Question 1

All of the following are causes of pneumoperitoneum except?

Accepted Answer

Hirschsprung's disease. **Explanation:**

**Pneumoperitoneum** refers to the presence of free air within the peritoneal cavity, most commonly caused by the perforation of a hollow viscus.

**Why Hirschsprung’s Disease is the correct answer:**
Hirschsprung’s disease is a functional bowel obstruction caused by the absence of ganglion cells in the distal colon. While it leads to massive bowel dilatation (**megacolon**), the bowel wall typically remains intact. Therefore, it presents with **pneumatosis intestinalis** (air within the bowel wall) or massive distension, but not pneumoperitoneum, unless a secondary complication like enterocolitis leads to a perforation (which is rare compared to the primary pathology).

**Analysis of Incorrect Options:**
*   **Perforated Peptic Ulcer:** This is the **most common cause** of spontaneous pneumoperitoneum. Gastric or duodenal contents and air escape into the peritoneal cavity.
*   **Laparoscopic Procedure:** This is a cause of **iatrogenic pneumoperitoneum**. Carbon dioxide (CO2) is intentionally insufflated into the abdomen to create a working space. Residual air can persist for several days post-surgery.
*   **Perforated Appendix:** While less common than peptic ulcers (due to the appendix often being walled off by the omentum), a free perforation of the appendix can release intraluminal gas into the peritoneum.

**NEET-PG High-Yield Pearls:**
*   **Most sensitive sign:** Air under the right diaphragm on an erect X-ray chest (can detect as little as 1–2 ml of air).
*   **Left Lateral Decubitus View:** The preferred position if the patient cannot stand; air is seen over the liver shadow.
*   **Rigler’s Sign:** Seeing both sides of the bowel wall due to free intraperitoneal air.
*   **Football Sign:** A large radiolucency outlining the entire peritoneal cavity in massive pneumoperitoneum (common in neonates). [Practice more Surgery questions on OnCourse]

Question 2

Hyperacute rejection is due to which of the following mechanisms?

Accepted Answer

Preformed antibodies. **Explanation:**

**Hyperacute Rejection** is an immediate, irreversible immunological reaction occurring within minutes to hours after organ transplantation.

**1. Why Option A is Correct:**
The mechanism is a **Type II Hypersensitivity reaction**. It is mediated by **preformed circulating antibodies** (IgG) in the recipient’s blood. These antibodies are directed against donor antigens (typically ABO blood group antigens or HLA Class I antigens). Upon reperfusion, these antibodies bind to the donor vascular endothelium, activating the **complement system**. This leads to rapid endothelial damage, platelet aggregation, and diffuse intravascular thrombosis, resulting in the "blue graft" appearance and graft necrosis.

**2. Why Other Options are Incorrect:**
*   **Option B:** Cytotoxic T lymphocyte (CD8+) mediated injury is the hallmark of **Acute Cellular Rejection**, which typically occurs days to weeks after transplant.
*   **Option C:** Endothelitis (inflammation of the vessel wall) is a feature of **Acute Antibody-Mediated Rejection**, but it is caused by *recipient* antibodies against donor tissue, not donor antibodies.
*   **Option D:** Macrophages play a role in chronic inflammation and delayed-type hypersensitivity but are not the primary mediators of the rapid vascular collapse seen in hyperacute rejection.

**3. High-Yield Clinical Pearls for NEET-PG:**
*   **Prevention:** Hyperacute rejection is prevented by **Cross-matching** (mixing recipient serum with donor lymphocytes) and ABO compatibility testing.
*   **Treatment:** There is no effective treatment once it starts; the graft must be **surgically removed**.
*   **Risk Factors:** Previous blood transfusions, multiple pregnancies, or prior organ transplants (all of which sensitize the recipient).
*   **Pathology:** Characterized by **Fibrinoid necrosis** of capillaries and "starry sky" appearance due to neutrophilic infiltration. [Practice more Surgery questions on OnCourse]

Question 3

Bochdalek hernia occurs through which anatomical structure?

Accepted Answer

Diaphragm. **Explanation:**

**Bochdalek hernia** is the most common type of **Congenital Diaphragmatic Hernia (CDH)**, accounting for approximately 85-90% of cases. It occurs due to the failure of the **pleuroperitoneal membrane** to fuse with the septum transversum and dorsal mesentery of the esophagus during embryonic development (usually between the 8th and 10th week). This results in a posterolateral defect in the **diaphragm**, most commonly on the **left side** (80-85%), allowing abdominal viscera to herniate into the thoracic cavity.

**Analysis of Incorrect Options:**
*   **B. Lumbar triangle:** Hernias through the superior lumbar triangle (Grynfeltt-Lesshaft) or inferior lumbar triangle (Petit) are types of lumbar hernias, not diaphragmatic.
*   **C. Femoral region:** This is the site for femoral hernias, which occur through the femoral canal, medial to the femoral vein.
*   **D. Obturator canal:** This is the site for obturator hernias, which typically present with the Howship-Romberg sign (pain in the medial thigh).

**High-Yield Clinical Pearls for NEET-PG:**
*   **Mnemonic:** **B**ochdalek is **B**ack and **B**ad (Posterolateral, associated with severe pulmonary hypoplasia). **M**orgagni is **M**edial/Anterior.
*   **Clinical Triad:** Scaphoid abdomen, respiratory distress, and shifted heart sounds.
*   **Radiology:** Chest X-ray shows air-filled bowel loops in the hemithorax and a mediastinal shift.
*   **Management:** Initial stabilization involves **intubation** (avoid bag-mask ventilation to prevent bowel distension) and **nasogastric suction**. Surgery is not an emergency; it is performed after stabilizing pulmonary hypertension. [Practice more Surgery questions on OnCourse]

Question 4

A 37-year-old woman presents with high fever (39.5°C), nausea, and vomiting. Physical examination reveals increased abdominal pain in the paraumbilical region, rebound tenderness over McBurney's point, and a positive psoas sign. Blood tests show marked leukocytosis. What is the most likely diagnosis?

Accepted Answer

Appendicitis. ### Explanation

**Correct Answer: B. Appendicitis**

The clinical presentation is a classic textbook case of **Acute Appendicitis**. The diagnosis is primarily clinical, based on the following findings:
*   **Paraumbilical pain:** This represents visceral pain from the T10 dermatome as the appendix distends.
*   **McBurney’s Point Tenderness:** As the parietal peritoneum becomes inflamed, the pain localizes to the Right Iliac Fossa (RIF).
*   **Psoas Sign:** Pain on extension of the right hip indicates an inflamed appendix in a **retrocecal** position, irritating the iliopsoas muscle.
*   **Systemic Signs:** High fever, nausea, vomiting, and marked leukocytosis (left shift) are indicative of an acute inflammatory/infectious process.

**Why Incorrect Options are Wrong:**
*   **A. Ectopic Pregnancy:** While it causes RIF pain, it is usually associated with amenorrhea, vaginal bleeding, and hemodynamic instability if ruptured. Fever and high leukocytosis are less common unless there is secondary infection.
*   **C. Cholecystitis:** Pain is typically localized in the **Right Upper Quadrant (RUQ)** and radiates to the right scapula (Boas' sign). Murphy’s sign would be positive, not McBurney’s.
*   **D. Nephrolithiasis:** Presents as "loin to groin" colicky pain. While it causes nausea, it rarely presents with high fever or rebound tenderness unless complicated by pyelonephritis.

**High-Yield Clinical Pearls for NEET-PG:**
*   **Alvarado Score (MANTRELS):** A score ≥7 is highly suggestive of appendicitis.
*   **Most common position:** Retrocecal (75%), followed by Pelvic (20%).
*   **Rovsing’s Sign:** Pain in the RIF when the Left Iliac Fossa is palpated.
*   **Investigation of Choice:** Contrast-Enhanced CT (CECT) is the gold standard in adults; Ultrasound is preferred in children and pregnant women. [Practice more Surgery questions on OnCourse]

Question 5

Splenectomy is done to tide over the acute crises of uncontrollable:

Accepted Answer

ITP. **Explanation:**

**1. Why ITP is the Correct Answer:**
Immune Thrombocytopenic Purpura (ITP) is an autoimmune condition where IgG autoantibodies coat platelets, leading to their premature destruction by splenic macrophages. In **acute, life-threatening crises** (such as intracranial or gastrointestinal hemorrhage) where medical management (steroids, IVIG, or platelet transfusions) fails to stabilize the patient, an **emergency splenectomy** is performed. Removing the spleen eliminates both the primary site of platelet destruction and a major source of autoantibody production, leading to a rapid rise in platelet counts.

**2. Why Other Options are Incorrect:**
*   **TTP (Thrombotic Thrombocytopenic Purpura):** The pathophysiology involves a deficiency of the ADAMTS13 enzyme, leading to microthrombi. The primary treatment is **Plasmapheresis (Plasma Exchange)**. Splenectomy is not indicated for acute crises and is rarely considered even in refractory cases.
*   **HUS (Hemolytic Uremic Syndrome):** This is primarily a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury (often Shiga-toxin mediated). Treatment is supportive (dialysis, fluids); splenectomy has no role in its management.

**3. Clinical Pearls for NEET-PG:**
*   **Indications for Splenectomy in ITP:** Failure of medical therapy (steroids are 1st line), contraindications to steroids, or emergency life-threatening bleeding.
*   **Vaccination Protocol:** For elective splenectomy, vaccinate **2 weeks before** surgery. For emergency splenectomy (like in acute ITP crisis), vaccinate **2 weeks after** surgery.
*   **Target Organisms:** *S. pneumoniae* (most common), *H. influenzae*, and *N. meningitidis*.
*   **Post-Splenectomy Blood Picture:** Look for **Howell-Jolly bodies** (most characteristic), Pappenheimer bodies, Heinz bodies, and target cells. [Practice more Surgery questions on OnCourse]

Surgery Questions

Topics

General Surgery Principles

Preoperative and Postoperative Care

Surgical Infections

Trauma

Head and Neck Surgery

Breast Surgery

Gastrointestinal Surgery

Hepatobiliary Surgery

Pancreatic Surgery

Colorectal Surgery

Vascular Surgery

Endocrine Surgery

Urology

Transplant Surgery

Oncological Surgery

Minimally Invasive Surgery

Bariatric Surgery

Plastic and Reconstructive Surgery

Pediatric Surgery

Surgical Oncology Principles

About Surgery Questions