Fig. 12.35: Chest X-ray PA view showing trachea and mediastinum deviated to left, cardiophrenic and costophrenic

angles are normal, homogenous hyperlucency in right

hemithorax suggestive of right-sided pneumothorax.

Fig. 12.36: Chest X-ray PA view showing trachea central,

cardiophrenic and costophrenic angles are normal, bilateral

hyperlucent lung fields with hyperinlation, flattened diaphragm

and tubular heart suggestive of bilateral emphysema.

Causes of unilateral hypertranslucency on chest x-ray

Technical

Patient rotation

Incorrect centering of X-ray beam to grid

Chest wall abnormality

Asymmetric soft tissues

Mastectomy

Absent or underdeveloped pectoral muscles (Poland

syndrome)

Skeletal abnormality

Scoliosis

Airway disease

Large pneumothorax

Asymmetric emphysema

Bronchial obstruction

Previous bronchiolitis obliterans (Swyer–James

syndrome = Macleods syndrome)

Vascular disease

Pulmonary embolism

Causes of bilateral hyperlucent lung fields

Pulmonary emphysema

Pulmonary overinflation

Bilateral pneumothorax

Over exposure

Bilateral congenital lobar emphysema

Chronic bronchitis

Cystic fibrosis

Bronchiectasis

Asthma

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Fig. 12.37: Chest X-ray PA view showing homogeneous

opacity in the right hemithorax obliterating the costophrenic

angle, pleural based suggestive of loculated pleural

effusion.

Diffrential diagnosis—pleural mass/mesothelioma.

Fig. 12.38: Chest X-ray PA view showing bilateral hilar shadows,

lobulated (also subcarinal shadow) suggestive of

lymphadenopathy. Possible sarcoidosis.

Fig. 12.39: Chest X-ray PA view showing tracheal shift to

left, hyperlucency in right hemithorax with collapse lung margin (visceral pleural line) with obliteration of

costophrenic angle with mulitiple air fluid levels suggestive

of hydropneumothorax.

Fig. 12.40: Chest X-ray PA view showing air shadows in the

subcutaneous plane in the neck, axilla, anterior chest wall, muscles

suggestive of subcutaneous emphysema.

Figs. 12.41A and B: Chest X-ray PA view showing small millet sized (1–3 mm) shadows in bilateral lung fields suggestive of miliary mottling.

Differential diagnosis for miliary mottling:

Miliary tuberculosis

Tropical pulmonary eosinophilia

Sarcoidosis

Pneumocystis

Fungal diseases: Histoplasmosis, coccidioidomycosis, blastomycosis,

cryptococcosis

Coal miner’s pneumoconiosis

Acute extrinsic allergic alveolitis

Fibrosing alveolitis.

Varicella pneumonia

Opacities (2–5 mm) tending to remain

discrete:

Miliary/lymphangitis carcinomatosis

Lymphoma

Sarcoidosis.

Opacities (2–5 mm) tending to coalasce:

Multifocal pneumonia

Pulmonary edema

Extrinsic allergic alveolitis

Fat emboli.

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Those opacities having greater than-soft-tissue density:

Pulmonary hemosiderosis

Silicosis

Fig. 12.42: Chest X-ray PA view showing rounded

homogeneous lesion in the right mid zone—solitary

pulmonary nodule.

Fig. 12.43: Chest X-ray PA view showing multiple rounded

nodular opacities in bilateral lung fields—cannonball metastasis.

For more details refer to page number 360 of Exam

Preparatory Manual of Medicine for Undergraduates by the

same author.

Possible primary: Breast, thyroid, bowel, testes, renal cell

carcinoma (RCC), choriocarcinoma

Fig. 12.44: Chest X-ray PA view showing cardiomegaly with

bilateral nonhomogeneous opacity in mid and lower zones (bat wing

appearance) suggestive of pulmonary edema. Also patient has metallic mitral valve prosthesis.

Fig. 12.45: Chest X-ray PA view showing gross cardiomegaly w

stenciled heart borders, lungs clear. Suggestive of pericardia

effusion.

Differential diagnosis—Ebstein’s anomaly

Fig. 12.46: Chest X-ray PA view showing gross

cardiomegaly with stenciled heart borders, lungs clear.

Suggestive of pericardial effusion.

Differfential diagnosis—Ebstein’s anomaly

Fig. 12.47: Chest X-ray PA view showing cardiomegaly with

features of mitral valve disease—splaying of carina, double atrial

shadow (red arrows), straightening of left heart border, mitral valve metallic prosthesis.

Fig. 12.48: Chest X-ray PA view showing cardiomegaly

with features of mitral valve disease—splaying of carina,

double atrial shadow, straightening of left heart border,

enlarged left atrial appendage, prominent pulmonary artery.

Fig. 12.49: Chest X-ray PA view showing cardiomegaly with

features of mitral valve disease—splaying of carina, double atrial

shadow, straightening of left heart border, mitral valve metallic

prosthesis, enlarged left atrial appendage, prominent pulmonary

artery, prominent upper lobe veins (stag’s antler sign).

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Fig. 12.50: Chest X-ray PA view showing pulmonary

oligemia with upturned apex (right ventricle) suggestive

of tetralogy of Fallot (coeur-en-sabot).

Fig. 12.51: Chest X-ray PA view showing mild cardiomegaly, prominent

pulmonary artery, pulmonary plethora, prominent right atrium.

Suggestive of atrial septal defect—jug handle appearance.

Fig. 12.52: Chest X-ray PA view showing free air

under bilateral hemidiaphragm—pneumoperitoneum.

Causes:

Hollow viscus perforation

Postlaparotomy/laparoscopy

Subphrenic abscess

Tubal insufflation (Rubin’s test)

Minimum amount of air needed to produce this is 1

cc.

Fig. 12.53: Chest X-ray PA view showing interposition of transverse

colon between liver and right hemidiaphragm—Chilaiditi syndrome.

Fig. 12.54: Chest X-ray PA view showing trachea

central, cardiophrenic and costophrenic angles are

normal, nonhomogeneous opacity in bilateral upper

zone with multiple cavities suggestive of bilateral

upper lobe active tuberculosis.

X-ray signs of active tuberculosis—thin-walled

cavities, pleural effusion, interstitial fluffy

shadows.

X-ray signs of healed tuberculosis—thick-walled

cavities, fibrosis, calcification, pleural thickening.

Fig. 12.55: Chest X-ray PA view showing trachea deviated to right, mediastinum pulled to right, decreased size of right hemithorax with rib

crowding. Nonhomogeneous opacity in right hemithorax with multiple

cystic shadows suggestive of right-sided fibrosis with cystic

bronchiectasis possibly sequele of tuberculosis.

Fig. 12.56: Chest X-ray PA view showing trachea central,

cardiophrenic and costophrenic angles are normal, mediastinal widening suggestive of superior mediastinal mass.

Fig. 12.57: Chest X-ray PA view showing trachea central,

cardiophrenic and costophrenic angles are normal, rounded opacity

arising from the anterior mediastinum which is calcified—

mediastinal cyst.

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Fig. 12.58: Lateral X-ray of skull showing multiple

punched out lesions.

Differential diagnosis: Myleoma, metastasis, rarely

Langerhans cell histiocytosis.

Fig. 12.59: Lateral skull X-ray showing prognathism, thickened

skull vault, prominent air sinuses, enlarged sella turcica—

suggestive of acromegaly.

COMPUTED TOMOGRAPHY (FIGS. 12.60 TO 12.64)

Computed Tomography

Types

Spiral CT

Multislice CT—coronary CT angiography and calcium score

Electron beam CT—faster, used for cardiac application

High resolution CT (HRCT)—1–2 mm slices, investigation of choice for ILD and bronchiectasis.

CT density scale—Hounsfield units—range from −1,000 (black) to +1,000 (white).

0—attenuation value of water (considered as reference)

−1,000 Air

−100 Fat

0 Water

+60 Hemorrhage

+1,000 Calcification

Fig. 12.60: Plain CT head showing hyperdense shadow which is

concavo-convex in appearance suggestive of acute right

subdural hematoma.

Fig. 12.61: Plain CT head showing hyperdense shadow which

biconvex in appearance suggestive of acute left extradural

hematoma.

Fig. 12.62: Plain CT head showing hyperdense shadow in the right

basal ganglia suggestive of acute intraparenchymal hemorrhage.

Fig. 12.63: Plain CT head showing hypodense shadow in the rig

parietotemporal cortex suggestive of acute infarct (arrow).

Fig. 12.64: High-resolution computed tomography (HRCT) of chest. Varicose and cystic

bronchiectasis with mucus plugging in upper lobes.

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MAGNETIC RESONANCE IMAGING (FIGS. 12.65 AND 12.66)

Proton acts as a dipole with magnetic dipole movement and gyromagnetic properties.

Fig. 12.65: Magnetic resonance imaging.

Types of MRI sequences

T1—Spin lattice relaxation time

T2—Spin-spin relaxation time

Flair—Fluid attenuated inversion recovery—preferred in CNS demyelinating diseases like multiple

sclerosis

DWI/Diffusion weighted images—for detection of early infarcts

ADC (Apparent diffusion coefficient)

MR signal characteristics:

T1 T2

CSF Hypointense Hyperintense

Gray matter Gray White

White matter White Gray

Fat Hyperintense Less hyperintense

Tumors (most) -- Hyperintense

Melanoma Hyperintense Hypointense

Differential diagnosis

Cerebral abscess

Tuberculoma

Neurocysticercosis

Metastasis

Glioblastoma

Subacute infarct/hemorrhage

Demyelination

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Fig. 12.66: MRI brain showing ring enhancing lesion.

Radiation necrosis

Lymphoma

CONTRAST AGENTS

Contrast for X-ray/CT

Positive contrast agents Negative contrast agents

Water soluble

(Iodine containing agents)

Water insoluble

(Barium containing agents)

Air Water

High osmolar:

Urografin, Diatrizoate sodium, Conray

Low osmolar:

Optiray, Iodixanol

Note: Low osmolar agents are safer.

MRI Contrast Agents

Contain paramagnetic metal ions. For example: gadolinium ligated to diethylenetriaminepentaacetic

(DTPA).

Basic Instruments in Viva

C H A P T E R

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GASTRIC LAVAGE TUBE

Description

Used for gastric decontamination by removing toxic substances from

the stomach by sequential administration and reaspiration of small

volumes of fluid through this tube.

Other names—Ewald’s tube/boes tube.

Indications

For decontamination after oral consumption of poison.

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Contraindications

Corrosive ingestions or esophageal disease

Hydrocarbon or petroleum distillate ingestion

Convulsion

Cardiac dysrhythmias

The poison ingested is not toxic at any dose

The poison ingested is adsorbed by charcoal and adsorption is not

exceeded by the quantity of ingestion

Presented several (4-6) hours after consumption of the poison

A highly efficient antidote, such as N-acetylcysteine (NAC) is

available.

Technique of Performing Orogastric Lavage (Table 13.1)

Table 13.1: The technique of performing orogastric lavage.

Select the correct tube size

Adults and adolescents: 36–40 French

Children: 22–28 French

Procedure

1. If there is a potential airway compromise, endotracheal intubation should precede

orogastric lavage.

2. The patient should be kept in the left lateral decubitus position. Because the

pylorus points upward in this orientation, this positioning theoretically helps

prevent the xenobiotic from passing through the pylorus during the procedure.

3. Before insertion, the proper length of tubing to be passed should be measured

and marked on the tube. The length should allow the most promixal tube opening

to be passed beyond the lower esophageal sphincter.

4. After the tube is inserted, it is essential to confirm that the distal end of the tube is

in the stomach.

5. Any material present in the stomach should be withdrawn and immediate

instillation of activated charcoal should be considered for large ingestions of

xenobiotics that are known to be adsorbed by activated charcoal.

6. In adults, 250-mL aliquots of a room temperature saline lavage solution is instilled

via a funnel or lavage syringe. In children, aliquots should be 10 to 15 mL/kg to a

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maximum of 250 mL.

7. Orogastric lavage should continue for at least several liters in an adult and for at

least 0.5 to 1.0 L in a child or until no particulate matter returns and the effuent

lavage solution is clear.

8. After orogastric lavage, the same tube should be used to instill activated charcoal

if indicated.

Complications

Aspiration of gastric contents (3% of patients)

Esophageal rupture (rare)

Laryngospasm

Bradycardia.

LARYNGOSCOPE

Description

Laryngoscopes are usually left-handed tools designed to facilitate

visualization of the larynx. A laryngoscope consists of a handle, a

blade, and a light source. The most commonly used blades include

the curved Macintosh and the straight Miller blades.

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Indications

Patients requiring emergent intubation in conditions like acute

respiratory failure with inadequate oxygenation and ventilation.

In patients with altered sensorium for airway protection.

Nonemergent intubation occurs in the perioperative setting as

patients may require general anesthesia.

Contraindications

Suspected cervical spine injuries

Patients who have supraglottic or glottic pathology.

A relative contraindication to laryngoscopy includes patients with

anatomy that does not allow successful laryngoscopy use, injuries

to the area, or physiologic status that is not conducive to the

procedure.

METAL TRACHEOSTOMY TUBE

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Description

It consists of three parts—(1) outer cannula with flange (neck

plate), (2) inner cannula, and (3) an obturator.

Indications

Upper airway obstruction (e.g. stridor)

Prolonged intubation

Facilitation of ventilation support

For management of pulmonary secretions.

ENDOTRACHEAL TUBE

Description

It is a tube constructed of polyvinylchloride (PVC) that is placed

between the vocal cords into the trachea to provide oxygen and

inhaled gases to the lungs. It also serves to protect the lungs from

contamination, such as gastric contents and blood parts of

endotracheal (ET) tube.

The Tube

The endotracheal tube (ETT) has a length and diameter. The

endotracheal tubes size refers to its internal diameter in millimeters

(mm). PVC is not radio-opaque, and thus a radio-opaque linear

material is included throughout the length of the tube to make it

easier to visualize the placement on X-ray. Ideally, the distal tip of the

ETT is 4 cm (+/−2 cm) above the carina on chest X-ray in adults.

The Cuff

A cuff is an inflatable balloon at the distal end of the ETT. The inflated

cuff produces a seal against the tracheal wall; this prevents gastric

contents from entering the trachea and facilitates the execution of

positive pressure ventilation. The cuff inflates by attaching an

appropriate size syringe (10–20 mL for adult ETT) to the pilot balloon.

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The Bevel

To facilitate placement through the vocal cords and to provide

improved visualization ahead of the tip, the ETT has an angle or slant

known as a bevel.

The Murphy’s Eye

Endotracheal tubes have a built-in safety mechanism at the distal tip

known as Murphy’s eye, which is another opening in the tube

positioned in the distal lateral wall.

The Connector

Endotracheal tube connectors attach the ETT to the mechanical

ventilator tubing or an Ambu bag.

Indications

Acute respiratory failure, inadequate oxygenation, or ventilation,

Airway protection in a patient with depressed mental status.

In the perioperative setting, endotracheal tubes may be placed in

many clinical circumstances including patients receiving general

anesthesia, surgery involving

Less frequently to manage increased intracranial pressure or to

manage copious secretions or bleeding from the airway.

Contraindications

Severe airway trauma or obstruction that does not allow safe

placement of the tube

Severe cervical spine injury which requires complete

immobilization, and

Those patients with Mallampati III/IV classification suggesting

potentially difficult airway management.

AMBU BAG

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Description

A bag valve mask (BVM), Ambu bag or generically as a manual

resuscitator or “self-inflating bag”, is a hand-held device commonly

used to provide positive pressure ventilation to patients who are not

breathing or not breathing adequately.

The BVM consists of a flexible air chamber (the “bag”, roughly a

foot in length), attached to a face mask via a shutter valve.

Complications

Air inflating the stomach;

Lung injury from overstretching (called volutrauma); and/or

Lung injury from overpressurization (called barotrauma).

RYLES TUBE—NASOGASTRIC TUBE

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