A 4-month-old female born at 35 weeks (1 week NICU stay for RDS) tires quickly while nursing. Cardiac exam reveals a continuous flow murmur throughout systole and diastole, loudest just below the left clavicle. Which defect is most likely?
A) Complete transposition of the aorta and pulmonary artery
B) Isolated defect in the interventricular septum
C) Persistent flap-like opening in the interatrial wall
D) Shunt between the aorta and pulmonary artery
E) Stenosis of the valve between the left ventricle and aorta
D) Shunt between the aorta and pulmonary artery — Patent ductus arteriosus (PDA).
Key points:
Continuous “machine-like” murmur best heard in the left infraclavicular area.
More common in preterm infants.
Can cause tachypnea, poor feeding, and tiring with feeds from pulmonary overcirculation.
Treatment: medical closure with indomethacin/ibuprofen or catheter/surgical closure if needed.
In premature infants with a patent ductus arteriosus (PDA), which treatment is typically used to close the PDA?
A) Prostaglandin E1
B) Prostaglandin synthesis inhibitors (eg, indomethacin, ibuprofen)
C) Beta-blockers
D) ACE inhibitors
B) Prostaglandin synthesis inhibitors (eg, indomethacin, ibuprofen)
Used to close PDA in premature infants
If medication fails → surgical ligation
(Contrast: Prostaglandin E1 keeps PDA open)
A 3-year-old girl, previously developing normally except for mild hypotonia in infancy, becomes less interactive and shows new repetitive behaviors (hand wringing). Exam shows mild microcephaly, lack of eye contact, and constant midline hand movements. What is the most likely cause of her disorder?
A) CAG trinucleotide repeats
B) Deletion on the long arm of chromosome 22
C) Deletion on the short arm of chromosome 5
D) Mutation of the MECP2 gene
E) Trisomy 21
D) Mutation of the MECP2 gene — Rett syndrome
Key points:
Normal early development, followed by regression around 6–18 months
Features: hand-wringing, loss of social engagement, microcephaly, hypotonia
Genetics: X-linked dominant mutation in MECP2
Mostly affects females (males often do not survive infancy)
Which syndrome is caused by a deletion of the short arm of chromosome 5 and presents with laryngeal hypoplasia (“cat-like” cry), microcephaly, hypertelorism, and low-set ears?
A) Down syndrome
B) Cri-du-chat syndrome
C) DiGeorge syndrome
D) Rett syndrome
E) Huntington disease
B) Cri-du-chat syndrome
Which syndrome is caused by a cleft lip/palate, cardiac abnormalities, thymic aplasia, and recurrent infections?
A) DiGeorge syndrome
B) Down syndrome
C) Cri-du-chat syndrome
D) Rett syndrome
E) Huntington disease
22q11 deletion and presents with
A) DiGeorge syndrome
Which disorder is caused by CAG trinucleotide repeats on chromosome 4 and presents with chorea, hand writhing, behavioral/personality changes, and genetic anticipation?
A) Rett syndrome
B) Huntington disease
C) Down syndrome
D) DiGeorge syndrome
E) Cri-du-chat syndrome
B) Huntington disease
Why does trisomy 21 increase the risk of Alzheimer disease?
A) Caudate atrophy
B) Extra APP gene → more β-amyloid peptide
C) α-synuclein deposits
D) Pick bodies composed of tau protein
E) Prion accumulation
B) Extra APP gene → more β-amyloid peptide
APP (amyloid precursor protein) is encoded on chromosome 21
Overproduction → formation of extracellular amyloid plaques
Which pathological findings are characteristic of Alzheimer disease in patients with Down syndrome?
A) Caudate atrophy
B) Amyloid plaques and neurofibrillary tangles
C) Lewy bodies
D) Pick bodies
E) Prion deposits
B) Amyloid plaques and neurofibrillary tangles
Diffuse cortical atrophy
Extracellular amyloid (senile) plaques
Intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein
Which disorder is characterized by dementia, visual hallucinations, and parkinsonian features, with α-synuclein deposits?
A) Huntington disease
B) Alzheimer disease
C) Lewy body dementia
D) Pick disease
E) Creutzfeldt-Jakob disease
C) Lewy body dementia
Pathology: α-synuclein deposits (Lewy bodies) in neurons
Clinical: Dementia + visual hallucinations, Parkinsonism
Not associated with Down syndrome
Which disorder is characterized by dementia, aphasia, parkinsonism, personality changes, and Pick bodies composed of tau protein?
A) Huntington disease
B) Alzheimer disease
C) Lewy body dementia
D) Pick disease
E) Creutzfeldt-Jakob disease
D) Pick disease
Pathology: Spherical Pick bodies of tau protein (silver stain)
Clinical: Frontotemporal dementia, personality/behavior changes, aphasia, parkinsonism
Not associated with Down syndrome
Which disorder is a rapidly progressive dementia with myoclonus, caused by prions (beta-pleated sheet proteins resistant to proteases)?
A) Huntington disease
B) Alzheimer disease
C) Lewy body dementia
D) Pick disease
E) Creutzfeldt-Jakob disease
E) Creutzfeldt-Jakob disease
Pathology: Prion accumulation (β-pleated sheet resistant to proteases)
Clinical: Rapid dementia, myoclonus, ataxia
Not associated with Down syndrome
A 2-month-old infant has recurrent viral infections and hypocalcemia (Ca 5.2 mg/dL). Chest radiograph shows absent thymic shadow. Laboratory studies reveal mild anemia. Which finding is most likely associated?
A) Mutation of lysosomal trafficking regulation
B) Trisomy 18
C) 22q11 deletion
D) XO
E) XXY
C) 22q11 deletion — DiGeorge syndrome
Key points:
Features: Thymic aplasia → T-cell deficiency → recurrent infections; hypocalcemia due to parathyroid hypoplasia
Genetics: 22q11.2 microdeletion
Other findings: Cardiac defects (especially conotruncal), cleft palate
Labs: Hypocalcemia, lymphopenia, mild anemia
CXR: Absent or small thymic shadow
A patient on chronic theophylline therapy develops palpitations, tachycardia, anxiety, dizziness, dyspnea, prolonged QT interval, and hypokalemia shortly after starting an antibiotic for a urinary tract infection. Which antimicrobial agent most likely triggered her symptoms?
A) Amoxicillin
B) Ciprofloxacin
C) Nitrofurantoin
D) Cephalexin
E) Trimethoprim
B) Ciprofloxacin
Key points:
Theophylline metabolism: CYP1A2 in the liver
Mechanism of toxicity: CYP1A2 inhibition → ↑ theophylline levels → toxicity
Symptoms: Tachycardia, palpitations, anxiety, GI upset, CNS stimulation, hypokalemia, arrhythmias
Fluoroquinolones (ciprofloxacin) are potent CYP1A2 inhibitors
Other fluoroquinolones: levofloxacin, moxifloxacin, gemifloxacin, ofloxacin
A 45-year-old woman presents with joint pain, fevers, and fatigue. She has a history of myocardial infarction 1 year ago, when she started a drug to prevent ventricular arrhythmias. Labs show elevated antihistone antibodies. Which antiarrhythmic is most likely responsible?
A) Amiodarone
B) Hydralazine
C) Lidocaine
D) Procainamide
E) Verapamil
D) Procainamide
Key points:
Drug-induced lupus (DILE): fever, arthralgias, myalgias, elevated antihistone antibodies
Common culprits: procainamide, hydralazine, isoniazid, minocycline, methyldopa
Antiarrhythmic context: Procainamide is used for ventricular and supraventricular arrhythmias
Other antiarrhythmics:
Amiodarone → pulmonary/hepatic toxicity, thyroid abnormalities
Lidocaine → CNS toxicity
Verapamil → constipation, bradycardia
The presence of antihistone antibodies is most characteristic of which condition?
A) Systemic lupus erythematosus (SLE)
B) Drug-induced lupus erythematosus (DILE)
C) Rheumatoid arthritis
D) Sjögren syndrome
E) Scleroderma
B) Drug-induced lupus erythematosus (DILE)
Key points:
Antihistone antibodies are positive in ~95% of DILE cases
Often associated with drugs such as procainamide, hydralazine, isoniazid, minocycline, methyldopa
SLE: ANA positive (95%), but only 50–70% have antihistone antibodies
Clinical features: fever, arthralgias, myalgias; usually no renal or CNS involvement
