A patient presents with redness, pain, and photophobia in the left eye. Slit-lamp examination reveals ciliary injection, corneal edema, and a mid-dilated pupil with fixed reaction to light. Which of the following conditions is most likely responsible for this presentation?

Correct Answer: A

Rationale: The correct answer is A: Anterior uveitis. This condition presents with redness, pain, and photophobia due to inflammation of the uveal tract. Ciliary injection, corneal edema, and mid-dilated pupil with fixed reaction to light are classic signs of anterior uveitis. The other choices can be ruled out based on specific findings: B: Acute angle-closure glaucoma would present with a high intraocular pressure, not fixed dilated pupil. C: Endophthalmitis typically presents with severe pain, hypopyon, and vitreous inflammation. D: Corneal abrasion would not cause ciliary injection or fixed dilated pupil.

Correct Answer: C

Rationale: The correct answer is C: Meningitis. The patient's symptoms of severe headache, photophobia, neck stiffness, nuchal rigidity, and positive Kernig and Brudzinski signs are classic signs of meningitis. Meningitis is an inflammation of the meninges surrounding the brain and spinal cord, leading to these specific neurological symptoms. Migraine headache (A) typically presents with a throbbing headache, nausea, and sensitivity to light and sound, but does not typically cause neck stiffness or positive meningeal signs. Cluster headache (B) is characterized by severe unilateral headache with autonomic symptoms like tearing or nasal congestion, but does not typically cause neck stiffness or positive meningeal signs. Subarachnoid hemorrhage (D) presents with sudden severe headache often described as "the worst headache of my life," and may cause neck stiffness, but typically does not present with photophobia or positive meningeal signs like Kernig and Brudzinski signs.

Correct Answer: C

Rationale: The correct answer is C: Group A beta-hemolytic Streptococcus (GAS). GAS is the most likely organism responsible for this presentation, known as acute bacterial tonsillitis. GAS commonly causes symptoms such as throat pain, odynophagia, fever, tonsillar enlargement with exudates, and cervical lymphadenopathy. Streptococcal pharyngitis is a common bacterial infection of the throat caused by GAS. The other options are less likely as Streptococcus pneumoniae typically causes pneumonia and Haemophilus influenzae is associated with respiratory tract infections. Epstein-Barr virus (EBV) commonly causes infectious mononucleosis, which presents with different symptoms than those described in the question.

Correct Answer: C

Rationale: The correct answer is C: Durable power of attorney. This legal document allows Mr. M to appoint his daughter as his healthcare proxy, granting her the authority to make medical decisions on his behalf if he becomes incapacitated. A: Expressed contract involves clear terms agreed upon by both parties, not relevant here. B: Implied contract arises from actions rather than explicit agreement, not applicable in this situation. D: A living will outlines an individual's medical treatment preferences, but does not grant decision-making authority to another person.

Correct Answer: A

Rationale: The correct answer is A: Myasthenia gravis. In myasthenia gravis, there is a decrease in acetylcholine receptors at the neuromuscular junction, leading to muscle weakness and fatigue. This occurs due to autoimmune destruction of these receptors. ALS (B) affects motor neurons, not acetylcholine receptors. Guillain-Barre syndrome (C) is an autoimmune disorder affecting peripheral nerves, not neuromuscular junctions. Muscular dystrophy (D) is a genetic disorder causing muscle degeneration, not affecting acetylcholine receptors.

Correct Answer: B

Rationale: The correct answer is B: Ectopic pregnancy. In this scenario, the combination of missed periods, positive pregnancy test, and empty uterus on ultrasound with fluid in the cul-de-sac is highly suggestive of an ectopic pregnancy. Ectopic pregnancy occurs when the fertilized egg implants outside the uterus, commonly in the fallopian tube. The presence of fluid in the cul-de-sac indicates possible blood from a ruptured ectopic pregnancy, causing the severe lower abdominal pain. Ovarian cyst rupture (A) typically presents with less severe pain. Septic abortion (C) would present with signs of infection and products of conception in the uterus. Ovarian torsion (D) would present with acute onset of unilateral lower abdominal pain and a palpable adnexal mass, not fluid in the cul-de-sac.

Correct Answer: B

Rationale: The correct answer is B: Acute myocardial infarction (MI) is the most common cause of cardiogenic shock. During an MI, there is significant damage to the heart muscle, leading to a decrease in cardiac output and subsequent shock. This results in inadequate tissue perfusion and oxygen delivery. Choices A, C, and D are incorrect because decreased hemoglobin level (A) may lead to anemia but is not the most common cause of cardiogenic shock. Hypotension (C) is a symptom of shock, not the cause. Coronary artery disease (D) is a risk factor for MI but not the direct cause of cardiogenic shock.

Correct Answer: B

Rationale: The primary reason for surgical repair of myelomeningocele is to correct the neurologic defect. This is because myelomeningocele is a type of neural tube defect where the spinal cord and its protective covering do not close properly. Surgical repair aims to close the opening in the spinal cord to prevent further damage, improve neurological function, and reduce the risk of complications such as paralysis and infection. The other choices are incorrect as they are not the primary goal of the surgery. Preventing infection (Choice A) is important but not the primary reason. Seizure disorders (Choice C) and hydrocephalus (Choice D) may be associated complications but are not the main purpose of the surgical repair.

Correct Answer: C

Rationale: The scenario described in the question is consistent with acute cholecystitis, which is inflammation of the gallbladder usually caused by an impacted gallstone in the cystic duct. The key clinical features of acute cholecystitis include fever, chills, right upper quadrant abdominal pain (which can be localized to the right upper quadrant), tenderness in the right upper abdomen, and a positive Murphy's sign (pain and inspiratory arrest upon palpation of the right upper quadrant). This condition is more common in pregnant women due to hormonal changes that can lead to gallstone formation and subsequent inflammation of the gallbladder. Ectopic pregnancy, pelvic inflammatory disease, and ovarian torsion typically present with different clinical features compared to those described in acute cholecystitis.