COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Gastrointestinal and Nutritional Health Questions and Answers — Questions and Answers
Question 1: A 24-year-old male presents with a 6-month history of recurrent bloody diarrhea, lower abdominal cramping, and tenesmus. Colonoscopy reveals continuous, erythematous, and friable mucosa starting at the rectum and extending proximally to the splenic flexure. The inflammation is confined to the mucosal and submucosal layers. Which of the following is the most likely diagnosis?
- Crohn's disease
- Irritable bowel syndrome
- Ulcerative colitis (Correct answer)
- Celiac disease
Correct answer: Ulcerative colitis
The patient's presentation of bloody diarrhea, tenesmus, and colonoscopic findings of continuous inflammation limited to the mucosa starting in the rectum are classic for ulcerative colitis. Crohn's disease typically presents with discontinuous (skip lesions) and transmural inflammation and can occur anywhere in the GI tract. Irritable bowel syndrome does not have inflammatory findings on colonoscopy, and celiac disease primarily affects the small intestine.
Question 2: A 62-year-old male who underwent a total gastrectomy for gastric cancer four years ago presents with progressive fatigue, a 'pins and needles' sensation in his lower extremities, and difficulty with balance. Laboratory studies show a hemoglobin of 9.5 g/dL and a mean corpuscular volume (MCV) of 115 fL. Which of the following nutritional deficiencies is the most likely cause of his signs and symptoms?
- Vitamin C
- Thiamine (Vitamin B1)
- Iron
- Cobalamin (Vitamin B12) (Correct answer)
Correct answer: Cobalamin (Vitamin B12)
Total gastrectomy removes parietal cells, which are responsible for producing intrinsic factor. Intrinsic factor is essential for the absorption of Vitamin B12 (cobalamin) in the terminal ileum. Its absence leads to B12 deficiency, causing both macrocytic anemia and the neurological symptoms of subacute combined degeneration of the spinal cord.
Question 3: An osteopathic physician is performing a structural exam on a patient with a history of recurrent urinary tract infections and flank pain. The physician notes boggy tissue texture changes, paraspinal muscle hypertonicity, and tenderness at the T10-T11 vertebral levels. This viscerosomatic reflex is most commonly associated with pathology of which organ system?
- Kidneys and upper ureters (Correct answer)
- Appendix and cecum
- Liver and gallbladder
- Descending and sigmoid colon
Correct answer: Kidneys and upper ureters
The sympathetic innervation to the kidneys and upper ureters originates from the T10-T11 spinal cord segments. Visceral pathology in these organs can cause a reflexive facilitation and somatic dysfunction at these corresponding spinal levels. The appendix is typically T12, the liver/gallbladder is T6-T9, and the descending/sigmoid colon is T12-L2.
Question 4: A 45-year-old man with a history of heavy alcohol use presents to the emergency department with severe, constant epigastric pain that radiates to his back. The pain began 10 hours ago and is associated with nausea and two episodes of vomiting. On examination, he is febrile and has marked tenderness in the epigastric region. Which of the following laboratory findings is the most specific for diagnosing his condition?
- Serum lipase >3 times the upper limit of normal (Correct answer)
- Serum amylase >3 times the upper limit of normal
- Elevated C-reactive protein
- Leukocytosis
Correct answer: Serum lipase >3 times the upper limit of normal
The clinical presentation is highly suggestive of acute pancreatitis. While both serum amylase and lipase are typically elevated, serum lipase is more specific to the pancreas and remains elevated for a longer period than amylase. Amylase can be elevated in other conditions, such as salivary gland disorders or bowel obstruction. C-reactive protein and leukocytosis are non-specific markers of inflammation.
Question 5: A 65-year-old male with a long history of chronic hepatitis C infection is diagnosed with cirrhosis. During an upper endoscopy for evaluation of dyspepsia, numerous large, tortuous veins are noted in the distal esophagus. What is the primary pathophysiologic mechanism responsible for the formation of these varices?
- Decreased plasma oncotic pressure
- Portal hypertension (Correct answer)
- Hepatic encephalopathy
- Increased synthesis of prothrombin
Correct answer: Portal hypertension
Cirrhosis causes fibrosis and increased resistance to blood flow through the liver, leading to elevated pressure in the portal venous system, a condition known as portal hypertension. This increased pressure forces blood to be shunted through collateral vessels, such as the submucosal veins in the distal esophagus, causing them to become dilated and tortuous (varices).
Question 6: A 30-year-old woman presents with chronic diarrhea, abdominal bloating, and an intensely pruritic, papulovesicular rash on her elbows and buttocks. A skin biopsy confirms dermatitis herpetiformis. Which of the following serologic tests is considered the most specific for the underlying gastrointestinal condition?
- Anti-Saccharomyces cerevisiae antibodies (ASCA)
- Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA)
- Anti-tissue transglutaminase (tTG) IgA antibody (Correct answer)
- Anti-smooth muscle antibodies (ASMA)
Correct answer: Anti-tissue transglutaminase (tTG) IgA antibody
The patient's clinical picture, including dermatitis herpetiformis, is pathognomonic for celiac disease. The most sensitive and specific serologic screening test for celiac disease is the anti-tissue transglutaminase (tTG) IgA antibody. ASCA is associated with Crohn's disease, p-ANCA is often found in ulcerative colitis, and ASMA is a marker for autoimmune hepatitis.
