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Ultimate Board Review 1

Terms in this set (2000)

B) Placenta previa

Painless third-trimester bleeding was a common presentation for placenta previa in the past; however, now most cases of placenta previa are detected antenatally with ultrasound before the onset of significant bleeding. This patient has had no prenatal care and is at increased risk for complications. Placenta previa is characterized by placental tissue that overlies or is adjacent to the cervical os. Placenta previa typically presents as painless vaginal bleeding in the second or third trimester. Between 70% and 80% of patients with placenta previa will have at least one bleeding episode. Patients at risk of placenta previa include increasing parity or maternal age, cigarette smoking, and prior uterine surgery. About 10% to 20% of patients present with uterine contractions before bleeding, and fewer than 10% remain asymptomatic. Of patients with bleeding, one third will present before 30 weeks' gestation, one third between 30 and 36 weeks' gestation, and one third after 36 weeks' gestation. Patients with early-onset bleeding (<30 weeks' gestation) have the greatest risk for blood transfusion and associated perinatal morbidity and mortality. The bleeding is believed to occur from disruption of placental blood vessels in association with the development and thinning of the lower uterine segment. Patients with placenta previa who present preterm with vaginal bleeding require hospitalization and immediate evaluation to assess maternal-fetal stability. In at least 50% of women who present with asymptomatic previa, delivery can be delayed for more than 4 weeks, including patients with initial bleeding episodes greater than 500 mL.
A) Consult Obstetrics and Gynecology

Ectopic pregnancy is a life-threatening illness that must be considered in all women of childbearing age who present with abdominal pain, pelvic pain, abnormal vaginal bleeding, amenorrhea, or evidence of unexplained hypovolemia. Until pregnancy is ruled out or a uterine pregnancy is confirmed, ectopic pregnancy should remain high on the differential. An ectopic pregnancy is any pregnancy that implants outside of the uterine cavity. The vast majority of ectopic implantations occur in the fallopian tubes, although abdominal, cervical, and cesarean scar pregnancies can occur. Diagnosis is confirmed by a positive hCG test (either urine or serum) and evidence of implantation outside the uterus (either by ultrasound, laparoscopically or surgically). A positive pregnancy test with an unknown location of implantation does not confirm the diagnosis, but whenever an intrauterine pregnancy cannot be confirmed, ectopic implantation should be considered. Due to the life-threatening nature of the illness, any hypotensive patient with strong suspicion for an ectopic pregnancy warrants an emergent consult to Obstetrics and Gynecology for possible operative management.

Although obtaining a complete blood count (B), serum human chorionic gonadotropin levels (C), and a pelvic ultrasound (D) can aid in the diagnosis of ectopic pregnancy, in an unstable patient with high suspicion for ectopic pregnancy, these diagnostic tests should not delay mobilization of resources that can provide definitive care.
A 35-year-old man is admitted to the hospital with progressive shortness of breath, fever, and worsening cough. The patient had been in good health until 2 months ago, when he began losing weight. This was associated with anorexia, intermittent diarrhea, night sweats, and then a nonproductive cough. He had lost more than 20 pounds by the time he was admitted to the hospital. His past medical history is unremarkable. He has been divorced for 5 years, and he has 1 child. He is employed as a medical equipment salesman, traveling extensively in the Midwest. He admits to drinking alcohol in large amounts on weekends, but he denies tobacco and intravenous drug use. He gives history of a previous homosexual encounter. Physical examination shows that the chest was normal to percussion and clear by auscultation, except for a few scattered ronchi. The heart is normal except for tachycardia. The abdomen is soft with normal bowel sounds. Genitalia are normal; however, there is a painful 2 cm ulceration at the anal verge. The neurologic exam is unremarkable. Chest radiological findings show diffuse bilateral interstitial infiltrates. Arterial blood gases on room air show pO2- 57mmHg, pCO2 31 mmHg, and pH 7.45. His alveolar-arterial O2 gradient is 55mmHg. Bronchoalveolar lavage fluid with lung biopsy shows the presence of cysts. Sputum cytology is negative for acid-fast bacilli. What is the most likely diagnosis?

A) AIDS-related tuberculosis
B) Secondary syphilis
C) Pneumocystis pneumonia
D) Lung cancer
E) Legionella pneumonia
A 35-year-old man is admitted to the hospital with progressive shortness of breath, fever, and worsening cough. The patient had been in good health until 2 months ago, when he began losing weight. This was associated with anorexia, intermittent diarrhea, night sweats, and then a nonproductive cough. He had lost more than 20 pounds by the time he was admitted to the hospital. His past medical history is unremarkable. He has been divorced for 5 years, and he has 1 child. He is employed as a medical equipment salesman, traveling extensively in the Midwest. He admits to drinking alcohol in large amounts on weekends, but he denies tobacco and intravenous drug use. He gives history of a previous homosexual encounter. Physical examination shows that the chest was normal to percussion and clear by auscultation, except for a few scattered ronchi. The heart is normal except for tachycardia. The abdomen is soft with normal bowel sounds. Genitalia are normal; however, there is a painful 2 cm ulceration at the anal verge. The neurologic exam is unremarkable. Chest radiological findings show diffuse bilateral interstitial infiltrates. Arterial blood gases on room air show pO2- 57mmHg, pCO2 31 mmHg, and pH 7.45. His alveolar-arterial O2 gradient is 55mmHg. Bronchoalveolar lavage fluid with lung biopsy shows the presence of cysts. Sputum cytology is negative for acid-fast bacilli. What is the most likely diagnosis?

A) AIDS-related tuberculosis
B) Secondary syphilis
C) Pneumocystis pneumonia
D) Lung cancer
E) Legionella pneumonia
E) Ethambutol

his patient has all the complaints and symptoms of pulmonary tuberculosis (TB). Direct sputum examination by Ziehl-Nielsen stain also helps the diagnosis, but it is still not confirmatory. Sputum needs to be cultured to check what kind of mycobacterium is causing this disease. It is important to start the treatment as soon as the culture is sent. The standard treatment for adult respiratory/pulmonary TB includes a complete 6-month regimen comprising of 2 months initial phase with 4 drugs, which include rifampin, isoniazid, pyrazinamide, and ethambutol. This is followed by a 4-month continuation phase consisting of 2 drugs: rifampin and isoniazid. Irrespective of the bacteriological status of the sputum, this is the recommended standard treatment for respiratory tuberculosis (including isolated pleural effusion or mediastinal lymphadenopathy). The 4th drug, ethambutol, may be omitted in patients with a low risk of resistance to isoniazid. Ethambutol should be started in individuals who are known or suspected to be HIV positive, in those who have had previous treatment, and in immigrants and refugees of any ethnic group who are considered to have a significantly higher risk of resistance to isoniazid and other drugs. Like most medications, antituberculosis drugs also have some side effects. Since treatment is long-term, it is essential that patients are warned about and checked for side effects. If side effects are not explained well to the patient, it will decrease the compliance. The adverse effect of ethambutol is retrobulbar neuritis. The important side effects of anti-tubercular drugs are: INH: Hepatotoxicity, peripheral neuritis, cutaneous hypersensitivity, rarely can cause optic neuritis RMP: Hepatotoxicity, nephrotoxicity, red discoloration of the body fluids, 'Flu-syndrome,' and thrombocytopenic purpura PZA: Hepatotoxicity, hyperuricemia ETH: Retrobulbar neuritis STM: Nephrotoxicity, ototoxicity
C) Lisinopril

Lisinopril, an ACE Inhibitor, should help decrease albuminuria, prevent progression of diabetic kidney disease from micro to macroalbuminuria, and prevent a decline in glomerular filtration rate. This class of medications has been studied extensively for these purposes. Angiotensin II receptor blockers (e.g., irbesartan) may also reduce urinary albumin to normal levels. Monotherapy with either of these classes of medications should be attempted first in patients with microalbuminuria. This will test tolerance, effectiveness, and adverse reaction such as hyperkalemia. For patients with greater degrees of albuminuria (e.g., 1 g/day), poor response to monotherapy and blood pressure control, and no hyperkalemia associated with therapy, combination therapy should be considered. Combination therapy with both ACE inhibitors (e.g., lisinopril) and angiotensin II receptor blockers (e.g., irbesartan) is used to treat both diabetic and non-diabetic kidney disease. These medications act on different parts of the renin angiotensin system. In combination, irbesartan could block the effect of angiotensin produced by non-ACE pathways and lisinopril could block the production of angiotensin stimulated by irbesartan in a negative feedback system; however, combination therapy is usually preceded by monotherapy. Although combination therapy is currently being used in both diabetic and non-diabetic kidney disease, this therapy still being researched. It is unknown whether monotherapy alone is sufficient. It does not appear to be sufficient in all patients, particularly those with persistent micro and macroalbuminuria despite monotherapy.
B) If the fluid has a protein concentration below 3 g/dL

After the diagnosis of ascites is made by physical examination, all patients with new-onset ascites should undergo abdominal paracentesis and ascitic fluid analysis. The most important tests to order for fluid analysis include protein concentration and cell count. Fluids with protein concentration above 3 g/dL are designated as exudates. Those with values below 3 g/dL are designated as transudates. Diseases usually associated with transudates include congestive heart failure, cirrhosis, constrictive pericarditis, inferior vena cava obstruction, hypoalbuminemia, Meigs syndrome, and some cases of nephrotic syndrome. The amount of albumin in the ascitic fluid compared to the serum albumin (the Serum Ascites Albumin Gradient, SAAG) can be indicative of the cause of ascites. Ascites related to hypertension, cirrhosis, or congestive heart failure generally shows a SAAG greater than 1.1 g/dL. Exudates are more commonly seen with peritoneal neoplasm, pancreatic ascites, myxedema, and tuberculous peritonitis. A large number of red blood cells in the fluid or grossly bloody ascites suggests a diagnosis of neoplasm. An acidic fluid and leukocyte count of more than 500/mm3 strongly suggests a peritoneal infection or inflammatory process. Other tests that should be ordered in the appropriate clinical setting include cytologic examination, lactic dehydrogenase (LDH), specific tumor markers, glucose, and cultures for bacteria, mycobacteria, and fungi.
B) Secondary hyperparathyroidism

This patient has stage 3 kidney disease, based on her glomerular filtration rate of 60 ml/min/1.73 m2 and her proteinuria. It is also likely that she has hyperparathyroidism. Disorders of calcium and phosphorus balance are common in kidney disease and should be evaluated starting early in the course of disease to prevent complications. Vitamin D levels, calcium and phosphorus levels, and parathyroid hormone levels (PTH) should be checked in all patients with stages 3 - 5 chronic kidney disease. Decreasing glomerular filtration rates lead to phosphorus retention. Decreased renal synthesis of hydroxylated vitamin D leads to decreased intestinal calcium reabsorption and hypocalcemia. Together, hyperphosphatemia, hypocalcemia, and hypovitaminosis D lead to hyperparathyroidism. Vitamin D usually suppresses PTH synthesis and secretion. Vitamin D deficiency removes this negative feedback, leading to hyperparathyroidism. Correction of calcium-phosphate balance is important; when it is abnormal, it can lead to vascular and valvular calcification and increased risk of cardiac death. Her phosphorus level is elevated, not low. Goal levels for patients with stages 3 and 4 kidney disease are 2.7 - 4.6 mg/dl. Her calcium level is low, not elevated. Her corrected level should be >8 mg/dl. Her PTH level is 150. Patients with stage 3 should have levels in the 35-70 pg/ml range (Brenner, ch. 52), according to National Kidney Foundation guidelines. No mention is made of Vitamin A levels in this vignette. Her vitamin D levels are low, which is consistent with impaired hydroxylation of the vitamin D compound by her kidneys. Patients with levels <30 ng/dl should be supplemented with ergocalciferol. Hypervitaminosis D (Vitamin D intoxication) occurs in the accidental or intentional intake of vitamin D or vitamin D compounds including vitamin D, vitamin D fortified milk, etc. High levels of vitamin D would be noted in this case. Additionally, since Vitamin D suppresses PTH, low levels of PTH would be noted. Vitamin D causes increased gastrointestinal calcium absorption and increased serum calcium levels. Symptoms are those of hypercalcemia (bone and abdominal pain, weakness, confusion, and possibly hematuria/flank pain/poor urine flow if renal stones develop). Treatment involves promoting kaliuresis (excreting potassium in the urine.) with volume expansion and possibly loop diuretics and steroids.
D) Observation only for pseudocyst

A pseudocyst is formed when pancreatic fluid leaks and is confined by organs adjacent to the pancreas. Eventually, a fibrous wall forms around the collection. Most cysts regress spontaneously over a period of several weeks, but in some cases complications such as bleeding, abscess formation, and intractable pain may occur. Several interventional approaches — surgical, radiologic and endoscopic — have been tried. Endoscopic ultrasound has gained popularity in the management of pseudocysts, as it can identify complex cyst wall structures, in particular pseudoaneurysms, do fine-needle aspiration to rule out a neoplasm, and find a favorable spot for drainage. Ruling out a cystic pancreas neoplasm before endoscopic drainage is essential, as attempts at transgastric emptying of a neoplasm can have disastrous effects and compromise further surgical management of the neoplasia. Indications for intervention are intractable pain, expanding lesions, and infection. A frequently quoted study found that complications such as bleeding, abscess formation, or perforation rose sharply after 6 weeks of observation, and that intervention is warranted if a pseudocyst does not resolve in this period. However, more recent studies have challenged this assumption and proposed that observing asymptomatic pseudocysts for longer periods is safe. Pseudoaneurysms are found in 10% of pseudocysts. Signs suggesting a pseudoaneurysm include overt bleeding, sudden pseudocyst enlargement, and an abrupt fall in hematocrit. Their presence is a concern when drainage is considered and does not lead to a higher overall bleeding rate or constitute indication for intervention. Angiography has higher sensitivity and can perform therapeutics, but an angio-CT scan has adequate sensitivity for ruling out a pseudoaneurysm before proceeding with therapeutics. When intervention is warranted, angiographic coil embolization and operative resection can be performed.
B) Full colonoscopy

Iron-deficiency anemia in an adult should prompt for evaluation of a gastrointestinal source of bleeding. This is especially important because a malignant etiology, particularly colorectal cancer, is possible. The signs and symptoms of colon cancer vary according to the tumor's site in the colon. Distal tumors are more frequently associated with hematochezia and obstruction, while proximal neoplasia tends to produce more chronic obstruction with proximal dilatation, intermittent bleeding with iron-deficiency anemia, and a palpable mass. Recurrent infarctions lead to intermittent luminal obstruction and episodic diarrhea. Some lesions grow to a considerable size before diagnosis. In this patient, the diagnostic technique with the highest yield is full colonoscopy. It permits visualization of the whole colon; it also permits performing a biopsy for histopathologic confirmation of the diagnosis. In selected cases, colonoscopic dilatation or stent placement can alleviate obstruction before surgery is performed. Some authorities recommend routine upper endoscopy while investigating lower gastrointestinal bleeding. In some series, upper endoscopy revealed a missed bleeding source in as many as 10% of patients, and altered management in nearly 50% cases. A fecal occult blood test (FOBT) is redundant, given the presence of active bleeding and the overt signs of iron-deficiency anemia. FOBT is useful in colon cancer screening, despite its high false-positive rates (e.g., from non-cancer bleeding or foods reactive with the test reagent). Another caveat is that cancers may bleed intermittently, thereby yielding a false-negative result on a random FOBT. Barium enema is less sensitive than colonoscopy and is unable to perform biopsy. Despite these disadvantages, some authorities recommend its use for colon cancer screening.
B) Pantroprazole, amoxicillin, and clarithromycin twice daily for 2 weeks

There are several regimens recommended for H. pylori infection, which is an important cause of peptic ulcer disease and should be treated if found associated with symptoms. The choice of the regimen depends on considerations such as cost, side effects, and ease of administration. Allergy to one of the medications, as well as intolerance, should also be taken into account. Any proton pump inhibitor (PPI) with amoxicillin 1000 mg twice daily and clarithromycin 500 mg twice daily for 2 weeks or PPI with metronidazole 500mg twice daily and clarithromycin 500mg twice daily for 2 weeks are recommended. These are the triple drug therapies available. The other regimens suggested are bismuth, metronidazole, and tetracycline 4 times daily for 2 weeks along with PPI twice daily for 2 weeks or H2 receptor antagonist twice daily for 4 weeks (quadruple drug therapy). Dual therapy with a proton pump inhibitor and an antibiotic (amoxicillin or clarithromycin) is not recommended as primary therapy, since eradication rates are much lower than the above regimens. The most common side effect is a metallic taste in the mouth due to clarithromycin or metronidazole. Amoxicillin can cause diarrhea or a rash. Clarithromycin can also cause nausea, vomiting, abdominal pain, and (rarely) QT prolongation. Metronidazole can cause peripheral neuropathy, seizures, and a disulfiram-like reaction when taken with alcohol. Tetracycline is teratogenic and causes photosensitivity.
E) Carboxyhemoglobin level

The family has CO poisoning. Carboxyhemoglobin is formed when inhaled CO binds to hemoglobin after being absorbed into the bloodstream. CO has an affinity for hemoglobin that is 250 times that of oxygen. Both oxygen transport and delivery to tissues are reduced as carboxyhemoglobin interferes with the dissociation of oxygen that should be provided until symptoms resolve and carboxyhemoglobin levels decrease to 5% or less. Delivery of 100% oxygen reduces the elimination half-life of CO to 1 hour from 4-5 hours.

Hint: Hemoglobin level gives no indication of how much is bound to oxygen versus how much may be bound to CO. Thus, a hemoglobin level may be normal, and yet most of it may be bound to CO as carboxyhemoglobin

Hint: Pulse oximetry that measures oxygen saturation is falsely normal because oxyhemoglobin and carboxyhemoglobin cannot be differentiated. Pulse oximeters use 2 light emitting diodes (a red one and an infrared light). Oxygenated hemoglobin absorbs infrared light and nonoxygenated hemoglobin absorbs red light. The pulse oximeter determines the relative absorption of each and gives the percentage of oxygenated versus nonoxygenated hemoglobin present. With significant carboxyhemoglobinemia, the oximeter will reflect only the oxygen saturation of normal hemoglobin and not the percentage of hemoglobin bound to carbon monoxide.

Hint: Blood gas analysis may show metabolic acidosis with a normal arterial oxygen tension (PaO2) as measurement of dissolved oxygen, and it can overestimate the true oxygen saturation of hemoglobin.

Hint: Urinalysis may show myoglobinuria due to eventual muscle necrosis as CO binds to myoglobin, decreasing its oxygen-carrying capacity.
C) CT scan of the sinuses

This patient is suffering from chronic sinusitis. Repeated regimens of different antibiotics have not provided him relief, and now he fits the criteria for chronic sinusitis, including 12 weeks of symptoms. Chronic sinusitis is most commonly caused by streptococcus pneumoniae, Haemophilus influenzae, and moraxella catarrhalis. Together, these 3 bacteria account for 70% cases. A limited CT scan of the sinuses defines the location and extent of disease and helps in deciding further management. It is quick, low cost, and sensitive. CT scanning also helps in delineating anastomotic blockage of the osteomeatal complex; therefore, there is a role for it in cases of endoscopic surgery.

Hint: Plain X-rays are no longer recommended; they are not sensitive enough in the visualization of the sinuses, and they often miss findings

Hint: MRI of the sinuses tells us more about the soft tissue pathology, but bony structures cannot be studied in detail. MRI is done if malignancy is suspected or there are signs and symptoms of possible intracranial extension.

Hint: Nasal cultures can be contaminated with colonized organisms in the nose, such as staphylococcus aureus, and do not correlate well with culture obtained from the sinuses. Endoscopically-guided cultures of secretions in the middle meatus or within a sinus are usually not done in clinical practice, even though occasionally it may provide the exact causative pathogen.

Hint: A 3-week course of antibiotics may relieve symptoms briefly, but it is unlikely to cure him, especially since he already has had several courses. Amoxicillin-clavulanate or cefuroxime are traditionally used for 3 weeks. In intractable cases, a 6-week course may also be given. Clarithromycin and clindamycin are used for patients who are allergic to penicillin. Quinolones are only used if cultures show Gram-negative bacteria.