Dr C.S. Singh

• Severe abdominal pain, requiring the clinician to make an urgent therapeutic decision.

• Differential diagnosis of an acute abdomen includes a wide spectrum of disorders, ranging from life-threatening diseases to benign self-limiting conditions

• Management may vary from emergency surgery to reassurance of the patient and misdiagnosis may easily result in delayed necessary treatment or unnecessary surgery.

• Sonography and CT are the aids

Findings may be normal in patients who need emergency surgery (such as appendicitis) and may be abnormal in patients without a surgical disease (like salpingitis).

A plain abdominal film has a limited value in the evaluation of abdominal pain.

A normal film does not exclude an ileus or other pathology and may falsely reassure the clinician.

TYPES Pneumoperitoneum-/free air/intraperitoneal air

Retroperintoneal air

Air in the bowel wall (pneumatosis intestinalis)

Air in the biliary system (pneumobilia)

The patient should be positioned sitting upright for 10-20 minutes prior to acquiring the erect chest X-ray image.

This allows any free intra-abdominal gas to rise up, forming a crescent beneath the diaphragm. It is said that as little as 1ml of gas can be detected in this way.

Rupture of a hollow viscus Perforated peptic ulcer Trauma Perforated diverticulitis (usually seals off) Perforated carcinoma

Post-op --5-7 days normal, should get less with successive studies

NOT ruptured appendix (seals off)

Crescent sign Chilaiditis sign Riglers Football sign Falciform ligament sign Triangle sign

Free air under the diaphragm

Best demonstrated on upright chest x rays or left lat decubitus

Easier to see under right diaphragm

May mimic air underthe diaphragm

Look for haustral folds Get left lateral

decubitus to confirm

In patients who have cirrhosis or flattened diaphragms due to lung hyperinflation, a void is created within the upper abdomen above the liver. This space may be filled by bowel. If this bowel is air filled then it may mimic free gas.

Bowel wall visualised on both sides due to intra and extraluminal airUsually large amounts of free airMay be confused with overlapping loops of bowel, confirm with upright view

Seen with massive pneumoperitoneum

Most often in children with necrotising enterocolitis

Paediatric Adult

In supine position air collects anterior to abdominal viscera

Normally invisible.

Supine film, free air rises over anterior surface of liver

Sufficient free air, left and right hemi- diaphragms

appear continous

The triangle sign refers to small triangles of free gas that can typically be positioned between the large bowel and the flank

Recognised by: Streaky, linear appearance outlining retroperitoneal

structures Mottled, blotchy appearance Relatively fixed position

May outline: Psoas muscles Kidneys, ureters, bladder Aorta or IVC Subphrenic spaces

Bowel perforation (appendix, ileum, colon)

Trauma (blunt or penetrating)

Iatrogenic Foreign body Gas producing

infection

This patient has free air in the retroperitoneal space. The air is seen surrounding the lateral border of the right kidney (white arrow). There is other evidence of free gas including Rigler's sign.

If you are not confident that the appearance is pneumoretroperitoneum, you can try an erect and decubitus view to see if the gas moves. If the gas is seen to move, it's not in the retroperitoneum.

Primary Pneumatosis cystoides intestinalis (rare)

usually affects left colon Produces cyst-like collections of air in the submucosa or serosa

Secondary Diseases with bowel wall necrosis Obstructing lesions of the bowel that raise intraluminal pressure

Complications Rupture into peritoneal cavity Dissection of air into portal venous system

Intramural air, best appreciated in profile

One or two tube-like branching lucencies in the RUQ, confoined to location of major bile ducts

“Normal” if Sphincter of Oddi incompetence Previous surgery including sphincterotomy or

transplantation of CBD

Pathology (uncommon) Gallstone ileus: gallstone erodes through wall of GB

into the duodenum producing a fistula between the bowel and the biliary system.

Stone impacts in small bowel = mechanical SBO. “ileus” misnomer

Portal venous air usually associated with bowel necrosis -noted within 2 cm of

the liver capsule Air is peripheral

rather than central

Numerous branching structures

Normal Appendix At sonography and CT the appendix is seen as

a blind-ending nonperistaltic tubular structure arising from the base of the cecum.

Do not mistake a small bowel loop for the appendix.

The outer-to-outer diameter of the appendix is the most important imaging criterion.

Long Axis Short Axis

TARGET SIGN

Diameter larger than 6 mm

Usually surrounded by inflamed fat

Presence of a fecolith Hypervascularity on power Doppler

Mesenteric lymphadenitis is a mimicker of appendicitis. It is the second most common cause of right lower

quadrant pain after appendicitis. It is defined as a benign self-limiting inflammation of

right-sided mesenteric lymph nodes without an identifiable underlying inflammatory process - often in children than in adults..

Diagnosis can only be made confidently when a normal appendix is found, because adenopathy also frequently occurs with appendicitis.

Key finding: Lymphadenopathy with a normal appendix and normal mesenteric fat

Normal Appendix Mesenteric Adeniopathy

It is a very common condition in older patients. Diverticula- A characteristic muscle abnormality

in the sigmoid colon with typical ‘out pouching’ from the colonic wall

Diverticulosis - presence of diverticula, Diverticulitis – refers to inflammatory changes within one or more diverticula

U S G and CT show diverticulosis with segmental colonic wall thickening and inflammatory changes in the fat surrounding a diverticulum Complications of Diverticulitis such as abscess formation or perforation, can best be excluded with CT.

Cholecystitis Occurs when a calculus obstructs the cystic duct.

The trapped bile causes inflammation of the gallbladder wall.

U S G is the preferred imaging method for the evaluation of cholecystitis, also allowing assessment of the compressibility of the gallbladder.

The diagnosis of a hydropic gallbladder is solely made on the non-compressability of the gallbladder.

Causes Adhesions 80% Hernia 15% Tumors, intussusception, midgut volvulus, etc.

  Loops proximal to the point of obstruction will become dilated and fluid-filled - Usually greater than 2.5-3 cm in size

Step-ladder pattern of bowel loops on supine view Step-ladder air-fluid levels on erect/decubitus

views Stretch sign on supine view String-of-pearls sign on erect/decubitus views Fluid-filled bowel may be more significant than air-

filled bowel

Maximum Normal Diameter of bowelSmall bowel 3cmLarge bowel 6cmCaecum 9cm

SBO Supine

Air fluid levels

Loops arrange themselves from left upper to right lower quadrant in distal SBO

The 'Small Bowel Feces Sign' (SBFS) - seen at the zone of transition thus facilitating identification of the cause of the obstruction.

Causes Carcinoma of the colon - 80% Volvulus - 5% Diverticulitis - 5% Fecal impaction - 5%

The cecum is the most distensible part of the colon

A cecum of 9 cm diameter is cause for concern

A cecum of 11 cm is impending perforation

Colon dilates from point of obstruction backwards

Little/no air fluid levels (colon reabsorbs water)

Little or no air in rectum/sigmoid

Seen in infants Represents dilatation of the proximal

duodenum and stomach. It is seen in both radiographs and ultrasound,

and can be identified antenatally  Seen in duodenal atresia.

Duodenal Atresia

Caused by:

LUQ Soft tissue massORHead of intussusception in distal transverse colon

The large and small bowel are extensively airfilled but not dilated.

The large and small bowel "look the same".

A volvulus always extends away from the area of twist.Sigmoid volvulus can only move upwards and usually goes to the right upper quadrant. Caecal volvulus can go almost anywhere.

Twisting of loop of intestine around its mesenteric attachment site-Volvulus

80% sigmoid 20% cecum

Massively dilated sigmoid loop (an air-filled, dilated viscus) arising from the pelvis

inverted U -shaped appearance, with the limbs of the sigmoid loop directed toward the pelvis

The interposed loops produce the white-stripe sign

Loss of haustra

Proximal Dilated large bowel loop

*

Ba. enema study -contrast material shows abrupt termination of the contrast material column in a beaklike point.

Caecum-retroperitoneal structure, not susceptible to twisting.

20% of individuals there is congenital incomplete peritoneal covering of the caecum

Increased incidence caecal volvulus

The massively dilated caecum no longer lies in the right iliac fossa (RIF)

Calcificaion seen in the area of Pancreas colon cut-off sign of air in dilated transverse

colon to the splenic flexure Localized ileus in left upper quadrant a paucity of gas from fluid-filled bowel Left pleural effusion

Colon Cut Off Sign

Radioation Hazards-Introduction

DR C.S.SINGH

Introduction

• Myths created by the film industry– Spider Man, The Hulk, Teenage Mutant

Ninja Turtles– Radioactive Material Glows

Risk• The statistical probability that

personal injury will result from some action – smoking, speeding, extreme sports, etc., – ionizing radiation exposure

Ionizing Radiation Exposure Effects

• Somatic Effect (Prompt or Delayed)– Stochastic Effect (Cancer) - probability of effect

occurring increases as doses increases. No Threshold– Non-Stochastic Effect (Cataracts) - severity of the

effect varies with dosage. Threshold dose

• Teratogenic Effects (Offspring while in-utero)– mental retardation – malformations

Ionizing Radiation Exposure Effects (Con’t)

• Genetic Effects (Future Generations)– Anemia – Epilepsy– Diabetes– Asthma

Physical Factors of Effects

• Acute dose vs. Chronic Dose

Physical Factors of Effects

• Acute dose vs. Chronic Dose• Whole body irradiation vs. partial

body irradiation

• Radiation causes ionizations in the molecules of living cells

• At low doses, for ex. from background radiation, the cells repair the damage rapidly.

• At higher doses (up to 100 rem), the cells might not be able to repair the damage - the cells may either be changed permanently / die.

• Most cells that die - body can just replace them. • Cells changed permanently - produce abnormal cells

when they divide - thus these cells may lead to cancer.

Characters• The onset and type of symptoms depends on the radiation

exposure.• smaller doses - gastrointestinal effects - nausea and vomiting

and symptoms related to falling blood counts such as infection and bleeding.

• Relatively larger doses - neurological effects and rapid death.• Similar symptoms may appear months to years after exposure

as chronic radiation syndrome when the dose rate is too low to cause the acute form. 

• Radiation exposure - increase the probability of developing different types of cancers. 

Problems with Models

• Cancers are indistinguishable• Ionizing radiation is not only cause of

cancer• Long latency period of cancer• Cannot perform human experiment• Studies may suggest radiation as the

cause of cancer but cannot identify

Cancer Facts

• Causes - Many Risk increases after age 40

• Risk factors–Personal Habits, Environmental

factors, Occupational hazards

What is cancer? - uncontrolled growth and spread of abnormal cells

Cancer Facts (Con’t)

– 40% Male/Female• Death of cancer victims

– 50% of personnel who develop cancer will die

• Overall death rate from cancer– 20%

Cancers frequently linked to radiation

Breast cancer

Thyroid cancer

Leukemia

Is Radiation Safe?• Safer than normal risk associated with

many activities encountered daily

Something Extra

• Irradiating Food

• Radon

Summary

• There may be a slight increase in the risk of developing cancer