Thymoma
most common neoplasm of the anterior mediastinum, accounting for 20-25% of all mediastinal tumors and 50% of anterior mediastinal masses. Its
... [Show More] peak incidence occurs in the fourth and fifth decades of life; the mean age of patients is 52 years
thymoma
• one third to one half are asymptomatic, and one third present with local symptoms related to the tumor's encroachment on surrounding structures. These patients may present with cough, chest pain, superior vena cava syndrome, dysphagia, and hoarseness if the recurrent laryngeal nerve is involved. One third of cases are found incidentally on radiographic examinations during a workup for MG.
The diagnosis of a thymoma usually is clinically based on
• radiologic findings. Laboratory studies generally are not indicated.
• Imaging Studies
a. Radiography
• Posteroanterior (PA) and lateral chest radiographs can detect most thymomas. On the PA view, the lesion typically appears as a smooth mass in the upper half of the chest, overlying the superior portion of the cardiac shadow near the junction of the heart and great vessels.
Thymoma
• mass usually projects predominantly into one of the hemithoraces. On the right, the silhouette sign is present and the ascending portion of the aortic arch is obliterated. Conversely, if the thymoma is on the left, the silhouette sign is obscured and the aortic knob is identified behind the mass.
imaging procedure of choice in patients with myasthenia gravis
CT
patient presents with atypical features or is found to have an invasive tumor and is under consideration for induction therapy what is needed
a preoperative biopsy •
The limited anterior mediastinotomy (Chamberlain approach) is the standard approach that typically is performed over the projection of the tumor. A thoracoscopic approach for biopsy also can be used.
The Masaoka system
most commonly accepted staging system for thymomas
I Macroscopically and microscopically completely encapsulated
IIA Microscopic transcapsular invasion
IIB Macroscopic invasion into surrounding fatty tissue or grossly adherent to but not through mediastinal pleura or pericardium
III Macroscopic invasion into neighboring organs (ie, pericardium, great vessels, or lung)
IVA Pleural or pericardial dissemination
IVB Lymphogenous or hematogenous metastasis
WHO histologic classification Type and Histologic description
Stage Definition
A Tumor in which foci having features of type A thymoma are admixed with foci rich in lymphocytes
B1 Tumor resembles normal functional thymus; combines large expanses having an appearance practically indistinguishable from that of normal thymic cortex with areas resembling thymic medulla
B2 Tumor in which neoplastic epithelial component appears as scattered plump cells with vesicular nuclei and distinct nucleoli among a heavy population of lymphocytes; perivascular spaces are common and sometimes very prominent; a perivascular arrangement of tumor cells resulting in a palisading effect may be seen.
B3 Thymoma predominantly composed of epithelial cells having a round or polygonal shape and exhibiting no or mild atypia; they are admixed with a mild component of lymphocytes, resulting in a sheetlike growth of the neoplastic epithelial cells
C Thymic tumor exhibiting clear-cut cytologic atypia and a set of cytoarchitectural features no longer specific to the thymus, but rather analogous to those seen in carcinomas of the other organs; type C thymomas lack immature lymphocytes; whatever lymphocytes may be present are mature and usually admixed with plasma cells
Treatment and management of thymomas
A. Chemotherapy
B. Corticosteroids
Tuberculosis medication regimen
1. Isoniazid 300mg, rifampin 600mg, pyrazinamide 1.5-2.0 gm and ethambutol 15mg/kg or streptomycin 15mg/kg daily initially.
2. If the isolate proves to be fully susceptible to INH and RIF, then the fourth drug may be dropped.
3. Continue the first three drugs daily for 2 months, then 4 more months of INH and RIF daily.
• Persons with HIV should be treated for nine months.
• A variety of DOT options are also available at twice/thee times weekly dosing.
Those with positive TB skin test should receive ___ months of INH.
6 mos
PPD positive if:
1. A positive test is 5mm for HIV infected persons, contacts of a known case, or persons with a chest film typical for TB.
2. A positive test is 10mm for immigrants from high prevalence areas, or those in high risk groups, including health care workers.
3. A positive test is 15mm for all others not in high prevalence groups.
hypovolemic shock
results from low cardiac output due to low blood volume, such as in a massive hemorrhage or fluid loss from severe burns
cardiogenic shock
results from low cardiac output due to myocardial pump failure
Treatment for neurogenic shock
Fluid replacement and alpha agonists
Central Venous Pressure
A measure of the pressure exerted by fluid in the right atrium; indicative of right sided heart function
Normal: 0-6
CVP Elevation
Ex. Fluid overload, cardiogenic shock
Conditions that cause an increase in the amount of fluid in the R atrium
CVP Decreased
Ex. Dehydration, Distributive shock
Conditions that cause a decrease in the amount of fluid in the R atrium
Pulmonary Artery Pressure
a measure of the systolic and diastolic pressures in the pulmonary artery
Normal: 15-25/5-15
PAP Elevation
Ex. Hypervolemia, pulmonary HTN
Conditions that cause an increase in the amount of fluid in the pulmonary artery OR conditions that decrease the elasticity of the pulmonary artery
PAP Decreased
Ex. Hypovolemia
Conditions that cause a decrease in the amount of fluid in the pulmonary artery
Pulmonary Capillary Wedge Pressure aka Pulmonary Artery Occlusion Pressure
Measure of the pressure in the L ventricle at end-diastole (maximal stretch); indicative of left-sided heart function
-Reflection of the tendency to develop pulmonary edema. To optimize cardiac performance and minimize tendency for pulmonary edema, the PCWP should be kept at the lowest point at which cardiac performance is acceptable.
Normal 6-12
PCWP Elevation
Ex. Hypovolemia
Conditions that decrease the pressure in the L ventricle at end diastole
Cardiac Output
The amount of fluid in liters per minute that the heart pumps into systemic circulation. Product of HR x SV
Normal 4-8
CO Elevation
Ex. Inotropic agents, excess fluid
Factors that increase the HR or increase the amount of blood that the heart puts out with each beat
CO Decreased
Ex. Drugs that decrease contractility, hypovolemia
Factors that decrease HR or decrease the amount of blood that the heart puts out with each beat
Cardiac Index
The cardiac output/body surface area; more accurate measure than CO because this value takes body surface area into account
Normal 2.5-4 L/min
Systemic Vascular Resistance
The resistance provided by the systemic circulation against which the L ventricle must pump blood; calculated by the following formula: MAP- mean CVP x 80)/CO
Normal 800-1200 dynes/sec/cm-5
Labs and Diagnostics of Hypovolemic Shock
Decreased CO/CI
Decreased CVP
Decreased PWCP
*Increased SVR
Decreased SvO2
Management of Hypovolemic Shock
Fluid resuscitation is mainstay of treatment
PRBCs when indicated by Hgb/Hct
Cardiogenic Shock
A loss of effective contractile function results in impaired cardiac output, impaired O2 delivery, and reduced tissue perfusion
Causes: "acute pump failure"
Acute MI
Ventricular aneurysm
Dysrhythmia
Pericardial tamponade
Hypoxemia
Pulmonary edema
Acute valvular regurgitation
Acute VSD
Labs and diagnostics of Cardiogenic Shock
Decreased CO/CI
Increased CVP
Increased PWCP
Increased SVR
Decreased SvO2
Management of Obstructive Shock
Maintain blood pressure while initiating treatment of underlying cause
Fluid administration with use of vasopressors (Norepi, Dopamine)
Labs and diagnosics of Obstructive Shock
Decreased CO/CI
Increased SVP
Increased PVR
Decreased PWCP
Increased CVR
Increased SVO
Obstructive Shock
Inadequate cardiac output as a result of impaired ventricular filling
Causes:
Massive pulmonary embolus--most common cause
Tension pneumothorax
Acute cardiac tamponade
Obstructed valvular disease
Disease of pulmonary vasculature
perforated peptic ulcer
pain almost always begins in the epigastrium, but as the leaked gastric contents track down the right paracolic gutter, pain may descend to the right lower quadrant with even diminution of the epigastric pain
Sharp superficial constant pain due to severe peritoneal irritation is typical of:
of perforated ulcer or a ruptured appendix, ovarian cyst, or ectopic pregnancy.
abdominal pain that is intermittent, vague, deep-seated, and crescendo at first but soon becomes sharper, unremitting, and better localized:
small bowel obstruction
characteristic of gastroenteritis
copious watery diarrhea
blood stained diarrhea suggest:
ulcerative colitis or Crohns disease or bacillary or amebic dysentery
gastroduodenal lesion or Mallory-Weiss syndrome
Hematochezia/hematemesis
A scalphoid contracted abdomen is seen with
perforated ulcer
A raised serum amylase corroborates a clinical dx of
acute pancreatitis
diagnostic sensitivity of about 80% for acute appendicitis
abdominal ultrasound
imaging study of choice for evaluating patients with acute right upper quadrant abdominal pain and suprapubic pain
Ultrasonography
Gas stoppage sign
An occasional patient will deny pain but c/o of a vague feeling of abdominal fullness that feels as though it might be relieved by a bowel movement. This visceral sensationis due to reflex ileus induced by an inflammation lesion walled off from the free peritoneal cavity, as in retrocecal or retroileal appendicitis.
sudden upper abdominal pain, nausea and vomiting, and elevated serum amylase.
Acute pancreatitis
Cause: Alcohol, Drug Induced, Ideopathic, Blockage
Acute pancreatitis
characterized by chronic pain, pancreatic calcification on x-ray, and exocrine (steatorrhea) or endocrine (diabetes mellitus) insufficiency
Chronic pancreatitis
Pancreatitis Diagnosis
• Serum amylase
• Serum lipase
• Aspartate transaminase (AST), alanine transaminase (ALT), bilirubin
• Serum electrolytes: *Hyperkalemia and Hyperlipidemia
• CBC
• Abdominal x-ray
• Chest x-ray
• Abdominal US (if biliary'
Perforated bowel symptoms
• severe stomach pain.
• chills.
• fever.
• nausea.
• vomiting.
Blumberg's sign
pressing firmly and steadily on a patient's abdomen for a minute or two, and then releasing your hand suddenly. If pt finds this agonizingly painful, the sign is positive.
Rovsing's sign
pressure to left lower abdomen causes pain in his right lower abdomen
tenderness in the left lower quadrant, and the left colon is sometimes palpable as a firm tubular structure. Fever and leukocytosis are absent in pts with pain but no inflammation.
Diverticulitis
CT scan of the abdomen and pelvis with intravenous contrast is the preferred initial imaging study
Diverticulitis
patients are managed with bowel rest, intravenous fluids, and systemic broad-spectrum antibiotics. Common regimens cover colonic flora and are chosen based on the patient's allergies and previous antibiotic exposure. Common regimens include a beta-lactam/beta-lactamase inhibitor, a carbapenem, or the combination of a fluoroquinolone plus metronidazole
Diverticulitis
resection of two-thirds to three-fourths of the distal stomach.
Subtotal gastrectomy
Deficiencies of the fat-soluble vitamins (A,D,E, and K), calcium iron, vitamin B12 and folate are affected.
gastrectomy
Complications of post-gastrectomy syndrome include
anemia as a result of vitamin B12 or iron malabsorption and osteoporosis
Gastroparesis
Delayed gastric emptying is seen occasionally after gastric surgery.
Prokinetic agents (e.g. metoclopramide) are often helpful, but some cases are refractory to any therapy except completion gastrectomy and Rou-en-Y esophagojejunostomy (i.e. total gastrectomy).
disadvantage is recurrent ulceration in about 10% of patients
vagotomy
H pylori tx
lansoprazole, 30 mg twice daily for 14 days; amoxicillin, 1 g twice daily for 14 days; and clarithromycin, 500 mg twice daily for 14 days.
Gastrinoma s/s
• Acid hypersecretion- usually from peptic ulcer disease
• Some pts. have severe diarrhea
• Hemorrhage, perforation, and obstruction are common
1. Most gastrinomas occur in the submucosa of the duodenum; others are found in the pancreas and rarely as primary tumors of the liver or ovary.
2. About 1/3 of pts. Have the multiple endocrine neoplasia type I syndrome (MEN 1), which is characterized by a family history of endocrinopathy and the presence of tumors in the others glands, especially the parathyroid glands and pituitary. Pts. with MEN 1 usually have multiple gastrinomas.
Tx of gastrinoma
1. Initial treatment should consist of proton pump inhibitor (eg, omeprazole 20-40 mg, once or twice "daily) or H2 blocking agents (eg, cimetidine, 300-600 mg, four times daily; ranitidine, 300-450 mg, four times daily). The dose should be adjusted to keep gastric H+ output below 5 mEq in the hour preceding the next dose." Or surgrical intervention.
bezoars
concretions formed in the stomach
Trichobezoars
composed of hair and are usually found in young girls who pick at their hair and swallow it
gastric bezoars tx
broken up and dispersed by endoscopy. Neglected lesions with complications (ie, bleeding or perforation) require gastrectomy
Zollinger-Ellison syndrome
manifested by gastric acid hypersecretion casused by a gastrin-producing tumor (gastrinoma).
Pyloric Obstruction
obstruction of the gastroduodenal junction as a result of edema, muscular spasm, and scarring
Zollinger-Ellison syndrome
• Peptic ulcer disease (often severe) in 95%
• Gastric hypersecretion
• Elevated serum gastrin
• Non-B islet cell tumor of the pancreas or duodenum
• The normal pancreas does not contain appreciable amounts of gastrin.
• TRT: same as gastrinoma
Child-Pugh classification
based on amount of ascites, degree of encephalopathy, albumin t.bili and PTT/PT levels; this predicts mortality in pts with cirrhosis after hepatic resection
Pyloric Obstruction
• Gradually increasing pain over weeks or months
• Anorexia
• Vomiting
• Failure to gain relief from antacids
• Weight loss
• Dehydration and malnutrition (may not always be present) "Measurement of serum electrolytes shows hypochloremia, hypokalemia, hyponatremia, and increased bicarbonate."
• Peristalsis of the distended abdomen may be visible
• Upper abdominal tenderness
Saline Load TEST
simple means of assessing the degree of pyloric obstruction and is useful in following the patient's progress during the first few days of nasogastric suction.
Through the nasogastric tube, 700 mL of normal saline (at room temperature) is infused over 3-5 minutes, and the tube is clamped. Thirty minutes later, the stomach is aspirated and the residual volume of saline recorded. Recovery of more than 350 mL indicates obstruction
Pyloric Obstruction tx
decompression of the stomach for 48-72 hours, the saline load test should be repeated. If this indicates sufficient improvement, the tube should be withdrawn and a liquid diet may be started. Gradual resumption of solid foods is permitted as tolerated. If no improvement for 5-7 days surgical treatment is needed with vagotomy and drainage procedure.
up to ____ of liver can be removed
80%
After liver resection, regeneration starts within
24hr, considerable regeneration within 10 days and completed by 4-5wks
MELD score
used to improve allocation of liver transplant to cirrhosis pts with highest risk of death; also used to assess liver function in pts undergoing resection
Liver resection follow up labs
-T.Bili: increases after surgery but returns to normal as regeneration progresses; persistent rise may indicate liver failure and perihepatic fluid collection(biloma)
-Albumin: decreases
-PTT/PT: increases : give FFP when INR>2.0
-Ascites: give diuretics
-Hypoglycemia: 5% Dextrose solutions; profound hypoglycemia concern for liver failure
-Phos/Mg/K+: decreases and must be replaced
-AST/ALT: decreases then normalizes
-ALK PHOS: initially normal then rises and remains for days to weeks
Pregnant women and spontaneous hepatic rupture
-most are due to hepatic tumors (adenoma >5cm are at risk; 20-40%)
-many cases of normal rupture occur during or after pregnancy r/t preeclampsi/eclampsia or HELLP Syndrome (hemolysis, increased enzymes, decreased PLT)
-suspect rupture in all pregnant or postpartum pts (esp. if hypertensive) if complaining of acute discomfort of upper abdomen
-spont. rupture may also occur with hepatic hemioangioma, typhoid fever, malaria, TB, syphilis, polyarthritis nodosa, DM
-Progression: intrahepatic hemorrhage to subcapsular hematoma to capsular rupture to free intra abd hemorrhage
-Diagnosis: CT scan; angiography with hepatic artery embolization effective for controlling bleeding; if not successful then emergency laparotomy and intraoperative mgmt.
Hepatic hemangiomas
-most common site is liver and more common with women
-are cavernous type rather than capillary type
-most are small solitary subcapsular growths found during laparotomy or imaging study; pain is uncommon in tumors< 8-10cm diameter
-Complications: hemorrhagic shock from spont. rupture and Kasaback-Merritt syndrome(children); very rare
Hepatic hemantiomas
-Hallmark features: nodular peripheral enhancement on arterial phase with progressive central enhancement on the more delayed images; MRI appear very bright on T2 weighted images
-only reasons to resect are for symptoms: pain or diagnostic uncertainty
-Symptomatic hemangiomas: can be excised by lobectomy or enucleation
-vast majority incidentally found remain stable and asymptomatic
-progressive growth of asymptomatic in a short time is considered indication for resection
Hepatic adenomas s/s
-predominantly seen in women of childbearing age and appears to be related to oral contraceptives (Mestranol containing compounds)
-tumors are soft, yellow tan, well circumscribed masses of moderate size (2-15cm); symptomatic are 8-15cm
-50% of pts are asymptomatic
-Symptoms: right upper quadrant pain
-Complications: spont. hemorrhage into tumor with subsequent rupture intraperitoneal bleeding ; strong association with acute bleeding episodes from adenoma with pregnancy
-general recommendation is that they should be resected because of risks of malignant changes and spont. hemorrhage
-lesions <5cm should be watched with serial images
-small adenomas may regress if oral contraceptive is discontinued
-symptomatic and large asymptomatic should be resected
-if hemorrhaging, emergent resection or hepatic artery embolization
Portal hypertension with alcoholic liver disease
caused by increased volume of portal blood flow or increased resistance to flow
-increased flow in AV fistula
-progressive sinusoidal develops to resistance increases to portal pressure increase to formation of varices [Show Less]