How Good Are Ankle Rules for Determining If a Patient Needs An X-Ray?

Patient Presentation
A 16-year-old male came to clinic with a 24 hour history of right ankle injury. He had been playing basketball and had an inversion injury. He denied any pops or other sounds at the time. He had not been able to walk right after the injury. He had elevated the leg, used intermittent ice and had some ibuprofen, yet he was still having a reasonable amount of pain and was still limping. The past medical history was negative for other extremity injuries.

The pertinent physical exam showed a well-appearing male with normal vital signs and growth parameters. His left ankle was moderately bruised and swollen over the lateral malleolar area. He had tenderness over the posterior talofibular and fibulocalcaneal ligaments. There was no tenderness along the fibula itself but the swelling made the examination difficult to tell. He also wasn’t sure if there was pain near the 5th metacarpal. The medial malleolus, tibia and navicular had no pain with palpation. There was no other foot pain and he was neurovascularly intact.

The diagnosis of a possible ankle sprain versus fracture was made. The pediatric resident said that he knew that there were criteria for when you should get an ankle x-ray but wasn’t sure what they were nor how good they were for diagnosing fractures. The attending physician reviewed the Ottawa Ankle Rules with him, demonstrating that the patient was not able to walk and had swelling that compromised the examination making it difficult to tell if there was point tenderness in some key areas or not. The radiologic evaluation showed no fracture. The patient was placed into a removeble aircast and crutches. He was referred to physical therapy for rehabilitation as the patient was finishing his basketball season but was starting another sport in 3 weeks.

Discussion
Ankle sprains result from force around the ankle that exceeds the tensile strength of the supporting ligaments of the ankle but less than that which breaks the ankle bones. The ankle capsule – ligament complex has 5 primary ligaments:

Medial ankle – the deltoid is the strongest ligament in the ankle and has two parts:

  • Superficial deltoid ligament – runs from the medial malleolus to the calcaneus posteriorly
  • Deep deltoid ligament – runs from medial malleolus to the talus

Lateral ankle – these ligaments act like 3 guidewires to the lateral ankle and are generally injuried in the following order:

  • Anterior talofibular ligament – runs anteriorly to the lateral malleolus
  • Fibulocalcaneal ligament – runs laterally to the lateral malleolus
  • Posterior talofibular ligament – runs posterior to the lateral malleolus

Most ankle injuries involve an inversion of the ankle. The ability to walk generally excludes a fracture. People with third-degree ankle sprains often give a history of an audible snap. The physical examination revels intact skin with swelling. Pain upon motion is common as is point tenderness over the ligaments. An anterior drawer sign indicates anterior talofibular ligament rupture.

Clinical decision rules are tools to help clinicians make diagnostic decisions. There are two validated ankle decision rules that can help clinicians determine if an ankle injury requires a radiograph.

The Ottawa Ankle Rules
An ankle radiograph is only recommended if there is any pain in the malleolar areas plus one of the following

    1. Bone tenderness posterior aspect of the distal 6 cm of the tibia
    2. Bone tenderness posterior aspect of the distal 6 cm of the fibula
    3. Inability to bear weight (taking 4 complete steps)

A foot series radiograph is only recommended if there is any pain in the midfoot areas plus one of the following

    1. Bone tenderness of the navicular bone
    2. Bone tenderness at the 5th metatarsal
    3. Inability to bear weight (taking 4 complete steps)

The Ottawa Ankle Rules are used in the adult and pediatric populations.

The Low Risk Ankle Rules
“The Low Risk Ankle Rules states that if a child with an ankle injury has a low-risk examination (i.e., tenderness and swelling isolated to the distal fibula and/or adjacent lateral ligaments distal to the tibial anterior joint line), ankle radiography may not be necessary to further exclude a high-risk ankle injury…”
A high-risk injury includes any fracture of the foot, distal tibia and fibula proximal to the distal physis, tibiofibuar syndemosis injury and ankle dislocations.”
Low risk injuries are managed by supportive splinting and returning to activities as tolerated. Low risk injuries would include avulsion fractures of the distal fibula or lateral talus, and non-displaced Salter-Harris type I and II of the distal fibula and lateral ankle sprains.

Obviously overall clinical judgment must be kept in mind. If there is significant swelling such that the entire area cannot be palpated properly, there is potential neurovascular compromise, the patient’s mental status is compromised, or for some other reason the area cannot be properly evaluated then radiographs should be considered.

Learning Point
A systematic review and meta-analysis of using the Ottawa Ankle rules found the sensitivity to be ~99% and specificity of ~35%. The pediatric age group has a slightly lower sensitivity (97.9%) and lower specificity (21%).
This study supports that if the clinical examination indicates a low risk injury, then radiographs are not indicated. If the examination indicates a potential high risk injury, then the radiographs would be indicated because the clinical examination cannot discern well enough if a fracture is present or not.

Use of the Low Risk Ankle Rule was evaluated in a Canadian study of 3-16 year old children. The study found a decrease in radiographs by 22% using the Low Risk Ankle Rules. Overall the sensitivity was 100% and the specificity was 53.1%.
This study supports that if the examination indicates a low risk injury, then radiographs are not indicated. Fractures that were missed in the low risk group (i.e. false negatives) were low risk fractures that were treated like ankle sprains. If the examination indicated a potential high risk injury, then the radiographs would be indicated because the clinical examination cannot discern well enough if a fracture is present or not.
This group also found cost savings of $37 Canadian dollars per patient.

While most of the studies using these ankle rules are in emergency departments or physician offices some time period after the injury, similar data has been shown for athletic trainers treating acute (<1 hour after injury) ankle injuries.
In this study, which utilized the Ottawa Ankle Rules, it is understandable that the need for radiographs was overestimated (i.e. false positive clinical examination) because of increased pain, guarding and/or unwillingness to bear weight right after the injury. In this study, the sensitivity was 88% but had 0 specificity. The authors point out that negative clinical findings ruled out the need for radiographs and decision making "…based on the totality of the examination findings is the best filter in determining referral for radiographs."

Questions for Further Discussion
1. What are the Ottawa Rules for knees?
2. What other validated clinical decision rules do you use?

Related Cases

    Symptom/Presentation: Pain

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, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Ankle Injuries and Disorders and Sprains and Strains.

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.

Boutis K, Grootendorst P, Willan A, et. al.. Effect of the Low Risk Ankle Rule on the frequency of radiography in children with ankle injuries. CMAJ. 2013 Oct 15;185(15):E731-8.

Boutis K, von Keyserlingk C, Willan A, et.al.. Cost Consequence Analysis of Implementing the Low Risk Ankle Rule in Emergency Departments. Ann Emerg Med. 2015 Nov;66(5):455-463.e4.

Browne GJ, Barnett PL. Common sports-related musculoskeletal injuries presenting to the emergency department. J Paediatr Child Health. 2016 Feb;52(2):231-6.

David S, Gray K, Russell JA, Starkey C. Validation of the Ottawa Ankle Rules for Acute Foot and Ankle Injuries. J Sport Rehabil. 2016 Feb;25(1):48-51.

Beckenkamp PR, Lin CC, Macaskill P, Michaleff ZA, Maher CG, Moseley AM. Diagnostic accuracy of the Ottawa Ankle and Midfoot Rules: a systematic review with meta-analysis. Br J Sports Med. 2016 Nov 24. pii: bjsports-2016-096858. doi: 10.1136/bjsports-2016-096858. [Epub ahead of print]

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

How Common is α-1-Antitrypsin Deficiency?

Patient Presentation
A 4-year-old male came to clinic with a 3 day history of rhinorrhea and cough. The night before he developed a fever to 101.5°F. and was complaining of left ear pain. He had received ibuprofen with relief. He was drinking and urinating well. The past medical history was positive for α-1-Antitrypsin Deficiency diagnosed in the neonatal period because of prolonged jaundice.

The pertinent physical exam showed a mildly-ill appearing male with normal vital signs except for a temperature of 100.6°F. His growth parameters were between 10-50%. HEENT showed moderate clear rhinorrhea, normal pharynx, and a supprative effusion behind the left tympanic membrane with distorted landmarks. His right tympanic membrane was slightly erythematous but not bulging and without fluid. His lungs were clear. His abdomen was soft, and non-tender without organomegaly. His skin was normal. The diagnosis of left supprative otitis media was made in a patient with α-1-antitrypsin deficiency. The pediatrician prescribed amoxicillin for the ear infection. The parent said, “He’s had that before and it wasn’t a problem. We just want to stay away from any medicines that could cause liver problems because of his problem though.” The patient receive his seasonal influenza vaccine that day also.

Discussion
α-1-Antitrypsin Deficiency (A1AT) is a common single-gene mutation disease that is homozygous recessive. The normal allele is called M and the most common abnormal allele is Z. There are other alleles though. The gene codes for one of the primary protease inhibitors in the serum, thus those who are homozygous for the Z gene are sometimes referred to as “PIZZ” or “PIZ.” α-1-Antitrypsin is found in all body tissues but is especially important in the serum and lung. As noted it is one of the primary neutrophil protease inhibitors in the serum, and acts to neutralize these enzymes when they leak into the extracellular fluid during inflammation. The Z mutation causes the synthesis of an abnormal protein which is retained in the hepatocytes and accumulates instead of being secreted. This can cause chronic liver disease including cirrhosis and hepatic failure. The Z mutation also causes emphysema in young to middle-aged adults. The natural history of the disease process can be quite variable.

Pediatric patients may be asymptomatic or present with cholestatic hepatitis, hepatomegaly, and nutrition/growth problems. Other important problems include chronic liver disease with cirrhosis and fibrosis (lifetime risk ~50% for ZZ patients). Hepatocellular carcinaoma risk is increased. The lungs are particularly sensitive to A1AT. Lung infections, asthma, and emphasema occur and smoking or second-hand smoke increases the risk of serious lung disease. Lung disease more commonly presents in the adult population. Panniculitis and secondary vasculitis have also been reported in the literature. Treatment is supportive and can include organ transplant of the liver or lung. Treatment by giving α-1-Antitrypsin have not been very successful.

Learning Point
A1AT is one of the most common single gene mutations occurring in ~ 1:2,000 – 3,500 births in North American and European populations. There are ~100,000 people affected in the United States but the disease can be unrecognized and thus undiagnosed. This is particularly true because of the variation in the disease presentation.

As this is one of the most common genetic mutations, potentially it is a candidate for neonatal screening and further studies have been called for.

Questions for Further Discussion
1. What is in the differential diagnosis of conjugated hyperbilirubinemia? A review can be found here.
2. What is in the differential diagnosis of unconjugated hyperbilirubinemia? A review can be found here.
3. What are indications for solid organ transplantation?

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, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: alpha-1-Antitrypsin Deficiency.

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.

Fregonese L, Stolk J. Hereditary alpha-1-antitrypsin deficiency and its clinical consequences. Orphanet J Rare Dis. 2008 Jun 19;3:16.

Teckman J, Pardee E, Howell RR, et.al.. Appropriateness of newborn screening for α1-antitrypsin deficiency. J Pediatr Gastroenterol Nutr. 2014 Feb;58(2):199-203.

Lane CR, Tonelli AR. Lung transplantation in chronic obstructive pulmonary disease: patient selection and special considerations. Int J Chron Obstruct Pulmon Dis. 2015 Oct 9;10:2137-46.

Online Mendelian Inheritance in Man. Alpha-1-Antitrypsin Deficiency; A1ATD. Available from the Internet at http://www.omim.org/entry/613490?search=alpha%201%20anti-trypsin&highlight=1%20alpha%20trypsin%20anti%20antitrypsin (rev. 8/4/16, cited 2/13/17).

Gotzsche PC, Johansen HK. Intravenous alpha-1 antitrypsin augmentation therapy for treating patients with alpha-1 antitrypsin deficiency and lung disease. Cochrane Database Syst Rev. 2016 Sep 20;9:CD007851.

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

Date
April 24, 2017

Short Spring Break

PediatricEducation.org is taking a short spring break. The next case will be published in on April 24. In the meantime, please take a look at the different Differential Diagnoses, Symptom and Disease Cases listed at the top of the page. Maybe even a few spring flowers outside your window too.

We appreciate your patronage,
Donna D’Alessandro and Michael D’Alessandro, curators.

What Are the Clinical Symptoms Associated with Friedreich Ataxia?

Patient Presentation
A 12-year-old female came to clinic for her health supervision visit. She complained of new onset intoeing that had been occurring for more than 6 months. She had not seen a physician for more than 2 years and the family could provide few details about the history. She said that she was more “clumsy” over time and would trip and occasionally fall even when walking on even ground. She denied any pain, numbness, tingling, difficulty with walking distances or up stairs, or fine motor problems including writing, tieing shoes, brushing teeth or eating. She denied any visual problems. They weren’t sure if it was getting worse but the intoeing was obvious to other people. She denied any trauma or infectious diseases other than a cold. The travel and animal contact history was negative and she denied any anxiety or depressive symptoms. Her grades at school were the same and she had the same several friends. The family was moving to another state soon.

The past medical history showed her to be underimmuized, but she was fully immunized for varicella. The family history was negative for any neurological or orthopaedic problems including no intoeing or outtoeing as a younger child. The review of systems showed no fevers, nausea, emesis, changes in hair or skin, or dysuria.

The pertinent physical exam showed a well-appearing female with normal vital signs and growth parameters around the 50th percentile. HEENT showed pupils to be equal, round and reactive to light and accommodation and no nystagmus. Visual acuity was 20/30 bilaterally. Thyroid was normal size without masses. Lungs, heart, and abdomen were normal. She was Tanner 2 for breast. Her skin had a few open comedomes on her checks and nose. Neurologically her cranial nerves were intact. Her strength was normal in upper and lower extremities. She had +1/+2 deep tendon reflexes in the lower extremities and had positive Babinski reflexes. There was no clonus. Sensation and position sense were equivocal in the lower extremities because the patient didn’t seem to fully understand the questioning. She did not appear to have a direct sensory level though. She had normal deep tendon reflexes in the upper extremities. She appeared to have normal rapid alternating movements, but had some past pointing with finger-to-nose testing. She had had a positive Rhomberg test, but negative Gower maneuver. When walking she had intoeing bilaterally and a wider-based gait.

The diagnosis of a chronic, possibly progressive, neurological condition affecting mainly the lower extremities was made. The differential diagnoses included infection (which seemed unlikely), tumor affecting the spinal cord or cerebellum, or a underlying hereditary disease including ataxias. The patient’s clinical course showed that she was referred to a pediatric neurologist who felt her clinical examination was most consistent with a hereditary ataxia, most likely Friedreich ataxia. The family wanted minimal testing, so genetic testing was sent and was positive for Friedreich ataxia. The family moved to another state soon after the diagnosis.

Discussion
Friedreich ataxia (FRDA) was first extensively described in a series of papers from 1863-1877 by Nikolaus Friedreich at the University of Heidelberg, Germany. In 1996 the genetic mutation was described. It is an autosomal recessively inherited, homologous expansion of the GAA repeat in intron 1 of the frataxin gene on chromosome 9q13. It causes a transcription error leading to a decrease in frataxin which is a mitochondrial protein involved in iron metabolism and other cell functions. Frataxin is seen mainly in the central and peripheral nervous systems, heart, pancreas and skeleton. Frataxin is produced but in decreased amounts, and lack of frataxin causes in-utero lethality of the embryo.

FRDA is the most common cause of autosomal recessive ataxia. Point estimates are up to prevalence 3/100,000 and it is estimated that ~9000 patients in the United States with FRDA at any given time. Age of onset is in early teens with a mean of ~15 years with most cases developing by 25 years, although genetic testing has allowed more adult patients to be identified. FRDA is unfortunately progressive and patients’ have a decreased lifespan at 40 years (+/- 20 years). There is a correlation with the number of repeats with an increased number having increased disease severity. There is no generational anticipation where subsequent generations have increased severity or onset at earlier ages.

Unfortunately, FRDA is progressive and many treatments help to support the patients and decrease side effects to help with mobility and nursing care. Potential treatments being used include antioxidants, frataxin-inducing agents and gene therapy.

Learning Point
Patients with FRDA can have several presentations including neurological problems, scoliosis or pes planus, or sometimes cardiomyopathy. Neurological symptoms usually associated with FRDA include gait and limb ataxia, decreased tendon reflexes, positive Babinski reflex, loss of position and vibratory sense and dysarthria. Older individuals may have an atypical presentation with preservation of tendon reflexes or very slow progression.

Clinical symptoms of Friedreich ataxia include:

  • Neurological
    • Gait ataxia
    • Distal extremity
      • Dysmetria
      • Atrophy and/or weakness
      • Loss of vibratory and proprioception
      • Sensory neuropathy – “stocking and glove”
      • Loss of stretch muscle reflexes
      • Babinski sign positive
    • Head and Neck
      • Nystagmus
      • Head titubation
      • Dysarthria
      • Blindness (rare)
      • Diminished speech perception
      • Vestibular dysfunction
  • Heart
    • Cardiomyopathy – usually hypertropic but can be dilated
    • Mural thrombi can occur and cause embolic strokes
  • Skeletal
    • Scoliosis – very common and progressive
    • Pes cavus
  • Endocrine
    • Diabetes mellitus

Questions for Further Discussion
1. What causes ataxia in general? A review can be found here.
2. What causes hereditary ataxia?
3. What causes intoeing or outtoeing in younger age groups? A review can be found here.

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, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Friedreich Ataxia and Degenerative Nerve Diseases.

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.

Koeppen AH. Friedreich’s ataxia: pathology, pathogenesis, and molecular genetics. J Neurol Sci. 2011 Apr 15;303(1-2):1-12.

Jayadev S, Bird TD. Hereditary ataxias: overview. Genet Med. 2013 Sep;15(9):673-83.

Aranca TV, Jones TM, Shaw JD, et.al.. Emerging therapies in Friedreich’s ataxia. Neurodegener Dis Manag. 2016;6(1):49-65.

OMIM. Friedreich Ataxia 1; FRDA. Available from the Internet at http://www.omim.org/entry/229300?search=FXN/frataxin&highlight=frataxin%20fxnfrataxin%20fxn (rev. 9/13/16, cited 2/6/17).

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