While participating in sports, it is not uncommon for people to be subjected to sudden rotational injuries that result in the abrupt rotation of the cerebral cortex around the more fixed midbrain structures. This can interrupt input and outflow from the reticular activating system and result in what clinical phenomenon?

Correct Answer: C

Rationale: Step 1: Sudden rotational injuries can disrupt brain function. Step 2: Abrupt rotation of the cerebral cortex can affect the reticular activating system. Step 3: Disruption of the reticular activating system can lead to altered consciousness. Step 4: Altered consciousness is a hallmark of a concussion. Therefore, the correct answer is C: Concussion. Other choices are incorrect because an epidural hematoma involves bleeding between the skull and dura (A), uncal herniation involves brain shifting through tentorium (B), and contrecoup injury occurs opposite the site of impact (D).

Correct Answer: B

Rationale: Postdatism refers to a pregnancy that extends beyond the normal gestation period of 280 days. The correct answer is B (294 days) as it is more than the standard 280-day term. Choice A (280 days) is the normal term, not postdatism. Choices C (290 days) and D (287 days) are also below the 294-day mark, making them incorrect for defining postdatism.

Correct Answer: A

Rationale: The correct answer is A because secondary postpartum hemorrhage typically occurs between the 8th-14th day postpartum and can extend up to 6 weeks after delivery. This timeframe aligns with the physiological changes and healing process after childbirth. Choice B is incorrect because it contradicts the established timeframe for secondary postpartum hemorrhage. Choice C is incorrect as secondary postpartum hemorrhage is not rare but rather a recognized complication that can occur after childbirth. Choice D is incorrect as secondary postpartum hemorrhage does not happen sporadically, but rather follows a defined timeframe based on postpartum physiological changes.

Correct Answer: A

Rationale: The correct answer is A: Avoidance of elective surgery and nonessential medications. This is the initial management for a patient with thrombocytopenia and abnormal bleeding time, possibly indicating immune thrombocytopenic purpura (ITP). Avoiding surgery and medications that can worsen thrombocytopenia is crucial to prevent bleeding complications. Prednisone (B) is not the first-line treatment for ITP, especially without confirming the diagnosis. Monoclonal antibody therapy (C) such as rituximab is usually reserved for refractory cases. Splenectomy (D) is considered only if other treatments fail as a last resort.

Correct Answer: A

Rationale: The correct answer is A: Prevent alveoli of the lungs from collapsing. Surfactant reduces surface tension in the alveoli, preventing them from collapsing during exhalation and maintaining lung compliance. B, C, and D are incorrect because surfactant primarily affects lung mechanics, not the initiation of breathing, maturity of the respiratory center, or immediate regulation of breathing upon birth.

Correct Answer: C

Rationale: The correct answer is C: Oligohydramnios. Shoulder presentation occurs when the baby presents shoulder-first rather than head-first during birth. Oligohydramnios, a condition characterized by low levels of amniotic fluid, can lead to decreased uterine space, increasing the chances of abnormal fetal positioning. Macerated fetus (A) is associated with fetal decomposition, not shoulder presentation. Postdates pregnancy (B) is linked to increased risk of macrosomia but not shoulder presentation. Placenta abruption (D) is a separation of the placenta from the uterus, not a direct cause of shoulder presentation.

Correct Answer: B

Rationale: The correct answer is B: Acute pancreatitis. The clinical presentation of sudden, severe upper abdominal pain not related to food intake, along with the patient's position (lying on right side with hips and knees flexed), and presence of involuntary guarding suggest acute pancreatitis. The elevated white blood cell count indicates an inflammatory process. Dissecting aortic aneurysm (A) typically presents with abrupt, severe chest or back pain radiating to the abdomen, with signs of shock. Perforated peptic ulcer (C) presents with sudden, severe abdominal pain often related to food intake, with signs of peritonitis. Mallory-Weiss tear (D) presents with hematemesis after forceful or prolonged vomiting.

Correct Answer: C

Rationale: The correct answer is C: Occipito-posterior. This position occurs when the baby's head is facing forward but towards the mother's spine. This position can cause intense back pain during labor because the baby's head puts pressure on the mother's lower back. Occipito-anterior (A) is the most common and ideal position for labor. Transverse position (B) is when the baby is lying sideways, which may cause prolonged labor but not necessarily intense back pain. Occipito-lateral (D) is a less common position where the baby's head is facing sideways, which may not specifically cause intense back pain.

Correct Answer: A

Rationale: The engaging diameter in a face presentation is the sub-mento vertical diameter. This is the correct answer because it represents the distance from the tip of the chin (mentum) to the highest point on the skull (vertex), which is the most critical diameter for the face to descend through the pelvis during childbirth. Choice B (Sub-mento bregmatic diameter) is incorrect because it represents the distance from the tip of the chin to the anterior fontanelle, not the highest point on the skull. Choice C (Mento vertical diameter) is incorrect because it refers to the distance from the chin to the base of the skull, not the highest point on the skull. Choice D (Sub-occipito bregmatic diameter) is incorrect because it represents the distance from the base of the skull to the anterior fontanelle, not involving the chin.