NBME Surgery Form 4 - Answers & Explanations
Updated: Feb 25, 2020
1) Enemas • Enema → washout of hard stools/constipation in the bowel
2) Size of the abnormality • Larger AV fistula → ↑ venous return → high cardiac output heart failure
3) Increased scrotal temperature • Stasis of venous blood → ↑ temp → damage to sperm
4) Refuse to proceed with the operation
• Non maleficence
5) Carotid plaque • Cholesterol emboli that lodge into the retinal artery usually originate from an ulcerated atheromatous plaque within the carotid arteries (Hollenhorst plaque)
6) Hypovolemic • ↓ Cardiac index, ↓ pulm arterial pressure, ↓ PCWP, ↑ SVR = hypovolemic shock
• Anaphylactic shock: ↓ SVR, ↑ cardiac index
• Cardiogenic shock: ↓ cardiac index, ↑ PCWP
• Septic shock: ↓ SVR, ↑ cardiac index
7) Tension pneumothorax
• Typical scenario after insertion of central line (iatrogenic pneumothorax is a common
complication)
• Decreased breath sounds, JVD, shortness of breath
8) Gastrin
• Zollinger-Ellison syndrome (gastrinoma) • ↑ gastrin → ↑ acid levels → erosion of of mucosa/vessels → hematemesis
9) Slipped capital femoral epiphysis • Displaced epiphysis relative to femoral neck → hip/knee pain with limp
• Common in obese pre-teens
10) Toxic synovitis
• Toxic synovitis = transient synovitis
• Common cause of hip pain and limping in children following a viral infection (cold or diarrhea)
11) Removal of the percutaneous intravenous catheter after completion of piperacillin and tazobactam therapy
• Patient had line in for 6 weeks (way over his 14 day abx course) → bacteremia → infective endocarditis
• PIC lines → ↑ risk for catheter-associated bloodstream infections
12) Penile cancer • Elderly uncircumcised man with ulcer growing in size over 6 months • Having foreskin (lack of circumcision) acts as a nidus for infection/inflammation
13) Esophagogastroduodenoscopy • Endoscopy can confirm diagnosis of hiatal hernia and rule out malignancy (patient has red flag symptoms/history)
14) Arteriography with runoff
• Popliteal artery aneurysm → acute limb ischemia due to thrombosis of aneurysm or acute thromboembolism
• Runoff = visualization of vessels beyond the occlusion
15) Ulcerative colitis • High ALP + narrow bile ducts = Primary sclerosing cholangitis (PSC)
• PSC is associated with UC
16) Administration of heparin
• Patient has a pulmonary embolism
• Starting anticoagulation in a hemodynamically stable patients 48-72 hours after surgery is generally safe and wont increase the risk of bleeding
17) Asbestos • Pleural effusion with extensive soft tissue densities (pleural plaques)
• Mesothelioma = bloody pleural effusion
18) Transfusion of packed red blood cells
• Macroangiopathic anemia due to mechanical shearing → schistocytes → replace with pRBCs
• No thrombocytopenia (like in TTP), thus no need for whole blood
19) Enteral tube feedings • Jejunostomy should be used for enteral feedings (more patient autonomy, less expensive, and less adverse reactions in comparison to TPN)
20) No further testing is indicated • Mass with central scar (characteristic feature) = focal nodular hyperplasia
• Managed conservatively - no malignant potential
21) Ruptured intracerebral aneurysm
• HTN + bradycardia = signs of ↑ ICP
• Rupture of aneurysm → abrupt change in ICP (other options wouldn’t cause an abrupt change)
22) Ruptured abdominal aortic aneurysm • Hypotension and Sudden collapse with lower back pain
23) Intraductal papilloma • Bloody nipple discharge with no palpable masses
24) Increased pulmonary vascular resistance • Holosystolic murmur indicates the VSD wasn’t successfully repaired
• VSD with Eisenmenger syndrome
25) Adhesions • History of surgery with symptoms of bowel obstruction - most commonly due to adhesions
26) Oxycodone therapy
• Severe cancer pain awakening the patient from sleep should be treated with long acting opioids (etc. fentanyl patch, oxycodone) + short acting opioids for breakthrough pain (etc. morphine)
• Acetaminophen treats mild cancer pain
• Codeine treats moderate cancer pain
27) Debridement and application of a sterile dressing to the open wound
• Shouldn’t close any dirty/infected wounds - closure, grafting or a flap would just incubate the bacteria
• Should cover gram (+) and anaerobes using amoxicillin and clavulanate
28) Immediate surgical exploration of the upper abdomen
• Free air under diaphragm = perforated viscus → Ex-Lap
29) Impaired cough mechanism • Cough threshold is raised after surgery and mucociliary escalator may be inhibited by ET intubation
30) X-ray of the cervical spine
• ABCDE primary survey - must evaluate cervical spine to ensure airway isn’t/wont become compromised
• Abdomen is non tender, lungs are clear to auscultation and CXR is normal - no need for further abdominal or chest imaging
31) Phosphorus • Hyperparathyroidism → hypercalcemia, bone resorption, and ↑ excretion of phosphorus
32) Meckel diverticulum • Pertechnetate scan uptake by heterotypic gastric mucosa
33) Chronic lymphocytic thyroiditis (Hashimoto disease) • Antibodies against thyroid peroxidase (antimicrosomal) and thyroglobulin
34) Sigmoidoscopy-guided placement of a rectal tube • Sigmoidoscopy to untwist the sigmoid volvulus • Rectal tube is left in to ↓ chance of recurrence in the acute setting
35) Reexcision of the biopsy site • Positive margins → reexcision (must remove cancer before proceeding with adjuvant therapy)
36) Pyoderma gangrenosum • Associated with inflammatory bowel disease
• Sharply demarcated ulcer with purulent base
37) Stricture of the distal esophagus • Dysphagia for solids not liquids = mechanical rather than motor problem
• 6 years of GERD → stricture
38) Overproduction of bilirubin
• 10 units of blood will lead to extreme amounts of RBC breakdown
• Direct:Indirect bilirubin ratio is 1:1 indicating that the problem does not have to do with excretion
39) Clostridium difficile infection • Hospitalized patient taking antibiotics and PPI with fever and abdominal pain
• Pseudomembranes = patchy white mucosa
40) Intubation with hyperventilation • GCS < 8 → intubate and hyperventilate • Hyperventilation washes out the CO2 → cerebral vasoconstriction → ↓ ICP
41) Complete small-bowel obstruction • Adhesions from hysterectomy (previous surgery), active bowel sounds in rush with abdominal cramps, constipation = SBO obstruction
42) Direct pressure to the bleeding laceration
• Direct pressure to stop bleeding
• Closed reduction can be delayed up to 72 hours in presence of more severe injuries
• Don’t need transfusion at the moment since the patient is stable (SBP > 100) on crystalloids
43) Laparotomy • Free air under diaphragm = perforated viscus → Ex-Lap
44) Rupture of the bladder
• Bladder dome rupture → urine leakage (→ anuria) → chemical peritonitis → lower abdominal pain
• Next step: cystourethrogram
45) Spironolactone therapy
• Bilateral adrenal hyperplasia is treated with medication (mineralcorticoid receptor antagonists)
• Unilateral adrenal hyperplasia is surgically removed
46) Lung abscess • Hospitalized patient on ventilation → ↑ risk of aspiration (→ abscess) • A supine, hospitalized patient aspirates to the right upper lobe (dependent portion)
47) Sitz bath • Sitz bath → ↑ blood flow to area of fissure → promotes/accelerates healing
48) Hypomagnesemia • Alcoholic → poor nutrition → ↑ risk of hypomagnesemia • Profound magnesium depletion → ↓ PTH release → hypocalcemia
49) Streptococcus pyogenes (group A) • Group A strep is the MCC of erysipelas • Red, tender painful plaque with sharply demarcated edges
50) Biopsy of the mass • Squamous cell carcinoma (SCC) of the anus is more common in HIV+
○ There is higher prevalence of high-risk anal HPV strains and anal cancer in HIV+ patients
○ There is a close relationship between HPV and SCC • Dx: biopsy • Tx: Nigro chemoradiation protocol followed by surgery
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