptoms?
Definition
tube thoracostomy
Term
What is the typical demographic of pts with primary pneumothorax?
Definition
male, tall, slender, 15-35 yoa; smoking increases risk
Term
What is the most common demographic of a pt with secondary spontaneous pneumothorax?
Definition
over 50 with COPD
Term
What is a catamenial secondary spontaneous pneumothorax?
Definition
due to pulmonary endometriosis, occuring usually with menstruation
Term
What percent of spontaneous pneumothorax require surgical intervention?
Definition
15-20%
Term
When is surgery indicated for correction of spontaneous pneumothorax?
Definition
first time spontaneous pneumothorax when there is persistent air leakage (3-5 days), when the lung fails to reexpand, in patients who are at high risk for recurrence (bilateral pneumothoraces, a previous history of contralateral pneumothorax, significant bullous disease on radiographs), in patients who have limited access to medical care (those living in remote areas), and in patients whose occupation produces an increased risk (SCUBA divers, pilots)
Term
What is the recurrence rate of spontaneous pneumothorax after the first occurence? second occurence? third occurence?
Definition
first= 30%; second= 50%; third= 80%
Term
What is done during surgical treatment of a spontaneous pneumothorax?
Definition
pleurodesis and resection of the blebs by either thorascopic approach or thoracotomy
Term
What are the physical exam findings associated with acute lung injury?
Definition
nonspecific; diminished breath sounds and scattered rhonchi
Term
What is the typical CXR with ALI?
Definition
bilateral nonsegmental infiltrates
Term
What does an ABG of a pt with ALI typically show?
Definition
hypoxia
Term
What is the typical chest x ray associated with PE?
Definition
normal
Term
What is the strict definition of ALI?
Definition
acute onset respiratory insufficiency, PaO2: FiO2 of less than 300, bilateral infilatrates, PCWP of less than 18 mmHg
Term
What should be in the ddx of a pt with ALI?
Definition
aspiration pneumonitis, atypical pneumonia, atelectasis and PE
Term
What is the pathophys of aspiration?
Definition
spillage of gastric contents into the bronchial tree causing direct injury to the airways, which can progress to a chemical burn or pneumonitis (esp when pH <3) and predispose to bacterial pneumonia; when the aspirated gastric contents contain particulate matter, bronchoscopy may be helpful in clearing the airway
Term
Pts with aspiration pneumonitis have what chance of developing pneumonia if they are given empirical antibiotics?
Definition
50%
Term
Why are post op pts at higher risk for pneumonia?
Definition
incisional pain frequently affects the patients ability to clear airway mucus, leading to small airway obstruction and ineffective bacteria clearance
Term
In high risk surgical patients, what is the risk of developing a clinically significant PE? fatal PE?
Definition
2-3%; 1%
Term
What are the clinical hallmarks of PE?
Definition
acute onset hypoxia associated with anxiety leading to tachypnea and hypocarbia without significant CXR abnormalities
Term
What is the pathophys behind morbidity of lung contusions?
Definition
direct parenchymal injury and bronchoalveolar hemorrhage, causing VQ mismatch leading to hypoxia. This condition is worsened by chest wall injury pain leading to atelectasis in the uninvolved lung
Term
What is the most severe form of ALI?
Definition
ASRDS
Term
What is ARDS?
Definition
condition encompassing a spectrum of lung injuries characterized by increasing hypoxia and decreasing lung compliance while the PaO2:FIO2 is <200
Term
What is the pathophys of ARDS?
Definition
injury to pulmonary endothelial cells leads to an intense inflammatory response; inhomogeneous involvement of the lung occurs with interstitial and alveolar edema, hyaline membrane deposition, and eventual fibrosis; These changes manifest clinically as severe hypoxia, decreased lung compliance and increased dead space ventilation
Term
What are the symptoms of atelectasis?
Definition
low grade fever and mild respiratory insufficiency
Term
What is the pathophys of cardiogenic pulmonary edema?
Definition
myocardial dysfunction causes pulmonary interstitial edema; the increase in the amount of interstitial water compresses the fragile bronchovascular structures, thereby increasing the B/Q mismatch and resulting in hypoxia
Term
Pts with respiratory insufficiency and lethargy/diminished mentation may benefit from what treatment?
Definition
intubation to protect against against aspiration
Term
When should a patient with respiratory insufficiency be intubated?
Definition
lethargy, inability to maintain a PaO2 of 60 mmHg or an oxygen saturation of more than 91% with a supplemental nonrebreathing O2 mask (both indicative of significant alveolar arterial A/a gradient)
Term
How is a pts adequacy of ventilation assesed?
Definition
observe pt's respiratory efforts, subjective symptoms, measurement of PaCO2 by ABG analysis
Term
Why is there a decrease in pulmonary compliance when there is a lung injury?
Definition
inflammatory cells and fluid are sequesterd in the lungs leading to a decrease in pulmonary compliance and an increase in the work of breathing
Term
What does the ALI prodrome look like?
Definition
SOB, tachypnea
Term
Pts with mild acute post op respiratory insufficiency can be treated with noninvasive tx such as ...
Definition
suplemental O2, CPAP (useful for atelectasis), chest physiotherapy, including bronchodilators and mucolytic agents (useful for atelectasis, pneumonia, and reactive airway disease)
Term
What are the pressures created by conventional ventillation?
Definition
supraatmospheric pressure creating positive transpulmonary pressure ensuring inflation of the lungs; exhalation is passive and occurs after release of positive pressure
Term
What are the major settings in conventional ventilation?
Definition
volume and pressure controlled, where the tidal volume delivery is based on either volume- or pressure- limiting settings
Term
What is high frequency ventilation?
Definition
very small tidal volumes (1 mL/kg) at a high rate (100-400 breaths per minute)
Term
Is high frequency ventilation useful?
Definition
important in treating respiratory insufficiency in neonates; but not hte same success with adults
Term
What is the theoretical advantage of liquid ventilation?
Definition
reduces the amount of energy necessary to overcome surface tension at the gas liquid interface of alveoli and because disease lungs have less surfactant, liquid ventilation can improve lung compliance
Term
Is liquid ventilation better for ARDS?
Definition
need more studies to determine
Term
What is extracorporeal life support?
Definition
a heart lung machine can take over pulmonary and/or cardiac function; if cardiac function is adequate, a venovenous circuit can be used to remove CO2 and oxygenate the blood
Term
What's another name for extracorporeal pulmonary bypass?
Definition
cardiopulmonary bypass
Term
What is negative pressure pulmonary edema?
Definition
ALI secondary to forced inspiration against a closed or narrow airway resulting in "negative-pressure pulmonary edema"
Term
What is the treatment for negative pressure pulmonary edema?
Definition
unusual variant of acute lung injury and is often self-limiting with supportive care that include mechanical ventilation and IV fluids
Term
What are the complications that can result from abdomenal fascia dehiscence?
Definition
abdominal evisceration, enterocutaneous fistulas, and incisional hernias
Term
What are the patient factors that predispose to abdominal fascia dehiscence after surgery?
Definition
age over 70, diabetes mellitus, malnutrition, perioperative pulmonary disease, corticosteroid use, smoking
Term
What two factors guide the management of fascia dehiscence fuond in the early postoperative period?
Definition
stability of the intraabdominal contents (based on appearance of the wound and whether it has occured after fibrous scar has formed) and teh presence of absence of ongoing infection
Term
For a patient with abdomenal fascia dehiscence when do you immediately take them back to the OR?
Definition
pts at risk for evisceration, enterocutaneous fistula, or uncontrolled sepsis
Term
What causes enterocutaneous fistulas?
Definition
can develop from wound dehiscence and direct trauma to the underlying bowel or can be the primary processleading to wound dehiscence
Term
What is the prognosis of enterocutaneous fistula?
Definition
can be a devastating complication leading to septic and metabolic derangements, long-term disability, and mortality
Term
T/F Incisional hernias are usually evident after the skin has healed and bandages are removed.
Definition
false; can remain undetectable for as long as 5 years after the operation
Term
What are the phases of wound healing?
Definition
inflammatory, proliferation, and remodeling phases
Term
What happens during the inflammatory phase of wound healing?
Definition
inflammatory cells function in sterilizing the wound and secreting growth factors stimulating fibroblasts and keratinocytes in the wound repair process
Term
What happens during the proliferation phase of wound healing?
Definition
deposition of fibrin-fibrinogen matrix and collagen, resulting in formation of the wound matrix and an increase in wound strength
Term
What happens during the remodeling phase of wound healing?
Definition
capillary regression leads to a less vascularized wound, and with collagen cross-linking there is a gradual increase in wound tensile strength
Term
How does infection delay wound healing?
Definition
leads to delays in fibroblast proliferation, wound matrix synthesis and deposition
Term
How does inadequate nutrition affect wound healing?
Definition
vitamin C deficiency leads to inadequate collagen production, vitamin A deficiency leads to impaired fibroplasias, collagen synthesis/crosslinking, and epithelialization, vitamin B6 deficiency causes impaired collagen cross-linking
Term
How does oxygenation affect wound healing?
Definition
collagen synthesis is augmented with oxygen supplementation
Term
How do corticosteroids affect wound healing?
Definition
reduce wound inflammation, collagen synthesis and contraction
Term
How does DM affect wound healing?
Definition
microvascular occlusive disease leads to poor wound perfusion; impair keratinocyte growth factor and platelet derived growth factor functions in the wound
Term
What percent of patients who undergo abdominal surgery develop fascial defects?
Definition
2-20%
Term
By how much does having a wound infection increase your risk of abdominal fascial dehiscence?
Definition
4x
Term
Excessive fluid drainage from an abdomenal wound should make you think about what complication?
Definition
wound dehiscence
Term
When does the inflammation stage of wound healing o ccur?
Definition
days 1-3
Term
When does the proliferation stage of wound healing occur?
Definition
days 3 through 25
Term
When does the remodeling phase of wound healing occur?
Definition
day 21 to 1-2 years
Term
When post op is the highest likelihood of evisceration with dehiscence?
Definition
first two weeks
Term
Why is it not recommended to immediately correct all abdominal wounds that have fascial dehiscence?
Definition
because vasodilation and fibrosis during weeks 2 and 3 contributes to increased technical difficulty in reoperation during this time
Term
What are the post op complications more common in incisional hernias vs inguinal hernias?
Definition
wound infection rate (7-20% for incisional) and recurrence rate (20-50%)
Term
What are the technical factors related toabdominal closure failure?
Definition
inadequate tissue incorporation, inappropriate sutures/inappropriate suture placement, inadequate patient relaxation, excessive tension
Term
What are the different types of mesh that can be used for hernia repair?
Definition
polypropylene, composite mesh (expanded polytetraflouroethylene, PTFE, on the inside with polypropylene on the outside), biosynthetic prostehsis containing collagen harvested from cadavers or porcine sources
Term
What is the danger of using polypropylene mesh?
Definition
increased risk of erosion into the hollow viscus and subsequent enterocutaneous fistula formation
Term
When might you use a biosynthetic mesh?
Definition
high-risk, contaminated wounds
Term
Which is better for incisional hernias? primary repair vs with mesh? open or laparoscopic?
Definition
primary repair is better; laparoscopic and open are the same
Term
When is the tensile strength of a wound back to normal fascia strength?
Definition
is at 75-80% strength at 8 weeks and thereafter continues to strengthen but never is a strong as uninjured tissue
Term
What type of suture material should be avoided in closing an infected abdomen?
Definition
braided, nonabsorbable suture material is associated with entrapment of infected debris within the suture material and may lead to an increased number of infections
Term
How much suture do you need for a given wound length?
Definition
4x as much suture as the wound is long
Term
T/F Reclosure of a previously healed fascial incision is associated with lower strength of healing and increased wound breakdown
Definition
true
Term
Where are common places for a post op pt to get infections?
Definition
UTI, pneumonia, blood borne, incision, IV catheter infection, antibiotic associated colitis
Term
What can a CT scan show you if you suspect intraabdominal infection?
Definition
abcesses or inflammatory changes without abscesses that is suggestive of persistent secondary peritonitis
Term
What is the treatment for persistent secondary peritonitis?
Definition
may be caused by inappropriate or inadequate antimicrobial therapy; in tehse cases, treatment consists of extending the course of therapy or modifying the antimicrobial regimen
Term
At what point is a temp a fever?
Definition
higher than 38.0 to 38.5 C; 100.4 to 101.3 F
Term
What are teh different categories of surgical site infections?
Definition
superficial=above the fascia, and deep= involving the fascia
Term
How are superficial surgical site infections treated?
Definition
wound exploration and drainage of the infected material, although systemic antibiotic therapy may be needed when there is extensive surrounding cellulitis (>2cm from the incision margins) or if the patient is immunocompromised
Term
What is a deep surgical space infection?
Definition
also referrred to as intra-abdominal nifections in teh setting of post operative abdominal surgery, they include secondary peritonitis, tertiary peritonitis, and intra-abdominal abscesses
Term
What is secondary microbial peritonitis?
Definition
spillage of endogenous microbes into the peritoneal cavity following viscera perforation
Term
What determines the persistence of secondary microbial peritonitis?
Definition
microbial inoculum volume, the inhibitory and synergistic effects of the polymicrobial environment and host response
Term
What is tertiary microbial peritonitis?
Definition
occurs in ptswho fail to recover from intra-abdominal infections despite surgical and/or antimicrobial therapy because of diminished host peritoneal response; frequently due to low virulence or opportunistic pathogens such as staph epidermidis, enterococcus faecalis, and candida species
Term
How does the abdomen wall off infection?
Definition
fibrin deposition, omental containment, and ileus of the small bowel
Term
What types of bacteria are present in the gut?
Definition
anaerobes and gram negatives
Term
What are noninfectious etiologies that can cause fever in a hospitalized surgical patient?
Definition
systemic inflammatory response syndrome, endocrinopathies (adrenal insuffieceincy, thyrotoxicosis), drug reactions and transfusion reactions
Term
How many microbes are in the colon versus the stomach?
Definition
stomach= 10^2 to 10^3
colon= 10^11 to 10^14
Term
What is the body's reaction to infection in the peritoneum?
Definition
peritoneal macrophage and PMN recruitment, development of ileus and fibropurulent peritonitis to localize the spillage; translymphatic clearance of sequestered microbes and inflammatory cells, leading to the resolution of peritonitis
Term
What are the goals in management of secondary peritonitis directed at?
Definition
eliminating the source of microbial spillage and early initiation of preemptive antibiotic therapy
Term
What percent of people with secondary peritonitis continue to have complications such as recurrent 2ndary peritonitis, tertiary peritonitis, or intraabdominal abscesses?
Definition
15-30%
Term
What is standard dual agent therapy for intraabdominal infections?
Definition
aminoglycoside plus metronidazole or clindamycin (this regimen should be used with extreme caution for older patients and those with renal insufficiency; aminoglycoside peak and trough levels should be monitored closely with prolonged use in most if not all patients)
Term
What is nonstandard dual agent therapy for intraabdominal infections?
Definition
1) second or third generation cephalosporin (cefotetan, cefoxitin, ceftriaxone, cefotaxime, cefepime) plus metronidazole or clindamycin
2) flouroquinolone (cipro, levo, gati) plus metronidazole or clindamycin
Term
What is single agent therapy for intraabdominal infections?
Definition
mild or moderate infection= cefoxitin, cefotetan, ceftriaxone, ampicilllin-sulbactam
Imipenem= cilastatin, meropenim, piperacillin-tazobactam, ticeracillin-clavulanate
Term
What are the major causes of persistent secondary peritonitis?
Definition
inappropriate selection of and insufficient duration of antimicrobial therapy
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