Nystagmus in Children — MCQs
Which of the following is true about multiple sclerosis except
Scleral Expansion Bands are used in the management of:
A 60-year-old man from a poor socioeconomic environment is admitted with an acute illness characterized by mental disturbances. On examination, he has bilateral sixth nerve palsies and an ataxic gait. He is diagnosed with Wernicke's encephalopathy. Which of the following is the most appropriate treatment?
A 62-year-old patient presents with left-sided arm and leg weakness, right-sided facial paralysis with lateral rectus gaze palsy, and nystagmus. Based on the clinical presentation, which of the following syndromes is most consistent with these symptoms?
Ataxia, nystagmus, and ophthalmoplegia are seen in which of the following conditions?
In a patient with right vestibular neuronitis, what will be the finding on the head impulse test?
What is the critical period for the development of the fixation reflex?
Which of the following conditions is inherited in an autosomal dominant pattern?
Which of the following extraocular muscles of the eye is involved in intorsion, depression, and abduction of the eyeball?
Modified Kastenbaum surgery is done for which condition?
Nystagmus in Children Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is true about multiple sclerosis except
- A. Nystagmus on adducting eye
- B. One and half syndrome
- C. Pendular nystagmus (Correct Answer)
- D. Nystagmus on abducting eye
Explanation: ***Pendular nystagmus*** - **Pendular nystagmus** is a rhythmic oscillation of the eyes that is not typically described as a classic finding in **multiple sclerosis (MS)**. While nystagmus (involuntary eye movements) is common in MS due to demyelination in the brainstem or cerebellum, the specific pattern usually observed is **jerk nystagmus**. - **Pendular nystagmus** is characterized by equal velocity in both directions of movement, lacking a fast and slow phase, and is more commonly associated with conditions like congenital nystagmus or severe visual impairment. *Nystagmus on adducting eye* - **Nystagmus on adducting eye** is a component of **internuclear ophthalmoplegia (INO)**, which is a classic brainstem syndrome caused by demyelination in the **medial longitudinal fasciculus (MLF)** in MS [1]. - In INO, the adducting eye exhibits nystagmus, while the abducting eye shows normal movement or mild nystagmus. *One and half syndrome* - **One and a half syndrome** is a severe form of INO, indicating a more extensive lesion in the **paramedian pontine reticular formation (PPRF)** and the adjacent **medial longitudinal fasciculus (MLF)**. - This syndrome results in the inability to move one eye horizontally past the midline (half a gaze paralysis) and the other eye only in abduction (one gaze paralysis), with nystagmus in the abducting eye. It is a highly characteristic finding in MS. *Nystagmus on abducting eye* - The **abducting eye** in **internuclear ophthalmoplegia (INO)**, a common manifestation of MS, often exhibits **nystagmus**. - This is due to the compensatory increase in neural impulse to the abducting eye to overcome the weak adduction of the contralateral eye, further indicating a lesion in the **medial longitudinal fasciculus (MLF)**.
Question 2: Scleral Expansion Bands are used in the management of:
- A. Astigmatism
- B. Keratoconus
- C. Presbyopia (Correct Answer)
- D. Myopia
Explanation: ***Presbyopia*** - **Scleral expansion bands** are a surgical treatment strategy designed to restore the eye's ability to accommodate by altering the biomechanics of the sclera and ciliary body. - They aim to improve the range of motion of the ciliary body, thereby allowing the **lens to change shape** more effectively for near vision in **presbyopic** patients. *Astigmatism* - **Astigmatism** is primarily caused by an **irregularly shaped cornea** or lens, leading to blurred vision at all distances. - It is typically managed with corrective lenses (glasses or contact lenses) or refractive surgeries like **LASIK** or **PRK**, which reshape the cornea. *Keratoconus* - **Keratoconus** is a progressive eye disease where the **cornea thins** and bulges into a cone-like shape, causing distorted vision. - Treatments include rigid gas permeable contact lenses, **corneal collagen cross-linking** to halt progression, and in severe cases, corneal transplant. *Myopia* - **Myopia**, or nearsightedness, occurs when the eye focuses images in front of the retina, often due to an **elongated eyeball** or excessive corneal curvature. - It is commonly corrected with concave lenses, contact lenses, or refractive surgeries such as **LASIK** or **PRK** to flatten the cornea.
Question 3: A 60-year-old man from a poor socioeconomic environment is admitted with an acute illness characterized by mental disturbances. On examination, he has bilateral sixth nerve palsies and an ataxic gait. He is diagnosed with Wernicke's encephalopathy. Which of the following is the most appropriate treatment?
- A. Lecithin
- B. Vitamin D
- C. Thiamine (Correct Answer)
- D. Phenytoin
Explanation: ***Thiamine*** - Wernicke's encephalopathy is primarily caused by **thiamine (vitamin B1) deficiency**, often seen in individuals with **alcoholism** or **poor nutrition**, leading to the classic triad of **ataxia**, **ophthalmoplegia**, and **confusion** [1], [2]. - Immediate intravenous administration of **thiamine** is the most appropriate treatment to prevent progression and potentially reverse neurological symptoms [3]. *Lecithin* - **Lecithin** is a fatty substance, sometimes used as a supplement for cognitive function or liver health, but it has no role in the treatment of **Wernicke's encephalopathy**. - It does not address the underlying **thiamine deficiency** that causes the symptoms of Wernicke's encephalopathy. *Vitamin D* - **Vitamin D** plays a crucial role in bone health and calcium metabolism and has various other systemic effects, but it is not involved in the pathogenesis or treatment of **Wernicke's encephalopathy**. - Administering vitamin D would not address the **neurological symptoms** caused by thiamine deficiency. *Phenytoin* - **Phenytoin** is an antiepileptic drug used to treat seizures and certain types of arrhythmias, but it is not indicated for the management of **Wernicke's encephalopathy**. - Its mechanism of action is unrelated to the **thiamine deficiency** responsible for this condition, and it would not alleviate the neurological deficits.
Question 4: A 62-year-old patient presents with left-sided arm and leg weakness, right-sided facial paralysis with lateral rectus gaze palsy, and nystagmus. Based on the clinical presentation, which of the following syndromes is most consistent with these symptoms?
- A. Foville syndrome (Correct Answer)
- B. Benedict's syndrome
- C. Millard-Gubler syndrome
- D. Wallenberg syndrome
Explanation: ***Foville syndrome*** - This syndrome is characterized by a **pontine lesion** affecting the **abducens nucleus (cranial nerve VI)**, leading to ipsilateral gaze palsy, and the **facial nucleus (cranial nerve VII)**, causing ipsilateral facial weakness. [1] - The **crossed hemiparesis (left-sided arm and leg weakness)** results from involvement of the corticospinal tracts, and **nystagmus** can occur due to vestibular nucleus involvement, consistent with the patient's presentation. [1] *Benedict's syndrome* - This is a midbrain syndrome involving the **red nucleus** and **oculomotor nerve (cranial nerve III)**, causing ipsilateral oculomotor palsy and contralateral cerebellar ataxia. - It does not explain the patient's **facial weakness** or **abducens palsy**. *Millard-Gubler syndrome* - This pontine syndrome involves the **abducens nerve (cranial nerve VI)** and **facial nerve (cranial nerve VII)** in the pontine base, leading to ipsilateral gaze palsy and ipsilateral facial paralysis. - However, the hemiparesis in Millard-Gubler syndrome is typically **contralateral** to the lesion, but the facial paralysis and gaze palsy are usually due to direct nerve involvement rather than nuclear involvement, and **nystagmus** is not a characteristic feature. *Wallenberg syndrome* - This syndrome, also known as **lateral medullary syndrome**, is caused by a lesion in the **dorsolateral medulla** and presents with a constellation of symptoms including **ipsilateral ataxia**, **Horner's syndrome**, **high-pitched dysphagia**, and **contralateral loss of pain and temperature sensation**. [1] - It does not typically involve **facial weakness**, **abducens palsy**, or **hemiparesis** in the manner described.
Question 5: Ataxia, nystagmus, and ophthalmoplegia are seen in which of the following conditions?
- A. 3rd nerve palsy
- B. Wernicke encephalopathy (Correct Answer)
- C. Myasthenia gravis
- D. Chronic progressive external ophthalmoplegia
Explanation: ***Wernicke encephalopathy*** - This condition is characterized by the classic triad of **ataxia**, **nystagmus**, and **ophthalmoplegia** (often presenting as external ophthalmoplegia), alongside confusion [2]. - It results from a **thiamine (vitamin B1) deficiency** [2], [3], commonly seen in chronic alcoholics or individuals with severe malnutrition. *Myasthenia gravis* - This is an **autoimmune disorder** affecting the neuromuscular junction, leading to fluctuating muscle weakness that worsens with activity [1]. - While it can cause **ophthalmoplegia** (especially ptosis and diplopia), it does not typically present with ataxia or nystagmus. *3rd nerve palsy* - A **third nerve palsy** specifically affects the oculomotor nerve, causing a constellation of symptoms including ptosis, pupillary dilation, and inability to move the eye up, down, or medially. - While it causes **ophthalmoplegia** affecting one eye, it does not typically cause nystagmus or ataxia. *Chronic progressive external ophthalmoplegia* - This is a mitochondrial disorder characterized by **slowly progressive weakness** of the extraocular muscles, leading to bilateral ptosis and limitation of eye movements. - It causes a specific type of **ophthalmoplegia** but is not typically associated with nystagmus or prominent ataxia.
Question 6: In a patient with right vestibular neuronitis, what will be the finding on the head impulse test?
- A. Head turned to right, corrective saccade to the left (Correct Answer)
- B. Head turned to left, corrective saccade to the right
- C. Head turned to right, no corrective saccade
- D. Head turned to left, no corrective saccade
Explanation: ***Head turned to right, corrective saccade to the left*** - In **right vestibular neuronitis**, the right vestibular apparatus is impaired, affecting the **vestibulo-ocular reflex (VOR)** on that side. - During the head impulse test, when the head is rapidly turned **to the right** (toward the affected side), the impaired VOR cannot maintain eye fixation on the target. - The eyes initially move **with the head** (to the right), then a visible **corrective saccade** (catch-up saccade) brings them **back to the left** to refixate on the target. - This corrective saccade is the **hallmark positive finding** in head impulse test for right vestibular dysfunction. *Head turned to left, corrective saccade to the right* - This would indicate a **left vestibular lesion**, not right vestibular neuronitis. - When turning the head to the left with left vestibular dysfunction, a corrective saccade to the right would be observed. *Head turned to right, no corrective saccade* - This would indicate **normal VOR function** on the right side. - A normal response shows no corrective saccade because the eyes maintain fixation throughout the head turn. - This is the **opposite** of what is expected in right vestibular neuronitis. *Head turned to left, no corrective saccade* - This indicates normal VOR function on the left side. - In right vestibular neuronitis, turning the head to the left (away from the affected side) typically shows **normal VOR** with no corrective saccade needed.
Question 7: What is the critical period for the development of the fixation reflex?
- A. 2-4 months of age (Correct Answer)
- B. 6-8 months of age
- C. 2 years
- D. 3 years
Explanation: **Explanation:** The development of visual function in infants follows a specific chronological sequence. The **fixation reflex** is the ability of the eyes to focus on and follow an object. While a rudimentary fixation reflex is present at birth, it undergoes a critical maturation phase between **2 to 4 months of age**. By the end of the 4th month, a healthy infant should demonstrate steady, central, and maintained fixation. * **Why Option A is correct:** The neural pathways connecting the retina to the visual cortex and the motor pathways for ocular movement mature rapidly during this window. If an infant does not show steady fixation by 4 months, it is a clinical red flag for sensory deprivation (like congenital cataracts) or neurological delay. * **Why Options B, C, and D are incorrect:** By **6-8 months**, higher-order functions like stereopsis (depth perception) are maturing. **2 to 3 years** represents the tail end of the "plastic period" for amblyopia treatment, but the foundational reflex of fixation is established much earlier in infancy. **High-Yield Clinical Pearls for NEET-PG:** * **Visual Acuity at Birth:** Approximately 6/60 to 6/120 (reaches adult levels of 6/6 by 3–5 years). * **Stereopsis:** Begins at 3–4 months and is well-developed by 6 months. * **Critical Period for Amblyopia:** The period during which the visual system is plastic and sensitive to abnormal visual input; it lasts from birth until approximately **7–9 years of age**. * **Accommodation:** Reaches adult-like levels by **4 months**.
Question 8: Which of the following conditions is inherited in an autosomal dominant pattern?
- A. Retinoblastoma (Correct Answer)
- B. Ataxia telangiectasia
- C. Bloom's syndrome
- D. Xeroderma pigmentosa
Explanation: **Explanation:** The correct answer is **Retinoblastoma (Option A)**. Retinoblastoma is the most common primary intraocular malignancy of childhood. While 60% of cases are sporadic and unilateral, 40% are hereditary. Hereditary retinoblastoma follows an **Autosomal Dominant** inheritance pattern with high penetrance (90%). It is caused by a mutation in the **RB1 gene** located on chromosome **13q14**. According to **Knudson’s Two-Hit Hypothesis**, in hereditary cases, the first mutation (hit) is germline (inherited), and the second is somatic. This explains why hereditary cases are often bilateral, multifocal, and present at an earlier age. **Why the other options are incorrect:** * **Ataxia Telangiectasia (Option B):** This is an **Autosomal Recessive** multisystem disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, and immunodeficiency. It involves a defect in the ATM gene (DNA repair). * **Bloom’s Syndrome (Option C):** This is an **Autosomal Recessive** disorder characterized by short stature, photosensitivity, and genomic instability due to mutations in the BLM gene. * **Xeroderma Pigmentosa (Option D):** This is an **Autosomal Recessive** condition caused by a defect in nucleotide excision repair, leading to extreme sensitivity to UV light and a high risk of skin malignancies. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex). * **Second most common sign:** Strabismus. * **Pathognomonic Histology:** Flexner-Wintersteiner rosettes. * **Calcification:** Present in 90% of cases (visible on CT/Ultrasound B-scan); a key diagnostic feature. * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pinealoblastoma.
Question 9: Which of the following extraocular muscles of the eye is involved in intorsion, depression, and abduction of the eyeball?
- A. Inferior rectus
- B. Superior rectus
- C. Inferior oblique
- D. Superior oblique (Correct Answer)
Explanation: **Explanation:** The actions of the extraocular muscles are determined by their anatomical origin and insertion relative to the center of rotation of the eyeball. **1. Why Superior Oblique (SO) is correct:** The Superior Oblique originates from the body of the sphenoid, passes through the **trochlea** (acting as a functional origin), and inserts into the postero-superior quadrant of the globe. Because it inserts behind the equator and approaches from the front-medial side, its contraction results in: * **Primary Action:** Intorsion (Inward rotation) * **Secondary Action:** Depression (Downwards) * **Tertiary Action:** Abduction (Outwards) * *Mnemonic:* **"SIN"** (Superior muscles are Intorters) and **"Obliques are Abductors."** **2. Why the other options are incorrect:** * **Inferior Rectus (IR):** Its primary action is depression, but its secondary actions are **extorsion** and **adduction**. * **Superior Rectus (SR):** Its primary action is elevation. Its secondary actions are **intorsion** and **adduction**. * **Inferior Oblique (IO):** Its primary action is **extorsion**. Its secondary actions are elevation and abduction. **High-Yield Clinical Pearls for NEET-PG:** * **RAD Rule:** Recti are Adductors (except Lateral Rectus). * **SIN Rule:** Superior muscles (SR & SO) are Intorters; Inferior muscles (IR & IO) are Extorters. * **Oblique Rule:** Obliques are Abductors; Recti are Adductors. * **Nerve Supply:** All muscles are supplied by CN III except Superior Oblique (**CN IV** - Trochlear) and Lateral Rectus (**CN VI** - Abducens) [Formula: **LR6SO4**]. * **Clinical Testing:** To isolate the Superior Oblique’s action of depression, the eye must be placed in an **adducted** position.
Question 10: Modified Kastenbaum surgery is done for which condition?
- A. Esotropia
- B. Nystagmus (Correct Answer)
- C. Superior oblique palsy
- D. Third nerve palsy
Explanation: **Explanation:** **Modified Kastenbaum Surgery** (also known as the Kastenbaum-Anderson procedure) is a surgical technique specifically designed to treat **Nystagmus** associated with a significant **null point** and a compensatory **head turn**. ### Why Nystagmus is Correct: In many patients with congenital nystagmus, there is a specific gaze position (the "null point") where the nystagmus intensity is minimal and visual acuity is maximal. To utilize this null point, patients often adopt an abnormal head posture (AHP). The goal of the Modified Kastenbaum procedure is to "move the eyes to where the head is." By surgically shifting the eyes toward the direction of the head turn (using a "recess-resect" procedure on both eyes), the null point is shifted to the primary position, thereby correcting the head turn and improving binocular visual function. ### Why Other Options are Incorrect: * **Esotropia:** Managed by weakening the medial recti (recession) or strengthening the lateral recti (resection), but not via the specific four-muscle transposition logic of Kastenbaum. * **Superior Oblique Palsy:** Typically treated with the **Harada-Ito procedure** (for torsion) or inferior oblique weakening. * **Third Nerve Palsy:** Managed by procedures like the **Nishida procedure** or large recess-resect operations, but Kastenbaum is not indicated as it requires functioning horizontal muscles in both eyes. ### High-Yield Clinical Pearls for NEET-PG: * **The Rule of 5-6-7-8:** A classic Kastenbaum involves: MR recession (5mm), LR resection (8mm) in one eye; and LR recession (7mm), MR resection (6mm) in the other. * **Indication:** Only performed when the head turn is stable and significant (usually >15-20 degrees). * **Faden Operation:** Another high-yield nystagmus surgery (Cüppers' procedure) used to weaken a muscle in its field of action without affecting the primary position.
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