Correct Answer: C. Herpes – simplex virus
Herpes simplex virus (HSV-1, rarely HSV-2) causes punched-out ulcers in the esophagus—a pathognomonic finding that distinguishes it from other infectious esophagitis. These ulcers are characterized by sharply demarcated, discrete lesions with a clean base and raised erythematous margins, resembling a punch-biopsy defect. Histologically, HSV produces Cowdry type A intranuclear inclusions and multinucleated giant cells in the epithelium. The virus directly invades the squamous epithelium, causing focal necrosis and ulceration. HSV esophagitis typically presents with severe odynophagia, dysphagia, and substernal chest pain in immunocompromised patients (HIV/AIDS, post-transplant) or occasionally in immunocompetent individuals during primary infection. The punched-out appearance is the gold standard for HSV diagnosis on endoscopy, distinguishing it from the diffuse, confluent ulceration seen with CMV or the pseudomembranous plaques of Candida. Indian guidelines and Harrison's emphasize this morphologic distinction as the key diagnostic feature.
Why the other options are wrong
A. Cytomegalovirus — CMV causes giant ulcers with a shaggy, hemorrhagic base and irregular margins—not punched-out lesions. CMV ulcers are typically large, solitary, and located in the distal esophagus, often with a characteristic 'volcano-like' appearance. While both are viral, CMV produces a different histologic pattern (owl's-eye inclusions, not Cowdry A) and a distinct endoscopic morphology that is not punched-out. B. Candida — Candida causes pseudomembranous esophagitis with white, removable plaques on an erythematous base—not punched-out ulcers. Candida is a superficial infection of the mucosa and does not produce the sharply demarcated, deep ulceration characteristic of HSV. Candida is the most common esophageal infection in India among immunocompromised patients, but its endoscopic appearance is distinctly different. D. Acid — Acid reflux causes diffuse, erosive esophagitis with multiple shallow erosions and a granular appearance—not discrete punched-out ulcers. Acid-induced injury is typically in the distal esophagus and lacks the sharply demarcated borders and clean base of HSV ulcers. This is a distractor testing whether students confuse infectious with chemical esophagitis.
High-Yield Facts
- Punched-out ulcers are pathognomonic for HSV esophagitis; they are sharply demarcated with clean bases and raised erythematous margins.
- Cowdry type A intranuclear inclusions and multinucleated giant cells are the histologic hallmark of HSV esophagitis.
- HSV esophagitis occurs predominantly in immunocompromised patients (CD4 <50 cells/μL in HIV, post-transplant) but can occur in immunocompetent individuals.
- CMV causes giant ulcers with shaggy bases; Candida causes pseudomembranes; acid causes diffuse erosions—all distinct from HSV's punched-out pattern.
- Odynophagia (pain on swallowing) is the cardinal symptom; diagnosis is confirmed by endoscopy with biopsy showing viral inclusions.
Mnemonics
HSV vs CMV vs Candida Esophagitis PUNCH = Punched-out (HSV), GIANT = Giant ulcers (CMV), PLAQUES = Pseudomembranous plaques (Candida). Use this when comparing infectious esophagitis on endoscopy. Viral Inclusions Memory Hook Cowdry A = HSV (A comes before C alphabetically; Cowdry A comes before Cowdry B). Owl's eyes = CMV (CMV sounds like 'see-em-vee'—remember the owl's-eye look). Quick recall for histology.
NBE Trap
NBE pairs "ulcers in esophagus" with multiple infectious agents to test whether students know the specific morphologic pattern (punched-out = HSV) rather than just "which virus causes esophagitis." Students who memorize "CMV causes esophagitis" without knowing the ulcer morphology will incorrectly choose CMV.
Clinical Pearl
In Indian HIV clinics, when a patient with CD4 <100 presents with severe odynophagia and endoscopy shows punched-out ulcers, start IV acyclovir immediately while awaiting biopsy confirmation—HSV esophagitis can progress to perforation if untreated, and the punched-out appearance is reliable enough for empiric therapy.
_Reference: Harrison's Principles of Internal Medicine, Ch. 283 (Esophageal Disorders); Robbins & Cotran Pathologic Basis of Disease, Ch. 17 (Gastrointestinal Tract)_