Gallbladder Cancer

Gallbladder cancer is the 6^th most common digestive cancer in the United States. American Cancer Society statistics estimate 6,000 new cases in 2009. Although the incidence rate is fairly low in the U.S. the death rate is high, because most new cases are not found until the cancer has spread beyond the gallbladder. Only 20% of gallbladder cancers are found in the early stages (before metastasis). This cancer is more common in females and usually occurs at age 60 or older. Obesity is also a risk factor because obese individuals are more likely to have gallstones. Native and Mexican Americans also have higher gallbladder cancer rates than other American ethnic groups. Chronic inflammation of the gallbladder and large gallstones are thought to increase cancer risk. Researchers now believe that inflammation and gallstones may cause the gallbladder to drain more slowly. This exposes the gallbladder to more bile and can irritate the gallbladder lining. It also increases the amount of time the cells are exposed to carcinogens which may be in the bile. All of these factors can result in malignant changes to the gallbladder cells.

Symptoms of gallbladder cancer can include upper right quadrant pain and tenderness (worse after eating a fatty meal), nausea, vomiting, weight loss and jaundice. These symptoms may also be seen in people with gallstones so having these symptoms is more likely to be gallstones than cancer. Lab tests may show an elevated serum bilirubin as well as cancer markers in more advanced stages.

The following imaging studies may be used for diagnosis: Ultrasound, ERCP, CT (with oral/IV contrast), and MRI. Ultrasound is usually the first modality used because of low cost. Treatment is based on the staging on the disease but is usually surgical, followed by chemotherapy and radiation therapy. Unfortunately, only 20 - 25% of gallbladder cancers are found early enough to be treated by surgery only. 5 year survival rates for stage 2 – 5 gallbladder cancers are low, from 2% to 7%. 5 year survival rates for cancer that has not spread beyond the gallbladder range from 29% to 81%.

This contrast CT image shows invasion of the liver (arrow) and a malignant gallbladder mass and gallstone (arrowhead).

References:

American Cancer Society Detailed Guide: Gallbladder Cancer. Accessed February 8, 2010 at http://www.cancer.org/docroot/CRI/CRI_2_3x.asp?rnav=cridg&dt=68

MayoClinic.com. Gallbladder Cancer. Accessed February 8, 2010 at http://www.mayoclinic.com/health/gallbladder-cancer/ds00425

Image: RadioGraphics September 2008 vol. 28 no. 5 1307-1323. Accessed February 8, 2010 at http://radiographics.rsna.org/content/28/5/1307/F13.large.jpg

Histoplasmosis

I wanted to do my blog on histoplasmosis this week because I have a good friend whose mother lost her eyesight due to the disease. Some of you may know that Indianapolis had a large histoplasmosis outbreak in 1978. Many epidemiologists in the city believed it was related to the old Riverside Amusement Park being demolished. The amusement park was vacant for 8 years prior to demolition and was a popular bird roost. My friend’s parents lived near the amusement park during the demolition and her mother contracted a severe case of histoplasmosis during the city outbreak. Blood cultures taken from high school students in 1978 showed the highest concentration of infections in the census tract directly adjacent to the amusement park (Wheat, 1992).

Histoplasmosis is an infection caused by the soil fungus Histplasma capsulatum. The fungus is widespread in the Midwestern U.S. and is most common in areas that have three to five years of accumulated bird and/or bat droppings. Once those droppings are disturbed in any way they literally release billions of spores into the air, ready to be inhaled into the lungs – the primary infection site. This puts construction and demolition workers at particularly high risk, especially if they work in old buildings which may have bird or bat roost areas.

The disease usually results in mild respiratory illness similar to the common cold, but it can be more severe depending on the immune status of the patient and the dose of inhaled spores. Signs of more severe histoplasmosis infection can include chronic cough, chest pain, hemoptysis and fever. The disease is diagnosed by looking in sputum, lung tissue and CSF for signs of the fungus. Chest x-ray and/or chest CT is usually performed. Treatment is with antifungal medications to control lung infection but lung scarring (granulomas) often occur. This CT image shows granulomas from histoplasmosis. Severe illness can lead to permanent lung damage and blindness.

Most people who live in Indiana will have been infected by the spores by the time they reach adulthood and usually the body’s immune system will overcome the infection without any kind of treatment. However, anyone who has had a severe case of histoplasmosis with lung involvement should be regularly monitored for Ocular Histoplasmosis Syndrome (OHS), which is a leading cause of vision loss in Americans between the ages of 20 and 40. This is what happened to my friend’s mom. OHS occurs when the histoplasmosis spores spread from the lungs to the choroid layer of the eye. The spores cause scar tissue to form which then damages the retina resulting in vision loss. These scars are called “histo spots” and can be seen in an eye examination. Those spots along with retinal swelling indicate the OHS disease in the eye. Laser treatment can sometimes slow the progression of the disease.

References:

Histoplasmosis. Accessed January 12, 2010 at http://www.nlm.nih.gov/medlineplus/ency/article/001082.htm

IN.gov. Histoplasmosis: A Hoosier Concern. Accessed January 12, 2010 at http://www.in.gov/isdh/23254.htm

Medic8.com. Ocular Histoplasmosis Syndrome (OHS). Accessed January 12, 2010 at http://www.medic8.com/eye-disorders/histoplasmosis.htm

Wheat, L. (1992). Histoplasmosis in Indianapolis. Clinical Infectious Diseases, March 1992. Vol. 14, S1. The University of Chicago Press. Accessed January 12, 2010 at http://www.jstor.org/pss/4456398

Image:

http://www.medscape.com/content/2003/00/46/10/461046/art-ar461046.fig5.jpg

The lemon sign

For my blog this week I wanted to learn more about spina bifida. Occasionally in the clinic we will see a case of spina bifida occulta when scanning a lumbar spine. However, I wanted to learn more about how more severe cases are diagnosed in utero. I found an interesting article which talked about the “lemon sign” on ultrasound. This sign is strongly associated with spina bifida. The image on the left shows the normal contour of a skull in an 18 wk fetus in utero. The image on the right is of a 20 week old fetus with spina bifida (note the lemon shape). The scans are transverse at the level of the ventricles. The lemon shape is caused by a loss of the normal shape of the frontal bones and it is suspected that a decrease in intracranial pressure causes the brain to shift downward, thus resulting in the depressed skull. For some reason the frontal bones are most sensitive to the pressure change. Interestingly this sign will disappear as the fetus matures so this sign is most useful in ultrasound before 24 weeks, especially in cases of open spina bifida. The lemon sign can also indicate other conditions but seeing this sign in an ultrasound prior to 24 weeks means the ultrasound tech should evaluate the spine more closely looking for other signs of spina bifida. In addition, the cranium needs to be evaluated for the 4 signs of spina bifida – ventriculomegaly, microcephaly, obliteration of the cisterna magna (w/absent cerebellum), and abnormal anterior curvature of the cerebellum.

Spina bifida occurs about seven times in every 10,000 live births. Folic Acid supplementation before and during pregnancy has been shown to decrease the risk of spina bifida in the fetus. Ultrasound or amniocentesis tests for spina bifida are usually ordered if alphafetaprotein (AFP) results are elevated in the mother’s second semester quadruple screen blood test. Effects of spina bifida on the fetus can be mild to severe and can include spinal abnormalities, hydrocephalus, paralysis, and urinary and/or fecal incontinence. Prenatal diagnosis is important, allowing the parents the option of in-utero surgery, surgery after birth, or pregnancy termination.

Images and References:

Spina Bifida Association. Accessed December 8, 2009 at http://www.spinabifidaassociation.org/site/c.liKWL7PLLrF/b.2642323/k.8E10/Spina_Bifida.htm

Thomas, M. (2003). The Lemon Sign. Radiology. RSNA Journals Online. Accessed December 8, 2009 at http://radiology.rsna.org/content/228/1/206.full

Thoracic Compression Fractures and Osteoporosis

For my blog this week I decided to write about thoracic vertebral compression fracture since this is a common reason for CT scans at my clinical site. Vertebral compression fractures are typically caused by osteoporosis and a severe fracture can cause a great deal of pain for the elderly patient. This pain can begin to interfere with the ability to perform tasks of daily living.

Vertebral fractures will affect 25% of postmenopausal women in the U.S. The risk increases with advancing age and rises to 40% by age 80. Of great concern is the mortality rate for these women. It is 15% higher than for the same age group without fractures.

Acute fractures usually occur with some trauma, like a fall, tripping over an object or a lifting injury. If the osteoporosis is severe something as simple as lying in bed or sneezing can cause a fracture. The force usually causes the anterior portion of the thoracic body to compress, forming a wedge. The fracture is considered “burst” if the entire vertebra compresses. Over time and with multiple fractures the patient will lose height and become kyphotic. Many fractures go undiagnosed because older patients may expect back pain as a sign of aging or arthritis.

Compression fractures in the thoracic area are usually in the T8 – T12 area. CT is usually used to confirm plain film and physical exam diagnosis, show spinal cord narrowing and assess the stability of a fracture. MR is used if the patient is showing symptoms of spinal cord impingement. Nuclear Medicine is also used for diagnosis because new fractures will appear “hot” on the scan but healed fractures will not.

Conservative treatment for stable fracture includes muscle relaxants, back brace, NSAID’s if well tolerated, and physical therapy. Mild exercise is encouraged once the fracture is fully healed. Some patients may require either vertebroplasty or kyphoplasty, where cement is injected into the collapsed vertebral body to increase stability. This CT image shows a thoracic compression fracture.

Image: http://www.urmc.rochester.edu/smd/Rad/neuroimages/CTT-spine.jpg accessed November 30, 2009

Reference: Old, J. & Calvert, M. (2003). Vertebral Compression Fractures in the Elderly. AAFP, January 1 2004. Accessed November 30, 2009 at http://www.aafp.org/afp/20040101/111.html

Odontoid Fracture

For my blog this week I wanted to learn more about Odontoid fracture. The facility where I work weekend option diagnostic x-ray is going to become a Trauma One facility in the next few years so we will be seeing more severe trauma. And we recently had a patient come into my clinical location for repeat scans post C-2 fracture. He had been in a car accident 8 months prior and sustained a severe whiplash injury to his neck. He told me that he had been in the back seat of the car when it was rear-ended at high speed. The fact that he wasn’t wearing his seat belt actually saved his life because he was only flung forward. He was told by his physicians that had he been caught by the seat belt and flung backward as well the force would have severed his spinal cord and killed him instantly.

I was amazed that he walked into the clinic. He told me he was put into a collar and onto a backboard at the accident scene. He had an immediate CT scan in the ER which showed the fracture. His first surgery was an anterior screw for stability similar to image #4 on the right. I forgot to ask him if he wore a halo after this surgery but I would guess that he did since this seems to be the conventional treatment. He told me that the initial screw started to migrate causing him pain and numbness so a second surgery was performed replacing the first screw with posterior hardware. We were scanning in CT that day to assess the healing and stability of the second set of hardware (similar to image #1 on the left). Unfortunately I don’t have his actual images to post here.

I learned that there are 3 types of Odontoid fracture and most are caused by MVA’s and falls. 1/3 of C-spine injuries occur at C2 and ½ at C6-C7. The majority of fatal injuries occur at C1 or C2 and they tend to occur due to extreme flexion, extension or rotation. They are classified by their location on the dens. Type I goes through the very top of the dens and is very rare, only about 5% of cases. Type II is shown in the middle two images here and is through the base of the dens. This represents about 60% of dens fractures and is the most common type. Type III is through the body of C2 and doesn’t actually involve the dens and is about 30% of fractures. CT is better for demonstrating fractures and MR is used to show the extent of soft tissue, disc, ligament and spinal cord involvement.

Type I fractures are usually treated with a hard collar. Type II fractures are treated surgically as described above with the addition of a stabilizing halo for several months. My patient told me he just feels lucky to be alive. After seeing his images, I must say I agree!

References and Images:

http://www.learningradiology.com/caseofweek/caseoftheweekpix2007-1/cow248arr.jpg

http://www.ispub.com/ispub/ijss/volume_3_number_1/spinal_stenosis_c1_2_following_redo_surgery_for_failed_odontoid_screw_fixation_scrutinizing_the_odontoid_fracture_classification/spinal-fig2.jpg

http://www.thebarrow.org/stellent/groups/public/@xinternet_con_bni/documents/webcontent/bqjpg120.jpg

http://images.google.com/imgres?imgurl=http://www.learningradiology.com/caseofweek/caseoftheweekpix2007-1/cow248arr.jpg&imgrefurl=http://www.learningradiology.com/archives2007/COW%2520248-Dens%2520Fracture/densfxcorrect.html&usg=__9b3ipB8OObNWJB1UHLHw2svtEAA=&h=332&w=604&sz=38&hl=en&start=2&sig2=scLSLDfPMqpXROTBDOmmYA&um=1&itbs=1&tbnid=ip3Up3zf1tX1MM:&tbnh=74&tbnw=135&prev=/images%3Fq%3Dodontoid%2Bfracture%26hl%3Den%26sa%3DX%26um%3D1&ei=-gkMS_LfLIG8MPSC0dgC