6. A 65-year-old diabetic male with a creatinine of 1.6 was started on an angiotensin-converting enzyme inhibitor for hypertension and presents to the emergency room with weakness. His other medications include a statin for hypercholesterolemia, a beta blocker and spironolactone for congestive heart failure, insulin for diabetes, and aspirin.
Laboratory examinations include:
• K: 7.2 meq/L
• Creatinine: 1.8
• Glucose: 400 mg/dL
• CPK: 400 IU/L
1. A 60-year-old male is brought in by ambulance and is unable to speak. The EMS personnel tell you that a neighbor informed them he has had a stroke in the past. There are no family members present. His serum sodium is 118 meq/L. Which of the following is the most helpful first step in the assessment of this patient’s hyponatremia?
1. The answer is c. (See Harrison's Chapter 46). The first step in the clinical assessment if hyponatremia is a thorough history and physical exam, including the assessment of extracellular fluid status. Increased ECF in the setting of hyponatremia may be due to heart failure, hepatic cirrhosis, nephrotic syndrome, or renal insufficiency. A normal ECF in the same setting would indicate a disorder such as SIADH, whereas a decreased ECF would lead to a determination of urine Na concentration to further determine whether the hyponatremia was due to extrarenal versus intrarenal sodium loss.
Determination of plasma osmolality is helpful in the setting of hyponatremia. Most patients with hyponatremia will present with a low plasma osmolality. A high plasma osmolality indicates disorders such as hyper-glycemia and a normal plasma osmolality can indicate disorders such as hyperproteinemia and hyperlipidemia. In a clinical setting such as this, determination of ECF status as you are performing the physical exam (history would be limited due to patient’s inability to communicate) would be most appropriate. You would not wait for the plasma osmolality before beginning assessment and development of an initial differential diagnosis. Helpful laboratory assessment in the face of hyponatremia includes plasma osmolality, urine osmolality, and urine K and Na concentration.
2. A 65-year-old man presents with painless hematuria. He has a 45-year history of tobacco use. He denies fever, chills, and dysuria. General physical exam is unremarkable. On rectal exam, the prostate is small, nonnodular, and nontender. A urinalysis shows 100 red blood cells per high-power field. No white cells or protein are present. Three months previously, the patient had an abdominal ultrasound for right upper quadrant pain; on review, both kidneys were normal. Which of the following is the most useful diagnostic test at this time?
2. The answer is d. (See Harrison's Chapter 45 and Chapter 90). Unexplained gross hematuria requires evaluation. Patients who have gross hematuria in association with clear-cut urinary tract infection are usually treated and followed with a repeat urinalysis to confirm clearing of the RBCs, but this patient has no symptoms of urinary tract infection. Although benign causes (prostatitis, renal stones) are most common, as many as 15% of patients with gross hematuria will have bladder cancer. Cigarette smoking increases the risk of bladder cancer two-to fourfold. Exposure to aniline dyes, chronic cyclophosphamide treatment, external beam radiation, and Schistosoma infection of the bladder are other risk factors. This patient should be referred to a urologist for cystoscopy to rule out transitional cell carcinoma of the bladder. If no lesion is found, CT scanning of the kidneys would be indicated despite the previous negative sonogram.
3. A 40-year-old woman complains of headache associated with visual disturbance. Which of the following histories suggests migraine headache as a likely diagnosis?
3. The answer is A. (See Harrison's Chapter 15). The differential diagnosis of headaches associated with neurological or visual dysfunction is important because it encompasses a variety of disorders, some quite serious and others relatively benign. Classic (or neurological) migraine is generally a familial disorder that begins in childhood or early adult life. Typically, the onset of an episode is marked by the progression of a neurological disturbance over 5 to 15 min, followed by a unilateral (or occasionally bilateral) throbbing headache for several hours up to a day. The most common neurological disturbance involves formed or unformed flashes of light that impair vision in one of the visual fields (scintillating scotoma). Other possible neurological symptoms include numbness and tingling of the unilat¬eral face, lips, and hand; weakness of an arm or leg; mild aphasia; and mental confusion. The transience of the neurological symptoms distinguishes migraine from other, more serious conditions that cause headaches. Persistence of a visual field defect, speech disturbance, or mild hemiparesis suggests a focal lesion (e.g., arteriovenous malformation with hemorrhage or infarct). In the case of persistent ataxia, limb incoordination, and nausea, one should consider a posterior fossa (possibly cerebellar) mass lesion. Monocular visual loss in an elderly patient with throbbing headaches should initiate a search for cranial (temporal) arteritis. This should include a sedimentation rate (usually elevated) and a temporal artery biopsy (which would show a giant cell arteritis). Fifty percent of these patients have the generalized muscle aches seen with polymyalgia rheumatica. Unilateral orbital or retroorbital headaches that occur nightly for a period of 2 to 8 weeks are characteristic of cluster headaches. These headaches are often associated with ipsilateral injection of the conjunctivum, nasal stuffiness, rhinorrhea, and, less commonly, miosis, ptosis, and cheek edema. Although both migraine and cluster headaches may respond to treatment with ergotamine, they are generally considered to be distinct entities.
4. A 30-year-old male patient complains of fever and sore throat for several days. The patient presents to you today with additional complaints of hoarseness, difficulty breathing, and drooling. On examination, the patient is febrile and has inspiratory stridor. Which of the following is the best course of action?
5. The answer is c. (See Harrison's Chapter 31.) This patient, with the development of hoarseness, breathing difficulty, and stridor, is likely to have acute epiglottitis. Because of the possibility of impending airway obstruction, the patient should be admitted to an intensive care unit for close monitoring. The diagnosis can be confirmed by indirect laryngoscopy or soft tissue x-rays of the neck, which may show an enlarged epiglottis. Otolaryngology consult should be obtained. The most likely organism causing this infection is Haemophilus influenzae. Many of these organisms are ?-lactamase-producing and would be resistant to ampicillin. The clinical findings are not consistent with the presentation of streptococcal pharyngitis. Lateral neck films would be more useful than a chest x-ray. Classic findings on lateral neck films would be the thumbprint sign.
Questions are from Pre-Test Medicine, 11E
