INSTALACIONES SECUNDARIAS .1 ALUMBRADO

It is the most common fatal cancer in the United States, accounting for 28% of all cancer deaths and has the distinction of being one of the few cancers with a continually rising mortality rate. Smoking is the most important etiologic factor linked to lung cancer and is responsible for as many as 85% of cases. All lung cancers are associated with smoking. The occasional nonsmoker who has lung cancer develops adenocarcinoma. The risk due to smoking is directly related to the number of pack-years. Asbestos exposure increases the risk of bronchogenic carcinoma 75 times that in the nonexposed normal patients.

Types of Bronchogenic Carcinoma Adenocarcinoma

It is now the most frequent histologic subtype. They are classically peripheral tumors arising from the peripheral airways and alveoli. This lesion metastasizes widely to extra thoracic sites such as liver, adrenal glands, brain, and bone. Asbestos exposure can be an underlying causative agent. Adenocarcinoma is usually associated with pleural effusions that have high hyaluronidase levels.

Diagnosis often requires thoracotomy with pleural biopsy.

Squamous Cell Carcinoma

Tends to originate in the central airways. It is associated with cavitary lesions. It metastasizes by direct extension into the hilar nodes and mediastinum. These lesions are associated with hypercalcemia from the secretion of a parathyroid hormone-like substance (diagnosis clincher).

Small Cell Carcinoma

These are centrally located lesions. It is a rapidly growing lesion that metastasizes early to distant sites like adenocarcinoma and has poor prognosis, even if detected early. It’s most common cause of venacaval obstruction syndrome. This carcinoma is typically associated with various paraneoplastic syndromes like Eaton-Lambert syndrome, syndrome of inappropriate antidiuretic hormone (SIADH), etc.

Large-Cell Carcinoma

It is a peripherally located lesion. It can metastasize to distant locations late in the course of disease and in early stages is associated with cavitation.

Clinical Features

The most common symptom at the time of diagnosis is cough, weight loss, and dyspnea. Other associated symptoms include hemoptysis, chest wall pain, and repeated pneumonic processes due to postobstructive pneumonia. Presence of hoarseness indicates nonresec-table carcinoma. Adenocarcinomas are known to cause hypercoagulable state sometimes and present as trousseau’s syndrome. Some typical mechanical obstruction syndromes seen in patients with bronchogenic carcinoma are:

1. Superior vena cava syndrome: Presents with dyspnea, cough, prominent venous pattern on the face and the chest, dilated neck veins, upper extremity and facial edema, plethora, facial cyanosis, papilledema, feeling of fullness in the head.

2. Pancoast tumor: Due to superior sulcus tumor that causes pain in the shoulder, medial forearm, arm, scapula; bone destruction, horner syndrome, hand muscle atrophy.

3. Acute spinal cord compression presents with sensory deficits, urinary incontinence or retention, vertebral pain, paraplegia.

4. Paraneoplastic syndromes: It may present with following entities:

• Cushing syndrome

• Lambert-Eaton syndrome

• Myasthenic syndrome

• Hypercalcemia

• SIADH

4. Ogilvie intestinal pseudo-obstruction: It presents with nausea, vomiting, abdominal discomfort, early satiety, change in bowel habits, and weight loss.

Diagnosis

There is no available screening test for lung cancer at this time.

• Sputum cytology: It has low detection rate and is most useful in squamous cell carcinoma because it is intraluminal and centrally located.

• Chest X ray: It may show pulmonary nodule, mass, or infiltrate, mediastinal widening, atelectasis (suggests central airway obstruction), hilar enlargement, pleural effusion.

• CT: It is the criterion standard for staging; however, it rarely is indicated emergently. CT of head and neck is best modality for diagnosis of Superior vena cava syndrome.

• Bronchoscopy: Is best for centrally located lesions and is helpful in staging.

• Needle aspiration biopsy: is good for peripheral nodules with pleural fluid aspirate.

• Mediastinoscopy is useful in diagnosing and staging mediastinal tumors.

Treatment

Surgery offers the best chance of cure. Unresectability of a lesion is indicated by:

• weight loss> 10%

• bone pain or other extrathoracic metastases

• CNS symptoms (treated by radiation or chemotherapy)

• superior vena cava syndrome

• hoarseness

• mediastinal adenopathy on the contralateral side

• split-lung (of healthy lung that is not to be resected) test tidal volume < 800 ml

• tumor involving the trachea, esophagus, pericardium, or chest wall.

Radiation therapy controls local disease and is most commonly used to palliate symptoms. Metastasis involving CNS is treated by radiation and chemotherapy.

Resectable lesions of small cell carcinoma are treated with chemotherapy (etoposide and platinum). Surgery is not indicated for these lesions. Non-small cell lesions that are not resectable are treated with chemotherapy (CAP-cyclophosphamide, adriamycin, and platinum) and radiation therapy. Effusions are sclerosed with tetracycline.

‘99er’-Pancoast tumor- radiation therapy with surgery is most common treatment. For metastatic pancoast tumor, radiation therapy alone.

‘99er’-Radiation lung injury- is seen in approximately 10% of cases of bronchogenic carcinoma treated by radiation therapy. Acute radiation pneumonitis develops 2-3 months after exposure and presents with insidious onset of shortness of breath and chest pain. There is sharp demarcation of pulmonary infiltrate on chest X-ray and its close correspondence to the previously irradiated area, which is highly characteristic of radiation pneumonitis.

ANEMIA

It is defined as a decrease in red blood cell (RBC) mass, when hematocrit (Hct) is <40 in men or <37 in women, or hemoglobin is < 14 in men or < 12 in women. Anemia, like fever, is a symptom of disease that requires investigation to determine the underlying etiology and is not a disease in itself.

Classification

Morphological approach for classification is most popular where anemia is classified by the size of red blood cells

along with their heme content. The size is reflected in the mean corpuscular volume (MCV)

• Microcytic (<80 fl): Iron deficiency, thalassemia, sideroblastosis, and lead poisoning.

• Normocytic (80-100 fl): Usually in initial stages of all anemias, hemolytic anemias, and anemia of chronic disease (may be normocytic or microcytic).

• Macrocytic (>100 fl): Vitamin B₁₂ or folic acid deficiency (most common), also in alcoholism, liver disease, or due to chemotherapeutic agents (methotrexate) or medications (zidovudine, phenytoin).

Table 7.1: Various types of RBCs

Cell type Characteristic Seen in

Spherocytes Loss of central pallor, stains more densely, Hereditary spherocytosis and certain

often microcytic acquired hemolytic anemias

Target cell Hypochromic with central “target” Liver disease, thalassemia, hemoglobin D,

of hemoglobin postsplenectomy

Leptocyte Hypochromic cell with a normal diameter Thalassemia and decreased MCV

Elliptocyte Oval to cigar shaped Hereditary elliptocytosis, vitamin B₁₂ and folate deficiency

Schistocyte Fragmented helmet- or triangular- Microangiopathic anemia, artificial heart

shaped RBCs valves, uremia, malignant hypertension

Stomatocyte Slitlike area of central pallor in erythrocyte Liver disease, acute alcoholism, malignancies, hereditary stomatocytosis, and artifact

Tear-shaped RBCs Drop-shaped erythrocyte, often microcytic. Myelofibrosis and infiltration of marrow with tumor. Thalassemia

Acanthocyte Five to 10 spicules of various lengths and In lipid abnormalities, liver disease at irregular interval on surface of RBCs.

Echinocyte Evenly distributed spicules on surface Uremia, peptic ulcer, gastric carcinoma, of RBCs, usually 10-30 pyruvic kinase deficiency, preparative artifact Sickle cell Elongated cell with pointed ends Hemoglobin S and certain types of

hemoglobin C and I

Hematology

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Clinical Features

Proper clinical history and physical examination of each anemic patient helps a lot to reach the exact etiology of anemia. The severity of symptoms is very much related to the underlying health of the patient. Patient usually presents with fatigue, poor exercise tolerance, tiredness with dyspnea and lightheadedness on exertion is severe disease. As disease progresses he may present with confusion and altered mental status and eventually death may occur because of MI, if anemia is not corrected in time. On examination patient has pallor, tachycardia, and a systolic ejection murmur (in moderately severe anemia).

Diagnosis

Initially, order a complete blood count (CBC), MCV, peripheral blood smear, reticulocyte count, iron studies (serum iron, ferritin, TIBC), serum folate, vitamin B₁₂, TSH, hemolysis labs (unconjugated bilirubin, haptoglobin, Coomb‘s test, LDH), DIC panel (fibrinogen, D-dimer). Keep an eye if pancytopenia is there.

Treatment

Fluid resuscitation and RBC transfusion are mainstay of treatment for severe anemia. Transfusion should be done to ensure Hb> 9 mg/dL (> 8 mg/dL for CAD patient). But transfusion should be more of based on clinical grounds and not on lab values, like an asymptomatic patient whose Hb on routine examination is found out to be 7 mg/dL do not require an immediate transfusion.

MICROCYTIC ANEMIA