Explanation:

The correct answer is "Asthma." This answer is correct because asthma is an inflammatory airway condition that is characteristically improved symptomatically and quantitatively (in terms of pulmonary function tests, including FEV1 readings) with bronchodilator administration (e.g. albuterol, the beta-2 adrenergic agonist administered in this patient). In this patient who presented for evaluation of wheezing, a characteristic symptom of asthma, his substantial response to bronchodilator administration makes the likelihood of an asthma diagnosis very high. 

Chronic Obstructive Pulmonary Disease (COPD) is an obstructive physiology of the airways often due to chronic tobacco smoking. While bronchodilators may be of some clinical value in these patients, their FEV1 readings characteristically do not correct after bronchodilator administration, as this is a major method in which COPD can be distinguished from asthma and other inflammatory airway conditions. 

Sarcoidosis, lung cancer, and throat cancer symptoms would not necessarily improve with bronchodilator administration, nor would pulmonary function test readings in patients with these conditions.

Explanation:

The correct answer is "continuous positive airway pressure mask (CPAP)." This is the correct answer as a CPAP mask helps to force airway into the lungs that is otherwise obstructed by the patient's oropharyngeal anatomy at standard breathing pressures due to obstructive sleep apnea. When wearing a CPAP mask (typically when sleeping), snoring is reduced, and oxygenation is improved, allowing patients to have a more restful sleep and feel less fatigued the following day. 

While medications like metoprolol, insulin, and metformin may be beneficial to the patient in treating his conditions co-morbid to obstructive sleep apnea, they do not have a direct effect on treating his sleep apnea or the resultant fatigue.

Tamsulosin is an alpha-adrenergic blocker and can be used to treat benign prostatic hyperplasia among other conditions, but not obstructive sleep apnea. 

Explanation: Simple silicosis results in mild ventilation restriction and fibrosis on chest x-ray. Simple silicosis often results from long-term exposure to relatively low concentrations of silica dust, where symptoms usually appear 10-30 years after exposure.

Explanation:

Pneumococcal (bacterial) pneumonia typically presents with an abrupt onset of fever, shaking chills, and a productive cough (usually rust in color). Usually viral pneumonias will present with a dry non productive cough and associated with other viral infections. 

Explanation:

Due to their susceptibility to suffocation, infants are more at risk of mortality than older children, pregnant women, or the elderly during pertussis infection. Mortality in infants with this condition can be as high as 2%. There is also an increase in infant co-moridities such as pneumonia, encephalopathy, seizures, and failure to thrive.

Explanation:

The correct answer is "Attempt to obtain and review a prior x-ray." This is the correct answer because while the patient appears to have a very concerning story for a primary lung neoplasm given his age and smoking history, or a metastasis from another neoplasm, if this nodule was noted on a prior x-ray, especially a much older x-ray, and is unchanged, then the degree of concern about the nodule is much lower, given its stability over time. On the contrary, if you can obtain a recent prior x-ray and the nodule is not present on that scan, or has grown since that scan, then the level of concern about the nodule should be greater, and should guide clinical decision-making as such.

Measures such as biopsy, surgery, chemotherapy, or radiotherapy administration are all possible future steps if indeed this pulmonary nodule turns out to be a malignant neoplasm. That being said, there is no definite evidence at this time that the patient's nodule is of malignant origin, and should this nodule be something that has been stable on prior x-rays for multiple years, then the level of concern should be far lower, and the need for more invasive measures would be obviated.

Explanation:

Microcephaly denotes a congenital abnormality of the forebrain in which an infant is born with a diminished brain size. Potential causes include fetal alcohol syndrome, congenital rubella, and trisomy 18. 

The other answers are all examples of congenital forebrain birth defects:

• Anencephaly is the complete absence of major portions of the brain, skull, and scalp.
• Agyri is the absence of gyri.
• Polymicrogyri is a condition in which gyri are too many, too small, and very shallow.

Explanation:

Anencephaly and other neural tube defects have been linked to maternal deficiency of folate. This is most likely due to folate's role in methylation and nucleic acid synthesis. The other nutrients listed are all important to maternal health but have no known correlation with neural tube defects such as anencephaly.

Explanation:

Periventricular leukomalacia is the most common finding on autopsy of newborns with cerebral palsy. PVL involves the softening of the brain tissue and subsequent death of the white matter. This is caused by lack of blood flow to the periventricular area of the brain, which results in necrosis and gliosis of brain tissue. Neonates born with PVL are likely to have mental impairment, motor disorders, and compromised vision and hearing. PVL is usually diagnosed with ultrasound of the head. None of the other conditions listed typically present with this finding.

Explanation:

It is normal for a child's head to be slightly misshapen immediately following birth. The infant's skull is composed of bony plates connected by membranes (fontanelles), allowing for accommodation of the baby's growing brain. Caput succedaneum (swelling of the scalp) can also be found following a long delivery. A misshapen head usually resolves on its own and is normal but does not require any medical intervention.