Surgery: UWorld Flashcards
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.
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
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.
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.
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 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.
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 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 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.
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.
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.
What is the management of a patient with pulmonary contusions?
Close monitoring and intubation with mechanical ventilation in severe instances
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 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 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.
How is acute appendicitis diagnosed?
It is a clinical diagnosis
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 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.
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
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 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
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
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
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.
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.
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 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 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 is the most common etiology of small bowel obstruction?
Adhesions (typically post-operative)
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.
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.
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
Tachypnea, tachycardia, hypotension, mental changes, thrombocytopenia, and petechia in the setting of long bone fracture are characteristic of what?
Fat embolism
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.
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.
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.
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 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.
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.
What is typically asymptomatic (symptoms would include pain associated with fractures or with arthritis resulting from bone deformity) and diagnosed when an increased bone-specific alkaline phosphatase is discovered on routine laboratory testing (serum calcium and phosphorus are normal)?
Paget disease of the bone
Paget disease of the bone (osteitis deformans) is a disease of unkown etiology that is characterized by disordered bone remodeling. Specifically, osteoclast activity is increased leading to drastically enhanced bone resorption which results in accelerated osteoblast activity in an effort to rebuild the degraded bone. The result is formation of structurally inferior woven bone at various sites throughout the body. The woven bone formed in Paget disease lesions is larger than normal bone and is prone to bowing and fracture.
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
Weakness and atrophy of the hypothenar and interosseous muscles characterize what palsy?
Klumpke’s palsy
Damage to the lower trunk (C8 and T1) of the brachial plexus which primarily affects muscles innervated by the ulnar nerve. “Claw hand” deformity may also result.
- What muscles are innervated by the femoral nerve?
- The femoral nerve provides sensation for what part of the leg?
- The femoral nerve innervates the muscles of the anterior compartment of the thigh, and is therfore responsible for knee extension and hip flexion
- The femoral nerve provides sensation to the anterior thigh and medial leg via the saphenous branch
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.
What presents as flank or abdominal pain radiating to the groin, along with nausea and vomiting?
Urinary calculi (Renal colic)
Unlike patients with an acute abdomen, patients with urinary stones are often writhing in pain and unable to sit still in the exam room. These patients do not have peritoneal irritation so movement does not worsen their pain.
What occurs when the gallbladder becomes distended as it contracts against an obstructed cystic duct?
Biliary colic
The pain is typically exacerbated by fatty meals and resolves completely between episodes. Fever and leukocytosis are not present.
What typically causes severe periumbilical abdominal pain out of proportion to findings on physical exam, and is accompanied by nausea, vomiting, and fecal blood?
Bowel ischemia
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.
Patients who present with localized right lower quadrant findings have a high incidence of perforation with abscess formation when they present how long after symptom onset?
>48hours: High risk of perforation into the peritoneal and retroperitoneal spaces, causing peritonitis or an abscess. Patients at this stage can have additional symptoms of fever, leukocytosis, reactive thrombocytosis
>5days: Likely have a contained abscess and appear more stable than patients who present within 72 hours of symptom onset.
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.
Atelectasis is a common postoperative complication that results from shallow breathing and weak cough due to pain, and is most common on what postop day(s) following abdominal or thoracoabdominal surgery?
POD#2-3
- All patients with smoke inhalation should be suspected to have what?
- What is the appropriate treatment?
- Acute carbon monoxide poisoning
- 100% oxygen via a nonrebreather facemask
What nerve is involved in tarsal tunnel syndrome?
Tibial nerve
The tibial nerve is compressed as it passes through the ankle. Tarsal tunnel syndrome is caused by a fracture of the bones around the ankle. Patients typically present with burning, numbness, and aching of the distal plantar (not dorsal) surface of the foot or toes that sometimes radiates up the calf.
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
What is Cushing’s reflex
What does it indicate?
- Hypertension, bradycardia, and respiratory depression
- Elevated intracranial pressure
Nasopharyngeal cancer (NPC) is most common in patients of Mediterranean and Far Eastern descent and is strongly associated with what?
Epstein-Barr virus infection
NPC is usually asymptomatic until disease is advanced; most NPC is metastatic at the time of diagnosis. Patients with NPC often present with recurrent otitis media (resulting from eustachian tube obstruction by tumor), recurrent epistaxis, and/or nasal obstruction.
Communicating hydroceles that persist beyond 12 months of age are unlikely to resolve spontaneously and put the patient at increased risk of what?
Indirect inguinal hernia
Surgical intervention is indicated in such cases.
What are 4 ways to lower intracranial pressure?
- Elevate head: increases venous outflow from head
- Sedation: Decreases metabolic demand and controls HTN
- IV Mannitol: Extraction of free water out of brain tissue
- Hyperventilation: CO2 washout, leading to cerebral vasoconstriction
What is the most common cause of acute mesenteric ischemia?
An embolus from the heart
Injury to the lower trunk of the brachial plexus (originating from C8 and T1) results in what?
Klumpke’s palsy
This palsy primarily affects muscles innervated by the ulnar nerve, which supplies most of the intrinsic muscles of the hand. Weakness and atrophy of the hypothenar and interosseous muscles characterize this palsy, and “claw hand” deformity may also result. Injury to this trunk typically results from sudden upward pulling on the arm.
All hemodynamically unstable patients with penetrating abdominal trauma must undergo what immediately?
Exploratory laparotomy
To diagnose and treat the source of bleeding as well as to diagnose and treat perforation of any abdominal viscus in an effort to prevent sepsis.
What nerve is most commonly injured in conjunction with a humeral neck fracture?
Axillary nerve
What is the imaging modality of choice for diagnosing urinary calculi?
Non-contrast spiral CT of abdomen and pelvis
Abdominal and palevic X-ray will identify radiopaque, calcium-containing stones. Other types of urinary stones, accounting for at least 15% of cases, are not visible on plain X-ray. Also this X-ray can miss small stones and gives no information about obstruction. An intravenous pyelogram (IVP) uses IV contrast and plain X-ray to visualize the urinary system. IVP was the test of choice in the past for diagnosing urinary stones, but because of the risk of contrast-related reactions with IVP, non-contrast CT is now preferred. Ultrasonography can be used if the patient is pregnant to reduce radiation exposure, however, this can also miss some small stones.
A popping sound, intense knee pain, and effusion at the time of injury is indicative of what?
Anterior cruciate ligament (ACL) tear
What is the difference between the evaluation of a palpable breast abnormality in a patient under age 30 and a patient over age 30?
- >30: Evaluation with ultrasound and mammogram
- <30: Evaluation with ultrasound only
In <30 year olds, simple cysts can have needle aspiration (if desired), whereas complex cysts and solid masses require image guided core biopsies.
What usually presents with severe unilateral flank pain that radiates into the groin?
Acute renal colic
What are 5 causes of immediate (within a few hours) postoperative fever?
- Febrile nonhemolytic transfusion reaction
- Prior infection or trauma
- Inflammation due to surgery
- Malignant hyperthermia
- Medications
What is a common cause of limp in otherwise healthy children?
Transient synovitis of the hip
There are no associated radiographic abnormalities.
What are the first physiologic changes when hemorrhage occurs?
Tachycardia and peripheral vascular constriction
A cresentic collection on CT scan of the head is consistent with what?
Subdural hematoma