Correct Answer: E Section: (none)

Explanation:

Asymptomatic microscopic hematuria is defined by the American Urological Association as three or more RBCs per high power field on urinary sediment from two out of three properly collected urinalyses. A proper sample can be a midstream clean-catch specimen. The urine dipstick is roughly 91100% sensitive and 6599% specific for detection of RBCs, Hgb, and myoglobin. Urine dipstick is not reliable in distinguishing myoglobin from Hgb or RBCs. Therefore, urinalysis with microscopy should be ordered to assess the number of RBCs per high power field. Microscopic hematuria is usually an incidental finding but deserves a thorough workup, as 10% can be due to malignancy. The initial approach is to repeat the urinalysis to rule out infection. If the urinalysis suggests infection by the presence of WBCs or nitrites, a culture should be ordered and the patient treated appropriately. If RBCs are present without any leukocytes, nitrites, or epithelial cells on the repeated urinalysis, a proper workup should ensue. After history and physical are done to rule out risk factors, comorbidities, or other etiologies to account for the hematuria, one must look to diagnostic tests. A serum creatinine is useful to assess for renal insufficiency. During the course of the workup, if the urinalysis and serum creatinine suggest a glomerular etiology (casts, elevated creatinine, dysmorphic RBCs) a renal consultation and possible renal biopsy may be warranted. Evaluation of the upper tract with either an IVP or CT scan of the abdomen/pelvis with and without contrast should be ordered to rule out renal cell carcinoma, nephrolithiasis, or aneurysms. Next, the lower tract should be visualized by cystoscopy and washings sent for cytology. If all the above workup is negative, the patient can be reassured and followed with a repeat urinalysis in 6 months.

Correct Answer: D Section: (none)

Explanation:

The patient has hypotonic hyponatremia, which can lead to increased water shifting into the brain, resulting in cerebral edema. This patient has nothing in history or physical examination to suggest a stroke or the presence of sepsis as the etiology of his altered mental status. Central pontine myelinolysis is a potentially devastating neurologic complication that can result from the treatment of hyponatremia, not hyponatremia itself. While respiratory acidosis could potentially contribute to this patient's change in mental status, cerebral edema due to hypotonicity is the most likely etiology. The patient's laboratory studies indicate a low plasma osmolality with an inappropriately increased urine osmolality. With this degree of hypotonicity, the urine should be maximally dilute (osmolality of <100 mOsmol/kg H2O). The high urine osmolality suggests the presence of antidiuretic hormone. In psychogenic polydipsia, the urine would be maximally dilute. Choice C is unlikely since his physical examination does not suggest volume depletion; furthermore, the patient is taking a calcium channel blocker, not a diuretic, for the treatment of his hypertension. Decreased expression of renal collecting duct water channels would lead to water wasting and, thus, the development of diabetes insipidus and hypernatremia. The patient has symptomatic hypotonic hyponatremia with signs of cerebral edema.

This requires immediate attention. Choices A, C, and E are essentially hypotonic solutions which should be withheld in patients with hyponatremia. The serum sodium in this case should be increased by at least 5% for the treatment of cerebral edema. The use of 0.9% saline would require nearly 5 L of infusate to address this cerebral edema. This could lead to pulmonary edema and volume overload. The use of hypertonic saline (3% saline) is the ideal solution to use in this scenario, as the infusion of 3% saline will correct the symptoms while avoiding volume overload. As in all cases of hyponatremia management, frequent serum sodium assays are necessary in order to avoid too rapid of a correction, which could result in neurologic injury--pontine myelinolysis.

Correct Answer: C Section: (none)

Explanation:

Iron-deficiency anemia (IDA) is characterized by a low MCV, low ferritin, and a high erythrocyte protoporphyrin in serum. Microcytosis and hypochromia are the hallmark in the peripheral smear. Elevated erythrocyte protoporphyrin in serum can also be seen in anemia of chronic disease and chronic lead poisoning. The USPSTF recommends screening pregnant women for IDA, but found insufficient evidence to recommend for or against routine screening in other asymptomatic persons. However, the guidelines did recommend routine iron supplementation in asymptomatic infants 612 months of age who are at high risk of IDA. Infants are considered to be at high risk if they are living in poverty; are Black, Native American, or Alaskan Native; are immigrants from a developing country; are preterm or low birth weight; or if their primary dietary intake is unfortified cow's milk. The most common cause of cobalamin deficiency is pernicious anemia. Rarely, hypersecretion of gastric acid (i.e., Zollinger-Ellison syndrome) results in cobalamin deficiency. The peripheral smears in folate and cobalamin deficiency are indistinguishable, showing macrocytosis and hypersegmented neutrophils. Both methylmalonic acid and homocysteine levels become elevated with cobalamin deficiency. Folate deficiency is caused by decreased intake, increased utilization, or impaired absorption. Because body stores of folate are low, persons who have an inadequate consumption will become anemic in several months. The recommended amount of dietary folate is 400 g/day. Anemia is not a diagnosis in itself; it is an objective sign of the presence of a disease. It is always secondary to an underlying condition. In most cases, a thorough history and physical examination can help elicit the pathogenesis of the anemia and direct appropriate treatment.

Correct Answer: B Section: (none)

Explanation: Contraction of hollow organs against obstruction or excessive contraction causes colic. Typical ureteral colic is severe, sudden in onset, radiates from the loin to the groin, and is associated with an urge to urinate. Blood clots and calculi in the ureter can cause colic, the latter being more common. Urine examination demonstrates macroscopic or microscopic hematuria

Correct Answer: A Section: (none)

Explanation:

The child's mother demonstrates factitious disorder by proxy, categorized by a parent or caretaker intentionally inducing an illness in someone under their care. Confronting the mother in the emergency room setting would likely lead to defensiveness, denial, and anger. The mother could possibly leave abruptly with the child. Having a psychiatrist present in this situation may also create a similar result. While a referral to urology and treatment of the infection may be indicated and appropriate, it does not address the immediate concern, which is the mother's abuse of her son. As factitious disorder by proxy is considered a form of child abuse, the physician has the legal obligation to notify child protective services. Admitting the boy to the hospital will both enable treatment of his medical illness and provide time for the proper authorities to intervene if necessary. The conscious production of symptoms for secondary gain (e.g., avoidance of work, school, jail, military service) is the rationale behind malingering. Although the mother's apparent concern for her child may appear expectable, her elaborate methods of abusing her son demonstrate significant pathology. The unconscious production of symptoms or signs due to unconscious conflict is the classic drive in conversion disorder. The motivation for factitious disorder is believed to be the purposeful production of an illness in order to assume the sick role (DSM IV-TR).