What Causes Anisocoria?

Patient Presentation
A 14-year-old male came to clinic after a history of hitting his head on a goal post while playing soccer 6 days before. He had “seen stars” initially but said he felt relatively well for the rest of practice. He had a soccer game the following day where he said he felt “slow and tired.” He had a dull generalized headache since the incident that waxed and waned from a dull headache to moderate (6/10 rating). The headache was worse with increases in sound and light. Sleep was okay and he was not having problems necessarily listening at school or doing his homework but was more tired. He told his parents about the symptoms on day 5 and the parents made this appointment. The past medical history showed no head injuries or neurological problems.

The pertinent physical exam showed normal vital signs with growth parameters in the 50-90% for age. His neurological examination was normal including balance and gait. His mental status examination was normal. His sport concussion assessment tool had 8 of 22 symptoms with most in the mild range. His parent endorsed 5 symptoms.

The diagnosis of a concussion was made. The patient was asked to do brain rest for 1 week, given head injury instructions and asked to return to clinic in one week. The patient’s clinical course was that the following week he saw a different clinician and showed that he had been going to school still but had not been participating in athletics. He had continued symptoms but were slightly improved symptoms with only 6 on the sports assessment tool but headache and tiredness were his main complaints. He denied any vision problems. On physical examination he had a right pupil that was 3-4 mm and a left pupil that was 2-3 mm in size. Both were round, reactive to light and accommodation. All extra ocular movements were intact. There was no increased lacrimation and his disc margins were sharp. He said he was still a little tender where he had hit the pole with his head but a detailed head and neck and neurological examination revealed no focal findings.

The diagnosis of concussions with a new notation of anisocoria was made. His mother said she couldn’t really remember him having different sized pupils but that she had one herself which the clinician noted to be about 1 mm different in size. As the patient had no neurological findings and his overall symptoms were improving, it was decided to watch him and the family would call with any vision or neurological changes. They decided together that he could continue going to school but no atheletics. The patient’s clinical course showed that he still had a similar physical examination and he was slowly improving with only 3 symptoms noted on repeated sport concussion assessment tool but still with some headaches. Followup after one more week showed the patient still to have anisocoria but no symptoms.

Discussion
Anisocoria is a common physical finding caused by the mechanical imbalance of the iris dilator (sympathetic innervation causing dilation) and sphincter muscles (parasympathetic innervation causes miosis).

Which pupil is abnormal is important to determine. “Anisocoria greater in the light signifies an abnormal large pupil, whereas anisocoria in the dark indicates an abnormal small pupil.” The pupillary size should be noted along with any changes with accommodation, extra ocular movements and lighting. The time it takes to revert to the baseline pupillary size can also be helpful. Any ptosis, lacrimation and pain should be noted. Evidence of papilledema should be looked for. Additionally, a thorough head and neck examination and neurological examination are important to look for additional diagnostic clues. While a generalist may not be able to interpret all of these signs and symptoms, gathering this information and discussion with an ophthalmologist and/or neurologist can be helpful.

Physiologic anisocoria is common with approximately 15-30% of the normal population having this physical finding. “Physiologic anisocoria should be longstanding, neurologically isolated, less than 1 mm in size discrepancy, and stable in light and dark conditions.” Old photographs may be helpful and reassuring.

Evaluation for anisocoria may include pharmacologic testing, and imaging of the head and/or neck and potentially other body areas.

Learning Point
The differential diagnosis of anisocoria includes:

  • Physiologic
  • Third nerve palsy
    • Mid-range dilation not reactive to light or convergence
    • Can be caused by mass/compressive lesions or other reasons the nerve is irritated
    • Aneurysms as a cause are uncommon in children and may cause pain
  • Tonic or Adie pupil
    • Large pupil in young women that slowly dilates after accommodation
    • Usually unilateral but can be bilateral
  • Horner syndrome
    • Classic triad of miosis (unilateral), ptosis and anhidrosis
    • Causes of Horner syndrome includes various benign and malignant tumors, syndromes, vascular abnormalities, trauma and deep infections of the neck
    • Often congenital including birth trauma as a cause
  • Drugs
    • Usually due to accidental exposure including:
      • Dilators: scopolamine, ipratropium, glycopyrrolate, nasal vasoconstrictors and plants such as blue nightshade, Jimson weed and Angel’s trumpet
      • Constrictors: clonidine, opioids, organophosphates, pilocarpine and prostaglandin
  • Trigeminal autonomic cephalgias
    • Headaches with unilateral sympathetic problems including rhinorrhea and increased lacrimation. Horner syndrome with ptosis can be seen
    • Autoimmune autonomic ganglionopathy
      • Autoantibodies target autonomic ganglia and anisocoria can be seen
      • Other dysautonomia syndrome often occur

Questions for Further Discussion
1. What is the general guidance for return to learning after head injury? A review can be found here
2. How long do concussive symptoms last? A review can be found here
3. What causes ptosis? A review can be found here
4. How common is ocular trauma? A review can be found here
5. List of the autonomic nervous system disorders?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Eye Diseases and Autonomic Nervous System Disorders.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Patel R, Davis C, Sivaswamy L. Anisocoria–not always cause for alarm. J Pediatr. 2014;164(6):1497. doi:10.1016/j.jpeds.2014.02.004

Gross JR, McClelland CM, Lee MS. An approach to anisocoria. Curr Opin Ophthalmol. 2016;27(6):486-492. doi:10.1097/ICU.0000000000000316

Harer K, Alverson B. Eye-opening Etiologies. Hosp Pediatr. 2018;8(5):300-301. doi:10.1542/hpeds.2017-0204

McEachern W, Walz A, Dantuluri K, Dulek D, Betters K. Case 3: Anisocoria in a 5-year old Girl. Pediatr Rev. 2019;40(7):366-368. doi:10.1542/pir.2018-0132

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

Summertime Break

Summertime! PediatricEducation.org is taking a summer break. The next case will be published on August 23. In the meantime, please take a look at the different Archives and Curriculum Maps listed at the top of the page.

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Can Rusty Nails Cause Tetanus?

Patient Presentation
An 11-year-old male came to clinic for his health maintenance examination. He and his father had no concerns. The pertinent physical exam revealed normal vital signs and growth parameters were in the 10-25%. His examination was normal.

The diagnosis of a healthy male was made. As the pediatrician was discussing the vaccines he needed he asked, “Is it true you can get tetanus from stepping on a rusty nail?” The pediatrician said usually no, but anything that possibly has germs on it if it gets into your body can cause problems. “That’s why anytime you have a wound you should always clean it with soap and water and watch it to see if it gets red or causes pain. If it does you need to tell your parents and maybe come see me,” she told him. She went on “You need a tetanus shot at least every 10 years, so we tell people to get them on their “0” birthdays like when you are 20, 30, or 40 years old. That way you are always up to date.”

Discussion
Clostridium tetani is a gram-positive bacillus that is anaerobic and spore forming. Tetanus spores are found universally worldwide in the soil and the stool of animals and people. The spores are hardy and can persist in a variety of environments. Contamination through the skin in wounds (especially deep puncture wounds) and the umbilicus are the primary entry points. It is not unusual for the organism not to grow in cultures. The bacteria grow in low oxygen environments and produces a potential neurotoxin which blocks the myoneural junction. Incubation period is 3-21 days, averaging 10 days. Neonatal tetanus generally start with crying and feeding problems 3-7 days after birth (can be up to 28 days) with progression to spasms. Tetanus symptoms occur gradually over 1-7 days and can progress to opisthotonus. These spasms are often provoked by external stimuli. Death can occur because of diaphragmatic spasm and laryngospasm. The spasms persist for about 1 week and then subside over a period of weeks in those who recover. Death can occur because of diaphragmatic spasm and laryngospasm. It is fatal without treatment and even with treatment has a death rate of 10-20%.

With immunization tetanus is almost 100% preventable. Tetanus is not transmitted person to person and herd immunity cannot help prevent the disease. Parents must be educated and advised of the seriousness of the disease. Immunity is not lifelong. Everyone should receive a primary series, and at least a booster shot every 10 years. Boosters may be necessary more often however.

Learning Point
Tetanus spores can contaminate any break in the skin but are more likely in:

  • Contaminated wounds with feces, dirt or even saliva
  • Puncture wounds
  • Burns
  • Crush injuries
  • Injuries with devitalized tissue – hence wound debridement is important

Rusty nails by themselves do not cause tetanus. Rusty nails are the quintessential image of what causes tetanus, and most likely someone used this image to convey the problem of contamination with tetanus spores. However it is the potential contamination of the nail with tetanus spores that is the problem not the rust itself. Nails though, are a perfect instrument to deliver whatever contamination could be on them. They cause deep wounds that are difficult to clean, and which can provide the low oxygen environment for tetanus spores to start growing bacteria in.

There is a 2020 case report of a rusty nail that had been thrown up by a lawnmower and lodged in the lung which required removal. The patient did not acquire tetanus.

Questions for Further Discussion
1. Where can you find the recommended vaccinations for locations around the world?
2. How are deep puncture wounds treated?
3. What organisms commonly contaminate deep puncture wounds?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Tetanus and Tetanus, Diphtheria, and Pertussis Vaccines.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Rhinesmith E, Fu L. Tetanus Disease, Treatment, Management. Pediatrics in Review. 2018;39(8):430-432. doi:10.1542/pir.2017-0238

Saplakoglu Y, Mar 18 2019. Do Rusty Nails Really Give You Tetanus? livescience.com. Accessed April 27, 2021. https://www.livescience.com/65007-do-rusty-nails-cause-tetanus.html

Kawamoto N, Okita R, Furukawa M, et al. Penetrating pulmonary injury due to a thrown rusty nail while using a lawn mower: a case report. AME Case Reports. 2020;4(0). doi:10.21037/acr-20-87

Centers for Disease Control, Tetanus Causes and Transmission, Published April 7, 2021. Accessed April 27, 2021. https://www.cdc.gov/tetanus/about/causes-transmission.html

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

How Do You Treat Immersion Foot Injury?

Patient Presentation
A 17-year-old male came to clinic  because of irritated feet. He had started a summer job at a car wash and was spending long days in a humid, wet environment. He initially had used the impermeable coat, pants and boots that his employer offered, but found the coat and pants were very uncomfortable as he felt they made him hotter and wetter. Therefore he wore cotton clothing. He also wore the boots but noted that water often seeped into the boots and noted “I just have wet feet all day.” He used cotton socks and would not change them during his work day. “My feet are just wet and when I get home they are always wrinkled and white like being in the bathtub too long. In the past week or so, my feet are sorer too and it seems like it is taking longer for the skin to be normal after I get home. There are some places that are cracking and peeling a bit and even when I put the athlete’s foot lotion on that I used before. It’s not helping,” described the teenager. He complained also that his hands were becoming more reddened.

The pertinent physical exam showed normal vital signs and growth. His feet were palish, with wrinkling especially around the nail beds, and edges of the heel and ball of foot with some small cracking in those areas. There was no specific scale or erythema or obvious trauma such as a blister. His feet felt somewhat cold but there was good capillary refill and pulses were intact. His hands also showed marked dryness and mild erythema overall. His legs and arms also showed some mild dryness but less severe than his hands and feet.

The diagnosis of immersion injury was made. The teen was instructed to use layered water-wicking socks with some cushion to protect his feet in the boots. These he should change whenever he has a break. The doctor also recommended that he use the impermeable pants and make sure they go over the boots to direct the water away from the boots and feet. “I’d recommend using gloves too to protect your hands,” noted the doctor. The teen protested that other workers didn’t do this and he didn’t have time during breaks, but the doctor said, “I know it can be a problem, but the water is worse for you. Besides fisherman and other people who work outside all the time seem to be able to do it. If you don’t take care of your feet it will get worse and you won’t be able to walk and work. That won’t be great will it?,” he stated. “It’s also loud at the car wash so you should wear your ear plugs too,” the doctor noted as he left the room.

Discussion
All occupations have some type of potential health consequences. Some are obvious because of the environment such as kitchen workers, first responders, helicopter pilots, etc. Others are may be less obvious or not considered such as slip and falls, cleaning supply chemical exposure, animal bites for postal and utility workers, etc. Noise and lifting objects are often overlooked problems in some settings but obvious in others such as construction. Protective measures, especially appropriate education and training and protective clothing and safety gear are obviously important for performing the work as safely as possible. Most employers want to keep their employees safe and well. Teenagers especially often do not have the experience and may also not be aware of the potential health hazards at their workplace. Parents and teens should consider all the potential occupational risks when deciding to take a job. Teens and parents can look at the US Department of Labor’s website for more information about laws here and other government websites for safety tips at Youth.Gov and OSHA.

Water is necessary for life. It is needed for growing of organic materials and also one of the most ubiquitous and easiest solvents to use for hygiene and cleaning. Therefore water is important in almost any job including: farming, landscaping, industrial production and manufacturing, and recreational activities such as lifeguarding etc. Some jobs are obvious such as fishing, shipping, commercial diver, oil rig worker, sailor, river guide, etc. But others are less obvious such as working in a car wash. When considering occupational health, it is important to ask specifically about what the person does in the job. For example, a surveyor or archaeologist may work in very wet settings and are outside in all types of weather.

A car wash has many potential occupational hazards. There are moving vehicles and moving washing equipment which can cause mechanical and noise injuries. Additionally, there are chemicals being used as well as gas fumes which can cause lung, eye and dermatological problems. It is obviously a wet environment as well. The working surfaces are impermeable and hard which can cause orthopaedic problems too.

Learning Point
Exposure to wet or muddy conditions whether they are in warm or cold conditions can cause immersion skin problems. Prolonged contact with water increases irritation and dermatitis of the skin, increases the risk of mycosal and bacterial infections, and makes the skin more at risk for trauma effects such as thermal injury, pressure or chemicals. Over time changes can include hyperkeratosis, pain and parethesias, and even necrosis and gangrene.

“Warm-water-immersion foot [or tropical immersion foot] is a syndrome characterized by painful, white, wrinkled soles due to hyperhydration of the plantar straum corneum. This leads to maceration and chronic inflammation and vasculitis.” Because it is a warm environment, infections can be common.

Cold-water-immersion foot is better known as trench foot and has been well described in many literatures, especially the military. Similar problems to wet immersion occur. Additional injuries such as hypothermia and frostbite can occur.

The main treatment for immersion skin problems is prevention. Preventing skin from becoming wet in the first place by using protective clothing that is properly fitted (ill-fitting clothing cause localized trauma), changing into dry clothing regularly (e.g. clean, layered and loose to promote circulation), monitoring for trauma such as blisters and secondary infections such as tinea, allowing enough time between exposures for the skin to recover, and decreasing venous stasis by keeping legs elevated and gently rubbing mild lubricants to prevent drying and increase venous circulation. Keeping the body a normal temperature and preventing hypothermia is important. The skin is usually best warmed at room temperature as additional heating could potentially cause thermal injury.

Questions for Further Discussion
1. How is frostbite similar to trench foot? A review can be found here
2. How do you treat hyperthermia and hypothermia?
3. How do you treat a drowning victim?
4. What were some of your own jobs and the potential occupational health risks?

Related Cases

    Symptom/Presentation: Rash

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Foot Injuries and Disorders and Frostbite.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Zani MLC, Lazzarini R, Silva-Junior JS. Warm-water immersion foot among car wash workers. Rev Bras Med Trab. 2017;15(3):217-221. doi:10.5327/Z1679443520170021

Hall A, Sexton J, Lynch B, et al. Frostbite and Immersion Foot Care. Mil Med. 2018;183(suppl_2):168-171. doi:10.1093/milmed/usy085

Rathjen NA, Shahbodaghi SD, Brown JA. Hypothermia and Cold Weather Injuries. Am Fam Physician. 2019;100(11):680-686.

Mistry K, Ondhia C, Levell NJ. A review of trench foot: a disease of the past in the present. Clin Exp Dermatol. 2020;45(1):10-14. doi:10.1111/ced.14031

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa