Question:
A newborn presents with recurrent tonic seizures, generalized stiffness, and exaggerated response to light (photosensitivity). EEG is normal. There is no improvement with standard anticonvulsants. What is the most likely diagnosis?
A newborn presents with recurrent tonic seizures, generalized stiffness, and exaggerated response to light (photosensitivity). EEG is normal. There is no improvement with standard anticonvulsants. What is the most likely diagnosis?
Show Hint
Hyperekplexia Diagnostic Pearl: Generalized neonatal stiffness + Normal EEG + Exaggerated startle on nose-tap (non-habituating) $\rightarrow$ Mutation in GLRA1 (Glycine receptor). Treatment of choice: Clonazepam!
Updated On: Sep 3, 2026
- Pyridoxine-dependent epilepsy
- Hyperekplexia
- Early infantile epileptic encephalopathy
- Benign neonatal seizures
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Concept:
Hyperekplexia (startle disease stiff-baby syndrome) is a rare, non-epileptic neurogenetic disorder characterized by exaggerated, non-habituating startle responses to tactile, auditory, or visual stimuli, and generalized neonatal hypertonia.
Explanation:
• Hyperekplexia is most commonly inherited in an autosomal dominant or recessive pattern due to mutations in the GLRA1 gene (encoding the alpha-1 subunit of the inhibitory glycine receptor), or less commonly GLRB or SLC6A5.
• Impaired glycinergic inhibitory neurotransmission in the brainstem and spinal cord leads to uninhibited motor startle reflexes and persistent muscular rigidity that diminishes during sleep.
• The hallmark presentation is marked neonatal stiffness, exaggerated startle response to sudden unexpected sensory stimuli (tapping the nose, tactile taps, auditory or visual stimuli), and episodic life-threatening apnea or tonic spasms.
• Because these paroxysmal episodes are non-epileptic in origin, the interictal and ictal EEG is completely normal, and standard antiepileptic drugs (e.g., phenobarbital, phenytoin) are entirely ineffective.
• Tapping the tip of the nose elicits an exaggerated startle reflex with non-habituating head retraction (pathognomonic clinical test).
• The therapeutic drug of choice is Clonazepam (a GABA-A receptor agonist that enhances inhibitory tone), and acute hypertonia-induced apnea is relieved by the Vigevano maneuver (forced head-to-knees flexion).
Final Answer:
The clinical features of neonatal stiffness, exaggerated stimulus-induced startle responses, a normal EEG, and non-responsiveness to anticonvulsants are diagnostic of Hyperekplexia.
Hyperekplexia (startle disease stiff-baby syndrome) is a rare, non-epileptic neurogenetic disorder characterized by exaggerated, non-habituating startle responses to tactile, auditory, or visual stimuli, and generalized neonatal hypertonia.
Explanation:
• Hyperekplexia is most commonly inherited in an autosomal dominant or recessive pattern due to mutations in the GLRA1 gene (encoding the alpha-1 subunit of the inhibitory glycine receptor), or less commonly GLRB or SLC6A5.
• Impaired glycinergic inhibitory neurotransmission in the brainstem and spinal cord leads to uninhibited motor startle reflexes and persistent muscular rigidity that diminishes during sleep.
• The hallmark presentation is marked neonatal stiffness, exaggerated startle response to sudden unexpected sensory stimuli (tapping the nose, tactile taps, auditory or visual stimuli), and episodic life-threatening apnea or tonic spasms.
• Because these paroxysmal episodes are non-epileptic in origin, the interictal and ictal EEG is completely normal, and standard antiepileptic drugs (e.g., phenobarbital, phenytoin) are entirely ineffective.
• Tapping the tip of the nose elicits an exaggerated startle reflex with non-habituating head retraction (pathognomonic clinical test).
• The therapeutic drug of choice is Clonazepam (a GABA-A receptor agonist that enhances inhibitory tone), and acute hypertonia-induced apnea is relieved by the Vigevano maneuver (forced head-to-knees flexion).
Final Answer:
The clinical features of neonatal stiffness, exaggerated stimulus-induced startle responses, a normal EEG, and non-responsiveness to anticonvulsants are diagnostic of Hyperekplexia.
Was this answer helpful?
0
0
Top NEET SS Paediatrics Questions
- A 2-year-old child presents with persistent fever for 4 days. Examination shows conjunctival injection and periungual desquamation, but criteria for complete Kawasaki disease are not met. You plan to evaluate for incomplete Kawasaki disease as per AHA guidelines. Which of the following investigations is NOT routinely recommended in this evaluation?
- A 27-year-old pregnant woman with systemic lupus erythematosus (SLE) is concerned about the risk of congenital heart block in her fetus due to anti-Ro/SSA antibodies. Which of the following medications is not recommended antenatally to prevent cardiac manifestations of neonatal lupus?
- A 2-week-old infant presents with a photosensitive annular erythematous rash on the face. ECG reveals complete heart block. Which is the most likely diagnosis?
- A 10-year-old child presents with arthritis involving the wrist and first MCP joint. Examination shows nail pitting. Which of the following is the most likely diagnosis?
- A 14-year-old girl with SLE presents with edema and nephrotic-range proteinuria. Renal biopsy shows diffuse thickening of the glomerular basement membrane without proliferative lesions. This corresponds to which class of lupus nephritis?
View More Questions
Top NEET SS Pediatric Neurology Questions
- A 10-year-old boy presents with focal seizures. MRI brain shows multiple small ring-enhancing lesions suggestive of neurocysticercosis. What is the appropriate management?
- Following respiratory breathing pattern is seen in which lesion?
- A 10-year-old girl presents with fever and altered sensorium. MRI shows large, fluffy hyperintensities in the white matter and cerebellum on T2-weighted images. What is the most probable diagnosis?
- A 2-year-old child presents with status epilepticus and a history of 4–5 prior seizure episodes, both focal and myoclonic. EEG shows 1–2 Hz spike-wave complexes. What is the most probable diagnosis?
- Which FDA-approved drug for spinal muscular atrophy (SMA) is administered intrathecally?
View More Questions
Top NEET SS Questions
- A liver transplant patient presents with diarrhoea, colitis, a total leukocyte count of 1800, and a positive blood CMV PCR. What is the next step in management?
- A 32-year-old male recovering from dengue fever initially showed clinical improvement but now presents with recurrence of high-grade fever, fatigue, and pancytopenia on day 10 of illness. He is hemodynamically stable with no bleeding manifestations. Which of the following investigations should be performed first to evaluate the cause of relapse and cytopenia?
- A 48-year-old man with chronic hepatitis C infection is being evaluated for risk factors associated with progression of liver disease. He has a 20-year history of infection, drinks alcohol occasionally, and has a high serum HCV RNA viral load. Which of the following factors is not associated with an increased risk of progression of liver disease in chronic HCV infection?
- A 28-year-old veterinary worker who previously received a full 3-dose pre-exposure rabies vaccination series is bitten by a stray dog while handling an animal in the clinic. The wound is cleaned immediately. What is the most appropriate post-exposure management?
- A 42-year-old patient undergoing chemotherapy for acute myeloid leukemia develops neutropenia (ANC $<$ 500) and is treated with broad-spectrum antibiotics. After initial recovery of neutrophil counts (ANC = 1500), he again develops high-grade fever and right upper quadrant abdominal pain. Imaging shows multiple small hypodense lesions in the liver and spleen. What is the most likely diagnosis?
View More Questions