A 7-year-old boy is brought to the physician by his mother because of a limp for the last 3 weeks. He has also had right hip pain during this period. The pain is aggravated when he runs. He had a runny nose and fever around a month ago that resolved with over-the-counter medications. He has no history of serious illness. His development is adequate for his age. His immunizations are up-to-date. He appears healthy. He is at the 60th percentile for height and at 65th percentile for weight. Vital signs are within normal limits. Examination shows an antalgic gait. The right groin is tender to palpation. Internal rotation and abduction of the right hip is limited by pain. The remainder of the examination shows no abnormalities. His hemoglobin concentration is 11.6 g/dL, leukocyte count is 8,900/mm3, and platelet count is 130,000/mm3. An x-ray of the pelvis is shown. Which of the following is the most likely underlying mechanism?
Q182
A previously healthy 13-year-old boy is brought to the physician because of a lump beneath his right nipple that he discovered 1 week ago while showering. He has allergic rhinitis treated with cetirizine. He is at the 65th percentile for height and 80th percentile for weight. Examination shows a mildly tender, firm, 2-cm subareolar mass in the right breast; there are no nipple or skin changes. The left breast shows no abnormalities. Sexual development is Tanner stage 3. Which of the following is the most likely explanation for this patient's breast lump?
Q183
A 7-week-old male presents to the pediatrician for vomiting. His parents report that three weeks ago the patient began vomiting after meals. They say that the vomitus appears to be normal stomach contents without streaks of red or green. His parents have already tried repositioning him during mealtimes and switching his formula to eliminate cow’s milk and soy. Despite these adjustments, the vomiting has become more frequent and forceful. The patient’s mother reports that he is voiding about four times per day and that his urine looks dark yellow. The patient has fallen one standard deviation off his growth curve. The patient's mother reports that the pregnancy was uncomplicated other than an episode of sinusitis in the third trimester, for which she was treated with azithromycin. In the office, the patient's temperature is 98.7°F (37.1°C), blood pressure is 58/41 mmHg, pulse is 166/min, and respirations are 16/min. On physical exam, the patient looks small for his age. His abdomen is soft, non-tender, and non-distended.
Which of the following is the best next step in management?
Q184
An 8-month-old girl is brought to her pediatrician because her mom is concerned that she may have a "lazy eye". She was born prematurely at 33 weeks and was 3 pounds at birth. Her mother also says that there is a history of visual problems that run in the family, which is why she wanted to make sure that her daughter was evaluated early. On presentation, she is found to have eyes that are misaligned both horizontally and vertically. Physical examination and labs reveal no underlying disorders, and the patient is discharged with occlusion therapy to help correct the misalignment. Which of the following would most likely have also been seen on physical exam?
Q185
A 12-month-old boy is brought to the pediatrician for a routine examination. Past medical history is significant for a pyloric myomectomy at 2 months of age after a few episodes of projectile vomiting. He has reached all appropriate developmental milestones. He currently lives with his parents and pet cat in a house built in the 1990s. He was weaned off of breast milk at 6 months of age. He is a very picky eater, but drinks 5–6 glasses of whole milk a day. The patient's height and weight are in the 50th percentile for his age and sex. The vital signs are within normal limits except for the presence of slight tachycardia. Physical examination reveals an alert infant with a slight pallor. Abdomen is soft and nondistended. A grade 2/6 systolic ejection murmur is noted in the left upper sternal border. Which of the following will most likely be expected in this patient's laboratory results?
Q186
A 15-year-old girl comes to the physician with her father for evaluation of short stature. She feels well overall but is concerned because all of her friends are taller than her. Her birth weight was normal. Menarche has not yet occurred. Her father says he also had short stature and late puberty. The girl is at the 5th percentile for height and 35th percentile for weight. Breast development is Tanner stage 2. Pubic and axillary hair is absent. An x-ray of the left hand and wrist shows a bone age of 12 years. Further evaluation of this patient is most likely to show which of the following sets of laboratory findings?
Q187
A 1-year-old boy is brought to the emergency department after his mother witnessed him swallow a nickel-sized battery a few hours ago. She denies any episodes of vomiting or hematemesis. The vital signs include: temperature 37.0°C (98.6°F), blood pressure 95/45 mm Hg, pulse 140/min, respiratory rate 15/min, and oxygen saturation 99% on room air. On physical examination, the patient is alert and responsive. The oropharynx is clear. The cardiac exam is significant for a grade 2/6 holosystolic murmur loudest at the left lower sternal border. The lungs are clear to auscultation. The abdomen is soft and nontender with no hepatosplenomegaly. Bowel sounds are present. What is the most appropriate next step in the management of this patient?
Q188
An 8-year-old boy is brought to the emergency department with severe dyspnea, fatigue, and vomiting. His mother reports that he has been lethargic for the last several days with an increase in urine output. She thinks he may even be losing weight, despite eating and drinking more than normal for the last couple weeks. Laboratory results are notable for glucose of 440, potassium of 5.8, pH of 7.14 and HCO3 of 17. After administrating IV fluids and insulin, which of the following would you expect?
Q189
An 18-month-old boy presents to the clinic with his mother for evaluation of a rash around the eyes and mouth. His mother states that the rash appeared 2 weeks ago and seems to be very itchy because the boy scratches his eyes often. The patient is up to date on all of his vaccinations and is meeting all developmental milestones. He has a history of asthma that was recently diagnosed. On examination, the patient is playful and alert. He has scaly, erythematous skin surrounding both eyes and his mouth. Bilateral pupils are equal and reactive to light and accommodation, and conjunctiva is clear, with no evidence of jaundice or exudates. The pharynx and oral mucosa are within normal limits, and no lesions are present. Expiratory wheezes can be heard in the lower lung fields bilaterally. What is the most likely diagnosis in this patient?
Q190
A 12-month-old boy presents with pallor, fatigue, and conjunctival pallor. Examination reveals a grade II systolic ejection murmur. Labs show: Leukocytes 6,500/mm^3, Hemoglobin 6.4 g/dL, Platelets 300,000/mm^3, MCV 71 µm^3, Reticulocytes 2.0%, Serum iron 34 mcg/dL, Ferritin 6 ng/mL (normal 7-140 ng/mL), TIBC 565 mcg/dL (normal 240-450 mcg/dL). Peripheral smear shows microcytosis and hypochromia. In addition to starting iron supplementation, what dietary modification is most important to address the underlying cause?
Growth/Development US Medical PG Practice Questions and MCQs
Question 181: A 7-year-old boy is brought to the physician by his mother because of a limp for the last 3 weeks. He has also had right hip pain during this period. The pain is aggravated when he runs. He had a runny nose and fever around a month ago that resolved with over-the-counter medications. He has no history of serious illness. His development is adequate for his age. His immunizations are up-to-date. He appears healthy. He is at the 60th percentile for height and at 65th percentile for weight. Vital signs are within normal limits. Examination shows an antalgic gait. The right groin is tender to palpation. Internal rotation and abduction of the right hip is limited by pain. The remainder of the examination shows no abnormalities. His hemoglobin concentration is 11.6 g/dL, leukocyte count is 8,900/mm3, and platelet count is 130,000/mm3. An x-ray of the pelvis is shown. Which of the following is the most likely underlying mechanism?
A. Viral infection
B. Bacterial infection of the joint
C. Unstable proximal femoral growth plate
D. Avascular necrosis of the femoral head (Correct Answer)
E. Immune-mediated synovial inflammation
Explanation: ***Avascular necrosis of the femoral head***
- The patient's age (7 years), chronic hip pain and limp, and absence of acute systemic symptoms, along with the **classic X-ray findings of fragmentation and increased density of the femoral epiphysis** (as seen in Legg-Calvé-Perthes disease), strongly indicate avascular necrosis of the femoral head.
- This condition is characterized by **interruption of the blood supply to the femoral head**, leading to collapse and deformity.
*Viral infection*
- While a recent viral infection could cause **transient synovitis**, its symptoms are typically acute and resolve much quicker, usually within 1-2 weeks, unlike the 3-week history here.
- Furthermore, **transient synovitis** does not lead to the distinct X-ray changes of avascular necrosis.
*Bacterial infection of the joint*
- A bacterial infection (septic arthritis) would present with more acute and severe symptoms, including **high fever, significant pain, inability to bear weight**, and elevated inflammatory markers (ESR, CRP).
- The X-ray findings would typically show **joint effusion and potentially bone destruction** in later stages, not the specific changes seen in avascular necrosis.
*Unstable proximal femoral growth plate*
- An unstable proximal femoral growth plate is characteristic of **slipped capital femoral epiphysis (SCFE)**, which typically occurs in adolescent, often obese, children (10-16 years old), **not in a 7-year-old child**.
- The X-ray would show **posterior and inferior displacement of the femoral epiphysis**, which is different from the fragmentation and increased density seen here.
*Immune-mediated synovial inflammation*
- Immune-mediated synovial inflammation, such as **juvenile idiopathic arthritis**, typically presents with **morning stiffness, chronic joint swelling**, and can affect multiple joints.
- While it can cause a limp and pain, the **distinctive X-ray findings of avascular necrosis** are not characteristic of this condition.
Question 182: A previously healthy 13-year-old boy is brought to the physician because of a lump beneath his right nipple that he discovered 1 week ago while showering. He has allergic rhinitis treated with cetirizine. He is at the 65th percentile for height and 80th percentile for weight. Examination shows a mildly tender, firm, 2-cm subareolar mass in the right breast; there are no nipple or skin changes. The left breast shows no abnormalities. Sexual development is Tanner stage 3. Which of the following is the most likely explanation for this patient's breast lump?
A. Adverse effect of medication
B. Invasive ductal carcinoma
C. Normal development (Correct Answer)
D. Leydig cell tumor
E. Hyperprolactinemia
Explanation: **Normal development**
- The patient's age (13 years old) and Tanner stage 3 sexual development are consistent with **pubertal gynecomastia**, which is a common and normal finding in adolescent males.
- The presentation of a **mildly tender, firm, subareolar mass** in one or both breasts is characteristic of physiological gynecomastia during puberty.
*Adverse effect of medication*
- While certain medications can cause gynecomastia, **cetirizine (an antihistamine)** is not typically associated with this side effect.
- The clinical presentation aligns more strongly with a **physiological process** given the patient's age and pubertal stage.
*Invasive ductal carcinoma*
- Breast cancer in adolescent males is **extremely rare** and usually presents with hard, irregular, fixed masses, often with skin dimpling or nipple discharge.
- The described mass is **mildly tender and subareolar**, which is more typical of benign gynecomastia.
*Leydig cell tumor*
- Leydig cell tumors can cause gynecomastia due to **increased estrogen production** or increased androgen-to-estrogen conversion.
- However, such tumors would typically present with other signs of **precocious puberty** or testicular abnormalities, which are not mentioned here.
*Hyperprolactinemia*
- High prolactin levels can cause gynecomastia, but they are also associated with **galactorrhea** (nipple discharge), which is not described in this patient.
- **Other causes of gynecomastia** are more common in adolescents than hyperprolactinemia.
Question 183: A 7-week-old male presents to the pediatrician for vomiting. His parents report that three weeks ago the patient began vomiting after meals. They say that the vomitus appears to be normal stomach contents without streaks of red or green. His parents have already tried repositioning him during mealtimes and switching his formula to eliminate cow’s milk and soy. Despite these adjustments, the vomiting has become more frequent and forceful. The patient’s mother reports that he is voiding about four times per day and that his urine looks dark yellow. The patient has fallen one standard deviation off his growth curve. The patient's mother reports that the pregnancy was uncomplicated other than an episode of sinusitis in the third trimester, for which she was treated with azithromycin. In the office, the patient's temperature is 98.7°F (37.1°C), blood pressure is 58/41 mmHg, pulse is 166/min, and respirations are 16/min. On physical exam, the patient looks small for his age. His abdomen is soft, non-tender, and non-distended.
Which of the following is the best next step in management?
A. MRI of the head
B. Intravenous hydration (Correct Answer)
C. Pyloromyotomy
D. Thickening feeds
E. Abdominal ultrasound
Explanation: ***Intravenous hydration***
- The patient exhibits signs of **dehydration** (dark yellow urine, decreased voiding, tachycardia, hypotension) and poor growth, necessitating immediate intravenous fluid resuscitation.
- This step is critical for stabilizing the patient before further diagnostic tests or definitive treatment for the underlying cause of vomiting.
*MRI of the head*
- While vomiting can be a sign of neurological issues, there are no other symptoms suggestive of increased **intracranial pressure** such as lethargy, seizures, or bulging fontanelles.
- Head imaging is not the immediate priority given the prominent signs of dehydration and lack of neurological red flags.
*Pyloromyotomy*
- This is the **definitive surgical treatment** for **pyloric stenosis**, which is a suspected diagnosis given the forceful, non-bilious vomiting and age.
- However, the patient's dehydration and electrolyte imbalances must be corrected *before* surgery to minimize surgical risks.
*Thickening feeds*
- Thickening feeds is commonly used for **gastroesophageal reflux**, but the patient's vomiting is described as "forceful" and increasing in frequency, which is more characteristic of an **obstructive** process rather than simple reflux.
- This intervention is unlikely to resolve the symptoms and does not address the immediate concern of dehydration.
*Abdominal ultrasound*
- An **abdominal ultrasound** is the diagnostic test of choice for **pyloric stenosis**, which is highly suspected given the patient's presentation of progressive, forceful, non-bilious vomiting in an infant.
- While essential for diagnosis, addressing the patient's immediate and life-threatening dehydration takes precedence over imaging.
Question 184: An 8-month-old girl is brought to her pediatrician because her mom is concerned that she may have a "lazy eye". She was born prematurely at 33 weeks and was 3 pounds at birth. Her mother also says that there is a history of visual problems that run in the family, which is why she wanted to make sure that her daughter was evaluated early. On presentation, she is found to have eyes that are misaligned both horizontally and vertically. Physical examination and labs reveal no underlying disorders, and the patient is discharged with occlusion therapy to help correct the misalignment. Which of the following would most likely have also been seen on physical exam?
A. Fundus neovascularization
B. Bitemporal hemianopsia
C. Nystagmus
D. Asymmetric corneal light reflex (Correct Answer)
E. Increased intraocular pressure
Explanation: ***Asymmetric corneal light reflex***
- This finding is **characteristic of strabismus**, where the misalignment of the eyes causes the light reflection to appear in different positions on each cornea.
- The premature birth and low birth weight are risk factors for strabismus, and the reported "lazy eye" and misalignment support this diagnosis.
*Fundus neovascularization*
- **Retinopathy of prematurity (ROP)**, often seen in premature infants, involves abnormal blood vessel growth in the retina, which can lead to vision loss.
- While ROP is a complication of prematurity and can cause vision problems, **neovascularization itself is not a direct consequence of strabismus** and is not typically a physical exam finding for strabismus alone.
*Bitemporal hemianopsia*
- This is a **visual field defect** causing loss of the outer halves of the visual field in both eyes due to a lesion at the optic chiasm.
- It is a **neurological sign**, not a direct physical manifestation of ocular misalignment, and would not be expected in a child with isolated strabismus.
*Nystagmus*
- Nystagmus is an **involuntary, rhythmic oscillation of the eyes**, which can be associated with various neurological conditions or visual impairments.
- While some cases of strabismus may be accompanied by nystagmus, it is **not a universal finding** and the description of misaligned eyes points more directly to an asymmetric corneal light reflex.
*Increased intraocular pressure*
- Elevated intraocular pressure is a hallmark of **glaucoma**, which can lead to optic nerve damage and vision loss.
- There is **no direct link between strabismus and increased intraocular pressure** as a primary finding.
Question 185: A 12-month-old boy is brought to the pediatrician for a routine examination. Past medical history is significant for a pyloric myomectomy at 2 months of age after a few episodes of projectile vomiting. He has reached all appropriate developmental milestones. He currently lives with his parents and pet cat in a house built in the 1990s. He was weaned off of breast milk at 6 months of age. He is a very picky eater, but drinks 5–6 glasses of whole milk a day. The patient's height and weight are in the 50th percentile for his age and sex. The vital signs are within normal limits except for the presence of slight tachycardia. Physical examination reveals an alert infant with a slight pallor. Abdomen is soft and nondistended. A grade 2/6 systolic ejection murmur is noted in the left upper sternal border. Which of the following will most likely be expected in this patient's laboratory results?
A. Increased Hb S levels
B. Decreased vitamin B12 levels
C. Metabolic alkalosis
D. Decreased hemoglobin (Correct Answer)
E. Increased lead levels
Explanation: ***Decreased hemoglobin***
- The patient's **picky eating habits**, combined with consuming **large amounts of whole milk** (low in iron), suggest a high risk for **iron deficiency anemia**.
- **Pallor** and **tachycardia** are classic signs of anemia, and a **systolic ejection murmur** can be a functional murmur due to increased cardiac output in anemic states.
*Increased Hb S levels*
- **Hb S** is characteristic of **sickle cell disease**, typically resulting in symptomatic episodes like **vaso-occlusive crises** and chronic anemia.
- The patient's presentation with dietary factors and pallor points more strongly to **nutritional anemia**, not a hemoglobinopathy.
*Decreased vitamin B12 levels*
- **Vitamin B12 deficiency** can cause megaloblastic anemia, but is usually associated with **neurological symptoms** and is less common at this age due to dietary intake habits.
- While prolonged exclusive breastfeeding could lead to B12 deficiency if the mother is deficient, the child was weaned at 6 months, and the symptoms are more consistent with iron deficiency.
*Metabolic alkalosis*
- **Metabolic alkalosis** was likely present during his previous illness involving **projectile vomiting** due to pyloric stenosis, but this has since been surgically corrected.
- His current symptoms of pallor and tachycardia are not indicative of an acid-base imbalance, but rather a circulatory issue like anemia.
*Increased lead levels*
- **Lead poisoning** can cause anemia and abdominal pain, but the patient's house was built in the 1990s (reducing the risk of lead paint exposure) and he has no history of pica.
- While it's a possibility, the specific dietary history of high milk intake and poor solid food consumption makes **iron deficiency anemia** a more direct and probable cause of his symptoms.
Question 186: A 15-year-old girl comes to the physician with her father for evaluation of short stature. She feels well overall but is concerned because all of her friends are taller than her. Her birth weight was normal. Menarche has not yet occurred. Her father says he also had short stature and late puberty. The girl is at the 5th percentile for height and 35th percentile for weight. Breast development is Tanner stage 2. Pubic and axillary hair is absent. An x-ray of the left hand and wrist shows a bone age of 12 years. Further evaluation of this patient is most likely to show which of the following sets of laboratory findings?
A. High FSH, High LH, Normal Estradiol, Normal Prolactin
B. Normal FSH, Normal LH, Normal Estradiol, Normal Prolactin
C. Normal FSH, Normal LH, Low Estradiol, Normal Prolactin
D. Low-normal FSH, Low-normal LH, Low Estradiol, Normal Prolactin (Correct Answer)
E. Low FSH, Low LH, Low Estradiol, Normal Prolactin
Explanation: ***Low-normal FSH, Low-normal LH, Low Estradiol, Normal Prolactin***
- This pattern is characteristic of **constitutional delay of growth and puberty (CDGP)**, where the hypothalamic-pituitary-gonadal (HPG) axis has not yet fully matured, resulting in low-normal gonadotropins and low estradiol.
- The key clinical features supporting CDGP include: **delayed bone age** (12 years vs chronologic age 15), **positive family history** of late puberty, normal growth velocity, and absence of pathological findings.
- In CDGP, gonadotropins are in the **low-normal or prepubertal range** but will eventually rise spontaneously as the HPG axis matures, distinguishing this from permanent hypogonadotropic hypogonadism.
- GnRH stimulation testing would show a pubertal (not prepubertal) response, confirming the functional delay rather than a pathologic deficiency.
*Low FSH, Low LH, Low Estradiol, Normal Prolactin*
- This pattern suggests **hypogonadotropic hypogonadism**, such as Kallmann syndrome or functional hypothalamic amenorrhea, where gonadotropins are frankly low (not just low-normal).
- While this also presents with low estradiol and delayed puberty, patients with hypogonadotropic hypogonadism typically lack the **positive family history** and would not show delayed bone age suggesting growth potential.
- The distinction is that in permanent hypogonadotropic hypogonadism, the HPG axis is deficient and will not mature spontaneously without hormonal treatment.
*High FSH, High LH, Normal Estradiol, Normal Prolactin*
- This combination is inconsistent with delayed puberty, as high gonadotropins indicate **hypergonadotropic hypogonadism** (primary ovarian failure such as Turner syndrome).
- Hypergonadotropic hypogonadism presents with **high FSH/LH and low estradiol** (not normal), as the pituitary attempts to stimulate non-responsive ovaries.
- This patient's delayed bone age and family history make a physiologic delay (CDGP) much more likely than ovarian failure.
*Normal FSH, Normal LH, Normal Estradiol, Normal Prolactin*
- **Normal estradiol** at age 15 would indicate that puberty is progressing appropriately, which contradicts this patient's clinical presentation.
- The patient has delayed menarche, absent pubic/axillary hair, only Tanner stage 2 breast development, and bone age of 12 years - all indicating **low estradiol** and delayed pubertal progression.
- If all hormones were normal, we would expect more advanced pubertal development at this age.
*Normal FSH, Normal LH, Low Estradiol, Normal Prolactin*
- While low estradiol correctly reflects delayed puberty, describing FSH and LH as fully "normal" is imprecise for CDGP.
- In CDGP, gonadotropins are characteristically in the **low-normal or prepubertal range**, not at robust normal adult levels, reflecting the immature but eventually functional HPG axis.
- The distinction between "normal" and "low-normal" gonadotropins is clinically important for differentiating constitutional delay from other causes of delayed puberty.
Question 187: A 1-year-old boy is brought to the emergency department after his mother witnessed him swallow a nickel-sized battery a few hours ago. She denies any episodes of vomiting or hematemesis. The vital signs include: temperature 37.0°C (98.6°F), blood pressure 95/45 mm Hg, pulse 140/min, respiratory rate 15/min, and oxygen saturation 99% on room air. On physical examination, the patient is alert and responsive. The oropharynx is clear. The cardiac exam is significant for a grade 2/6 holosystolic murmur loudest at the left lower sternal border. The lungs are clear to auscultation. The abdomen is soft and nontender with no hepatosplenomegaly. Bowel sounds are present. What is the most appropriate next step in the management of this patient?
A. Reassurance and observation for the next 24 hours
B. Computed tomography (CT) scan to confirm the diagnosis
C. Induce emesis to expel the battery
D. Immediate endoscopic removal (Correct Answer)
E. Induce gastrointestinal motility with metoclopramide to expel the battery
Explanation: ***Immediate endoscopic removal***
- Button battery ingestion in a young child requires **urgent imaging (chest/abdominal X-ray)** to localize the battery, followed by **immediate endoscopic removal if esophageal**.
- Button batteries lodged in the **esophagus** pose a significant risk of **esophageal caustic injury, perforation, or stricture formation** due to electrical current generation and leakage of alkaline contents within **2-4 hours**.
- Given the recent ingestion and high risk of esophageal lodgment in young children, the most appropriate next step is proceeding directly to **urgent endoscopic evaluation and removal**, as this addresses the time-critical nature of potential esophageal impaction.
- Even asymptomatic patients require urgent intervention due to the rapid progression of esophageal injury.
*Reassurance and observation for the next 24 hours*
- This approach is inappropriate for button battery ingestion due to the rapid and severe damage these batteries can cause to the esophageal mucosa if lodged.
- Delayed intervention increases the risk of **perforation, tracheoesophageal fistula formation, and mediastinitis**, which can be life-threatening.
- Observation alone is only appropriate for batteries that have passed into the stomach and are small (<20mm) in older children.
*Computed tomography (CT) scan to confirm the diagnosis*
- While imaging is necessary to localize the battery, **CT scan is not the appropriate initial imaging modality** as it exposes the child to unnecessary radiation and delays treatment.
- A simple **chest/abdominal radiograph** can quickly confirm the presence and location of the metallic foreign body, which is the imaging modality of choice.
- CT provides no additional benefit over plain radiography for battery localization.
*Induce emesis to expel the battery*
- Inducing emesis is **absolutely contraindicated** as it can worsen the situation by causing the battery to become lodged more firmly or lead to aspiration.
- There is significant risk of re-injury to the esophagus during expulsion and potential for the battery to become stuck in the oropharynx or airway.
- This intervention may also delay definitive management.
*Induce gastrointestinal motility with metoclopramide to expel the battery*
- Pharmacologic induction of gastrointestinal motility is **ineffective and potentially harmful** for managing button battery ingestion.
- This approach does not address the immediate danger of esophageal injury and may increase the risk of complications.
- Prokinetic agents have no role in the management of ingested foreign bodies, especially button batteries.
Question 188: An 8-year-old boy is brought to the emergency department with severe dyspnea, fatigue, and vomiting. His mother reports that he has been lethargic for the last several days with an increase in urine output. She thinks he may even be losing weight, despite eating and drinking more than normal for the last couple weeks. Laboratory results are notable for glucose of 440, potassium of 5.8, pH of 7.14 and HCO3 of 17. After administrating IV fluids and insulin, which of the following would you expect?
A. Increase in anion gap
B. Increase in serum glucose
C. Decrease in serum potassium (Correct Answer)
D. Decrease in pH
E. Decrease in serum bicarbonate
Explanation: ***Decrease in serum potassium***
- **Insulin therapy** drives **potassium** into cells, as it stimulates the **Na+/K+ ATPase pump**, leading to a decrease in serum potassium levels.
- The initial **hyperkalemia** (potassium 5.8) is due to extracellular fluid shifts and acidosis, which will correct as **DKA** resolves with treatment.
*Increase in anion gap*
- The presented patient has **diabetic ketoacidosis (DKA)**, which is characterized by a **high anion gap metabolic acidosis** (evidenced by low pH and bicarbonate).
- Treatment with **IV fluids and insulin** aims to resolve the ketoacidosis, which would consequently lead to a **decrease** in the **anion gap**, not an increase.
*Increase in serum glucose*
- The primary goal of **IV fluids and insulin** in **DKA** is to lower the critically high **serum glucose** levels by promoting glucose uptake into cells and inhibiting hepatic glucose production.
- Therefore, one would expect a **decrease** in serum glucose, not an increase, as treatment progresses.
*Decrease in pH*
- The patient's initial pH of 7.14 indicates **acidosis**, a hallmark of **DKA**.
- **Insulin therapy** and **fluid resuscitation** will resolve the ketoacidosis, leading to an **increase** in **pH** towards normal, not a further decrease.
*Decrease in serum bicarbonate*
- The patient already presents with **decreased serum bicarbonate** (17 mEq/L), which is consistent with **metabolic acidosis** due to DKA.
- Treatment with **fluids and insulin** will correct the acidosis by reducing ketone production, leading to an **increase** in **serum bicarbonate**, not a further decrease.
Question 189: An 18-month-old boy presents to the clinic with his mother for evaluation of a rash around the eyes and mouth. His mother states that the rash appeared 2 weeks ago and seems to be very itchy because the boy scratches his eyes often. The patient is up to date on all of his vaccinations and is meeting all developmental milestones. He has a history of asthma that was recently diagnosed. On examination, the patient is playful and alert. He has scaly, erythematous skin surrounding both eyes and his mouth. Bilateral pupils are equal and reactive to light and accommodation, and conjunctiva is clear, with no evidence of jaundice or exudates. The pharynx and oral mucosa are within normal limits, and no lesions are present. Expiratory wheezes can be heard in the lower lung fields bilaterally. What is the most likely diagnosis in this patient?
A. Impetigo
B. Bronchiolitis
C. Atopic dermatitis (Correct Answer)
D. Viral conjunctivitis
E. Scalded skin syndrome
Explanation: ***Atopic dermatitis***
- The combination of an **itchy, scaly, erythematous rash** around the eyes and mouth in an infant with a history of **asthma** strongly suggests atopic dermatitis, a condition linked to the **atopic triad**.
- **Exacerbating factors** like scratching and the typical facial distribution are common in young children with this condition.
*Impetigo*
- Impetigo typically presents with **"honey-crusted" lesions** and is caused by bacterial infection, which is not described.
- While it can be itchy, the appearance and association with asthma make it less likely.
*Bronchiolitis*
- Bronchiolitis is a **respiratory infection** primarily affecting infants, characterized by **wheezing** and respiratory distress, not a skin rash around the eyes and mouth.
- Although wheezing is present, it's attributed to the patient's asthma history rather than acute bronchiolitis.
*Viral conjunctivitis*
- Viral conjunctivitis would present with **red eyes**, **gritty sensation**, and often discharge, but typically not a scaly rash around the eyes or mouth.
- The patient's conjunctiva are described as clear, ruling out this diagnosis.
*Scalded skin syndrome*
- Scalded skin syndrome presents with **widespread blistering** and skin peeling, resembling a burn, which is distinct from the localized, erythematous, and scaly rash described.
- It is typically a more severe illness, not a localized itchy rash.
Question 190: A 12-month-old boy presents with pallor, fatigue, and conjunctival pallor. Examination reveals a grade II systolic ejection murmur. Labs show: Leukocytes 6,500/mm^3, Hemoglobin 6.4 g/dL, Platelets 300,000/mm^3, MCV 71 µm^3, Reticulocytes 2.0%, Serum iron 34 mcg/dL, Ferritin 6 ng/mL (normal 7-140 ng/mL), TIBC 565 mcg/dL (normal 240-450 mcg/dL). Peripheral smear shows microcytosis and hypochromia. In addition to starting iron supplementation, what dietary modification is most important to address the underlying cause?
A. Administer deferoxamine
B. Limit milk intake (Correct Answer)
C. Echocardiogram
D. Measure lead level
E. Iron supplementation
Explanation: ***Limit milk intake***
- The patient's presentation and lab results (low Hb, low MCV, low ferritin, high TIBC) are highly indicative of **iron deficiency anemia**. Excessive cow's milk intake (typically >24 oz/day) in infants is a leading cause of iron deficiency through multiple mechanisms: displacing iron-rich foods from the diet, causing occult gastrointestinal blood loss, and impairing iron absorption due to calcium content.
- With severe anemia (Hb 6.4 g/dL), **iron supplementation is essential** and should be started immediately (3-6 mg/kg/day elemental iron). However, addressing the underlying **dietary cause** by limiting milk to 16-24 oz/day and encouraging iron-rich foods (meat, fortified cereals) is crucial to prevent recurrence and ensure long-term resolution.
- This question tests understanding of the **etiology** of nutritional iron deficiency in toddlers, where excessive milk consumption is the most common preventable cause.
*Administer deferoxamine*
- **Deferoxamine** is a chelating agent used to treat **iron overload** (hemochromatosis, transfusional iron overload, acute iron poisoning).
- This patient has severe iron **deficiency**, so removing iron would be harmful and contraindicated.
*Echocardiogram*
- An **echocardiogram** evaluates cardiac structure and function, indicated for suspected structural heart disease or pathologic murmurs.
- The grade II systolic ejection murmur is likely a **flow murmur** from high cardiac output due to severe anemia. Once anemia is corrected, the murmur should resolve. Echocardiogram is not the priority and would only be considered if the murmur persists after anemia correction.
*Measure lead level*
- **Lead poisoning** can cause microcytic anemia and should be considered in at-risk children.
- However, lead poisoning typically shows **normal or elevated ferritin** (lead causes anemia of chronic disease plus iron dysregulation), whereas this patient has **very low ferritin (6 ng/mL)** and **markedly elevated TIBC (565)**, which are classic for iron deficiency, not lead toxicity.
*Iron supplementation*
- **Iron supplementation is absolutely necessary** for this patient with severe anemia (Hb 6.4 g/dL) and should be started immediately along with dietary counseling.
- However, the question specifically asks for the dietary modification needed **in addition to** iron supplementation to address the **underlying cause**. Without limiting excessive milk intake, iron deficiency will likely recur even with supplementation.
