Surgery: UWorld Flashcards
What form of shoulder dislocation is most common and is usually caused by a direct blow or a fall onto an outstretched arm, after which the patient holds the arm slightly abducted and externally rotated?
Anterior dislocation
What is the most common bone in the body to be affected by stress fractures?
The tibia
Stress fractures classically occur in the anterior part of the middle third of the tibia in patients involved in jumping sports and the posteromedial part of the distal third of the tibia in runners. X-rays are frequently normal during the initial evaluation.
What does a steady state respiratory quotient (RQ) close to 1.0 indicate?
A predominance of oxidation of carbohydrates and net lipogenesis
The RQ is the steady-state ratio of carbon dioxide (CO2) produced to oxygen (O2) consumed per unit time and may be used to make assessments of the metabolism taking place in particular organs or in the body as a whole. The RQ for protein and lipid as sole sources of energy are 0.8 and 0.7 respectively.
Dyspnea, hemoptysis, subcutaneous emphysema, audible crepitus on cardiac auscultation (Hamman sign), and sternal tenderness are all characteristic of what diagnosis?
Tracheobronchial tear
What is a good modality for evaluating cardiac systolic and diastolic functions, cardiac valves, and pericardial effusions?
Transthoracic echocardiography
Hip, groin, or knee pain plus an antalgic gait in a boy between age 4 and 10 is a classic presentation of what?
Legg-Calve-Perthes disease (Idiopathic avascular necrosis of the femoral capital epiphysis)
How do you confirm the diagnosis of retroperitoneal hemorrhage from an extension of a local vascular hematoma secondary to cardiac catheterization?
Non-contrast abdominal CT scan
Treatment is largely supportive. Patients who develop neurologic deficits in the ipsilateral extremity require urgent decompression of the hematoma.
Postprandial abdominal cramps, weakness, light-headedness, and diaphoresis in the setting of a recent partial gastrectomy are suggestive of what diagnosis?
Dumping syndrome
This is a common post-gastrectomy complication (up to 50% of patients with partial gastrectomy may experience this syndrome). The rate is lower for patients who underwent more conservative gastric surgery (IE proximal vagotomy). The pathophysiology of this condition involves rapid emptying of hypertonic gastric content into the duodenum and small intestine. This process leads to the fluid shift from intravascular space into the small intestine, release of intestinal vasoactive polypeptides, and stimulation of autonomic reflexes.
Following splenectomy, patients are at increased risk for sepsis secondary to which 3 bacteria?
- Streptococcus pneumoniae
- Neisseria Meningitidis
- Haemophilus influenzae
Splenectomy increases the risk of sepsis secondary to encapsulated bacteria. Pneumococcal vaccine boosters are required every 5 years. The spleen plays an important role in immune surveillance. As blood flows through it, antigens are samples by dendritic cells and presented to helper T-cells, which subsequently activate B-cells to differentiate into antibody-secreting plasma cells. In the absence of specific antibodies, phagocytes are unable to recognize and engulf encapsulated organisms, thereby allowing these organisms to multiply unchecked in the circulation.
Persistent pneumothorax and significant air leak following chest tube placement in a patient who has sustained blunt chest trauma suggests what?
Tracheobronchial rupture
Other findings include pneumomediastinum and subcutaneous emphysema.
What is the first step in management of a suspected urethral injury?
Retrograde urethrogram
The procedure can be used both to determine whether damage to the urethra has occurred and to determine the location of such damage within the urethra. Foley catheterization in the presence of a urethral injury will predispose the patient to abscess formation and worsening of the urethral damage.
Patients with blunt trauma should undergo what initial evaluation for intraperitoneal hemorrhage?
Focused assessment with sonography for trauma (FAST)
FAST can be done in a few minutes and has a high sensitivity and specificity for detecting hemoperitoneum, pericardial effusion, and intraperitoneal fluid.
What classically presents with dull abdominal pain and possibly bloody diarrhea acutely following abdominal aortic aneurysm repair
Colonic ischemia
Colonic ischemia follows up to 7% of such procedures due to interference of blood flow to the distal left colon. Common causes include loss of collateral circulation, manipulation of vessels with surgical instruments, prolonged aortic clamping and impaired blood flow through the inferior mesenteric artery.
What artery is commonly injured in a supracondylar fracture of the humerus (commonly seen in children)?
Brachial artery
What is the treatment for acute mediastinitis?
Drainage, surgical debridement, and prolonged antibiotic therapy.
Antibiotics alone do not appropriately treat mediastinitis. Even with appropriate treatment, acute mediastinitis has a mortality rate of 10-50%.
What is the preferred treatment of ruptured appendicitis with a contained abscess (appear stable >5 days after onset of symptoms)?
Antibiotics, IV fluids, and bowel rest because surgery has been associated with a higher morbiditiy
A CT scan may reveal an abscess that can be percutaneously drained. Most patients will require an interval appendectomy 6-8 weeks later to prevent future appendicitis.
What is characterized by early satiety, nausea, nonbilious vomiting, and weightloss?
Gastric outlet obstruction
What are the 3 main organs injured by blunt abdominal trauma?
Spleen, liver, and kidney
Evaluation with exploratory laparotomy.
- What muscles of the leg are innervated by the tibial nerve?
- The tibial nerve provides sensation to what region of the leg?
- The muscles of the posterior compartment of the thigh and leg, and the plantar muscles of the foot. These muscles control flexion of the knee and digits, and plantar flexion of the foot
- The tibial nerve provides sensation to the leg (except medial side) and plantar foot
CT scan of the head showing numerous minute punctuate hemorrhages with blurring of the gray-white matter interface is characteristic of what?
Diffuse axonal injury
This is the most significant cause of morbidity in patients with traumatic brain injuries. It is frequently due to traumatic deceleration injury and results in vegetative state.
What most commonly results from blunt trauma to the perineum (straddle injuries) or instrumentation of the urethra, and presents with perineal tenderness or hematoma, a normal prostate, and bleeding from the urethra?
Anterior urethral injury
This is the portion of the urethra distal to the urogenital diaphragm. Patients may not complain of inability to urinate, and delayed presentations may be complicated by sepsis secondary to extravasation of urine into the scrotum, perineum and/or abdominal wall.
What effect on risk of postoperative atelectasis does moving from supine to sitting have?
Moving from supine to sitting can increase the functional residual capacity by 20-35% and thus can help prevent postoperative atelectasis
What is the final stage of compartment syndrome in which the dead muscle has been replaced by fibrous tissue?
Volkmann’s ischemic contracture
Deep lacerations to the axillary region and axillary lymphadenectomy are common causes of injury to what nerve?
Long thoracic nerve
Damage causes scapular winging.
What is the gold standard for evaluating known peripheral artery disease (PAD) because it is highly sensitive and specific for determining the specific vessels involved?
Contrast arteriography
It is an invasive procedure requiring arterial puncture and the use of contrast dye. Arteriography is best reserved for an unclear diagnosis or when planning invasive interventions.
Air seen under the diaphragm (between liver and diaphragm for example) is of greatest concern for what?
Perforated peptic ulcer
No other diagnostic studies are required for this surgical emergency, and surgery consultation must be obtained immediately.
What should be suspected in all adult patients with blunt chest trauma who present with persistent jugular venous distension, tachy cardia, and hypotension despite aggressive fluid resuscitation?
Acute cardiac tamponade
Chest x-ray findings typically reveal a normal cardiac silhouette without tension pneumothroax.
What is the treatment for Legg-Calve-Perthes disease?
Conservative management with observation and bracing is the general treatment
Surgery may be indicated in cases where the femoral head is not well contained within the acetabulum.
Why is mechanical ventilation risky in a patient with hypovolemic shock?
It may cause circulatory collapse
Positive pressure mechanical ventilation increases intrathoracic pressure, which decreases venous return to the heart and thereby decreases the ventricular preload. This effect may cause circulatory collapse if the patient’s intravascular volume is not replaced before mechanical ventilation is attempted.
A palpable or audible snap occuring while slowly extending the leg at the knee from full flexion while simultaneously applying tibial torsion is indicative of what?
What sign is this?
Meniscal tear
This is McMurray’s sign
When do duodenal hematomas most commonly occur?
Following direct blunt abdominal trauma
More common in children
Syringomyelia classically presents with what?
Central cord syndrome
This is characterized by impaired strength and pain/temperature sensation in the upper extremities (or having a cape-like distribution), with preservation of dorsal column function. Syringomyelia is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord that can expand and elongate over time, destroying the spinal cord.
In evaluating a patient with a shoulder injury, a positive drop arm sign (arm drops rapidly from 90 degree abduction) is indicative of what?
Rotator cuff tear
The rotator cuff is formed by the tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis. The supraspinatus is most commonly injured, due to repeated bouts of ischemia near its insertion on the humerus induced by compression between the humerus and the acromion. The drop arm test is a maneuver that can help to diagnose a rotator cuff tear. Here, the patient’s arm is abducted passively to greater than 90 degrees, and the patient is then asked to lower the arm slowly. With a complete rotator cuff tearm the patient will be unable to lower the arm smoothly and it will appear to drop rapidly from near the 90 degree position.
Musculoskeletal infections, such as osteomyelitis or abscess, frequently result from hematogenous spread of organisms from another site, such as the skin. In such cases, what is the most common offending pathogen?
Staph aureus
What condition is characterized by rapidly progressive bilateral cellulitis of the submandibular and sublingual spaces?
Ludwig angina
The infection classically arises from an infected second or third mandibular molar; the organisms that typically cause the process are streptococcus and anaerobes. Asphyxiation is the most common cause of death in this disease.
Foot ulcers occuring on the plantar surface of the foot under points of greatest pressure, such as under the head of the first metatarsal bone are classically caused by what?
Peripheral neuropathy, microvascular insufficiency and immunosuppression
All three are present in diabetics. Diabetic foot ulcers typically occur on the sole of the foot on high-pressure weight bearing sites, such as below the head of the first metatarsal.
What is the management of a patient with pulmonary contusions?
Close monitoring and intubation with mechanical ventilation in severe instances
What is the diagnostic study of choice in a patient with suspected esophageal perforation?
Gastrografin-contrast esophagography
This demonstrates contrast leakage at the site of the perforation.
What may mimic appendicitis by causing anorexia and midabdominal/right lower quadrant pain?
Meckel’s diverticulitis
Chills and other signs of sepsis typically do not occur.
What is the most common infectious agent in acute bacterial parotitis?
Staphylococcus aureus
Parotitis is an inflammation of one or both parotid glands. This post-operative complication can be prevented with adequate fluid hydration and oral hygiene.
Abdominal pain and bloody diarrhea following an abdominal aortic aneurysm repair is concerning for what?
Bowel ischemia or infarction
Bowel ischemia is one known complication (1-7%) incidence of abdominal aortic aneurysm repair. It results from inadequate colonic collateral arterial perfusion to the left and sigmoid colon after loss of the inferior mesenteric artery during aortic graft placement.
What muscles are innervated by the obturator nerve?
What portion of the leg recieves sensory innervation from the obturator nerve?
- The obturator nerve innervates the muscles of the medial compartment of the thigh (gracilis, adductor longus, adductor brevis, anterior portion of adductor magnus) and controls adduction of the thigh.
- It provides sensation over the medial thigh
How is acute appendicitis diagnosed?
It is a clinical diagnosis
In a middle-aged adult, superficial unilateral hip pain that is exacerbated by external pressure to the upper lateral thigh (as when lying on the affected side in bed) suggests what?
Trochanteric bursitis
This is inflammation of the bursa surrounding the insertion of the gluteus medius onto the femur’s greater trochanter.
What is the most common cause of lower gastrointestinal hemorrhage in an elderly patient?
Diverticulosis
Bleeding from diverticulosis is typically painless. Diverticulosis should be distinguished from diverticulitis, which is characterized by abdominal pain and infectious symptoms, usually without associated bleeding.
What is the initial management of a patient with thermal inhalation injury to the upper airway?
Endotracheal intubation
What should be suspected in patients with a history of blunt trauma (motor vehicle accident), abnormal chest x-ray, left lower lung opacity, elevated hemidiaphragm, and mediastinal deviation?
Diaphragmatic rupture
Children can have delayed presentation with expansion of the diaphragmatic defect and herniation of abdominal organs.
What test is used to confirm the diagnosis of esophageal perforation?
A water-soluble contrast esophagram
What typically presents with lower abdominal pain, malaise, low-grade fever and a tender pelvic mass on rectal examination?
Pelvic abscess
Acute ruptured appendicitis may be complicated by pelvic abscess.
Oliguria, azotemia, and an elevated BUN/creatinine ratio of >20:1 in the post operative state most likely indicate what?
Acute pre-renal failure from hypovolemia
Urinary catheter obstruction should first be ruled out. The next step in the diagnosis/management of acute renal failure manifesting as oliguria or anuria is an IV fluid challenge.
When a wound fails to heal after a prolonged period, biopsies should be obtained to ensure that the ulcer has not degenerated into what?
Squamous cell carcinoma
When SCC arises within a burn wound, these ulcers are known as Marjolin ulcers.
Loss of motor function, pain, and temperature, but intact proprioception is characteristic of what?
Anterior cord syndrome
This is commonly associated with a burst fracture of the vertebra and is characterized by loss of motor function, pain, and temperature below the lesion. Proprioception remains intact.
A biconvex hematoma on head CT scan is diagnostic of what?
Epidural hematoma
All patients with a clavicular fracture should undergo what evaluation?
Neurovascular examination
This is to rule out injury to the underlying brachial plexus and subclavian artery
Absent bowel sounds with gaseous distention of both the small and large bowels is indicative of what?
Paralytic (adynamic) ileus
This classically follows abdominal surgery but can also occur in cases of retroperitoneal hemorrhage associated with vertebral fracture.
Non bleeding varices are managed with what?
Nonselective beta-adrenergic antagonists such as propranolol
Such therapy can reduce the risk of bleeding by up to half.
What is the most common etiology of small bowel obstruction?
Adhesions (typically post-operative)
What is given pre-operatively to patients with mild hemophilia A?
Desmopressin (DDAVP)
This is given to prevent excessive bleeding. It indirectly increases factor VIII levels by causing vWF release from endothelial cells.
What is transesophageal echocardiography helpful in diagnosing?
Aortic dissection
What potentially lethal postoperative complication commonly presents with neausea, vomiting, abdominal pain, hypoglycemia, and hypotension often in the setting of steroid-dependence?
Acute adrenal insufficiency
Exogenous steroids depress pituitary-adrenal axis and a stressful situation can precipitate an acute adrenal insufficiency.
What is the difference between the presentation of bowel ischemia and bowel infarction?
- Ischemia presents with sudden-onset severe poorly localized (visceral) midabdominal pain accompanied by nausea and vomiting but physical exam is unremarkable
- Infarction presents like ischemia but also with peritoneal signs (tenderness to palpation with guarding and rebound) and bloody stool
Surgery below the mandible, such as for a tumor of the submandibular salivary gland, would put one at risk for what type of injury?
Hypoglossal nerve injury resulting in tongue palsy
What kind of tear of the medial meniscus leads to locking of the knee joint during terminal extension?
A bucket handle tear
Severe pain, pain with passive range of motion, paresthesias, as well as pallor and paresis of the affected limb is all characteristic of what?
Compartment syndrome
The presence of pulses does not rule out compartment syndrome. Compartment syndrome may be caused by direct trauma (hemorrhage), prolonged compression of an extremity, or after revascularization of an acutely ischemic limb.
Injury to which nerve would cause loss of sensation of skin over the lateral three and a half fingers and lateral half of the palm?
Median nerve
What is the next step in management of someone with clinical signs of scaphoid fracture but a negative X-ray?
Thumb immobilization in a spica cast and repeated X-rays in 7-10 days
It can take up to 10 days to show abnormalities on X-rays. Scaphoid fractures are particularly concerning because of the tenuous blood supply of the scaphoid, making the proximal fracture fragment vulnerable to avascular necrosis.
What is the treatment for compartment syndrome?
Urgent Fasciotomy
What is the primary objective in the management of a rib fracture?
Pain relief
This will allow proper ventillation and prevent atelectasis and pneumonia.
All patients with penetrating injury and evidence of peritonitis or unstable hemodynamics need what?
Immediate laparotomy
Uric acid stones, which are radiolucent, have to be evaluated by what?
CT of the abdomen or intravenous pyelography
What is the treatment of choice for esophageal perforation?
- Antibiotic therapy
- Parenteral nutrition
- Surgical repair
What are some signs of peritoneal irritation (peritoneal signs)?
- Rebound tenderness
- Abdominal guarding
- Decreased bowel sounds
What is characterized by sudden onset pain, pulselessness, pallor, paresthesias, and paralysis in the affected limb of a patient with a low likelyhood of compartment syndrome?
Arterial embolism (Arterial occlusion of an extremity)
In contrast, arterial thrombosis results in slow, progressive narrowing of the vascular lumen in the affected limb (symptoms have insidious onset), and pulses in patients with arterial thrombosis are usually diminished bilaterally.
What is a hydrocele?
Fluid collection within the processus or tunica vaginalis (the peritoneal projection that accompanies the testis during its descent into the scrotum)
What results from lower extremity venous insufficiency due to valve incompetence?
- Edema
- Stasis dermatitis
- Venous ulceration
Valvular incompetence results in pooling of venous blood and increased pressures in post capillary venules. This increased pressure damages capillaries causing loss of fluid, plasma proteins, and erythrocytes into the tissue. Erythrocyte extravasation causes hemosiderin deposition and the classic coloration of stasis dermatitis. Inflammation of venules and capillaries as well as fibrin deposition and platelet aggregation cause microvascular disease and ultimately ulcerations will occur. Such disease classically occurs on the medial leg superior to the medial malleolus.
Which meniscus is more commonly injured?
The medial meniscus is more commonly injured than the lateral meniscus
What is the most effective strategy to prevent post-operative atelectasis?
Breathing exercies with incentive spirometer
Hoarseness can result from thyroid/parathyroid surgery with injury to what?
Recurrent laryngeal branch of the vagus nerve
What usually presents with nausea, vomiting, abdominal bloating, and dilated loops of bowel on abdominal x-ray?
Complete small bowel obstruction
Adhesions, typically post-operative, are the most common etiology.
What is the investigation of choice to diagnose an intraabdominal abscess?
CT scan
Patients with blunt abdominal trauma and positive findings on focused assessment with sonography for trauma (FAST) require what?
Emergent exploratory laparotomy
Epigastric tenderness and palpable crepitus in the suprasternal notch are characteristic of what?
Esophageal rupture
The retrosternal pain and crepitus in the suprasternal notch are the result of pneumomediastinum, which commonly occurs following rupture of the esophagus within the mediastinum.
In pediatric patients, what is the most common etiology of osteomyelitis?
Hematogenous seeding by Staph aureus
The infection tends to affect the metaphysis, with epiphyseal sparing. Radiographic evidence of osteomyelitis is subtle early in the course of the disease.
What rare complication of aortic aneurysm surgery presents with abrupt onset of weakness and bowel/bladder dysfunction?
Spinal cord ischemia with lower spastic paraplegia
The spinal cord derives its blood supply from the anterior spinal artery (ASA) and two posterior spinal arteries, which originate from the vertebral artery. The ASA has several small arteries feeding into it that originate from radicular arteries in the vertebral artery, intercostal arteries, and sometimes the aorta. The thoracic spinal cord is particularly dependent on these radicular arteries and the most vulnerable to infarction.
Tachypnea, tachycardia, hypotension, mental changes, thrombocytopenia, and petechia in the setting of long bone fracture are characteristic of what?
Fat embolism
Burning pain and paralysis in upper extremities with relative sparing of the lower extremities is characteristic of what?
Central cord syndrome
It is commonly seen in elderly secondary to a forced hyperextension type of injury to the neck.
What is the treatment for a patient with acute gastrointestinal perforation who is taking warfarin?
Emergent laparotomy with pre-operative administration of fresh frozen plasma
What is the next investigational step in the work-up of a solitary pulmonary nodule detected on chest x-ray?
CT scan
The data obtained should be coupled with demographic data to determine the patient’s risk of malignancy, which is necessary for determining further therapy. If malignancy is unlikely, serial CT scans for 2 years is appropriate. An indeterminate or suspicious finding on chest CT requires further investigation with biopsy or PET scan.
In case of an amputation injury, how should the amputated parts be preserved?
Wrapped in saline-moistened gauze, sealed in a plastic bag, and placed on ice
In a young individual who presents with a fleshy immobile mass on the midline hard palate, the most likely diagnosis is what?
Torus palatinus
This is a benign bony growth. It is thought to be due to both genetic and environmental factors and is more common in younger patients, women, and asians. No medical or surgical therapy is required unless the growth becomes symptomatic or interferes with speech or eating.
Crohn disease and other intestinal diseases causing fat malabsorption increase the absorption of what?
Oxalate
Increased absorption is the most common cause of symptomatic hyperoxaluria and oxalate stone formation.
- Positive trendelenburg sign (drooping of the contralateral hemipelvis below its normal horizontal level during monopedal stance) indicates weakness of which muscle(s)?
- Which nerve innervates the affected muscle(s)?
- Gluteus medius and minimus muscles
- Superior gluteal nerve
What kind of shoulder dislocation commonly occurs after a tonic-clonic seizure, with the patient holding the arm adducted and internally rotated?
Posterior dislocation
Neurovascular impairment is unusual.
What is the preferred way to establish an airway in an apneic patient with a cervical spine injury?
Orotracheal intubation with rapid sequence intubation (RSI)
This is the preferred route to manage unstable and apneic patients to protect the airway and provide oxygenation. 4 people are involved in RSI: one manually stabilizes the patient, one induces the patient with anesthesia, one applies cricoid pressure to prevent passive regurgitation until endotracheal tube placement is confirmed, and one places the endotracheal tube.
After blunt chest trauma, hemorrhagic shock associated with decreased breath sounds and dullness to percussion over one hemithorax and contralateral tracheal deviation is most likely due to what?
A large ipsilateral hemothorax
Each hemithorax is capable of holding up to 50% of the circulating blood volume. Tension pneumothorax would also produce hypotension, tachycardia, and tachypnea, with tracheal deviation but would reveal decreased breath sounds with hyperresonance to percussion of the affected hemithorax.
Dyspnea, tachypnea, chest pain, hypoxemia worsened by intravascular volume expansion, and patchy, irregular alveolar infiltrates on chest x-ray are indicative of what?
Pulmonary contusions
This would occur in the setting of blunt chest trauma. Pulmonary contusion is often not clinically evident immediately following an injury, and initial radiographic studies may be negative. Patients typically develop hypoxia and respiratory distress hours later as pulmonary edema sets in. Administration of large volumes of IV fluid may hasten this process. Pulmonary contusion complicates 30-75% of cases of severe blunt chest trauma.
What is the treatment of choice for acalculous cholecystitis in a critically ill patient?
The emergent treatment of choice is percutaneous cholecystostomy followed by cholecystectomy when the medical condition stabilizes
What is the treatment for penile fracture
Retrograde urethrogram followed by surgical exploration of the penis
Urethrogram is to assess for urethral injury. Surgery is to evacuate the hematoma and mend the torn tunica albuginea.
What results from disc degeneration in patients over age 40 and presents with neck pain and stiffness?
Cervical spondylosis
Patients may develop spinal stenosis, resulting in neurologic deficits.
What injury may be missed by CT scan during the first six hours following blunt trauma and if untreated can be complicated by a retroperitoneal abscess or pseudocyst?
Pancreatic injury (Contusion, crush injury, laceration, or transection)
Fever, chills, and deep abdominal pain suggest a retroperitoneal abscess.
