Trauma to the Central Nervous System — MCQs
Which of the following represents a secondary brain injury mechanism?
Post contusional syndrome includes:
A patient is brought to the emergency department following a head-on collision road traffic accident. He has sustained a head injury. His BP is 90/60 mmHg and tachycardia is present. The most likely cause of his hemodynamic instability is:
The earliest manifestation of increased intracranial pressure following head injury is:
A 20-year-old male presents to the emergency department with a head injury. Examination reveals normal consciousness, no neurological deficits, and blood in the tympanic membrane. What is the most likely cause?
A 43-year-old man presents to the emergency department after falling down a flight of stairs and landing on his head. He did not lose consciousness. He complains of severe headache, marked decreased acuity in hearing in the left ear, and a "runny nose" since the fall. On physical examination, he is found to have a left-sided Battle's sign (an ecchymosis in the area of the left mastoid process) and hemotympanum. He has a constant dripping of a clear, watery fluid through his nose. Findings on his neurologic examination, other than the hearing loss, are completely normal. X-ray studies will reveal which of the following?
A polytrauma patient's CT brain shows a crescent-shaped extra-axial collection with a concave inner margin. What is the most likely diagnosis?
Glasgow coma scale -moderate includes
What is the primary pathological mechanism in classical Guillain-Barré syndrome affecting the peripheral nervous system?
A child presented with microcephaly, hepatomegaly and periventricular calcification. What is the best specimen for diagnosis of CMV by PCR?
Trauma to the Central Nervous System Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following represents a secondary brain injury mechanism?
- A. Immediate axonal shearing
- B. Contusion at impact site
- C. Skull fracture
- D. Inflammatory response (Correct Answer)
Explanation: ***Inflammatory response*** - **Inflammatory response** is a classic **secondary brain injury mechanism** that occurs hours to days after initial trauma through delayed activation of **microglia**, **cytokine release**, and **neuroinflammation**. - It represents a **cascade of cellular processes** that develops after the primary injury, causing additional neuronal damage through **blood-brain barrier disruption**, **cerebral edema**, and **cellular apoptosis**. *Immediate axonal shearing* - **Immediate axonal shearing** is a **primary brain injury mechanism** that occurs at the exact moment of trauma due to **rotational and acceleration forces**. - It represents **direct mechanical damage** to axons during impact, not a delayed secondary process that develops after the initial injury. *Contusion at impact site* - **Contusion at impact site** is a **primary brain injury** resulting from **direct mechanical trauma** to brain tissue at the point of impact. - It occurs **immediately upon trauma** through direct tissue damage and hemorrhage, rather than through delayed secondary mechanisms. *Skull fracture* - **Skull fracture** is a **primary injury** that results from **direct mechanical force** applied to the skull during the traumatic event. - It represents **immediate structural damage** occurring at the moment of impact, not a secondary process that develops over time after initial trauma.
Question 2: Post contusional syndrome includes:
- A. Delirium
- B. Nausea & vomiting
- C. Headache (Correct Answer)
- D. All of the options
Explanation: ***Headache*** - **Headache** is the **most common and characteristic symptom** of **post-concussion syndrome (PCS)**, present in up to 90% of cases. - Typically described as tension-type or migraine-like headaches that persist for weeks to months after mild traumatic brain injury. - This is a **core diagnostic feature** of PCS according to ICD-10 (F07.2) and DSM-5 criteria. - Among the given options, this is the **most definitive symptom** of post-concussion syndrome. *Delirium* - **Delirium** is an acute confusional state with fluctuating consciousness, impaired attention, and cognitive dysfunction. - This is **NOT a feature of post-concussion syndrome**, which involves persistent symptoms in clear consciousness. - Delirium may occur immediately after severe traumatic brain injury but is not part of the chronic post-concussional syndrome picture. - Post-concussion syndrome involves cognitive difficulties (memory, concentration) but not delirium. *Nausea & vomiting* - **Nausea** can occur as part of post-concussion syndrome, particularly when associated with vestibular dysfunction or migraine-like headaches. - However, it is **less characteristic and less persistent** than headache, and is not present in all cases. - While recognized in ICD-10 criteria for PCS, nausea is not as defining or universal as headache. - Vomiting is less common in chronic PCS compared to acute concussion. *All of the options* - This is incorrect because **delirium is NOT a feature of post-concussion syndrome**. - While headache is the hallmark symptom and nausea can occur, delirium represents acute brain dysfunction, not the chronic syndrome. - PCS is characterized by persistent somatic (headache, dizziness), cognitive (concentration, memory problems), and psychological (irritability, anxiety) symptoms in clear consciousness.
Question 3: A patient is brought to the emergency department following a head-on collision road traffic accident. He has sustained a head injury. His BP is 90/60 mmHg and tachycardia is present. The most likely cause of his hemodynamic instability is:
- A. Intracranial hemorrhage
- B. Intraabdominal bleed (Correct Answer)
- C. Extradural hemorrhage (EDH)
- D. Subdural hemorrhage (SDH)
Explanation: ***Intraabdominal bleed*** - **Hypotension** and **tachycardia** following trauma, especially a head-on collision, strongly suggest significant blood loss. The brain itself cannot cause enough isolated blood loss to result in **hemodynamic instability** as severe as **hypotension** and **tachycardia**. - A comprehensive trauma assessment prioritizes identifying sources of internal hemorrhage, and an **intra-abdominal bleed** would be a prime suspect for **hypovolemic shock**. *Intracranial hemorrhage* - While a **head injury** can involve considerable blood loss within the skull, it typically does not lead to **hypotension** but rather to **hypertension** due to the **Cushing reflex**. - **Cushing reflex** involves **hypertension**, **bradycardia**, and **irregular respiration** in response to increased intracranial pressure. *Extradural hemorrhage (EDH)* - An **EDH** is an arterial bleed, often rapid, and leads to increased intracranial pressure. - Like other intracranial bleeds, it's more likely to cause **hypertension** (**Cushing's reflex**) rather than **hypotension**. *Subdural hemorrhage (SDH)* - An **SDH** is typically a venous bleed, slower than an arterial bleed, but also causes increased intracranial pressure. - This condition is also more likely to induce **hypertension** via the **Cushing reflex** than to cause systemic **hypotension**.
Question 4: The earliest manifestation of increased intracranial pressure following head injury is:
- A. Hemiparesis
- B. Ipsilateral pupillary dilatation
- C. Altered mental status (Correct Answer)
- D. Contralateral pupillary dilatation
Explanation: ***Altered mental status*** - **Altered mental status** (e.g., confusion, irritability, drowsiness) is often the earliest sign of increased intracranial pressure (ICP) due to its profound effect on global brain function. - This change reflects the **brain's reduced perfusion** and metabolic compromise as pressure within the rigid skull rises. *Hemiparesis* - **Hemiparesis** indicates focal neurological deficits, usually resulting from direct injury or significant pressure on specific motor pathways, which typically manifest later than global mental status changes. - It suggests a more advanced stage of neurological compromise or a localized mass effect. *Ipsilateral pupillary dilatation* - **Ipsilateral pupillary dilatation** is a classic sign of uncal herniation, where the temporal lobe compresses the **oculomotor nerve** (CN III) on the same side. - While critical, it is generally a *late and ominous sign* of significantly elevated ICP, indicating severe brainstem compression. *Contralateral pupillary dilatation* - **Contralateral pupillary dilatation** is highly unusual in the context of typical uncal herniation, which almost always causes *ipsilateral* signs due to direct compression. - Its presence would suggest atypical herniation patterns or other causes of pupillary asymmetry.
Question 5: A 20-year-old male presents to the emergency department with a head injury. Examination reveals normal consciousness, no neurological deficits, and blood in the tympanic membrane. What is the most likely cause?
- A. Subdural haemorrhage
- B. Basilar skull fracture (Correct Answer)
- C. Intraventricular haemorrhage
- D. Extradural haemorrhage
Explanation: ***Basilar skull fracture*** - **Blood in the tympanic membrane** (hemotympanum) is a classic sign of a **basilar skull fracture**, indicating a fracture extending into the petrous part of the temporal bone. - Despite the potential severity of a basilar fracture, patients can initially present with **normal consciousness** and **no focal neurological deficits**. - Other signs of basilar skull fracture include Battle's sign (postauricular ecchymosis), raccoon eyes (periorbital ecchymosis), and CSF rhinorrhea/otorrhea. *Subdural haemorrhage* - A subdural hemorrhage is a collection of blood between the **dura mater and arachnoid mater**, typically resulting in neurological deficits due to brain compression. - While head injury is the cause, it does not directly explain **blood in the tympanic membrane** as a primary finding. *Extradural haemorrhage* - An extradural (epidural) hemorrhage is often characterized by a **lucid interval** followed by rapid neurological deterioration due to arterial bleeding. - It does not typically manifest with **blood in the tympanic membrane** unless there's a co-occurring basilar fracture, which would be the more direct cause of the tympanic finding. *Intraventricular haemorrhage* - An intraventricular hemorrhage involves bleeding into the **brain's ventricular system** and is usually associated with significant neurological impairment and altered consciousness. - It does not cause **blood in the tympanic membrane**.
Question 6: A 43-year-old man presents to the emergency department after falling down a flight of stairs and landing on his head. He did not lose consciousness. He complains of severe headache, marked decreased acuity in hearing in the left ear, and a "runny nose" since the fall. On physical examination, he is found to have a left-sided Battle's sign (an ecchymosis in the area of the left mastoid process) and hemotympanum. He has a constant dripping of a clear, watery fluid through his nose. Findings on his neurologic examination, other than the hearing loss, are completely normal. X-ray studies will reveal which of the following?
- A. A temporal bone fracture with CSF rhinorrhea (Correct Answer)
- B. Occipital bone fracture
- C. A skull-base fracture with a mucocele
- D. A fracture of the cribriform plate with a CSF leak into the paranasal sinuses
Explanation: ***A temporal bone fracture with CSF rhinorrhea*** - The combination of **Battle's sign**, **hemotympanum**, unilateral hearing loss, and clear nasal discharge after head trauma strongly indicates a **temporal bone fracture**. - **CSF rhinorrhea** refers to cerebrospinal fluid leaking from the nose due to a skull base fracture involving the temporal bone, typically affecting the petrous part. - The CSF can reach the nasal cavity via the **eustachian tube** or through fracture lines extending to the middle ear and mastoid air cells. *Occipital bone fracture* - While occipital fractures are possible with head trauma, they do not directly explain the specific findings of **hemotympanum** or unilateral hearing loss. - An occipital fracture would typically cause symptoms related to damage to the **brainstem** or **cerebellum**, depending on the extent. *A skull-base fracture with a mucocele* - A **mucocele** is a cyst filled with mucus, usually resulting from obstruction of a sinus ostium, and is not an acute traumatic finding. - While a skull-base fracture is present, the presence of a mucocele does not fit the acute injury presentation. *A fracture of the cribriform plate with a CSF leak into the paranasal sinuses* - A **cribriform plate fracture** would result in CSF rhinorrhea, but it typically causes CSF to leak directly from the anterior cranial fossa into the nasal cavity. - It would not explain the **hemotympanum**, Battle's sign, or unilateral hearing loss, which are characteristic of **temporal bone injury**.
Question 7: A polytrauma patient's CT brain shows a crescent-shaped extra-axial collection with a concave inner margin. What is the most likely diagnosis?
- A. EDH
- B. SDH (Correct Answer)
- C. Contusion
- D. Diffuse axonal injury
Explanation: ***SDH*** - The image shows a **crescent-shaped collection** of hemorrhage with a concave inner margin, consistent with a **subdural hematoma** (SDH). - SDHs result from the tearing of **bridging veins** and typically conform to the brain's surface, crossing suture lines but not limited by bony sutures. *EDH* - An **epidural hematoma (EDH)** characteristically appears as a **lenticular** or **biconvex** shape on CT, not crescent-shaped. - EDHs are typically caused by arterial bleeding, often from the **middle meningeal artery**, and are limited by cranial sutures. *Contusion* - A **contusion** is brain tissue bruising that appears as **heterogeneous areas** of hemorrhage and edema within the brain parenchyma itself. - It would not manifest as a distinct extra-axial collection with a smooth, concave margin. *Diffuse axonal injury* - **Diffuse axonal injury (DAI)** involves widespread microscopic damage to axons, often at the gray-white matter junction. - It may appear as *punctate hemorrhages* or **small lesions** at these junctions on CT, but often the CT can be normal, and it would not present as a large extra-axial collection.
Question 8: Glasgow coma scale -moderate includes
- A. <3
- B. >12
- C. 9-12 (Correct Answer)
- D. 3-8
Explanation: ***9-12*** - A **Glasgow Coma Scale (GCS)** score between 9 and 12 is classified as **moderate head injury** or **moderate coma** [1]. - This range indicates significant impairment of consciousness, often requiring medical intervention and close monitoring. *<3* - A GCS score of **less than 3** is not clinically possible as the minimum score achievable is 3 (1 for each component: Eye, Verbal, Motor response). - This option is technically inaccurate based on the GCS scoring system. *>12* - A GCS score of **greater than 12** typically falls into the category of **mild head injury** (13-15) [1]. - Patients in this range usually have a better prognosis and less severe neurological deficits. *3-8* - A GCS score between **3 and 8** is indicative of **severe head injury** or **severe coma** [1]. - Patients in this range often require immediate critical care, including intubation and ventilatory support due to compromised airway reflexes.
Question 9: What is the primary pathological mechanism in classical Guillain-Barré syndrome affecting the peripheral nervous system?
- A. It blocks neurotransmitter release.
- B. It causes demyelination of peripheral nerves. (Correct Answer)
- C. It inhibits muscle contraction.
- D. It leads to axonal degeneration.
Explanation: ***It causes demyelination of peripheral nerves.*** - Classical Guillain-Barré syndrome (AIDP - Acute Inflammatory Demyelinating Polyneuropathy) is an autoimmune disorder where the immune system attacks the **myelin sheath** surrounding peripheral nerves. - This **demyelination** impairs nerve signal conduction, leading to weakness and paralysis. - AIDP represents the most common form of GBS in Western countries (~85-90% of cases). *It blocks neurotransmitter release.* - Conditions like **Lambert-Eaton myasthenic syndrome** primarily involve antibodies targeting presynaptic voltage-gated calcium channels, thereby reducing neurotransmitter release. - While GBS affects nerve conduction, its primary mechanism is not the blockage of neurotransmitter release at the synapse. *It inhibits muscle contraction.* - Inhibition of muscle contraction is a downstream effect of impaired nerve innervation, but the fundamental problem in GBS is with the **nerve itself**, not the muscle's ability to contract directly. - Conditions like **myasthenia gravis** directly affect neuromuscular transmission by blocking acetylcholine receptors on muscle fibers. *It leads to axonal degeneration.* - While **axonal variants** of GBS exist (AMAN - Acute Motor Axonal Neuropathy; AMSAN - Acute Motor-Sensory Axonal Neuropathy), particularly common in Asia, the **classical and most common form** is characterized by **primary demyelination** (AIDP). - Pure axonal degeneration as a primary pathology is seen in specific GBS variants, not the classical presentation. - Secondary axonal damage can occur in severe or prolonged cases.
Question 10: A child presented with microcephaly, hepatomegaly and periventricular calcification. What is the best specimen for diagnosis of CMV by PCR?
- A. CSF
- B. Blood
- C. Liver biopsy
- D. Urine (Correct Answer)
Explanation: ***Urine*** - **Urine** is the most sensitive and commonly used specimen for diagnosing **congenital CMV infection** via PCR, especially in neonates, due to high viral shedding in urine. - A positive urine CMV PCR within the first 2-3 weeks of life is highly indicative of **congenital CMV**, which can cause symptoms like **microcephaly**, **hepatomegaly**, and **periventricular calcifications**. *CSF* - While CMV can be detected in **CSF** in congenital infections, particularly in symptomatic cases with neurological involvement, it is less sensitive than urine for initial diagnosis. - **CSF PCR** is typically reserved for evaluating central nervous system involvement and may not detect systemic infection as reliably as urine. *Blood* - **Blood PCR** for CMV can be positive in congenital infection, but it can also be positive in postnatal CMV acquisition or maternal viremia without congenital transmission. - The presence of viral DNA in blood is transient, and its sensitivity for diagnosing congenital infection is generally lower than that of urine. *Liver biopsy* - **Liver biopsy** is an invasive procedure and is not the primary diagnostic method for CMV infection, although histological examination can reveal characteristic viral inclusions if there is significant hepatic involvement. - It carries risks and is typically performed only when other diagnostic methods are inconclusive or when assessing the extent of liver damage.
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