100+ Free CSHK Part 2 EMQ Practice Questions

Explanation: For low-risk papillary thyroid carcinomas (PTC) that are unifocal, < 4 cm, with no evidence of extrathyroidal extension, lymph node metastasis, or prior radiation history, a thyroid lobectomy is an acceptable and often preferred initial treatment option according to the American Thyroid Association (ATA) guidelines. It offers similar long-term survival outcomes to total thyroidectomy while significantly reducing the risk of complications such as permanent hypoparathyroidism and recurrent laryngeal nerve injury. Routine prophylactic central neck dissection is not recommended for T1/T2 low-risk PTC in the absence of clinical node involvement. Active surveillance is reserved for microcarcinomas (< 1 cm) under strict protocols.

Explanation: Technetium-99m sestamibi scintigraphy combined with Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) is the most sensitive and widely accepted primary localization study for identifying parathyroid adenomas, particularly when planning a minimally invasive parathyroidectomy (MIP). It provides functional localization (retaining the radiotracer longer in hyperfunctioning parathyroid tissue than in the thyroid) coupled with precise anatomical localization. Ultrasound is also commonly used but is highly examiner-dependent. 4D-CT is highly sensitive and typically reserved as a second-line study for discordant primary imaging or reoperative cases. Selective venous sampling is invasive and used only in complex reoperative cases where non-invasive imaging fails.

Explanation: For HER2-positive, hormone-receptor-negative (ER-/PR-) breast cancers larger than 1 cm (T2N0), standard adjuvant therapy consists of systemic chemotherapy combined with anti-HER2 targeted therapy (Trastuzumab) for a total duration of 1 year. The addition of Trastuzumab to chemotherapy significantly improves disease-free and overall survival in HER2-amplified breast cancers. Endocrine therapy is only effective for hormone-receptor-positive tumors. T-DM1 is indicated in the adjuvant setting only if patients have residual invasive disease after neoadjuvant systemic therapy. Systemic therapy is indicated for HER2-positive tumors > 1 cm even if lymph nodes are negative because of the aggressive biological nature of HER2-driven cancers.

Explanation: The initial staging modality of choice for gastric cancer following endoscopic biopsy confirmation is a contrast-enhanced CT scan of the chest, abdomen, and pelvis. This allows assessment of the primary tumor, regional lymph node involvement, and common sites of distant metastases (e.g. liver, lungs, peritoneum). Endoscopic ultrasound (EUS) is useful for assessing T-stage and N-stage but is performed after distant metastases are ruled out. Diagnostic laparoscopy is highly sensitive for detecting occult peritoneal metastases (which are often missed by CT) and is performed before planning curative surgery, but CT remains the first-line staging scan. PET/CT is not routinely used as a first-line modality and is less sensitive for signet ring or mucinous adenocarcinomas.

Explanation: According to the Tokyo Guidelines and multiple randomized clinical trials, early laparoscopic cholecystectomy (typically within 72 hours of symptom onset) is the treatment of choice for acute cholecystitis (Grade I or II) in patients who are fit for surgery. Early cholecystectomy reduces overall hospital stay, avoids the risk of recurrent attacks or progression during the interval period, and does not increase conversion or complication rates compared to delayed cholecystectomy. Conservative management with delayed interval cholecystectomy is associated with higher readmission rates for gallstone-related complications. Percutaneous cholecystostomy is reserved for severe acute cholecystitis (Grade III) or patients with high surgical risk/severe comorbidities who are unfit for urgent surgery. ERCP is indicated for suspected concurrent choledocholithiasis or acute cholangitis, not isolated acute cholecystitis.

Explanation: This patient presents with gallstone ileus, a mechanical small bowel obstruction caused by a large gallstone that has entered the bowel via a cholecystoenteric fistula (usually cholecystoduodenal). The abdominal X-ray demonstrates Rigler's triad: pneumobilia, mechanical bowel obstruction, and an ectopic gallstone. The standard surgical treatment is enterolithotomy, which involves making a longitudinal enterotomy proximal to the site of obstruction (most commonly the terminal ileum), extracting the stone, and closing the bowel. The entire bowel must be run to check for additional stones. Simultaneous fistula repair and cholecystectomy are generally avoided in the acute, emergency setting due to high complication rates in elderly patients with significant inflammation, unless there is a specific, pressing indication.

Explanation: For patients with infected necrotizing pancreatitis (suggested by the presence of gas bubbles on CT and clinical deterioration/sepsis), the 'step-up approach' is the standard of care, as demonstrated by the PANTER trial. This approach begins with broad-spectrum antibiotics and minimally invasive drainage (either percutaneous under image guidance or endoscopic transluminal catheter drainage). This temporizes sepsis and resolves symptoms in up to 35-40% of patients without needing necrosectomy. If clinical improvement is not seen, the next step is minimally invasive necrosectomy (e.g. video-assisted retroperitoneal debridement [VARD] or endoscopic necrosectomy). Immediate open necrosectomy is associated with high morbidity, multi-organ failure, and mortality, and should be avoided in the acute phase.

Explanation: Lynch syndrome (formerly Hereditary Non-Polyposis Colorectal Cancer, HNPCC) is an autosomal dominant condition caused by a germline mutation in one of the DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, PMS2) or the EPCAM gene. It is characterized by an increased risk of colorectal cancer (typically right-sided and presenting at an early age) and extracolonic malignancies, most commonly endometrial cancer in females, as well as ovarian, gastric, small bowel, and transitional cell urothelial cancers. The presence of MSI-H and loss of MSH2/MSH6 expression on IHC strongly point to Lynch syndrome. FAP presents with hundreds to thousands of adenomatous polyps due to APC gene mutations. Li-Fraumeni involves TP53 mutations causing sarcomas, breast, and adrenal cancers. Peutz-Jeghers features hamartomatous polyps and mucocutaneous pigmentation due to STK11 mutations.

Explanation: For patients with perforated diverticulitis presenting with purulent or feculent peritonitis (Hinchey Stage III or IV) who are hemodynamically unstable or have significant comorbidities, Hartmann's procedure (sigmoid colectomy with end colostomy and closure of the rectal stump) remains the traditional standard of care and safest option. It eliminates the septic source and avoids a high-risk primary anastomosis in an infected, inflamed abdomen. While primary anastomosis with a defunctioning loop ileostomy is increasingly considered in hemodynamically stable, younger patients without severe sepsis, Hartmann's is preferred in unstable septic patients. Laparoscopic lavage alone without resection was evaluated in trials (e.g. SCANDIV, LOLA) but showed higher rates of intra-abdominal abscesses and reinterventions, and is not recommended for Hinchey III/IV. Suture repair is not a recognized treatment for diverticular perforation.

Explanation: In patients with adhesive small bowel obstruction (SBO) who show no signs of clinical compromise, strangulation, or peritonitis (e.g. fever, persistent tachycardia, localized guarding, leukocytosis, or acidosis), initial non-operative management is the standard of care. This includes bowel rest (NPO), intravenous fluid resuscitation, correction of electrolyte imbalances, and nasogastric (NG) tube decompression. The administration of water-soluble contrast medium (such as Gastrografin) is both diagnostic and therapeutic; if the contrast reaches the colon on a follow-up X-ray within 8 to 24 hours, it predicts successful resolution of the obstruction in over 90% of cases and helps reduce the length of hospital stay. Immediate surgery is indicated if there are signs of bowel ischemia, strangulation, or if non-operative management fails after 24 to 72 hours. Oral laxatives are contraindicated in mechanical bowel obstruction.