Demyelinating and Degenerative Diseases Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Demyelinating and Degenerative Diseases. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Demyelinating and Degenerative Diseases Indian Medical PG Question 1: Which of the following symptoms is least likely to be associated with multiple sclerosis?
- A. Fatigue
- B. Spasticity
- C. Optic neuritis
- D. Resting tremor (Correct Answer)
Demyelinating and Degenerative Diseases Explanation: ***Resting tremor***
- A **resting tremor** is much more characteristic of **Parkinson's disease**, resulting from degeneration of **dopaminergic neurons** in the substantia nigra [2].
- While essential tremor and cerebellar tremors (intention tremor) can be seen in MS, a true resting tremor is **uncommon** in multiple sclerosis [1].
*Fatigue*
- **Fatigue** is one of the most common and debilitating symptoms in patients with multiple sclerosis, significantly impacting their quality of life.
- It often manifests as an overwhelming sense of **physical and mental exhaustion** that is disproportionate to activity and not relieved by rest [1].
*Spasticity*
- **Spasticity**, characterized by increased muscle tone and involuntary muscle stiffness or spasms, is a very common symptom in MS due to demyelination in the **corticospinal tracts**.
- It can lead to difficulties with movement, pain, and contractures.
*Optic neuritis*
- **Optic neuritis**, an inflammation of the optic nerve causing sudden vision loss, eye pain, and blurred vision, is a classic and often early symptom of MS.
- It is a result of **demyelination** of the optic nerve.
Demyelinating and Degenerative Diseases Indian Medical PG Question 2: What is the typical MRI finding in multiple sclerosis (MS)?
- A. Basal ganglia calcification
- B. Diffuse cortical atrophy
- C. Subdural hematoma
- D. Periventricular lesions (Correct Answer)
Demyelinating and Degenerative Diseases Explanation: ***Periventricular lesions***
- **Demyelinating plaques** in a periventricular distribution are a hallmark MRI finding in **multiple sclerosis**, often appearing as **Dawson's fingers**.
- These lesions reflect areas of **demyelination** and inflammation characteristic of the disease.
*Basal ganglia calcification*
- This finding is more commonly associated with conditions like **Fahr's disease**, **hypoparathyroidism**, or certain infections, not primary to MS.
- While calcifications can occur in rare cases of MS, they are not a typical or diagnostic feature.
*Diffuse cortical atrophy*
- **Cortical atrophy** can be present in later stages of MS, but it is a **non-specific** finding not unique to MS and not a primary diagnostic marker.
- It is more commonly seen in neurodegenerative diseases like **Alzheimer's disease** or in the elderly, and less characteristic of early MS.
*Subdural hematoma*
- A **subdural hematoma** is a collection of blood between the dura mater and arachnoid mater, usually due to trauma.
- This is an **acute neurological emergency** and entirely unrelated to the pathology and typical MRI features of multiple sclerosis.
Demyelinating and Degenerative Diseases Indian Medical PG Question 3: A 67-year-old male presents with progressive difficulty in walking, frequent falls, and stiffness in the legs. Neurological examination reveals increased muscle tone, brisk deep tendon reflexes, and a positive Babinski sign. MRI of the brain shows multiple white matter lesions. Which of the following is the most likely diagnosis?
- A. Amyotrophic lateral sclerosis
- B. Multiple sclerosis (Correct Answer)
- C. Parkinson's disease
- D. Primary lateral sclerosis
Demyelinating and Degenerative Diseases Explanation: ***Multiple sclerosis***
- The combination of **progressive neurological symptoms (walking difficulty, falls, leg stiffness)**, **upper motor neuron signs (increased muscle tone, brisk reflexes, positive Babinski)** and **multiple white matter lesions on MRI** is highly suggestive of **multiple sclerosis (MS)** [1].
- While MS typically presents in younger individuals, presentation in the late 60s, though less common, is possible and referred to as **late-onset MS** [1].
*Amyotrophic lateral sclerosis*
- **Amyotrophic lateral sclerosis (ALS)** involves both **upper and lower motor neuron degeneration**, but typically presents with significant **muscle wasting and fasciculations (lower motor neuron signs)** [3].
- The MRI findings of **multiple white matter lesions** are not characteristic of ALS [3].
*Parkinson's disease*
- **Parkinson's disease** is primarily characterized by **tremor at rest, bradykinesia, rigidity, and postural instability**, which are **extrapyramidal symptoms** [2].
- While stiffness and walking difficulty can occur, the presence of **brisk deep tendon reflexes** and a **positive Babinski sign (upper motor neuron signs)** are not typical for Parkinson's.
*Primary lateral sclerosis*
- **Primary lateral sclerosis (PLS)** is a **rare motor neuron disease** characterized by **pure upper motor neuron dysfunction**, leading to progressive **spasticity and weakness**.
- While PLS can explain the upper motor neuron signs, **multiple white matter lesions on MRI** are not a defining feature; rather, they are highly indicative of **demyelination seen in MS**.
Demyelinating and Degenerative Diseases Indian Medical PG Question 4: Spine MRI shows 'pencil-sharpened' vertebral bodies and 'H-shaped' vertebrae on T1-weighted images. Most likely diagnosis?
- A. Thalassemia
- B. Osteopetrosis
- C. Sickle cell disease (Correct Answer)
- D. Paget's disease
Demyelinating and Degenerative Diseases Explanation: ***Sickle cell disease***
- **Sickle cell disease** can lead to vertebral body changes due to **bone infarction** and **hyperplasia of hematopoietic marrow**, causing central depression and characteristic 'H-shaped' or 'pencil-sharpened' vertebrae.
- The abnormal hemoglobin in sickle cell anemia causes red blood cells to stiffen and form a crescent or "sickle" shape, leading to a host of debilitating symptoms and early death.
*Thalassemia*
- **Thalassemia** can cause widespread marrow expansion leading to generalized osteopenia and widened medullary spaces, but typically does not result in the focal 'H-shaped' vertebral changes seen with infarction.
- While it also causes anemia and bone changes, the specific vertebral findings described are not characteristic of thalassemia.
*Osteopetrosis*
- **Osteopetrosis** is characterized by **increased bone density** and brittle bones, often described as a "stone bone" appearance.
- This condition leads to thickened, sclerotic bones and does not produce the 'H-shaped' or 'pencil-sharpened' vertebral deformities.
*Paget's disease*
- **Paget's disease** is characterized by disorganized bone remodeling, leading to bone enlargement and deformity with a characteristic **"cotton wool" appearance** on imaging.
- While it affects vertebrae, it typically results in cortical thickening and coarsened trabeculae, not the specific 'H-shaped' deformity.
Demyelinating and Degenerative Diseases Indian Medical PG Question 5: Tigroid pattern on MRI is seen in -
- A. Wilson's disease
- B. Metachromatic leukodystrophy (Correct Answer)
- C. Parkinsonism
- D. GB syndrome
Demyelinating and Degenerative Diseases Explanation: ***Metachromatic leukodystrophy***
- The **tigroid pattern** on MRI, characterized by **perivascular sparing** within demyelinated white matter, is highly characteristic of metachromatic leukodystrophy.
- This pattern results from the accumulation of **sulfatides** in oligodendrocytes and macrophages, leading to central demyelination with spared U-fibers and white matter adjacent to vessels.
*Wilson's disease*
- Wilson's disease involves **copper accumulation** and typically presents with abnormalities in the **basal ganglia**, thalami, and brainstem.
- While it causes neurodegeneration, it does not produce a characteristic tigroid demyelination pattern.
*Parkinsonism*
- Parkinsonism refers to a group of neurological disorders characterized by motor symptoms like **bradykinesia, rigidity, tremor, and postural instability**.
- MRI findings in Parkinsonism often show **nigral degeneration** but do not typically involve a tigroid pattern of leukodystrophy.
*GB syndrome*
- **Guillain-Barré syndrome (GBS)** is an acute autoimmune peripheral neuropathy affecting the **peripheral nerves and nerve roots**.
- It does not involve central nervous system demyelination or display a tigroid pattern on brain MRI.
Demyelinating and Degenerative Diseases Indian Medical PG Question 6: Intra-tumoral calcification in the brain is seen in all except?
- A. Craniopharyngioma
- B. Meningioma
- C. Oligodendroglioma
- D. Hemangioblastoma (Correct Answer)
Demyelinating and Degenerative Diseases Explanation: **Explanation:**
The correct answer is **Hemangioblastoma**. In neuroradiology, identifying the presence or absence of calcification is a high-yield diagnostic marker for intracranial tumors.
**1. Why Hemangioblastoma is the correct answer:**
Hemangioblastomas are highly vascular, WHO Grade 1 tumors typically located in the posterior fossa (cerebellum). Characteristically, they present as a **cystic lesion with a highly enhancing mural nodule**. Crucially, hemangioblastomas **do not calcify**. Their primary imaging features are related to vascularity (flow voids on MRI) and associated erythropoietin production, which may lead to polycythemia.
**2. Why the other options are incorrect:**
* **Oligodendroglioma:** This is the "classic" answer for calcified brain tumors. Calcification is seen in **70–90%** of cases, often described as chunky or ribbon-like.
* **Craniopharyngioma:** In the pediatric population (adamantinomatous type), calcification is a hallmark, occurring in approximately **90%** of cases. It follows the "90% rule": 90% are cystic, 90% calcify, and 90% enhance.
* **Meningioma:** These are extra-axial tumors that frequently show calcification (about **20–25%**). When the calcification is diffuse and gritty, they are histologically termed "Psammomatous meningiomas."
**NEET-PG High-Yield Pearls:**
* **Mnemonic for Calcified Brain Tumors (Old Men Are Posh):** **O**ligodendroglioma, **M**eningioma, **A**strocytoma, **P**ineal tumors/ **P**apilloma (Choroid plexus).
* **Most common calcified tumor in children:** Craniopharyngioma.
* **Most common calcified tumor in adults:** Oligodendroglioma.
* **Hemangioblastoma Association:** Frequently associated with **Von Hippel-Lindau (VHL) syndrome**; look for retinal angiomas and renal cell carcinoma in clinical stems.
Demyelinating and Degenerative Diseases Indian Medical PG Question 7: Which of the following techniques is the best for differentiating recurrence of a brain tumor from radiation therapy-induced necrosis?
- A. MRI
- B. Contrast-enhanced MRI
- C. PET scan (Correct Answer)
- D. CT scan
Demyelinating and Degenerative Diseases Explanation: **Explanation:**
The differentiation between **tumor recurrence** and **radiation necrosis** is a common diagnostic dilemma because both entities appear similar on conventional imaging (enhancing mass with surrounding edema).
**Why PET Scan is the Correct Answer:**
The distinction is based on **metabolic activity**.
* **Tumor Recurrence:** Malignant cells are hypermetabolic and demonstrate high glucose uptake. Therefore, they appear as **"Hot" lesions** on FDG-PET (Fluorodeoxyglucose) or Amino Acid PET (e.g., Methionine-PET).
* **Radiation Necrosis:** This represents dead tissue and inflammatory changes, which are metabolically inactive. These appear as **"Cold" lesions** (photopenic) on PET scans.
This functional assessment makes PET the gold standard for differentiation.
**Why Other Options are Incorrect:**
* **MRI & Contrast-enhanced MRI (CE-MRI):** While MRI is the investigation of choice for initial diagnosis, it cannot reliably distinguish recurrence from necrosis. Both conditions cause a breakdown of the blood-brain barrier, leading to similar contrast enhancement and T2/FLAIR signals.
* **CT Scan:** CT lacks the soft-tissue resolution required for neuro-oncology and provides no metabolic information, making it the least sensitive modality for this purpose.
**NEET-PG High-Yield Pearls:**
* **MR Spectroscopy (MRS):** If PET is not an option, MRS is the next best functional MRI technique. Recurrence shows **increased Choline** (cell turnover) and **decreased NAA** (neuronal loss), whereas necrosis shows a "dead" spectrum (low peaks across the board or a Lactate/Lipid peak).
* **Perfusion MRI (rCBV):** Tumor recurrence typically shows **increased** relative Cerebral Blood Volume (rCBV) due to neoangiogenesis, while necrosis shows **decreased** rCBV.
* **Gold Standard:** Histopathology remains the definitive gold standard, but PET is the best non-invasive imaging technique.
Demyelinating and Degenerative Diseases Indian Medical PG Question 8: Which of the following brain tumors is typically hyperdense on CT scan?
- A. Ependymoma
- B. Medulloblastoma (Correct Answer)
- C. Oligodendroglioma
- D. Astrocytoma
Demyelinating and Degenerative Diseases Explanation: **Explanation:**
The density of a tumor on a non-contrast CT (NCCT) scan is primarily determined by its **cellularity** and the **nuclear-to-cytoplasmic (N:C) ratio**.
**1. Why Medulloblastoma is correct:**
Medulloblastoma is a "Small Round Blue Cell Tumor." These tumors are characterized by extremely high cellular density and very little cytoplasm. Because DNA and cellular proteins attenuate X-rays more than water or lipids, the high concentration of cells makes the tumor appear **hyperdense** relative to the normal brain parenchyma on NCCT. This is a classic radiological hallmark of medulloblastoma, typically seen in the midline (cerebellar vermis) of pediatric patients.
**2. Analysis of Incorrect Options:**
* **Ependymoma:** Usually appears isodense or heterogeneous on CT. While they often contain calcifications (which are hyperdense), the soft tissue component itself is not typically hyperdense.
* **Oligodendroglioma:** These are known for having the highest incidence of **calcification** (up to 90%), which is hyperdense. However, the tumor mass itself is usually hypo-to-isodense.
* **Astrocytoma:** Most low-grade astrocytomas are **hypodense** due to high water content and associated edema. High-grade gliomas (GBM) are usually heterogeneous due to necrosis and hemorrhage.
**3. High-Yield Clinical Pearls for NEET-PG:**
* **Hyperdense tumors on CT (Mnemonic: "M-L-G"):** **M**edulloblastoma, **L**ymphoma (Primary CNS), and **G**erm cell tumors/Meningioma.
* **Medulloblastoma:** Most common malignant brain tumor in children; associated with "drop metastases" (seeding via CSF).
* **Calcification Mnemonic:** "Old Elephants Can't Dance" (**O**ligodendroglioma, **E**pendymoma, **C**raniopharyngioma, **D**ysembryoplastic Neuroepithelial Tumor).
Demyelinating and Degenerative Diseases Indian Medical PG Question 9: A 7-year-old child presents with a posterior fossa mass characterized by cyst formation. On CT, the mass appears hypodense, while on T2-weighted MRI, it is hyperintense. Post-gadolinium administration, a nodular enhancement is observed. What is the most likely diagnosis?
- A. Medulloblastoma
- B. Ependymoma
- C. Astrocytoma (Correct Answer)
- D. Cysticercosis
Demyelinating and Degenerative Diseases Explanation: **Explanation:**
The clinical presentation and imaging findings are classic for a **Juvenile Pilocytic Astrocytoma (JPA)**, which is the most common brain tumor in children.
**1. Why Astrocytoma is correct:**
JPA typically arises in the cerebellum (posterior fossa). The pathognomonic radiological appearance is a **large cystic lesion with a brightly enhancing mural nodule**.
* **CT:** The cyst is hypodense (fluid-filled).
* **MRI T2:** The cyst fluid is hyperintense (similar to CSF).
* **Post-Contrast:** The mural nodule shows intense enhancement, while the cyst wall usually does not (unless it contains neoplastic cells).
**2. Why other options are incorrect:**
* **Medulloblastoma:** This is the most common *malignant* pediatric brain tumor. It typically appears as a **solid, hyperdense mass** on CT (due to high cellularity) arising from the roof of the 4th ventricle (midline/vermis). It rarely shows large cyst formation.
* **Ependymoma:** These typically arise from the floor of the 4th ventricle and are characterized by **"plasticity"** (squeezing through the foramina of Luschka and Magendie). Calcification is very common (50%), and they are usually heterogeneous rather than purely cystic with a nodule.
* **Cysticercosis:** While cystic, Neurocysticercosis (NCC) usually presents as multiple small parenchymal cysts (vesicular stage) with a visible "scolex" (dot sign) and is not typically a large posterior fossa mass in a child.
**3. High-Yield Clinical Pearls for NEET-PG:**
* **JPA Location:** Cerebellum is most common; also associated with **Optic Gliomas** in Neurofibromatosis Type 1 (NF1).
* **Histology:** Look for **Rosenthal fibers** (corkscrew-shaped eosinophilic bundles) and bipolar cells with long processes (pilocytic).
* **Prognosis:** Excellent (WHO Grade I); surgical resection is often curative.
* **Key Differentiator:** If a similar "cyst with a nodule" is seen in an **adult**, the diagnosis is likely **Hemangioblastoma** (associated with von Hippel-Lindau syndrome).
Demyelinating and Degenerative Diseases Indian Medical PG Question 10: Which of the following techniques is best for differentiating recurrence of a brain tumor from radiation therapy-induced necrosis?
- A. MRI
- B. Contrast-enhanced MRI
- C. PET scan (Correct Answer)
- D. CT scan
Demyelinating and Degenerative Diseases Explanation: **Explanation:**
Differentiating **tumor recurrence** from **radiation necrosis** is a common clinical dilemma because both entities can present with similar clinical symptoms and identical patterns of ring enhancement on conventional imaging.
**Why PET Scan is the Correct Answer:**
The differentiation relies on **metabolic activity**.
* **Tumor Recurrence:** Represents viable, proliferating neoplastic cells which are hypermetabolic. They show high uptake of radiopharmaceuticals like **18F-FDG** (Fluorodeoxyglucose) or amino acid tracers (e.g., 11C-Methionine).
* **Radiation Necrosis:** Represents dead tissue and vascular injury. It is metabolically inactive (hypometabolic) and shows little to no uptake on a PET scan.
**Why Other Options are Incorrect:**
* **MRI & Contrast-enhanced MRI:** While MRI is the gold standard for initial diagnosis, it cannot reliably distinguish these two. Both recurrence and necrosis cause breakdown of the blood-brain barrier, leading to **contrast enhancement** and surrounding edema (T2/FLAIR hyperintensity).
* **CT Scan:** CT has poor soft-tissue resolution compared to MRI and provides no metabolic information, making it ineffective for this specific differentiation.
**NEET-PG High-Yield Pearls:**
1. **MR Spectroscopy (MRS):** This is another high-yield modality. Recurrence shows **elevated Choline** (cell membrane turnover) and decreased NAA. Necrosis shows a "dead" spectrum with low metabolites and a **Lactate/Lipid peak**.
2. **MR Perfusion (rCBV):** Tumor recurrence shows **increased** relative Cerebral Blood Volume (rCBV) due to neoangiogenesis; necrosis shows decreased rCBV.
3. **Gold Standard:** While PET and MRS are the best imaging tools, the definitive gold standard remains **histopathology (biopsy)**.
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