Sudden Infant Death Syndrome — MCQs
An infant previously diagnosed with a large muscular VSD comes to the office with complaints from the mother of fatigue and poor feeding over the past month. You note the child has not gained weight since the previous visit 2 months ago. The child is apathetic, tachypneic, and has wheezes and crackles on lung auscultation. What is the most likely cardiac diagnosis based on this patient's presentation?
Fatal familial insomnia is associated with -
A 3-month-old baby presents with fever and respiratory rate of 60/min. The baby is irritable but feeding well. There is no stridor, no chest indrawing, and no convulsions. What is the diagnosis?
Which of the following terms is not associated with infant mortality?
What is the true statement regarding an 'at-risk baby'?
What is the most common cause of sudden cardiac death in adults?
In which of the following conditions is the implantation of an Automatic Implantable Cardioverter Defibrillator (AICD) indicated?
An athlete collapsed and expired while playing school basketball. Histology of the cardiac specimen is most likely to indicate which of the following conditions?
A 65 year old woman after total knee implant surgery complains of calf pain and swelling in the leg for the last 2 days. Later she complains of breathlessness and dies suddenly in the ward. Probable cause?
A child with fever with abdominal cramps & pus in stools, causative organism is ?
Sudden Infant Death Syndrome Indian Medical PG Practice Questions and MCQs
Question 1: An infant previously diagnosed with a large muscular VSD comes to the office with complaints from the mother of fatigue and poor feeding over the past month. You note the child has not gained weight since the previous visit 2 months ago. The child is apathetic, tachypneic, and has wheezes and crackles on lung auscultation. What is the most likely cardiac diagnosis based on this patient's presentation?
- A. Congenital heart block
- B. Prolonged QT syndrome
- C. Congestive heart failure (Correct Answer)
- D. Hypertrophic cardiomyopathy
Explanation: ***Congestive heart failure*** - The infant's symptoms of **fatigue**, **poor feeding**, **no weight gain**, **apathy**, **tachypnea**, and **wheezes/crackles** are classic signs of **congestive heart failure** in an infant. - A **large muscular VSD** can lead to significant left-to-right shunting, causing **pulmonary overcirculation** and symptoms of heart failure. *Congenital heart block* - This condition involves an abnormality in the heart's electrical conduction system, leading to a **slow heart rate (bradycardia)**. - While it can cause fatigue, it typically doesn't present with respiratory symptoms like **tachypnea** and **rales** unless profound bradycardia leads to heart failure. *Prolonged QT syndrome* - This is an **electrical disorder** that can cause **arrhythmias** and sudden cardiac death, often presenting with syncope or seizures. - It does not typically manifest with the signs of **pulmonary congestion** (wheezes, crackles) or feeding difficulties seen in this infant. *Hypertrophic cardiomyopathy* - This condition involves thickening of the heart muscle, leading to **outflow obstruction** and diastolic dysfunction. - While it can cause symptoms of poor feeding and fatigue, the prominent respiratory symptoms like **tachypnea** and **crackles** are more indicative of pulmonary venous congestion secondary to a large shunt.
Question 2: Fatal familial insomnia is associated with -
- A. Neoplastic disease
- B. Degenerative disease
- C. Prion disease (Correct Answer)
- D. Vascular disease
Explanation: ***Prion disease*** - **Fatal familial insomnia (FFI)** is a rare, inherited neurodegenerative disorder caused by a mutation in the **PRNP gene**, leading to the misfolding of the prion protein [1]. - The accumulation of these misfolded proteins primarily affects the **thalamus**, disrupting sleep and leading to progressive insomnia, autonomic dysfunction, and motor deficits. *Degenerative disease* - While FFI is a **neurodegenerative disease**, this option is too broad and does not specify the unique underlying cause, which is a prion protein [1]. - Other degenerative diseases like Alzheimer's or Parkinson's are not caused by prions and have different pathogenetic mechanisms and clinical presentations [1]. *Neoplastic disease* - **Neoplastic diseases** involve the uncontrolled growth of abnormal cells, leading to tumors (cancers). - FFI is not characterized by tumor formation or abnormal cell proliferation; instead, it is caused by protein misfolding. *Vascular disease* - **Vascular diseases** affect the blood vessels, such as stroke or atherosclerosis, leading to tissue damage due to impaired blood flow. - FFI does not involve damage to blood vessels or issues with blood supply; its pathology is centered on prion protein accumulation in brain tissue. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1284, 1288-1289.
Question 3: A 3-month-old baby presents with fever and respiratory rate of 60/min. The baby is irritable but feeding well. There is no stridor, no chest indrawing, and no convulsions. What is the diagnosis?
- A. Pneumonia (Correct Answer)
- B. Very severe pneumonia
- C. Severe pneumonia
- D. No Pneumonia
Explanation: ***Pneumonia*** - A respiratory rate of 60 breaths per minute in a 3-month-old infant meets the **WHO criteria for fast breathing**, which is the primary indicator for diagnosing **pneumonia** in this age group. - The absence of chest indrawing, stridor, or convulsions means this falls under **pneumonia**, not **severe** or **very severe pneumonia**. *Very severe pneumonia* - This would be diagnosed if there were **danger signs** such as inability to feed, lethargy, or convulsions, which are explicitly stated as absent. - Presence of **stridor** in a calm child or **severe malnutrition** would also suggest very severe pneumonia, none of which are mentioned. *Severe pneumonia* - This classification requires the presence of **chest indrawing** or **stridor** in a child, which are noted as absent in the clinical presentation. - While the child has fast breathing, the lack of additional severe signs distinguishes it from severe pneumonia. *No Pneumonia* - The presence of **fast breathing** (respiratory rate of 60 in a 3-month-old) is a clear sign of respiratory distress indicating **pneumonia**, according to WHO guidelines. - If the child had a normal respiratory rate and no other signs of respiratory illness, this option might be considered.
Question 4: Which of the following terms is not associated with infant mortality?
- A. Postneonatal mortality
- B. Late neonatal death
- C. Stillbirth (Correct Answer)
- D. Neonatal mortality
Explanation: ***Stillbirth*** - **Stillbirth** refers to the death of a fetus before or during birth, typically after 20 weeks of gestation, and is not classified as an infant mortality as the baby was stillborn. - While it is a significant adverse pregnancy outcome, it does not fall under the definition of **infant mortality**, which applies to live-born infants. *Neonatal mortality* - **Neonatal mortality** refers to the death of a live-born infant within the first 28 days of life. - This is a component of **infant mortality**, which measures deaths of live-born infants up to one year of age. *Postneonatal mortality* - **Postneonatal mortality** refers to the death of an infant after 28 days of life but before their first birthday. - This is also a component of **infant mortality**, covering deaths from day 29 up to 364 days. *Late neonatal death* - **Late neonatal death** refers to the death of a live-born infant occurring between 7 and 27 completed days of life. - This is a specific subset of **neonatal mortality** and therefore part of **infant mortality**.
Question 5: What is the true statement regarding an 'at-risk baby'?
- A. Mild malnutrition with weight slightly below expected norms.
- B. Socioeconomic risk due to high birth order (more than 3). (Correct Answer)
- C. Normal birth weight above the critical threshold of 2.5 kg.
- D. Severe malnutrition with weight significantly below expected norms.
Explanation: ***Socioeconomic risk due to high birth order (more than 3).*** - An **"at-risk baby"** is defined by specific criteria that identify infants vulnerable to adverse health outcomes during the neonatal and early infantile period. - **High birth order (>3)** is a recognized risk factor as per IAP (Indian Academy of Pediatrics) and WHO guidelines, primarily due to: - **Maternal depletion syndrome** (depleted maternal nutritional reserves from multiple pregnancies) - **Socioeconomic constraints** (limited resources spread across more children) - **Reduced parental attention** and care per child - Other criteria for "at-risk baby" include: birth weight <2.5 kg, preterm birth, birth asphyxia, congenital anomalies, and maternal risk factors. *Severe malnutrition with weight significantly below expected norms.* - This describes **severe acute malnutrition (SAM)** in an infant or child, which is a **nutritional disorder**, not a defining criterion of an "at-risk baby" at birth. - While malnutrition increases morbidity risk, the term "at-risk baby" specifically refers to **perinatal and neonatal risk factors** present at or around the time of birth. - SAM is a **consequence** that may develop later, rather than a defining characteristic of the "at-risk" classification. *Mild malnutrition with weight slightly below expected norms.* - **Mild malnutrition** is not a criterion for classifying a baby as "at-risk" in the standard pediatric definition. - The "at-risk baby" classification focuses on **specific measurable risk factors** (birth weight, gestational age, birth order, etc.) rather than mild nutritional deviations. *Normal birth weight above the critical threshold of 2.5 kg.* - A **normal birth weight (≥2.5 kg)** is actually a **protective factor** and indicates lower risk at birth. - This statement describes a baby who does **not meet the "at-risk" criteria** based on birth weight, though other risk factors could still be present. - Birth weight ≥2.5 kg is one indicator of adequate intrauterine growth and lower neonatal mortality risk.
Question 6: What is the most common cause of sudden cardiac death in adults?
- A. Cerebral haemorrhage
- B. Arrhythmias (Correct Answer)
- C. Ruptured aortic aneurysm
- D. Cancer
Explanation: ***Arrhythmias*** - The most common cause of sudden cardiac death in adults is due to **ventricular fibrillation** or **ventricular tachycardia**, which are types of arrhythmias [2]. - These lethal arrhythmias are frequently triggered by underlying **coronary artery disease** [3]. *Cerebral haemorrhage* - While a serious and life-threatening condition, **cerebral haemorrhage** is not the most common cause of sudden cardiac death. - It primarily affects the brain and its immediate consequences are related to neurological function, although secondary cardiac issues can occur. *Ruptured aortic aneurysm* - A **ruptured aortic aneurysm** is a catastrophic event leading to massive internal bleeding and rapid death [1]. - However, its incidence is significantly lower than that of sudden cardiac death due to arrhythmias. *Cancer* - **Cancer** can lead to death but typically not as a sudden event in the way of sudden cardiac death. - Death from cancer is usually a more protracted process, often due to widespread metastatic disease or complications of treatment.
Question 7: In which of the following conditions is the implantation of an Automatic Implantable Cardioverter Defibrillator (AICD) indicated?
- A. None of the options
- B. Ventricular tachycardia with structural heart disease (Correct Answer)
- C. Syncope due to arrhythmias
- D. Brugada syndrome
Explanation: ***Ventricular tachycardia with structural heart disease*** - An **AICD** is strongly indicated for patients with **sustained ventricular tachycardia (VT)** in the presence of **structural heart disease** due to the high risk of sudden cardiac death [1]. - In these cases, the AICD can deliver **therapy (antitachycardia pacing or defibrillation)** to terminate life-threatening arrhythmias [1]. *Syncope due to arrhythmias* - While syncope due to arrhythmias can be serious, an **AICD** is not always the first or only treatment and its indication depends on the specific arrhythmia and underlying cause. - Other treatments like **ablation**, **antiarrhythmic medications**, or a **pacemaker** might be more appropriate depending on the type of arrhythmia (e.g., bradycardia). *None of the options* - This option is incorrect because **ventricular tachycardia with structural heart disease** is a clear and well-established indication for AICD implantation [1]. - AICDs are a cornerstone in the secondary prevention of sudden cardiac death in high-risk patients. *Brugada syndrome* - While **Brugada syndrome** carries a risk of sudden cardiac death, AICD implantation is typically reserved for patients who have experienced **symptomatic arrhythmias** (e.g., syncope, aborted sudden cardiac death) or have certain high-risk features, not for all asymptomatic cases. - Risk stratification in Brugada syndrome is complex, and an AICD is not universally indicated for every diagnosed individual.
Question 8: An athlete collapsed and expired while playing school basketball. Histology of the cardiac specimen is most likely to indicate which of the following conditions?
- A. Dilated cardiomyopathy (DCM)
- B. Restrictive cardiomyopathy (RCM)
- C. Arrhythmogenic right ventricular dysplasia (ARVD)
- D. Hypertrophic cardiomyopathy (HCM) (Correct Answer)
Explanation: ***Hypertrophic cardiomyopathy (HCM)*** - The image shows **myocardial disarray and hypertrophy**, characterized by haphazardly arranged and abnormally branched cardiac muscle cells with large, irregular nuclei, which is a classic histologic finding in HCM [1]. - HCM is the most common cause of **sudden cardiac death in young athletes**, often during exertion, due to ventricular arrhythmias arising from the disarrayed myocardium [1]. *Dilated cardiomyopathy (DCM)* - Histology for DCM typically shows **myocyte atrophy**, thinning of the ventricular walls, and interstitial fibrosis, not the marked disarray and hypertrophy seen here [3]. - DCM leads to **progressive cardiac enlargement and systolic dysfunction**, and while it can cause sudden death, it is less common in athletes than HCM [4]. *Restrictive cardiomyopathy (RCM)* - RCM is characterized by **stiff, non-compliant ventricles** with impaired diastolic filling, often due to conditions like amyloidosis or sarcoidosis, showing interstitial infiltration or fibrosis. - The image does not show evidence of significant **interstitial infiltration or severe fibrosis** characteristic of RCM; instead, it highlights myocyte pathology. *Arrhythmogenic right ventricular dysplasia (ARVD)* - ARVD is characterized by the **replacement of right ventricular myocardium with fibrofatty tissue**, which would be evident histologically as fat and fibrous infiltration [2]. - While ARVD can cause sudden death in athletes, the displayed image primarily shows **myocyte hypertrophy and disarray**, not extensive fibrofatty replacement [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 577-578. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 576-577. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 576. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 559-560.
Question 9: A 65 year old woman after total knee implant surgery complains of calf pain and swelling in the leg for the last 2 days. Later she complains of breathlessness and dies suddenly in the ward. Probable cause?
- A. ARDS
- B. Pulmonary embolism (Correct Answer)
- C. Myocardial infarction
- D. Stroke
Explanation: ***Pulmonary embolism*** - The patient's presentation with **calf pain and swelling** after total knee replacement surgery suggests a **deep vein thrombosis (DVT)**. The subsequent sudden **breathlessness** and **death** are classic signs of a fatal pulmonary embolism originating from such a DVT. - Total knee replacement surgery is a significant risk factor for DVT due to **immobility**, **venous stasis**, and **hypercoagulability** associated with the surgery. *ARDS* - **Acute Respiratory Distress Syndrome (ARDS)** typically presents with severe hypoxemia and bilateral pulmonary infiltrates, and while it leads to breathlessness, the **acute onset of DVT symptoms** prior to respiratory distress is not characteristic of ARDS. - ARDS usually has a more protracted course, developing over hours to days, unlike the sudden death described. *Myocardial infarction* - A **myocardial infarction** would typically manifest with **chest pain**, radiation to the arm/jaw, and EKG changes, not with initial calf pain and swelling. - While it can cause sudden death, the preceding leg symptoms make it less probable compared to pulmonary embolism. *Stroke* - A **stroke** primarily involves neurological deficits such as sudden weakness, numbness, speech difficulties, or vision changes, not calf pain, swelling, or isolated breathlessness. - Sudden death from a stroke is usually due to massive cerebral hemorrhage or brainstem involvement, which would present differently.
Question 10: A child with fever with abdominal cramps & pus in stools, causative organism is ?
- A. EHEC
- B. ETEC
- C. EAEC (Correct Answer)
- D. EPEC
Explanation: ***EAEC (Enteroaggregative E. coli)*** - Among the E. coli strains listed, EAEC is the answer for this question, though **this is an atypical presentation**. - EAEC classically causes **persistent watery diarrhea** (>14 days) in children, often with **low-grade fever** and **abdominal pain**. - While EAEC primarily causes non-bloody diarrhea, it can occasionally produce **mucoid stools** with inflammatory cells due to mucosal inflammation from biofilm formation. - **Note:** The classic organism for fever + cramps + pus in stools would be **Shigella**, **Campylobacter**, or **EIEC (Enteroinvasive E. coli)** - not listed here. *EHEC (Enterohemorrhagic E. coli)* - EHEC (O157:H7) causes **hemorrhagic colitis** with bloody diarrhea due to **Shiga toxins**. - Can lead to **hemolytic uremic syndrome (HUS)** in children. - Characterized by **blood** rather than pus in stools, distinguishing it from typical dysentery. *ETEC (Enterotoxigenic E. coli)* - Most common cause of **traveler's diarrhea** and watery diarrhea in developing countries. - Produces **heat-labile (LT)** and **heat-stable (ST)** enterotoxins causing secretory diarrhea. - Results in profuse **watery stools without inflammation, blood, or pus**. *EPEC (Enteropathogenic E. coli)* - Leading cause of infantile diarrhea in developing countries. - Causes **attaching and effacing** lesions on intestinal mucosa. - Results in **watery diarrhea without significant inflammatory cells or pus** in stools.
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