A 4-year-old boy is brought to the emergency department by his parents due to right ear pain, swelling behind the ear, and fever for the past three days. History of Present Illness: The boy developed acute otitis media (AOM) one week ago and was prescribed oral amoxicillin, but his parents discontinued the medication after three days when his symptoms seemed to improve. Over the past three days, his ear pain worsened, and his parents noticed redness and swelling behind his right ear. He has been irritable, refusing to eat, and has had a persistent fever of 39.2°C (102.6°F). They also noticed that his right ear appears to be pushed forward. Past Medical History: Recurrent acute otitis media (AOM) (3 episodes in the past six months) No known allergies Vaccinations are up to date Family & Social History: No family history of recurrent ear infections or hearing loss Attends daycare (frequent upper respiratory infections) Physical Examination: General: Febrile (39.2°C / 102.6°F) Irritable but alert Head & Neck: Right postauricular erythema, swelling, and tenderness Auricle is displaced anteriorly and downward No fluctuance or skin breakdown over the mastoid region Otoscopy: Bulging, erythematous tympanic membrane on the right Purulent otorrhea present Left ear is normal Neurological Examination: Cranial nerves intact (no facial weakness) No signs of meningeal irritation (no neck stiffness, negative Kernig and Brudzinski signs) Diagnostic Workup: Laboratory Tests: White blood cell (WBC) count: 15,200/mm³ (elevated, suggests infection) C-reactive protein (CRP): Elevated Erythrocyte sedimentation rate (ESR): Elevated Based on this presentation, what is the most likely diagnosis?
A microbiologist is studying a bacterium that thrives in environments with high levels of reactive oxygen species (ROS). The bacterium produces a nickel-dependent enzyme that helps it survive oxidative stress. Question: Which of the following nickel-dependent enzymes is most likely responsible for detoxifying ROS in this bacterium?
A 45-year-old man presents with epigastric pain, nausea, and weight loss. Endoscopy reveals gastric ulcers, and a biopsy confirms the presence of Helicobacter pylori. The patient is diagnosed with a peptic ulcer disease caused by H. pylori infection. The bacterium is known to produce urease, an enzyme that neutralizes stomach acid, allowing it to colonize the gastric mucosa. Which of the following is the primary role of urease in H. pylori pathogenesis?
Case Scenario: A 48-year-old male presents with burning epigastric pain, bloating, and nausea, which worsens after meals. He reports frequent acid reflux and has a history of gastritis. A urea breath test is performed and confirms the presence of Helicobacter pylori, a bacterium that survives in the stomach by neutralizing acid. The physician explains that a nickel-dependent enzyme plays a key role in this bacterial survival. Which of the following nickel-dependent enzymes is responsible for Helicobacter pylori’s ability to colonize the stomach?
Case Scenario: A 35-year-old male presents with tremors, slurred speech, and jaundice. Ophthalmologic exam reveals Kayser-Fleischer rings, and liver biopsy confirms copper accumulation. His physician diagnoses Wilson’s disease, a genetic disorder of copper metabolism, and initiates chelation therapy. Which of the following best describes the primary pathological effect of copper excess in Wilson’s disease?
A 28-year-old male presents with tremors, dysarthria (slurred speech), and psychiatric symptoms. He also complains of abdominal pain and jaundice. Slit-lamp examination reveals Kayser-Fleischer rings in the cornea. The physician diagnoses Wilson’s disease, a disorder of copper metabolism. Which of the following best describes the pathophysiology of Wilson’s disease?
A 25-year-old woman presents with easy bruising, hyperelastic skin, and joint hypermobility. She reports a history of frequent joint dislocations and slow wound healing. On physical examination, her skin is notably stretchy, and her joints demonstrate an increased range of motion. Laboratory tests reveal normal serum copper levels, but genetic testing confirms a mutation in the LOX gene, which encodes lysyl oxidase. Which of the following is the primary role of lysyl oxidase in connective tissue?
Case Scenario: A 45-year-old female presents with muscle weakness and neurological symptoms. Laboratory tests show increased oxidative stress markers. The physician suspects a copper deficiency affecting an enzyme that neutralizes superoxide radicals. Which of the following enzymes requires copper for its antioxidant function?
A 6-month-old male infant presents with hypotonia, developmental delay, and sparse, kinky hair. Laboratory tests reveal low serum copper and ceruloplasmin levels. Genetic testing confirms a mutation in the ATP7A gene, consistent with Menkes disease. Which of the following copper-dependent enzymes is most likely impaired in this patient, contributing to the observed neurological symptoms?
Case Scenario: A 35-year-old male presents with fatigue, depression, and autonomic dysfunction. His laboratory tests reveal low norepinephrine levels and mild copper deficiency. His physician explains that copper is essential for an enzyme involved in catecholamine synthesis. Which of the following copper-dependent enzymes is responsible for converting dopamine to norepinephrine?
