A 4-year-old African-American girl is brought to the physician because of multiple episodes of bilateral leg pain for 4 months. The pain is crampy in nature, lasts up to an hour, and occurs primarily before her bedtime. Occasionally, she has woken up crying because of severe pain. The pain is reduced when her mother massages her legs. She has no pain while attending school or playing. Her mother has rheumatoid arthritis. The patient's temperature is 37°C (98.6°F), pulse is 90/min and blood pressure is 94/60 mm Hg. Physical examination shows no abnormalities. Her hemoglobin concentration is 12.1 g/dL, leukocyte count is 10,900/mm3 and platelet count is 230,000/mm3. Which of the following is the most appropriate next best step in management?
Q162
A 5-year-old boy presents to his pediatrician along with his parents due to episodes of “staring into space.” This symptom occurs several times a day and lasts only a few seconds. During these episodes, the boy does not respond to verbal or physical stimulation, and his parents deny him falling down or shaking. After the episode, the boy returns to his normal activity and is not confused. The parents deny any history of head trauma, recent medication use, or infection. Neurological exam is unremarkable. His episode is precipitated as he blows at a pinwheel. An EEG is performed, which shows 3-Hz spike and waveform. Which of the following is the best treatment option for this patient?
Q163
A 6-year-old boy presents to his primary care physician with hip pain that started this morning. The patient claims the pain is severe and is stopping him from skateboarding. The patient recently recovered from an upper respiratory infection that he caught from his siblings but has otherwise been healthy. The patient has a past medical history of obesity. His temperature is 98.1°F (36.7°C), blood pressure is 100/55 mmHg, pulse is 90/min, respirations are 22/min, and oxygen saturation is 98% on room air. On physical exam, you note an obese boy in no acute distress. Cardiopulmonary exam is within normal limits. Inspection of the hip reveals no abnormalities or swelling. The hip exhibits a normal range of motion and physical exam only elicits minor pain. The patient's gait appears normal and pain is elicited when the patient jumps or runs. Which of the following is the best next step in management for this patient's most likely diagnosis?
Q164
An asymptomatic 15-year-old high school wrestler with no family history of renal disease is completing his preseason physical exam. He submits a urine sample for a dipstick examination, which tests positive for protein. What is the next appropriate step in management?
Q165
A 4-month-old girl is brought to the physician by her mother because of a 4-day history of vomiting, poor feeding, and more frequent napping. She appears lethargic. Her vital signs are within normal limits. Physical examination shows a bulging, tense anterior fontanelle. Fundoscopic exam shows bilateral retinal hemorrhage. A complete blood count shows a leukocyte count of 8,000/mm3. An x-ray of the chest shows healing fractures of the 4th and 5th left ribs. Which of the following is the most likely cause of the patient's condition?
Q166
A 3-year-old girl is brought to the physician by her mother two days after the sudden onset of a rash. The mother says that the rash developed an hour after she bathed the child in hot water. Two weeks ago, the patient was diagnosed with a skin infection and was treated with penicillin V. She has been otherwise healthy but has missed several well-child examinations. She lives with her single mother, who recently lost her job and is now dependent on social assistance. The patient's mother has major depressive disorder and her maternal aunt has systemic lupus erythematosus. The girl's temperature is 36.8°C (98.2°F), pulse is 112/min, and blood pressure is 108/62 mm Hg. She has poor eye contact. Physical examination shows sharply delineated erythema on the lower extremities up to the umbilicus with sparing of the knees and flexor surfaces. Further evaluation is most likely to reveal which of the following?
Q167
An 8-year old boy is brought to the emergency department because he has been lethargic and has had several episodes of nausea and vomiting for the past day. He has also had increased thirst over the past two months. He has lost 5.4 kg (11.9 lbs) during this time. He is otherwise healthy and has no history of serious illness. His temperature is 37.5 °C (99.5 °F), blood pressure is 95/68 mm Hg, pulse is 110/min, and respirations are 30/min. He is somnolent and slightly confused. His mucous membranes are dry. Laboratory studies show:
Hemoglobin 16.2 g/dL
Leukocyte count 9,500/mm3
Platelet count 380,000/mm3
Serum
Na+ 130 mEq/L
K+ 5.5 mEq/L
Cl- 99 mEq/L
HCO3- 16 mEq/L
Creatinine 1.2 mg/dL
Glucose 570 mg/dL
Ketones positive
Blood gases, arterial
pH 7.25
pCO2 21 mm Hg
Which of the following is the most appropriate next step in management?
Q168
An otherwise healthy 14-year-old girl is brought to the emergency room by her father because of excessive thirst, excessive urination, and weight loss. Her symptoms started acutely 5 days ago. Vital signs reveal a temperature of 36.6°C (97.8°F), blood pressure of 100/65 mm Hg, and pulse of 105/min. Physical examination shows a thin girl with dry mucous membranes but normal skin turgor. Laboratory results are shown:
Random blood sugar 410 mg/dL
C-peptide undetectable
Serum beta-hydroxybutyrate negative
Which of the following is the best initial therapy for this patient?
Q169
A 3-year-old boy is brought to the physician for evaluation of developmental delay. He could sit alone at 12 months and started walking with support at the age of 2 years. He can name only very few familiar objects and uses simple two-word sentences. He cannot stack more than 2 blocks. His parents report that he does not like playing with other children. He is at the 80th percentile for head circumference, 85th percentile for height, and 50th percentile for weight. He has a long and narrow face as well as large protruding ears. His thumbs can be passively flexed to the ipsilateral forearm. This patient is at increased risk of developing which of the following conditions?
Q170
A previously healthy 14-year-old girl is brought to the emergency department by her mother because of abdominal pain, nausea, and vomiting for 6 hours. Over the past 6 weeks, she has also had increased frequency of urination, and she has been drinking more water than usual. She has lost 6 kg (13 lb) over the same time period despite having a good appetite. Her temperature is 37.1°C (98.8°F), pulse is 125/min, respirations are 32/min, and blood pressure is 94/58 mm Hg. She appears lethargic. Physical examination shows deep and labored breathing and dry mucous membranes. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Urine dipstick is positive for ketones and glucose. Further evaluation is most likely to show which of the following findings?
Growth/Development US Medical PG Practice Questions and MCQs
Question 161: A 4-year-old African-American girl is brought to the physician because of multiple episodes of bilateral leg pain for 4 months. The pain is crampy in nature, lasts up to an hour, and occurs primarily before her bedtime. Occasionally, she has woken up crying because of severe pain. The pain is reduced when her mother massages her legs. She has no pain while attending school or playing. Her mother has rheumatoid arthritis. The patient's temperature is 37°C (98.6°F), pulse is 90/min and blood pressure is 94/60 mm Hg. Physical examination shows no abnormalities. Her hemoglobin concentration is 12.1 g/dL, leukocyte count is 10,900/mm3 and platelet count is 230,000/mm3. Which of the following is the most appropriate next best step in management?
A. X-ray of the lower extremities
B. Reassurance (Correct Answer)
C. Nafcillin therapy
D. Antinuclear antibody
E. Pramipexole therapy
Explanation: ***Reassurance***
- The patient presents with classic symptoms of **growing pains**, characterized by bilateral leg pain that occurs primarily at night, improves with massage, and does not interfere with daily activities or cause physical findings.
- Given the benign nature of growing pains and the unremarkable physical examination and laboratory findings, reassurance and symptomatic management (like massage) are the most appropriate next steps.
*X-ray of the lower extremities*
- This is generally not indicated for typical growing pains as they are a diagnosis of exclusion and do not involve bone abnormalities.
- **Radiographs** would only be considered if there were atypical features like unilateral pain, persistent pain, limping, fever, or localized tenderness, which are absent here.
*Nafcillin therapy*
- Nafcillin is an antibiotic used to treat bacterial infections, particularly those caused by **Staphylococcus aureus**.
- There is no indication of a bacterial infection (e.g., fever, localized swelling, redness, elevated inflammatory markers) in this patient, making antibiotic therapy inappropriate.
*Antinuclear antibody*
- An antinuclear antibody (ANA) test is used to screen for **autoimmune diseases** like systemic lupus erythematosus (SLE) or juvenile idiopathic arthritis.
- While the mother has rheumatoid arthritis, the patient's symptoms are inconsistent with an autoimmune condition, lacking joint swelling, morning stiffness, or systemic symptoms, making an ANA screen premature.
*Pramipexole therapy*
- Pramipexole is primarily used to treat **Parkinson's disease** and **restless legs syndrome (RLS)**.
- Although RLS also presents with leg discomfort at night, it typically involves an *unpleasant sensation* and a *compelling urge to move the legs*, which is different from the crampy pain described as growing pains.
Question 162: A 5-year-old boy presents to his pediatrician along with his parents due to episodes of “staring into space.” This symptom occurs several times a day and lasts only a few seconds. During these episodes, the boy does not respond to verbal or physical stimulation, and his parents deny him falling down or shaking. After the episode, the boy returns to his normal activity and is not confused. The parents deny any history of head trauma, recent medication use, or infection. Neurological exam is unremarkable. His episode is precipitated as he blows at a pinwheel. An EEG is performed, which shows 3-Hz spike and waveform. Which of the following is the best treatment option for this patient?
A. Zonisamide
B. Valproic acid
C. Ethosuximide (Correct Answer)
D. Lamotrigine
E. Levetiracetam
Explanation: ***Ethosuximide***
- This patient presents with **childhood absence epilepsy (CAE)**, characterized by brief episodes of "staring into space," unresponsiveness, post-ictal normality, and precipitated by **hyperventilation** (like blowing a pinwheel). The EEG finding of **3-Hz spike-and-wave discharges** is pathognomonic for CAE.
- **Ethosuximide** is the first-line and most effective treatment for typical absence seizures, operating by blocking **T-type calcium channels** in thalamic neurons.
*Zonisamide*
- Zonisamide is a broad-spectrum antiepileptic drug that can be used for various seizure types, including **focal and generalized convulsive seizures**, but it is not the first-line treatment for typical absence seizures.
- Its mechanism involves blocking **sodium and calcium channels**, and its efficacy in absence seizures is not as well-established as ethosuximide.
*Valproic acid*
- Valproic acid is effective for both **absence seizures and generalized tonic-clonic seizures**, particularly when both types occur.
- However, due to its potential for more significant side effects, including **hepatotoxicity** and **teratogenicity**, it is generally considered a second-line treatment for uncomplicated CAE, especially in young children.
*Lamotrigine*
- Lamotrigine is an antiepileptic drug used for various seizure types, including **focal, generalized tonic-clonic**, and some **absence seizures**, but it is not considered first-line for typical absence seizures.
- It primarily acts by blocking **voltage-gated sodium channels** and can be used as an add-on therapy or for refractory cases.
*Levetiracetam*
- Levetiracetam is a broad-spectrum antiepileptic effective for **focal, myoclonic, and generalized tonic-clonic seizures**.
- While it can be used for absence seizures, it is generally **less effective** than ethosuximide or valproic acid for typical absence seizure control.
Question 163: A 6-year-old boy presents to his primary care physician with hip pain that started this morning. The patient claims the pain is severe and is stopping him from skateboarding. The patient recently recovered from an upper respiratory infection that he caught from his siblings but has otherwise been healthy. The patient has a past medical history of obesity. His temperature is 98.1°F (36.7°C), blood pressure is 100/55 mmHg, pulse is 90/min, respirations are 22/min, and oxygen saturation is 98% on room air. On physical exam, you note an obese boy in no acute distress. Cardiopulmonary exam is within normal limits. Inspection of the hip reveals no abnormalities or swelling. The hip exhibits a normal range of motion and physical exam only elicits minor pain. The patient's gait appears normal and pain is elicited when the patient jumps or runs. Which of the following is the best next step in management for this patient's most likely diagnosis?
A. Ibuprofen and rest (Correct Answer)
B. Radiography
C. CT scan
D. MRI
E. Aspiration and broad spectrum antibiotics
Explanation: ***Ibuprofen and rest***
- This patient's presentation with hip pain after an **upper respiratory infection**, normal physical exam findings except for pain on high-impact activities, and absence of fever, points towards **transient synovitis of the hip**.
- **Treatment for transient synovitis** is supportive, involving anti-inflammatory medications like ibuprofen and rest, as it is a self-limiting condition.
*Radiography*
- While imaging might be considered, **radiographs of the hip** are typically normal in transient synovitis and are primarily used to rule out other more serious conditions like Legg-Calvé-Perthes disease or slipped capital femoral epiphysis, which usually present with more distinct physical exam findings or chronic symptoms.
- Given the acute onset, recent viral illness, and mild exam findings, this is not the immediate next step for the most likely diagnosis.
*CT scan*
- A **CT scan** exposes the patient to radiation and is generally not indicated as a first-line diagnostic tool for transient synovitis due to its low diagnostic yield for this condition and higher cost compared to other modalities.
- It would only be considered if there was a strong suspicion of bony pathology not visible on plain radiographs or if surgery was being contemplated.
*MRI*
- An **MRI** would be highly sensitive for detecting inflammation or effusion in the hip joint, but it is an expensive and time-consuming procedure typically reserved for cases where the diagnosis is unclear or other serious conditions are strongly suspected (e.g., osteomyelitis, avascular necrosis).
- It is not necessary for the initial management of suspected transient synovitis, which is a clinical diagnosis.
*Aspiration and broad spectrum antibiotics*
- **Aspiration of the joint** and treatment with broad-spectrum antibiotics are indicated for **septic arthritis**, which is characterized by fever, significant pain with even gentle passive range of motion, and elevated inflammatory markers.
- This patient is afebrile, has only minor pain on physical exam, and has no systemic signs of infection, making septic arthritis highly unlikely.
Question 164: An asymptomatic 15-year-old high school wrestler with no family history of renal disease is completing his preseason physical exam. He submits a urine sample for a dipstick examination, which tests positive for protein. What is the next appropriate step in management?
A. Renal ultrasound
B. Urine culture
C. Repeat dipstick on a separate occasion (Correct Answer)
D. Spot urine-protein-to-creatinine ratio
E. 24 hour urine collection
Explanation: ***Repeat dipstick on a separate occasion***
- An asymptomatic patient with an isolated positive urine dipstick for protein, especially an active adolescent, often experiences **transient proteinuria** due to factors like exercise or stress.
- Repeating the dipstick on a separate occasion can help differentiate between transient and persistent proteinuria, with **orthostatic (postural) proteinuria** being a common benign cause in this age group.
*Renal ultrasound*
- **Renal ultrasound** is typically indicated for evaluating structural abnormalities of the kidneys, hydronephrosis, or in cases of persistent hematuria, recurrent UTIs, or declining renal function.
- It is not the initial step for isolated, asymptomatic proteinuria without other concerning symptoms.
*Urine culture*
- A **urine culture** is performed to diagnose urinary tract infections (UTIs) when symptoms like dysuria, frequency, or fever are present, or if the dipstick shows signs of infection (nitrites, leukocyte esterase).
- This patient is asymptomatic, and the primary concern is proteinuria, not infection.
*Spot urine-protein-to-creatinine ratio*
- The **spot urine protein-to-creatinine ratio** is used to quantify proteinuria, especially after persistent proteinuria has been established, or to monitor known renal disease.
- Before quantifying, it's crucial to confirm the proteinuria is persistent and not transient.
*24 hour urine collection*
- A **24-hour urine collection** is the gold standard for accurately measuring the total amount of protein excreted in a day.
- However, it is an inconvenient test and typically reserved for quantifying known persistent proteinuria, not as a first step after an initial positive dipstick in an asymptomatic individual.
Question 165: A 4-month-old girl is brought to the physician by her mother because of a 4-day history of vomiting, poor feeding, and more frequent napping. She appears lethargic. Her vital signs are within normal limits. Physical examination shows a bulging, tense anterior fontanelle. Fundoscopic exam shows bilateral retinal hemorrhage. A complete blood count shows a leukocyte count of 8,000/mm3. An x-ray of the chest shows healing fractures of the 4th and 5th left ribs. Which of the following is the most likely cause of the patient's condition?
A. Inherited connective tissue disorder
B. Malnutrition
C. Epidural hematoma
D. Bleeding from the germinal matrix
E. Shearing head injury (Correct Answer)
Explanation: ***Shearing head injury***
- The combination of **bulging fontanelle**, **retinal hemorrhages**, and **multiple healing rib fractures** in an infant is highly suspicious for **abusive head trauma**, also known as shaken baby syndrome.
- **Shearing forces** from rapid acceleration-deceleration cause diffuse axonal injury and tearing of bridging veins, leading to subdural hemorrhage, cerebral edema (manifesting as a bulging fontanelle), and retinal hemorrhages.
*Inherited connective tissue disorder*
- While some connective tissue disorders can lead to bone fragility, they typically do not explain the triad of **retinal hemorrhages**, **bulging fontanelle**, and **healing rib fractures** simultaneously as a primary presentation of acute neurological distress.
- Conditions like **osteogenesis imperfecta** would present with multiple fractures but typically without the acute neurological signs or retinal hemorrhages associated with head trauma.
*Malnutrition*
- Malnutrition would not cause acute signs of **increased intracranial pressure (bulging fontanelle)** or **retinal hemorrhages**.
- While severe malnutrition can weaken bones over time, it does not typically lead to the acute presentation of multiple **healing fractures** along with the specific neurological and ocular findings described.
*Epidural hematoma*
- An epidural hematoma typically results from a **direct impact** causing a skull fracture and tearing of an artery, leading to a space-occupying lesion.
- While it can cause some of the neurological signs (e.g., bulging fontanelle from increased intracranial pressure), it is less likely to produce **bilateral retinal hemorrhages** and **multiple healing rib fractures** as the primary cause of this constellation of findings.
*Bleeding from the germinal matrix*
- **Germinal matrix hemorrhage** primarily occurs in **premature infants** and is a consequence of immature cerebrovascular development.
- It is **rare in full-term, 4-month-old infants** and does not explain the presence of **rib fractures** or the mechanism of injury suggested by the overall clinical picture.
Question 166: A 3-year-old girl is brought to the physician by her mother two days after the sudden onset of a rash. The mother says that the rash developed an hour after she bathed the child in hot water. Two weeks ago, the patient was diagnosed with a skin infection and was treated with penicillin V. She has been otherwise healthy but has missed several well-child examinations. She lives with her single mother, who recently lost her job and is now dependent on social assistance. The patient's mother has major depressive disorder and her maternal aunt has systemic lupus erythematosus. The girl's temperature is 36.8°C (98.2°F), pulse is 112/min, and blood pressure is 108/62 mm Hg. She has poor eye contact. Physical examination shows sharply delineated erythema on the lower extremities up to the umbilicus with sparing of the knees and flexor surfaces. Further evaluation is most likely to reveal which of the following?
A. Dermatographism
B. Multiple injuries in different stages of healing (Correct Answer)
C. Ulcers of the oral mucosa
D. Malar rash with sparing of the nasolabial folds
E. Positive Nikolsky's sign
Explanation: ***Multiple injuries in different stages of healing***
- This scenario strongly suggests **child abuse**. The "rash" described is suspicious; it is a **sharply delineated erythema** on the lower extremities up to the umbilicus with sparing of the knees and flexor surfaces, appearing after a hot bath. This pattern is classic for a **scald injury**, which would be considered abuse if inflicted by hot water.
- The mother's claim of a sudden rash occurring an hour after a hot bath makes a thermal injury more likely, especially given her recent job loss, dependence on social assistance, and major depressive disorder, all of which are **risk factors for child abuse**. The child's poor eye contact also raises concerns.
*Dermatographism*
- **Dermatographism** is a form of urticaria where strokes or pressure on the skin cause raised, red lines.
- This condition presents as transient wheals and would not align with the described **sharply delineated erythema** in a specific distribution, nor would it be triggered only by a hot bath in this manner.
*Ulcers of the oral mucosa*
- **Oral ulcers** are common in various systemic conditions (e.g., aphthous stomatitis, viral infections, lupus) but are not directly suggested by a sudden onset of skin erythema after a hot bath.
- While some forms of abuse might involve oral injury, the described skin rash is not a typical presentation or associated finding that would lead one to specifically look for oral ulcers.
*Malar rash with sparing of the nasolabial folds*
- A **malar rash** (butterfly rash) is characteristic of **systemic lupus erythematosus (SLE)**, which the patient's maternal aunt has. However, this rash typically affects the cheeks and bridge of the nose.
- The patient's rash is described as **sharply delineated erythema** on the lower extremities up to the umbilicus, with sparing of specific areas, which is inconsistent with the distribution and appearance of a malar rash.
*Positive Nikolsky's sign*
- **Nikolsky's sign** involves the epidermal detachment upon light friction, indicative of blistering disorders like **pemphigus vulgaris** or **staphylococcal scalded skin syndrome (SSSS)**.
- While SSSS can cause widespread erythema and skin peeling, the description of **sharply delineated erythema** on specific body parts after a hot bath is more consistent with a thermal injury than the diffuse blistering and epidermal sloughing seen in SSSS.
Question 167: An 8-year old boy is brought to the emergency department because he has been lethargic and has had several episodes of nausea and vomiting for the past day. He has also had increased thirst over the past two months. He has lost 5.4 kg (11.9 lbs) during this time. He is otherwise healthy and has no history of serious illness. His temperature is 37.5 °C (99.5 °F), blood pressure is 95/68 mm Hg, pulse is 110/min, and respirations are 30/min. He is somnolent and slightly confused. His mucous membranes are dry. Laboratory studies show:
Hemoglobin 16.2 g/dL
Leukocyte count 9,500/mm3
Platelet count 380,000/mm3
Serum
Na+ 130 mEq/L
K+ 5.5 mEq/L
Cl- 99 mEq/L
HCO3- 16 mEq/L
Creatinine 1.2 mg/dL
Glucose 570 mg/dL
Ketones positive
Blood gases, arterial
pH 7.25
pCO2 21 mm Hg
Which of the following is the most appropriate next step in management?
A. Intravenous hydration with 0.45% normal saline and insulin
B. Intravenous hydration with 5% dextrose solution and 0.45% normal saline
C. Intravenous sodium bicarbonate
D. Intravenous hydration with 0.9% normal saline and insulin (Correct Answer)
E. Intravenous hydration with 0.9% normal saline and potassium chloride
Explanation: ***Intravenous hydration with 0.9% normal saline and insulin***
- This patient presents with **diabetic ketoacidosis (DKA)**, characterized by hyperglycemia (glucose 570 mg/dL), metabolic acidosis (pH 7.25, HCO3- 16 mEq/L, ketones positive), and dehydration (dry mucous membranes, increased thirst, weight loss).
- Initial management of DKA involves aggressive **volume expansion** with **0.9% normal saline** to restore perfusion and reduce hyperglycemia; subsequently, **insulin infusion** is started to correct hyperglycemia and halt ketogenesis.
*Intravenous hydration with 0.45% normal saline and insulin*
- While insulin is crucial, **0.45% normal saline (hypotonic saline)** is generally not the initial fluid of choice for DKA due to the risk of exacerbating cerebral edema, especially in children.
- **Isotonic saline (0.9% normal saline)** is preferred for initial resuscitation to rapidly restore extracellular fluid volume.
*Intravenous hydration with 5% dextrose solution and 0.45% normal saline*
- **5% dextrose solution** should only be added to intravenous fluids when the blood glucose level falls to around 200-250 mg/dL, to prevent hypoglycemia while continuing insulin to resolve ketosis.
- Administering dextrose initially would worsen the existing severe hyperglycemia.
*Intravenous sodium bicarbonate*
- **Sodium bicarbonate** is generally not recommended for mild to moderate DKA due to potential risks like cerebral edema and metabolic alkalosis, and potential paradoxical worsening of CNS acidosis.
- Bicarbonate therapy is reserved for **severe acidosis (pH < 6.9 or 7.0)** with hemodynamic instability or impaired cardiac contractility, which is not the case here.
*Intravenous hydration with 0.9% normal saline and potassium chloride*
- While **0.9% normal saline** is appropriate, this option lacks **insulin therapy**, which is essential for treating DKA by halting ketogenesis and correcting hyperglycemia.
- Although potassium supplementation will be necessary during DKA treatment (as insulin drives K+ into cells and can cause hypokalemia), the most appropriate **next step** is to initiate both fluid resuscitation and insulin therapy together.
- The patient's current potassium level of 5.5 mEq/L is at the upper limit of normal, but reflects total body potassium depletion; potassium should be added to maintenance fluids once adequate urine output is established.
Question 168: An otherwise healthy 14-year-old girl is brought to the emergency room by her father because of excessive thirst, excessive urination, and weight loss. Her symptoms started acutely 5 days ago. Vital signs reveal a temperature of 36.6°C (97.8°F), blood pressure of 100/65 mm Hg, and pulse of 105/min. Physical examination shows a thin girl with dry mucous membranes but normal skin turgor. Laboratory results are shown:
Random blood sugar 410 mg/dL
C-peptide undetectable
Serum beta-hydroxybutyrate negative
Which of the following is the best initial therapy for this patient?
A. Metformin
B. Glimepiride
C. Pramlintide
D. Basal-bolus insulin (Correct Answer)
E. Intravenous fluids, insulin infusion, and correction of electrolytes
Explanation: ***Basal-bolus insulin***
- This patient presents with **polyuria**, **polydipsia**, **weight loss**, **undetectable C-peptide**, and **severe hyperglycemia (410 mg/dL)**, consistent with **new-onset Type 1 Diabetes Mellitus**.
- Critically, the **beta-hydroxybutyrate is negative**, indicating this patient is **NOT in diabetic ketoacidosis (DKA)**.
- For new-onset Type 1 diabetes without ketoacidosis, the appropriate initial therapy is **subcutaneous basal-bolus insulin** regimen (long-acting basal insulin plus rapid-acting insulin with meals).
- The patient needs rehydration (which can be oral or IV) and insulin initiation, but does not require intensive care with insulin infusion since there is no ketoacidosis.
*Intravenous fluids, insulin infusion, and correction of electrolytes*
- This is the standard management for **diabetic ketoacidosis (DKA)** or **hyperosmolar hyperglycemic state (HHS)**.
- However, this patient has **negative beta-hydroxybutyrate**, ruling out DKA, and therefore does not require insulin infusion.
- Insulin infusion is reserved for critically ill patients with ketoacidosis or severe metabolic derangements requiring intensive monitoring.
*Metformin*
- **Metformin** is an oral hypoglycemic agent used primarily for **Type 2 Diabetes Mellitus**.
- It works by reducing hepatic glucose production and improving insulin sensitivity, but is not effective in Type 1 diabetes with absolute insulin deficiency.
- The **undetectable C-peptide** confirms this patient has no endogenous insulin production and requires exogenous insulin.
*Glimepiride*
- **Glimepiride** is a **sulfonylurea** that stimulates insulin release from pancreatic beta cells.
- It would not be effective in this patient due to **undetectable C-peptide**, indicating minimal to no functional beta cells.
- This medication is used in Type 2 diabetes, not Type 1 diabetes.
*Pramlintide*
- **Pramlintide** is an **amylin analog** used as adjunctive therapy in Type 1 and Type 2 diabetes to slow gastric emptying and suppress glucagon secretion.
- It is not a primary treatment for diabetes and would not address the fundamental issue of insulin deficiency.
- It must be used in conjunction with insulin therapy and is not appropriate as initial monotherapy.
Question 169: A 3-year-old boy is brought to the physician for evaluation of developmental delay. He could sit alone at 12 months and started walking with support at the age of 2 years. He can name only very few familiar objects and uses simple two-word sentences. He cannot stack more than 2 blocks. His parents report that he does not like playing with other children. He is at the 80th percentile for head circumference, 85th percentile for height, and 50th percentile for weight. He has a long and narrow face as well as large protruding ears. His thumbs can be passively flexed to the ipsilateral forearm. This patient is at increased risk of developing which of the following conditions?
A. Mitral regurgitation (Correct Answer)
B. Type 2 diabetes mellitus
C. Acute myeloid leukemia
D. Aortic dissection
E. Hyperuricemia
Explanation: ***Mitral regurgitation***
- The patient's presentation with **developmental delay**, **relatively large head circumference** (80th percentile), **long narrow face**, **large protruding ears**, and **hyperextensible joints** (thumbs to forearm) is highly suggestive of **fragile X syndrome**.
- **Mitral valve prolapse** leading to **mitral regurgitation** is a common cardiac manifestation of fragile X syndrome, occurring in **50-80% of adult males** with the condition, due to **connective tissue dysplasia**.
*Type 2 diabetes mellitus*
- This condition is primarily associated with **obesity**, **insulin resistance**, and genetic predispositions unrelated to the features presented in this patient.
- While fragile X patients may have general health concerns, there is **no specific increased risk** of developing type 2 diabetes mellitus directly linked to the syndrome's pathology.
*Acute myeloid leukemia*
- There is **no established association** between fragile X syndrome and an increased risk of developing **acute myeloid leukemia**.
- AML is a **hematologic malignancy** with different risk factors, such as exposure to certain chemicals or prior chemotherapy.
*Aortic dissection*
- Aortic dissection is typically associated with conditions affecting **connective tissue** like **Marfan syndrome** or **Ehlers-Danlos syndrome**, or with **hypertension**.
- While fragile X syndrome involves connective tissue abnormalities, **aortic dissection is not a typical or significantly increased risk** compared to other connective tissue disorders.
*Hyperuricemia*
- **Hyperuricemia** is most commonly associated with conditions like **gout**, **kidney disease**, or certain **genetic metabolic disorders** (e.g., Lesch-Nyhan syndrome).
- There is **no direct link** between fragile X syndrome and an increased risk of hyperuricemia.
Question 170: A previously healthy 14-year-old girl is brought to the emergency department by her mother because of abdominal pain, nausea, and vomiting for 6 hours. Over the past 6 weeks, she has also had increased frequency of urination, and she has been drinking more water than usual. She has lost 6 kg (13 lb) over the same time period despite having a good appetite. Her temperature is 37.1°C (98.8°F), pulse is 125/min, respirations are 32/min, and blood pressure is 94/58 mm Hg. She appears lethargic. Physical examination shows deep and labored breathing and dry mucous membranes. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Urine dipstick is positive for ketones and glucose. Further evaluation is most likely to show which of the following findings?
A. Excess water retention
B. Serum glucose concentration > 800 mg/dL
C. Increased arterial pCO2
D. Increased arterial blood pH
E. Decreased total body potassium (Correct Answer)
Explanation: ***Decreased total body potassium***
- This is the correct answer. In **diabetic ketoacidosis (DKA)**, patients have **significant total body potassium depletion** due to osmotic diuresis and urinary losses.
- **Serum potassium may initially appear normal or even elevated** due to acidosis-induced extracellular shift of potassium from cells.
- However, **total body potassium stores are markedly depleted**, and during treatment with insulin and fluids, severe hypokalemia can develop as potassium shifts back intracellularly.
*Excess water retention*
- The patient's symptoms, including **polydipsia**, **polyuria**, and **dry mucous membranes**, indicate **dehydration**, not excessive water retention.
- Her blood pressure of 94/58 mm Hg also suggests **volume depletion**.
*Serum glucose concentration > 800 mg/dL*
- While the patient has significant hyperglycemia (indicated by glucose in urine), **DKA** typically presents with glucose levels between **250-600 mg/dL**.
- Glucose levels >800 mg/dL are more characteristic of **hyperosmolar hyperglycemic state (HHS)**, which is less common in children and usually lacks significant ketosis.
*Increased arterial pCO2*
- The patient exhibits **Kussmaul respirations** (deep and labored breathing) and an increased respiratory rate (32/min), which are compensatory mechanisms for **metabolic acidosis**.
- This compensation leads to **decreased arterial pCO2** as the body tries to blow off CO2 to raise pH.
*Increased arterial blood pH*
- The symptoms, particularly **Kussmaul respirations** and the presence of **ketones** in the urine, strongly suggest **diabetic ketoacidosis (DKA)**.
- DKA is characterized by **severe metabolic acidosis**, meaning the arterial blood pH would be **decreased**, not increased.