IBD in pregnancy US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for IBD in pregnancy. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
IBD in pregnancy US Medical PG Question 1: A 4-week-old infant is brought to the physician by his mother because of blood-tinged stools for 3 days. He has also been passing whitish mucoid strings with the stools during this period. He was delivered at 38 weeks' gestation by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. He was monitored in the intensive care unit for a day prior to being discharged. His 6-year-old brother was treated for viral gastroenteritis one week ago. The patient is exclusively breastfed. He is at the 50th percentile for height and 60th percentile for weight. He appears healthy and active. His vital signs are within normal limits. Examination shows a soft and nontender abdomen. The liver is palpated just below the right costal margin. The remainder of the examination shows no abnormalities. Test of the stool for occult blood is positive. A complete blood count and serum concentrations of electrolytes and creatinine are within the reference range. Which of the following is the most appropriate next step in management?
- A. Perform stool antigen immunoassay
- B. Perform an air enema on the infant
- C. Assess for IgA (anti‑)tissue transglutaminase antibodies (tTG)
- D. Stop breastfeeding and switch to soy-based formula
- E. Continue breastfeeding and advise mother to avoid dairy and soy products (Correct Answer)
IBD in pregnancy Explanation: ***Continue breastfeeding and advise mother to avoid dairy and soy products***
- The infant's symptoms of **blood-tinged stools** and **mucoid strings**, along with a positive occult blood test, in an otherwise healthy, exclusively breastfed infant point towards **food protein-induced proctocolitis (FPIAP)**.
- The most common triggers for FPIAP are **cow's milk protein** and **soy protein** from the maternal diet transmitted through breast milk. The initial management involves the mother eliminating these proteins from her diet.
*Perform stool antigen immunoassay*
- This test is used to detect specific viral, bacterial, or parasitic antigens in stool, often for conditions like **rotavirus, giardiasis, or C. difficile**.
- The infant's clinical presentation with **no fever, vomiting, or diarrhea**, and an otherwise healthy appearance, makes an infectious cause less likely compared to FPIAP.
*Perform an air enema on the infant*
- An air enema is primarily a diagnostic and therapeutic intervention for **intussusception**, a condition where one segment of the intestine telescopes into another.
- Intussusception typically presents with sudden onset of severe, colicky abdominal pain, **"currant jelly" stools**, and often a palpable abdominal mass, none of which are described in this infant.
*Assess for IgA (anti‑)tissue transglutaminase antibodies (tTG)*
- This test is used to screen for **celiac disease**, an autoimmune disorder triggered by gluten consumption.
- Celiac disease typically presents after the introduction of **gluten-containing foods** into the diet, usually around 6-12 months of age, and is characterized by malabsorption symptoms like diarrhea, weight loss, and failure to thrive, which are absent here.
*Stop breastfeeding and switch to soy-based formula*
- Stopping breastfeeding is generally **not recommended** as breast milk provides numerous benefits.
- Switching to a **soy-based formula** may not resolve the issue, as many infants with cow's milk protein allergy also have a **soy protein allergy**. The preferred approach is to eliminate allergens from the maternal diet while continuing breastfeeding.
IBD in pregnancy US Medical PG Question 2: A 42-year-old G1P0 woman presents to an obstetrician for her first prenatal visit. She has been pregnant for about 10 weeks and is concerned about how pregnancy will affect her health. Specifically, she is afraid that her complicated medical history will be adversely affected by her pregnancy. Her past medical history is significant for mild polycythemia, obesity hypoventilation syndrome, easy bleeding, multiple sclerosis, and aortic regurgitation. Which of these disorders is most likely to increase in severity during the course of the pregnancy?
- A. Easy bleeding
- B. Hypoventilation (Correct Answer)
- C. Multiple sclerosis
- D. Polycythemia
- E. Heart murmur
IBD in pregnancy Explanation: ***Hypoventilation***
- Pregnancy leads to increased **oxygen consumption** and **carbon dioxide production**, requiring increased ventilation.
- In a patient with **obesity hypoventilation syndrome**, the already compromised respiratory drive and mechanics can worsen, leading to increased **hypercapnia** and **hypoxia**.
*Easy bleeding*
- Pregnancy is a **hypercoagulable state**, which typically reduces the risk of bleeding.
- While certain pregnancy complications (e.g., placental abruption) can cause bleeding, the overall physiological changes tend to **decrease primary bleeding tendencies**.
*Multiple sclerosis*
- Pregnancy typically has an **immunomodulatory effect** that can lead to a decrease in the frequency of MS relapses, especially in the third trimester.
- Relapses may increase postpartum, but during pregnancy itself, the condition often **stabilizes or improves**.
*Polycythemia*
- Pregnancy increases **plasma volume** significantly, which can lead to a relative **hemodilution**.
- This physiological change would likely **ameliorate mild polycythemia** rather than worsen it.
*Heart murmur*
- The murmur is due to **aortic regurgitation**, and while pregnancy increases **cardiac output** and **blood volume**, severe aortic regurgitation can worsen.
- However, the overall physiological changes of pregnancy result in **increased minute ventilation**, making hypoventilation a more direct and universally worsened problem with existing **obesity hypoventilation syndrome**.
IBD in pregnancy US Medical PG Question 3: A 25-year-old man presents with abdominal pain and bloody diarrhea. His symptoms have been recurrent for the past few months, and, currently, he says he is having on average four bowel movements daily, often bloody. He describes the pain as cramping and localized to the left side of his abdomen. He also says that he has lost around 4.5 kg (10 lb) over the past 3 months. There is no other significant past medical history and the patient is not on current medications. His temperature is 37.7° C (100.0° F), pulse rate is 100/min, respiratory rate is 18/min, and blood pressure is 123/85 mm Hg. On physical examination, there is mild tenderness to palpation in the lower left quadrant of the abdomen with no rebound or guarding. Laboratory studies show anemia and thrombocytosis. Colonoscopy is performed, which confirms the diagnosis of ulcerative colitis (UC). What is the mechanism of action of the recommended first-line medication for the treatment of this patient’s condition?
- A. Suppression of cellular and humoral immunity
- B. TNF-⍺ antagonism
- C. Inhibition of enzyme phospholipase A2
- D. Cross-linking of bacterial DNA
- E. Inhibition of leukotriene synthesis and lipoxygenase (Correct Answer)
IBD in pregnancy Explanation: ***Inhibition of leukotriene synthesis and lipoxygenase***
- The first-line medications for mild to moderate ulcerative colitis (UC) are **aminosalicylates** like **mesalamine** (5-ASA).
- Mesalamine is thought to exert its anti-inflammatory effects by inhibiting **leukotriene synthesis** and the **lipoxygenase pathway**, thereby reducing inflammation in the colon.
*Suppression of cellular and humoral immunity*
- This mechanism of action describes **immunosuppressants** such as azathioprine or methotrexate, which are typically used for more severe or refractory cases of UC, not as first-line therapy.
- These drugs broadly suppress the immune system, leading to a higher risk of infections and other side effects.
*TNF-⍺ antagonism*
- This is the mechanism of action of **biologic agents** like infliximab or adalimumab, which are reserved for moderate to severe UC that has not responded to conventional therapy.
- **TNF-α inhibitors** block the inflammatory cytokine TNF-α, reducing inflammation but are not the initial treatment choice.
*Inhibition of enzyme phospholipase A2*
- This mechanism describes **corticosteroids** such as prednisone or budesonide, which are used to induce remission in moderate to severe UC flares, but not as first-line maintenance therapy due to significant side effects.
- Corticosteroids inhibit **phospholipase A2**, thereby blocking the entire arachidonic acid cascade and the production of all inflammatory mediators.
*Cross-linking of bacterial DNA*
- This mechanism describes **antibiotics** like metronidazole or ciprofloxacin, which work by cross-linking DNA in bacteria.
- While antibiotics may be used in specific UC scenarios (such as pouchitis or suspected superimposed infection), UC itself is an idiopathic inflammatory disease, not a bacterial infection, and antibiotics are not first-line treatment for the underlying condition.
IBD in pregnancy US Medical PG Question 4: A 27-year-old G0P0 female presents to her OB/GYN for a preconception visit to seek advice before becoming pregnant. A detailed history reveals no prior medical or surgical history, and she appears to be in good health currently. Her vaccination history is up-to-date. She denies tobacco or recreational drug use and admits to drinking 2 glasses of wine per week. She states that she is looking to start trying to become pregnant within the next month, hopefully by the end of January. Which of the following is NOT recommended as a next step for this patient's preconception care?
- A. Begin 400 mcg folic acid supplementation
- B. Administer measles, mumps, rubella (MMR) vaccination (Correct Answer)
- C. Obtain rubella titer
- D. Obtain varicella zoster titer
- E. Recommend inactivated influenza vaccination
IBD in pregnancy Explanation: ***Administer measles, mumps, rubella (MMR) vaccination***
- Live-attenuated vaccines like **MMR** are contraindicated during pregnancy and should ideally be given **at least one month prior to conception**.
- If her vaccination history is up-to-date and she plans to conceive within the month, administering MMR is not recommended at this time without confirming immunity first.
*Begin 400 mcg folic acid supplementation*
- **Folic acid supplementation** at 400 mcg daily is recommended for all women of childbearing age to prevent **neural tube defects**, ideally starting at least one month before conception and continuing through the first trimester.
- This is a crucial step in preconception care to ensure adequate levels when the neural tube is forming.
*Obtain rubella titer*
- Checking a **rubella titer** is standard preconception care to determine immunity, as rubella infection during pregnancy can lead to serious congenital anomalies.
- If she is not immune, the MMR vaccine can be offered, but with a **one-month contraception period** before attempting conception.
*Obtain varicella zoster titer*
- Determining **varicella immunity** is important because congenital varicella syndrome can occur if a non-immune mother contracts chickenpox during pregnancy.
- If she is not immune, the **varicella vaccine** can be administered, followed by a **one-month waiting period** before conception.
*Recommend inactivated influenza vaccination*
- **Inactivated influenza vaccination** is safe and recommended during any stage of pregnancy, including the preconception period, to protect both the mother and newborn from severe influenza outcomes.
- It can be given even if she plans to conceive within the month, as it is not a live vaccine.
IBD in pregnancy US Medical PG Question 5: A 31-year-old woman comes to the emergency department because of a 4-day history of fever and diarrhea. She has abdominal cramps and frequent bowel movements of small quantities of stool with blood and mucus. She has had multiple similar episodes over the past 8 months. Her temperature is 38.1°C (100.6°F), pulse is 75/min, and blood pressure is 130/80 mm Hg. Bowel sounds are normal. The abdomen is soft. There is tenderness to palpation in the left lower quadrant with guarding and no rebound. She receives appropriate treatment and recovers. Two weeks later, colonoscopy shows polypoid growths flanked by linear ulcers. A colonic biopsy specimen shows mucosal edema with distorted crypts and inflammatory cells in the lamina propria. Which of the following is the most appropriate recommendation for this patient?
- A. Obtain genetic studies now
- B. Obtain barium follow-through radiography in 1 year
- C. Obtain glutamate dehydrogenase antigen immunoassay now
- D. Start annual magnetic resonance cholangiopancreatography screening in 10 years
- E. Start annual colonoscopy starting in 8 years (Correct Answer)
IBD in pregnancy Explanation: ***Start annual colonoscopy starting in 8 years***
- The patient's presentation with bloody diarrhea, abdominal cramps, and repetitive episodes is consistent with <b>inflammatory bowel disease (IBD)</b>, specifically likely <b>ulcerative colitis</b> given the left lower quadrant tenderness and colonic biopsy findings (distorted crypts, inflammatory cells in lamina propria).
- Patients with IBD, particularly ulcerative colitis affecting a significant portion of the colon and diagnosed at a younger age, are at increased risk for <b>colorectal cancer</b>. Annual colonoscopy screening is recommended 8–10 years after diagnosis for early detection and prevention.
*Obtain genetic studies now*
- While genetic factors play a role in IBD susceptibility, <b>genetic studies are not routinely indicated for diagnosis or management</b> of inflammatory bowel disease, nor do they guide current screening recommendations for colorectal cancer in IBD patients.
- Genetic studies would not provide immediate clinical benefit for this patient's acute symptoms or long-term management plan regarding cancer surveillance.
*Obtain barium follow-through radiography in 1 year*
- <b>Barium follow-through radiography</b> is primarily used to evaluate the small intestine, often in suspected Crohn's disease. This patient's symptoms and colonoscopy findings point towards colonic involvement, making this less appropriate.
- Furthermore, this imaging modality uses <b>ionizing radiation</b> and is less sensitive for detecting mucosal changes indicative of dysplasia or early cancer compared to colonoscopy.
*Obtain glutamate dehydrogenase antigen immunoassay now*
- <b>Glutamate dehydrogenase antigen immunoassay</b> is a test for <b><i>Clostridioides difficile</i> infection</b>. While C. difficile can cause severe diarrhea and colitis, the patient's history of recurrent episodes over 8 months and the specific colonoscopy findings (polypoid growths, linear ulcers, distorted crypts) are more characteristic of IBD.
- Although C. difficile infection can exacerbate IBD, it does not explain the chronic, recurrent nature of her illness or the long-term cancer surveillance needs.
*Start annual magnetic resonance cholangiopancreatography screening in 10 years*
- <b>MRCP screening</b> is used to monitor for <b>primary sclerosing cholangitis (PSC)</b>, a condition associated with IBD, particularly ulcerative colitis. However, PSC screening is performed <b>when clinically indicated</b> (e.g., elevated alkaline phosphatase, cholestatic symptoms), not as routine scheduled surveillance.
- This patient has no clinical features suggesting PSC at present, and there is no guideline recommending routine MRCP screening at a predetermined time interval for all IBD patients.
IBD in pregnancy US Medical PG Question 6: A 34-year-old woman, gravida 3, para 2, at 16 weeks' gestation comes to the physician because of nausea and recurrent burning epigastric discomfort for 1 month. Her symptoms are worse after heavy meals. She does not smoke or drink alcohol. Examination shows a uterus consistent in size with a 16-week gestation. Palpation of the abdomen elicits mild epigastric tenderness. The physician prescribes her medication to alleviate her symptoms. Treatment with which of the following drugs should be avoided in this patient?
- A. Magnesium hydroxide
- B. Sucralfate
- C. Pantoprazole
- D. Cimetidine
- E. Misoprostol (Correct Answer)
IBD in pregnancy Explanation: ***Misoprostol***
- **Misoprostol** is a prostaglandin E1 analog that stimulates uterine contractions, which can lead to **miscarriage** or **preterm labor**.
- Its **abortifacient properties** contraindicate its use in pregnancy, particularly for symptoms like heartburn.
*Magnesium hydroxide*
- **Magnesium hydroxide** is a common **antacid** that is generally considered safe for occasional use during pregnancy to relieve heartburn.
- While excessive doses can lead to **diarrhea**, it is not contraindicated and does not pose a direct threat to fetal development or pregnancy maintenance.
*Sucralfate*
- **Sucralfate** forms a protective barrier over ulcers and erosions in the GI tract and is minimally absorbed systemically, making it a safe option in pregnancy.
- It works locally and has no known teratogenic effects, often used for **gastric protection** during gestation.
*Pantoprazole*
- **Pantoprazole** is a **proton pump inhibitor (PPI)** that reduces stomach acid production and is generally considered safe for use in pregnancy when indicated for GERD or severe heartburn.
- It is classified as pregnancy category B or C, but extensive observational data have not shown an increased risk of malformations.
*Cimetidine*
- **Cimetidine** is an **H2 receptor antagonist** that decreases gastric acid secretion and is generally considered safe for use in pregnancy to treat heartburn or GERD.
- It is classified as pregnancy category B, and its use is well-established with no significant adverse fetal outcomes reported.
IBD in pregnancy US Medical PG Question 7: A 23-year-old woman with no significant past medical history currently on oral contraceptive pills presents to the emergency department with pleuritic chest pain. She states that it started today. Yesterday she had a trip and returned via plane. Her temperature is 98°F (36.7°C), blood pressure is 117/66 mmHg, pulse is 105/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam reveals tachycardia, a normal S1 and S2, and clear breath sounds. The patient’s lower extremities are non-tender and symmetric. Chest pain is not reproducible with position changes or palpation but is worsened with deep breaths. Which of the following is the most appropriate next test for this patient?
- A. D-dimer
- B. Ultrasound of the lower extremities
- C. Ventilation-perfusion scan
- D. CT angiogram (Correct Answer)
- E. Chest radiograph
IBD in pregnancy Explanation: ***CT angiogram***
- This patient has **HIGH probability for pulmonary embolism (PE)** based on **Wells criteria**: oral contraceptive use (hypercoagulable state), recent long-haul flight (immobilization), pleuritic chest pain, and tachycardia (pulse 105/min).
- With a **Wells score ≥4**, the appropriate next step is **definitive imaging with CT pulmonary angiography (CTPA)**, which is the **gold standard** for diagnosing PE.
- **D-dimer should be bypassed** in high-probability cases, as a negative result would not adequately rule out PE, and a positive result (expected in high-probability patients) would require CTPA anyway.
- CTPA provides direct visualization of pulmonary arterial thrombi and can also identify alternative diagnoses.
*D-dimer*
- D-dimer is appropriate for **low to moderate probability PE** (Wells score <4) where a negative result can safely rule out PE and avoid unnecessary imaging.
- In this **high-probability case**, D-dimer is likely to be positive regardless, making it an unnecessary intermediate step that delays definitive diagnosis.
- Using D-dimer in high-probability patients can lead to false reassurance if negative or simply confirms the need for CTPA if positive.
*Ultrasound of the lower extremities*
- Lower extremity ultrasound diagnoses **deep vein thrombosis (DVT)**, not PE directly.
- While finding DVT in a patient with suspected PE would support anticoagulation, **absence of DVT does not rule out PE**, as thrombi may have already embolized.
- This would delay appropriate diagnosis and is not the most direct test for suspected PE.
*Ventilation-perfusion scan*
- V/Q scan is reserved for patients with **contraindications to CT contrast** (severe renal insufficiency, contrast allergy) or pregnant patients where radiation exposure should be minimized.
- This young patient has no mentioned contraindications to contrast-enhanced CT.
- V/Q scanning is less specific than CTPA and often yields indeterminate results.
*Chest radiograph*
- Chest X-ray is often **normal in PE** or shows non-specific findings (Westermark sign, Hampton's hump are rare).
- While it may help exclude alternative diagnoses like pneumothorax or pneumonia, it cannot definitively diagnose or rule out PE.
- In a patient with high clinical suspicion for PE, delaying CTPA to obtain a chest X-ray is not optimal management.
IBD in pregnancy US Medical PG Question 8: A 67-year-old woman presents with right leg pain and swelling of 5 days’ duration. She has a history of hypertension for 15 years and had a recent hospitalization for pneumonia. She had been recuperating at home but on beginning to mobilize and walk, the right leg became painful and swollen. Her temperature is 37.1°C (98.7°F), the blood pressure is 130/80 mm Hg, and the pulse is 75/min. On physical examination, the right calf is 4 cm greater in circumference than the left when measured 10 cm below the tibial tuberosity. Dilated superficial veins are present on the right foot and the right leg is slightly redder than the left. There is some tenderness on palpation in the popliteal fossa behind the knee. Which of the following is the best initial step in the management of this patient’s condition?
- A. International normalized ratio (INR)
- B. Thrombophilia screen
- C. Wells’ clinical probability tool (Correct Answer)
- D. Computerized tomography (CT) with contrast
- E. Activated partial thromboplastin time (aPTT)
IBD in pregnancy Explanation: ***Wells' clinical probability tool***
- The patient presents with classic signs and symptoms of **deep vein thrombosis (DVT)**, including unilateral leg pain and swelling, dilated superficial veins, and tenderness. The Wells' clinical probability tool helps stratify the risk of DVT, guiding further diagnostic testing.
- Using this validated clinical decision rule for risk assessment is the **best initial step** to determine the likelihood of DVT before proceeding with imaging studies (compression ultrasound) or D-dimer testing.
- Based on the Wells' score, patients are categorized as low, moderate, or high probability, which then directs appropriate diagnostic testing and potential empiric anticoagulation.
*International normalized ratio (INR)*
- **INR** is used to monitor the effectiveness of **warfarin** therapy, an anticoagulant, and to assess liver function.
- It is not an initial diagnostic tool for DVT; rather, it is used **after a DVT diagnosis** has been made and anticoagulation with warfarin has been initiated.
*Thrombophilia screen*
- A **thrombophilia screen** investigates underlying genetic or acquired clotting disorders.
- This is typically performed **after a DVT diagnosis** in younger patients, those with recurrent DVT, or those with a family history of thrombosis, not as an initial diagnostic step unless there is strong suspicion for an underlying clotting disorder.
*Computerized tomography (CT) with contrast*
- A **CT with contrast** (specifically **CT venography**) can diagnose DVT, but it is not the **first-line imaging modality** for suspected DVT because of radiation exposure and contrast risks.
- **Compression ultrasonography** is generally the preferred initial imaging study for DVT, especially after a risk assessment using the Wells' score.
*Activated partial thromboplastin time (aPTT)*
- The **aPTT** is a measure of the intrinsic and common pathways of coagulation and is used to monitor **unfractionated heparin** therapy.
- It is not an initial diagnostic test for DVT; like INR, it is used **after diagnosis** for monitoring anticoagulant treatment.
IBD in pregnancy US Medical PG Question 9: A 17-year-old girl is brought to the physician by her parents for the evaluation of belly pain and a pruritic skin rash on her shoulders for the last 6 months. She describes feeling bloated after meals. Over the past 3 months, she has had multiple loose bowel movements per day. She appears thin. She is at the 20th percentile for height and 8th percentile for weight. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 16/min, and blood pressure is 120/78 mm Hg. Examination shows conjunctival pallor and inflammation of the corners of the mouth. There are several tense, grouped subepidermal blisters on the shoulders bilaterally. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Further evaluation of this patient is most likely to show which of the following findings?
- A. Increased serum lipase
- B. IgA tissue transglutaminase antibodies (Correct Answer)
- C. Oocysts on acid-fast stain
- D. Inflammation of the terminal ileum
- E. Esophageal webs
IBD in pregnancy Explanation: ***IgA tissue transglutaminase antibodies***
- The patient's symptoms of **belly pain**, **bloating**, **loose bowel movements**, **weight loss**, **growth failure** (low height and weight percentiles), and **pruritic skin rash** (dermatitis herpetiformis) are highly suggestive of **celiac disease**.
- **IgA tissue transglutaminase (tTG) antibodies** are the most sensitive and specific serological test for celiac disease.
*Increased serum lipase*
- **Increased serum lipase** is indicative of **pancreatitis**, which is not supported by the patient's symptoms or physical findings.
- While chronic pancreatitis can cause malabsorption, the characteristic skin rash and other gastrointestinal symptoms do not point to this diagnosis.
*Oocysts on acid-fast stain*
- **Oocysts on acid-fast stain** are used to diagnose **cryptosporidiosis** or other parasitic infections, which can cause chronic diarrhea but typically do not present with a characteristic skin rash like dermatitis herpetiformis.
- The presentation is more consistent with an autoimmune enteropathy rather than an infectious cause.
*Inflammation of the terminal ileum*
- **Inflammation of the terminal ileum** is characteristic of **Crohn's disease**, which can cause abdominal pain, diarrhea, and weight loss.
- However, the pruritic, blistering rash on the shoulders (dermatitis herpetiformis) is a hallmark of **celiac disease** and not typical for Crohn's disease.
*Esophageal webs*
- **Esophageal webs** are associated with **Plummer-Vinson syndrome**, which causes dysphagia and iron deficiency anemia.
- While this patient shows signs of anemia (conjunctival pallor), esophageal webs do not explain the chronic diarrhea, bloating, or the characteristic skin rash.
IBD in pregnancy US Medical PG Question 10: A 32-year-old man with Crohn disease is brought to the emergency department after he fainted at work. He says that he has been feeling increasingly fatigued and weak over the last several weeks though he has not previously had any episodes of syncope. On presentation he is found to be pale and agitated. A panel of lab tests is performed showing the following:
Hemoglobin: 10.2 g/dL
Hematocrit: 30.1%
Leukocyte count: 9,900 cells/mm^3 with normal differential
Platelet count: 290,000/mm^3
Mean corpuscular volume: 118 µm^3
Elevated homocysteine level
Normal methylmalonic acid level
Which of the following mechanisms explains how Crohn disease may have contributed to this patient's symptoms?
- A. Gastrointestinal blood loss
- B. Inflammation of the ileum
- C. Inflammation of the jejunum (Correct Answer)
- D. Release of acute phase proteins
- E. Inflammation of the duodenum
IBD in pregnancy Explanation: ***Inflammation of the jejunum***
- The patient's **macrocytic anemia** (MCV 118 fL) with **elevated homocysteine** and **normal methylmalonic acid** points to a **folate deficiency**.
- **Folate** is primarily absorbed in the **proximal small intestine**, particularly the **jejunum**; inflammation in this segment due to Crohn's disease would impair its absorption, leading to deficiency.
- While Crohn's disease classically affects the **terminal ileum**, it can involve any part of the GI tract, and **jejunal involvement** would specifically impair folate absorption.
*Gastrointestinal blood loss*
- Chronic gastrointestinal blood loss typically causes **microcytic anemia** due to iron deficiency, not the macrocytic anemia seen here.
- While Crohn's can cause bleeding, the **elevated homocysteine with normal methylmalonic acid** is specific for **folate deficiency**, not blood loss.
*Inflammation of the ileum*
- **Ileal inflammation** is the most common location in Crohn disease and primarily affects the absorption of **vitamin B12** and **bile salts**.
- **Vitamin B12 deficiency** would cause elevated **both homocysteine and methylmalonic acid** levels, which contradicts the normal methylmalonic acid observed in this patient.
*Release of acute phase proteins*
- **Acute phase proteins** are markers of inflammation and contribute to **anemia of chronic disease**, which is typically **normocytic** or mildly **microcytic**.
- This mechanism does not explain the **macrocytic anemia** with the specific biochemical pattern of elevated homocysteine and normal methylmalonic acid, which indicates **folate deficiency**.
*Inflammation of the duodenum*
- The **duodenum** is the primary site for **iron absorption**, though it also participates in **folate absorption** along with the jejunum.
- However, inflammation here would more likely lead to **iron deficiency anemia** (microcytic), and duodenal involvement is **less common** in Crohn disease compared to terminal ileal or jejunal disease.
- The clinical picture is most consistent with **jejunal inflammation** causing isolated folate malabsorption.
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