Wednesday, February 20, 2008

Orbital Cellulitis

Orbital cellulitis is an infection of the soft tissues of the orbit. The most common cause is the spread of an infection of the ethmoid sinuses. However, it can also occur as a result of direct infection cause by orbital trauma or surgery. Bacteria in the blood can also spread and cause optical cellulitis. The first picture above is of a patient with optical cellulitis of the left eye. (emedicine.com) The second image is an axial slice CT image of a patient with optical cellulitis. (Also from emedicine.com) This infection is most common in winter due to the increase in sinusitis. Children are more likely than adults to be affected. Some symptoms include lid edema, orbital pain, fever, headache, decreased vision, increased intra-ocular pressure and inability to open the eye.
To diagnose orbital cellulitis lab test are done as well as imaging studies. Lab tests include CBC, blood cultures and smear for Gram stain and culture of nasal discharge. A high resolution CT scan with pre and post contrast images are used with axial and coronal slices.

Treatment for orbital cellulitis is antibiotics for the infection, diuretics for increased intra-ocular pressure, nasal decongestant if cellulitis is secondary to sinusitis, and an antifungal if the cellulitis is attributed to a fungus.

Sunday, February 10, 2008

Craniopharyngioma

Craniopharyngiomas are tumors in the brain located at the base of the skull near the pituitary gland. Most craniopharyngiomas are benign tumors. They account for between 2%-4% of adult and between 5%-13% of childhood primary brain tumors. Patients with these tumors don't usually have symptoms until the tumor grows and pushes against the optic nerve, pituitary gland or the brain. Symptoms can include headache, nausea, vomiting, vision problems, balance issues, difficulty speaking, confusion, seizures, hearing difficulties, and hormonal disorders. To diagnose craniopharyngioma doctors can evaluate the patient clinically by testing their hearing, vision, balance, coordination, reflexes and hormone levels. Imaging studies can be used to confirm clinical evaluation. MRI would show good soft tissue contrast and is the imaging modality of choice. Other imaging could include CT, Angiogram, MRS, SPECT, and PET. Treatments for craniopharyngioma, given separate or together, can give patients a high rate of long term survival. Surgery, external radiation, stereotactic radiosurgery, and intracavity irradiation, are included in the therapies along with the occasional use of chemotherapy.

The images above are a sagittal T1 weighted MRI image on the left and an axial CT scan on the right, both showing a craniopharyngioma.

Friday, February 1, 2008

Bell's Palsy

Bell's Palsy is caused by trauma to the cranial nerve 7 or the facial nerve. The trauma or damage many scientists think is caused from viral menningitis or herpes simplex virus 1. The facial nerve swells and becomes inflammed. Paralysis of the facial muscules result. Many patients experience symptoms that progress quickly. The symptoms include eye and corner of the mouth drooping, tingling around lips, drooling, and dry eye and/or mouth. The majority of patient's with Bell's Palsy are affected unilaterally, bilateral facial paralisis caused by Bell's Palsy is rare. Some populations are more likely to develop Bell's Palsy. They include diabetics, pregnant women in their third trimester, and individuals with a weakend immune system. The diagonsis is usually found in a clinical examination. However, MRI may be used. In a T1 weighted scan with gadolinium the inflamed nerve can be seen. In the image above, the patient has a right sided inflamed facial nerve. Anti-viral and anti-inflamatory medications can be used to treat Bell's Palsy.