Dermatologic and ophthalmic uses for the office otoscope

February 2005

The magnifying lens of the diagnostic office otoscope can and should be used for much more than assistance in the otoscopic examination of the ear canal and tympanic membrane (TM). For help in identification of several dermatological conditions, magnification is sometimes necessary for an accurate diagnosis. I use my otoscope for such diagnostic purposes quite frequently. Although there are better instruments available for the purpose, such as the Dermatoscope (Welch Allyn Corp.) or high-power magnifying lenses, office otoscopes are available in every examining room and, in most situations, serve the purpose well. At a power of 2.5 times normal magnification, lesions are easier to see, including fine details that may not be apparent with unmagnified vision. Another practical use for the magnifying lens is identification of small specks of dirt on the inner palpebral surface of the eyelid or diagnosing epiblepharon or incurving lashes irritating the eye.

The pneumatic otoscope can and should be used for diagnosis of TM retraction pockets. When a small circular portion of the TM appears to be sucked inward toward the promontory of the inner ear, apply negative pressure by mouth or by partially pressing the pneumatic bulb attachment, seating the aural speculum firmly at the external auditory meatal opening, releasing the pressure on the pneumatic bulb and watching the invaginated area to see if it can be sucked upward toward the examiner’s eye. If the atelectatic area is immobile to the application of negative pressure by mouth or pneumatic bulb, it is probable that the area of atelectasis is fixed to the promontory, a condition called adhesive atelectasis. That condition demands careful examination under the magnifying otomicroscope in an otolaryngologist’s office. Complications of chronic untreated adhesive atelectasis include ischemic necrosis of the incus or stapes bones and formation of a nidus for middle ear cholesteatoma.

Testing for tube patency

The diagnostic otoscope can also be used to determine the patency of tympanostomy tubes. If a tympanostomy tube is not in the usual horizontal line, or if the tubal orifice appears to be occluded, application of gentle positive pressure should be accompanied by a flutter noise if the tympanostomy tube is patent. The noise is caused by the positive pressure traversing the tympanostomy tube, entering the middle ear space and exiting through the eustachian tube, which vibrates as the air traverses it and exits into the nasopharynx. If the tympanostomy tube is occluded, this flutter noise cannot be produced. If there is an effusion in the middle ear space, eustachian tube flutter will not be produced, and there will be reduced or absent TM mobility because of the impedance caused by the middle ear effusion.

Vaginoscopy

Several decades ago, in one of the “throwaway” medical journals, there was a short practical “pearl” about using 3-mm or 4-mm size aural specula attached to a therapeutic otoscope head to perform vaginoscopy when searching for an intravaginal foreign body in a young girl. Aural specula designed for cats and dogs have a 5- or 6- cm long straight portion, which can be inserted safely into a sedated but conscious young girl’s introitus. They may be purchased from veterinary surgical supply companies.

Practical tips for 2005

1. At-home collection of urine specimen for urinalysis and urine culture: When in a pinch situation, not as my routine, I have had success at requesting collection of a urine specimen by a somewhat unorthodox method. The parent of a young child, not yet toilet trained, is instructed to layer about six or seven sheets of paper towel and interpose them between the child’s genitalia and the diaper. When the child finally urinates, the saturated layer of paper towel closet to the child’s skin is peeled off and thrown away. The remaining sheets are either squeezed out into a sealable plastic bag or placed into the bag and squeezed out in the office. Urine leukocytes are preserved, and bacteria in infected urine pass through the first sheet and can be recovered by usual urine culture methods.
2. Method for collection of diarrhea stool specimen from an infant/toddler: Request the parent to reverse the plastic-lined diaper so that the plastic side is adjacent to the baby’s skin and the paper side is facing outside. When loose or watery stool is passed, the plastic is impervious and can be emptied into a sealable plastic bag or stool collection container.
3. Plantar wart treatment: Plantar warts are notoriously difficult to eradicate by the usual pediatric office methods of freezing or use of cantharidin or salicylic acid-containing wart remedies. More than 30 years ago, the senior pediatrician at my new pediatric practice advised me to use an old tried-and-true method that had an 80% rate of plantar wart elimination. The prescription is as follows: podophyllin resin, 1 g; linseed oil, 1 cc; lanolin, sufficient quantity to 5 g. Instructions to the parent include the following advice: After bathing or showering the child, dry the affected foot thoroughly. Dip a cotton-tip swab in petrolatum jelly and trace a circle around the plantar wart about 2 mm from the dome-shaped wart. Then, using another cotton-tip applicator, apply a small dab of the compound onto and for about 2 mm away from the plantar wart. Cover the wart and encircle the foot with duct tape or waterproof adhesive tape. This allows the podophyllin to absorb into the stratum corneum of the foot. Repeat the procedure every day for three or four weeks. Every three to four days, scrape off the gray-colored dead skin. When the hypertrophic keratin is level with the normal skin of the foot, scrape the wart in a downward conical design. Little by little, reapplication of the cream and scraping off the dead skin will create a cone-shaped depression in the foot. When the nidus of the plantar wart comes into contact with the mitotic poison podophyllin, the wart will turn into a gelatinous mess.

This procedure should be successful at least 75% of the time and save time, money and foot pain.

A happy and healthy New Year to all readers of this column.

Dr Schwartz is prudent in counselling that this method of urine collection should be evaluated comparing it to the "gold standard" before using it to decide on whether an infant has a urinary tract infection (UTI). It is likely that if white cells pass through the tissue, bacteria, which are much smaller. will pass through as well. Before labeling a baby as having a UTI one should use standard methods of urine collection. A diagnosis of UTI commits one to treatment, work up and follow up. It will make one very uncomfortable if a child on antimicrobials for a pseudo UTI continues to remain febrile. At that point a urinary culture is of little value since there will be high levels of antibiotic in the urine and one will be faced with the problem of determining the cause of fever in an infant on antimicrobial therapy.

— Philip A. Brunell, MD

For more information:

• Richard H. Schwartz, MD, is from the department of pediatrics at Inova Fairfax Hospital for Children, Falls Church, Va.