Nutrition support in surgical patients US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Nutrition support in surgical patients. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Nutrition support in surgical patients US Medical PG Question 1: Four days after admission to the hospital for anorexia nervosa, a 20-year-old woman has new-onset palpitations and paresthesias in all four limbs. Prior to admission, she was found unconscious by her parents on the floor of a residential treatment center. The patient was started on a trial of nutritional rehabilitation upon arrival to the hospital. Her temperature is 36°C (96.8°F), pulse is 47/min, and blood pressure is 90/60 mmHg. She is 160 cm tall and weighs 35 kg; BMI is 14 kg/m2. The patient appears emaciated. Examination shows lower leg edema. A 2/6 holosystolic murmur is heard over the 5th intercostal space at the midclavicular line. An ECG shows intermittent supraventricular tachycardia and QTc prolongation. Serum studies show:
Day 2 Day 4
Potassium (mEq/L) 3.5 2.7
Calcium (mg/dL) 8.5 7.8
Magnesium (mEq/L) 1.2 0.5
Phosphorus (mg/dL) 3.6 1.5
Which of the following is the most likely underlying cause of this patient's condition?
- A. Uncompensated metabolic alkalosis
- B. Thiamine deficiency
- C. Euthyroid sick syndrome
- D. Rapid gastric emptying
- E. Increased insulin release (Correct Answer)
Nutrition support in surgical patients Explanation: ***Increased insulin release***
- **Refeeding syndrome** is triggered by a sudden increase in carbohydrate intake after a period of starvation, leading to an abrupt rise in **insulin secretion**.
- Insulin shifts **potassium, phosphate, and magnesium** into cells, causing rapid and severe **hypokalemia, hypophosphatemia, and hypomagnesemia**, which manifest as cardiac arrhythmias, neurological symptoms (paresthesias), and muscle weakness.
*Uncompensated metabolic alkalosis*
- While metabolic alkalosis can occur in anorexia nervosa due to **vomiting**, it typically causes hypokalemia, not the widespread electrolyte derangements seen here.
- It does not directly explain the acute drop in **phosphate and magnesium** or the onset of refeeding syndrome symptoms.
*Thiamine deficiency*
- **Thiamine deficiency** can occur in malnourished patients and lead to Wernicke encephalopathy or Korsakoff syndrome, but it typically presents with ocular abnormalities, ataxia, and confusion, not primarily with the acute cardiac and electrolyte disturbances observed.
- While important for metabolism, it is not the **primary driver** of the acute electrolyte shifts characteristic of refeeding syndrome.
*Euthyroid sick syndrome*
- Characterized by **abnormal thyroid function tests** in a severely ill patient without primary thyroid disease, reflecting altered peripheral thyroid hormone metabolism.
- It does not directly cause the acute and severe **electrolyte abnormalities** (hypokalemia, hypophosphatemia, hypomagnesemia) or the specific clinical presentation of refeeding syndrome.
*Rapid gastric emptying*
- While rapid gastric emptying can be a feature in some eating disorders, it directly leads to symptoms like **dumping syndrome** (abdominal pain, diarrhea).
- It does not explain the profound **intracellular shift of electrolytes** and the resulting cardiac and neurological symptoms seen in this case.
Nutrition support in surgical patients US Medical PG Question 2: A 65-year-old man presents to the diabetes clinic for a check-up. He has been successfully managing his diabetes through diet alone, and has not experienced any complications related to retinopathy, neuropathy, or nephropathy. He recently started a new exercise regimen and is eager to see whether his weight has declined since his last visit. The nurse measures his height to be 170 cm and his weight to be 165 lb (75 kg). What range does this patient’s body mass index currently fall into?
- A. < 18.5
- B. > 30.0
- C. 25.0 - 29.9 (Correct Answer)
- D. 18.5 - 24.9
- E. > 40.0
Nutrition support in surgical patients Explanation: ***25.0 - 29.9***
- To calculate BMI, divide weight in kilograms by the square of height in meters: Weight = 75 kg, Height = 1.70 m.
- BMI = 75 / (1.70 * 1.70) = 75 / 2.89 ≈ **25.95 kg/m²**, which falls within the **overweight** range of 25.0 to 29.9.
*< 18.5*
- A BMI less than 18.5 indicates **underweight**.
- The calculated BMI of approximately 25.95 is significantly higher than this range.
*> 30.0*
- A BMI greater than 30.0 indicates **obesity**.
- The calculated BMI of approximately 25.95 is below this threshold, indicating the patient is not obese.
*18.5 - 24.9*
- A BMI between 18.5 and 24.9 is considered the **normal or healthy weight** range.
- The patient's BMI of approximately 25.95 is slightly above this range, placing him in the overweight category.
*> 40.0*
- A BMI greater than 40.0 indicates **morbid obesity** or **Class III obesity**.
- The patient's calculated BMI of 25.95 is substantially lower than this severe obesity classification.
Nutrition support in surgical patients US Medical PG Question 3: A 21-year-old woman presents to the clinic complaining of fatigue for the past 2 weeks. She reports that it is difficult for her to do strenuous tasks such as lifting heavy boxes at the bar she works at. She denies any precipitating factors, weight changes, nail changes, dry skin, chest pain, abdominal pain, or urinary changes. She is currently trying out a vegetarian diet for weight loss and overall wellness. Besides heavier than usual periods, the patient is otherwise healthy with no significant medical history. A physical examination demonstrates conjunctival pallor. Where in the gastrointestinal system is the most likely mineral that is deficient in the patient absorbed?
- A. Large intestine
- B. Ileum
- C. Jejunum
- D. Stomach
- E. Duodenum (Correct Answer)
Nutrition support in surgical patients Explanation: ***Duodenum***
- The patient's symptoms (fatigue, conjunctival pallor, heavy periods, vegetarian diet) are highly suggestive of **iron deficiency anemia**. The **duodenum** is the primary site for the absorption of dietary iron.
- Iron absorption is tightly regulated here to maintain iron homeostasis, and conditions like a vegetarian diet can reduce bioavailable iron, leading to deficiency.
*Large intestine*
- The large intestine is primarily involved in **water and electrolyte absorption** and the formation of stool.
- It does not play a significant role in the absorption of essential minerals like iron.
*Ileum*
- The ileum is the main site for the absorption of **bile salts** and **vitamin B12**.
- While it absorbs some nutrients, it is not the primary site for iron absorption.
*Jejunum*
- The jejunum is the main site for the absorption of most **nutrients**, including carbohydrates, proteins, and fats.
- While some iron absorption can occur here, the **duodenum** is the specialized and most significant site for this process.
*Stomach*
- The stomach's main roles include **digestion** of proteins and production of **intrinsic factor** for vitamin B12 absorption.
- While **acidic pH** in the stomach aids in converting ferric iron (Fe3+) to ferrous iron (Fe2+), which is more readily absorbed, direct iron absorption in the stomach lining is minimal.
Nutrition support in surgical patients US Medical PG Question 4: A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?
- A. "Does the diarrhea typically precede the constipation, or vice-versa?"
- B. "Is the diarrhea foul-smelling?"
- C. "Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"
- D. "Are the symptoms worse in the morning or at night?"
- E. "Can you tell me more about the symptoms you have been experiencing?" (Correct Answer)
Nutrition support in surgical patients Explanation: ***Can you tell me more about the symptoms you have been experiencing?***
- This **open-ended question** encourages the patient to provide a **comprehensive narrative** of their symptoms, including details about onset, frequency, duration, alleviating/aggravating factors, and associated symptoms, which is crucial for diagnosis.
- In a patient presenting with vague, intermittent symptoms like alternating constipation and diarrhea, allowing them to elaborate freely can reveal important clues that might not be captured by more targeted questions.
*Does the diarrhea typically precede the constipation, or vice-versa?*
- While knowing the sequence of symptoms can be helpful in understanding the **pattern of bowel dysfunction**, it is a very specific question that might overlook other important aspects of the patient's experience.
- It prematurely narrows the focus without first obtaining a broad understanding of the patient's overall symptomatic picture.
*Is the diarrhea foul-smelling?*
- Foul-smelling diarrhea can indicate **malabsorption** or **bacterial overgrowth**, which are important to consider in some gastrointestinal conditions.
- However, this is a **specific symptom inquiry** that should follow a more general exploration of the patient's symptoms, as it may not be relevant if other crucial details are missed.
*Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life*
- Quantifying pain intensity is useful for assessing the **severity of discomfort** and monitoring changes over time.
- However, for a patient with intermittent rather than acute, severe pain, understanding the **character, location, and triggers** of the pain is often more diagnostically valuable than just a numerical rating initially.
*Are the symptoms worse in the morning or at night?*
- Diurnal variation can be relevant in certain conditions, such as inflammatory bowel diseases where nocturnal symptoms might be more concerning, or functional disorders whose symptoms might be stress-related.
- This is another **specific question** that should come after gathering a more complete initial picture of the patient's symptoms to ensure no key information is overlooked.
Nutrition support in surgical patients US Medical PG Question 5: A 66-year-old man weighing 50 kg (110 lb) is admitted to the hospital because of sepsis complicated by acute respiratory distress syndrome. The physician decides to initiate total parenteral nutrition and prescribes short-term hypocaloric intake of 20 kcal/kg/day with 20% of the total energy requirement provided by proteins and 30% provided by fats. The physician calculates that a total volume of 1100 mL/day should be infused during the parenteral nutrition therapy to maintain fluid balance. A colloid containing 10 g/dL of albumin and an emulsion with a fat concentration of 33 g/dL are used to prepare parenteral nutrition modules. Which of the following is the most appropriate module to meet the carbohydrate requirement in this patient over the next 24 hours?
- A. 500 mL of 25% dextrose solution (Correct Answer)
- B. 750 mL of 25% dextrose solution
- C. 750 mL of 10% dextrose solution
- D. 500 mL of 10% dextrose solution
- E. 250 mL of 50% dextrose solution
Nutrition support in surgical patients Explanation: ***500 mL of 25% dextrose solution***
- The patient requires 1000 kcal/day total (50 kg * 20 kcal/kg/day). With 20% from protein (200 kcal) and 30% from fat (300 kcal), 500 kcal must come from carbohydrates. Given that **1 g of dextrose provides 3.4 kcal**, 500 kcal requires approximately 147 g of dextrose (500 kcal / 3.4 kcal/g). A **25% dextrose solution contains 250 g of dextrose per liter**, so 500 mL would provide 125 g of dextrose (0.5 L * 250 g/L), which translates to 425 kcal (125 g * 3.4 kcal/g). This is the closest and most appropriate option.
- While not exactly 500 kcal, this option delivers the closest amount of carbohydrate calories while fitting within fluid restrictions and is a common concentration used in TPN.
*750 mL of 25% dextrose solution*
- This option would provide approximately 187.5 g of dextrose (0.75 L * 250 g/L), resulting in 637.5 kcal. This is **too high a carbohydrate load** for the patient's calculated needs (500 kcal from carbs) and would exceed the desired energy distribution.
- Additionally, this volume might lead to **fluid overload** given the 1100 mL/day total fluid restriction.
*750 mL of 10% dextrose solution*
- This option provides approximately 75 g of dextrose (0.75 L * 100 g/L), resulting in 255 kcal. This is **insufficient to meet the required 500 kcal** from carbohydrates.
- While the volume is high, the caloric content from carbohydrate is low.
*500 mL of 10% dextrose solution*
- This option provides approximately 50 g of dextrose (0.5 L * 100 g/L), resulting in 170 kcal. This is **significantly below the target of 500 kcal** from carbohydrates and would lead to underfeeding.
- It would also leave a substantial amount of the 1100mL fluid volume unaccounted for if this were the only carbohydrate source.
*250 mL of 50% dextrose solution*
- This option provides approximately 125 g of dextrose (0.25 L * 500 g/L), resulting in 425 kcal. While the caloric content is similar to the correct answer, using **50% dextrose in a standard TPN formulation can be challenging** due to its high osmolality, and typically requires central line administration, which might not be practical for a "module" if other components dilute it.
- A 25% solution is generally preferred for its better compatibility within TPN admixtures and safer peripheral administration if necessary.
Nutrition support in surgical patients US Medical PG Question 6: One week after undergoing sigmoidectomy with end colostomy for complicated diverticulitis, a 67-year-old man has upper abdominal pain. During the surgery, he was transfused two units of packed red blood cells. His postoperative course was uncomplicated. Two days ago, he developed fever. He is currently receiving parenteral nutrition through a central venous catheter. He has type 2 diabetes mellitus, hypertension, and hypercholesterolemia. He is oriented to person, but not to place and time. Prior to admission, his medications included metformin, valsartan, aspirin, and atorvastatin. His temperature is 38.9°C (102.0°F), pulse is 120/min, and blood pressure is 100/60 mmHg. Examination shows jaundice of the conjunctivae. Abdominal examination shows tenderness to palpation in the right upper quadrant. There is no rebound tenderness or guarding; bowel sounds are hypoactive. Laboratory studies show:
Leukocytes 13,500 /mm3
Segmented neutrophils 75 %
Serum
Aspartate aminotransferase 140 IU/L
Alanine aminotransferase 85 IU/L
Alkaline phosphatase 150 IU/L
Bilirubin
Total 2.1 mg/dL
Direct 1.3 mg/dL
Amylase 20 IU/L
Which of the following is the most likely diagnosis in this patient?
- A. Acute pancreatitis
- B. Small bowel obstruction
- C. Hemolytic transfusion reaction
- D. Anastomotic insufficiency
- E. Acalculous cholecystitis (Correct Answer)
Nutrition support in surgical patients Explanation: ***Acalculous cholecystitis***
* This patient's clinical picture, including fever, **right upper quadrant tenderness**, **jaundice**, and elevated **liver enzymes** (AST, ALT, ALP, bilirubin), following a major abdominal surgery and **central venous parenteral nutrition**, is highly suggestive of acalculous cholecystitis.
* **Acalculous cholecystitis** often affects critically ill patients, especially those with trauma, burns, sepsis, or prolonged parenteral nutrition, due to gallbladder stasis and ischemia, even in the absence of gallstones.
*Acute pancreatitis*
* While the patient has upper abdominal pain, the **amylase level is normal** (20 IU/L), which rules out acute pancreatitis.
* **Acute pancreatitis** typically presents with severe epigastric pain radiating to the back and a significant elevation in amylase and lipase levels (usually 3 times the upper limit of normal).
*Small bowel obstruction*
* Symptoms of small bowel obstruction usually include **abdominal distension**, **crampy abdominal pain**, **vomiting**, and **absence of flatus/bowel movements**, along with characteristic findings on imaging.
* Although bowel sounds are hypoactive and the patient had surgery, the predominant features here (fever, jaundice, RUQ tenderness, elevated liver enzymes) point away from obstruction and more towards an inflammatory process involving the liver/biliary system.
*Hemolytic transfusion reaction*
* A **hemolytic transfusion reaction** would cause fever, chills, hemoglobinuria, flank pain, and jaundice, but would occur soon after the transfusion (within hours for acute reactions) and typically present with signs of acute kidney injury and disseminated intravascular coagulation, which are not described.
* The time frame (one week post-transfusion) and the localized right upper quadrant tenderness with liver enzyme elevations make this less likely.
*Anastomotic insufficiency*
* An **anastomotic leak** would typically present with severe abdominal pain, peritonitis (rebound tenderness, guarding), fever, and sepsis, often leading to abscess formation.
* This patient's examination **lacks rebound tenderness or guarding**, and the predominant findings of jaundice and elevated liver enzymes are not the primary features of an anastomotic leak.
Nutrition support in surgical patients US Medical PG Question 7: Three days after being admitted to the hospital because of a fall from the roof of a two-story building, a 27-year-old man is being monitored in the intensive care unit. On arrival, the patient was somnolent and not oriented to person, place, or time. A CT scan of the head showed an epidural hemorrhage that was 45 cm3 in size and a midline shift of 7 mm. Emergency surgery was performed with craniotomy and hematoma evacuation on the day of admission. Perioperatively, a bleeding vessel was identified and ligated. Postoperatively, the patient was transferred to the intensive care unit and placed on a ventilator. His temperature is 37°C (98.6°F), pulse is 67/min, and blood pressure is 117/78 mm Hg. The ventilator is set at a FiO2 of 55%, tidal volume of 520 mL, and positive end-expiratory pressure of 5.0 cm H2O. In addition to intravenous administration of fluids, which of the following is the most appropriate next step in managing this patient's nutrition?
- A. Enteral feeding via nasogastric tube (Correct Answer)
- B. Oral feeding
- C. Keep patient NPO
- D. Total parenteral nutrition
- E. Enteral feeding using a percutaneous endoscopic gastrostomy (PEG) tube
Nutrition support in surgical patients Explanation: ***Enteral feeding via nasogastric tube***
- This patient has been **somnolent** and on a ventilator for 3 days after a significant head injury, indicating a prolonged period without oral intake and an inability to protect his airway for oral feeding. **Early enteral nutrition** via a nasogastric tube is preferred in critically ill patients, especially those with head injuries, as it helps maintain gut integrity and reduces complications compared to parenteral nutrition.
- The patient's **hemodynamic stability** (blood pressure and pulse are within a reasonable range for a ventilated patient) suggests he can tolerate enteral feeding, and there are no signs of gut ischemia or ileus that would contraindicate it.
*Enteral feeding using a percutaneous endoscopic gastrostomy (PEG) tube*
- While a PEG tube provides enteral nutrition, it is typically reserved for patients requiring **long-term enteral support** (usually more than 4-6 weeks) or those who cannot tolerate a nasogastric tube.
- Given that it has only been 3 days post-injury, a **less invasive method** like a nasogastric tube is initially preferred.
*Oral feeding*
- The patient is described as **somnolent** and on a ventilator, meaning he is not awake enough or able to protect his airway to safely receive oral feeding.
- Attempting oral feeding in this state carries a high risk of **aspiration pneumonia**.
*Keep patient NPO*
- Keeping the patient NPO (nil per os) for an extended period in critical illness is associated with several negative outcomes, including **gut mucosal atrophy, increased infection risk**, and poorer clinical outcomes.
- After 3 days, initiating nutritional support is crucial to prevent these complications.
*Total parenteral nutrition*
- **Total parenteral nutrition (TPN)** is generally considered a last resort when the gastrointestinal tract is non-functional or enteral feeding is contraindicated.
- TPN is associated with a **higher risk of complications**, such as central line infections, liver dysfunction, and metabolic disturbances, compared to enteral feeding.
Nutrition support in surgical patients US Medical PG Question 8: A 30-year-old male gang member is brought to the emergency room with a gunshot wound to the abdomen. The patient was intubated and taken for an exploratory laparotomy, which found peritoneal hemorrhage and injury to the small bowel. He required 5 units of blood during this procedure. Following the operation, the patient was sedated and remained on a ventilator in the surgical intensive care unit (SICU). The next day, a central line is placed and the patient is started on total parenteral nutrition. Which of the following complications is most likely in this patient?
- A. Mesenteric ischemia
- B. Hypocalcemia
- C. Refeeding syndrome
- D. Sepsis (Correct Answer)
- E. Cholelithiasis
Nutrition support in surgical patients Explanation: ***Sepsis***
- This patient has undergone **major abdominal surgery** after a **gunshot wound**, which carries a high risk of **peritoneal contamination** and subsequent infection.
- He also has several risk factors for sepsis, including **intubation**, central line placement, and possibly prolonged ventilation, all of which increase the risk of nosocomial infections and subsequent sepsis.
*Mesenteric ischemia*
- While possible in critically ill patients, there is no direct evidence such as advanced age, atherosclerosis, or specific signs of **bowel ischemia** (e.g., severe abdominal pain disproportionate to exam, bloody diarrhea) presenting in this case.
- The initial injury was to the small bowel, but the current context points more to systemic complications rather than a focal vascular event.
*Hypocalcemia*
- Hypocalcemia can occur in critically ill patients due to various reasons, but it is not the *most likely* complication given the patient's presentation primarily focused on surgical trauma and subsequent interventions.
- Dilutional effects from massive transfusions or **citrate toxicity** could contribute to temporary hypocalcemia, but sepsis poses a more immediate and widespread threat.
*Refeeding syndrome*
- Refeeding syndrome occurs when severely malnourished patients are rapidly refed, leading to shifts in **electrolytes** (especially **phosphate**, potassium, magnesium).
- Although the patient is starting **total parenteral nutrition (TPN)**, there's no indication of prior severe malnutrition, making sepsis a more prominent immediate concern due to the gunshot wound and surgery.
*Cholelithiasis*
- **Cholelithiasis** (gallstones) can be a long-term complication of total parenteral nutrition (TPN) due to gallbladder stasis.
- However, it is unlikely to develop so acutely within a day of starting TPN and is thus not the most immediate or likely complication for this patient's acute critical state.
Nutrition support in surgical patients US Medical PG Question 9: A 65-year-old woman comes to the physician because of progressive weight loss for 3 months. Physical examination shows jaundice and a nontender, palpable gallbladder. A CT scan of the abdomen shows an ill-defined mass in the pancreatic head. She is scheduled for surgery to resect the pancreatic head, distal stomach, duodenum, early jejunum, gallbladder, and common bile duct and anastomose the jejunum to the remaining stomach, pancreas, and bile duct. Following surgery, this patient is at the greatest risk for which of the following?
- A. Wide-based gait
- B. Calcium oxalate kidney stones
- C. Microcytic anemia (Correct Answer)
- D. Increased bile production
- E. Hypercoagulable state
Nutrition support in surgical patients Explanation: ***Microcytic anemia***
- The surgical procedure described is a **Whipple procedure**, which involves partial gastrectomy and duodenectomy. This significant alteration to the upper GI tract can lead to **iron malabsorption**, as iron is primarily absorbed in the duodenum and proximal jejunum, and gastric acid is crucial for converting dietary iron to its absorbable ferrous form.
- **Iron deficiency** is the most common cause of **microcytic anemia**, characterized by small, pale red blood cells, due to impaired hemoglobin synthesis as a result of insufficient iron availability for the heme component.
*Wide-based gait*
- A **wide-based gait** is typically associated with **ataxia** or conditions affecting cerebellar function or proprioception, which are not direct complications of a Whipple procedure.
- While nutritional deficiencies can occur post-surgery, a wide-based gait specifically points to neurological impairment rather than postsurgical metabolic issues.
*Calcium oxalate kidney stones*
- **Calcium oxalate kidney stones** are often associated with conditions causing **hypercalciuria** or malabsorption of fat, which leads to increased oxalate absorption in the colon. While fat malabsorption can occur after a Whipple due to pancreatic insufficiency, dietary oxalate intake and hydration status are generally more significant determinants of stone formation.
- The surgery itself does not directly increase the risk for calcium oxalate kidney stones more than other listed complications.
*Increased bile production*
- A Whipple procedure involves the removal of the **gallbladder** and rerouting of the **bile duct** directly into the jejunum. This does not lead to increased bile production, but rather a different regulation and flow of bile.
- In fact, the absence of the gallbladder means there is no storage for bile, leading to a continuous, unregulated flow of bile into the small intestine, potentially contributing to maldigestion or diarrhea, but not "increased production."
*Hypercoagulable state*
- While surgery, including a Whipple procedure, can transiently increase the risk of a **hypercoagulable state** (e.g., deep vein thrombosis, pulmonary embolism) in the immediate postoperative period due to immobility and tissue injury, this risk is generally mitigated with prophylactic anticoagulation.
- The question asks about the **greatest risk** post-surgery, and long-term complications related to altered anatomy and malabsorption, such as microcytic anemia, are more direct and sustained consequences unique to the extent of the resection.
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