The Kawasaki Disease Enigma Continues 150 years Later

kawasaki disease

Kawasaki disease (KD), or mucocutaneous lymph nodes syndrome is an immune-mediated inflammation in the walls of medium-sized arteries throughout the body. It’s complications result in the coronary arteries expanding, heart attacks, and premature death.

As the leading cause of heart disease in North American and Japanese children, KD continues to bewilder clinicians and researchers – even in the midst of a global pandemic. Possible links to SARS-CoV2 has even stirred uneasiness in patients, and physicians making diagnoses.

Beginning in Victorian-era England, a young boy presented to the doctor’s office with symptoms suggestive of scarlet fever; however, noticing heart disease in this child was just baffling. Despite being unaware of this rare disease, it was beyond physicians at the time; since then, progress has been limited as clinicians still fail to comprehend the disease’s root cause.

Dating back to 1874, KD was discovered by Samuel Gee while he was dissecting the cadaver of a seven-year-old boy.

He noticed something strange, “The pericardium was natural. The heart natural in size, and the valves healthy. The coronary arteries were dilated into aneurysms at three places, namely, at the apex of the heart a small aneurysm the size of a pea; at the base of the right ventricle, close to the tip of the right auricular appendix, and near to the mouth of one of the coronary arteries, another aneurysm of the same size; and at the back of the heart, at the base of the ventricles, and in the sulcus between the ventricles, a third aneurysm the size of a horse bean. These aneurysms contained small recent clots, quite loose. The aorta near the valves, and the aortic cusp of the mitral valve, presented specks of atheroma.

From his autopsy, evident was that Gee found aneurysms in the coronary arteries running across the surface of the boy’s heart. He then placed the specimen in a jar and provided it to the Barts Pathology Museum in London. Little did he know, that his specimen marked evidence of the earliest recorded case of KD and sparked worldwide medical curiosity. Unfortunately, when physicians 100 years later were hoping to retrieve samples from the specimen containing the boy’s heart, they were informed that it was missing.

A few years later, the disease was recognized in 1967 by the Japanese physician, Tomikasu Kawasaki. Although some researchers claimed the virus was unknown, others stated KD resulted from a bacterial or fungal toxin. The windborne theory suggested that the disease was seasonal, and as such, the direction of the swaying wind played a role in infection. Others stated that since children’s immune systems are still developing and since they have just lost the protective antibodies from their mothers, they are susceptible to infection. Therefore, in Asian American household’s diets rich in soy put Asian children at greater risk due to the isoflavones. In the 1980s, the Center for Disease Control and Prevention (CDC) suspected chemicals as the cause of KD, inferring that disease stems from agents that trigger an overreaction of the patient’s immune system. No one knew exactly what the mechanism or cause of KD was, although many scientists speculated some theories.

Over the last decade, significant progress toward understanding the pathogenesis, history, and therapeutic interventions of KD has been fruitful. Treatment aimed at the intravenous infusion of gamma globulin antibodies derived from the plasma of blood donations has helped children recover. In contrast, other therapies of corticosteroids for immunoglobulin-resistant patients and tumor inhibitors such as etanercept, infliximab, and cyclosporin A have been other medications providing relief.

The most significant clinical debate was over the possible link between the rash and the cardiac complications seen in Asian American children. Factors responsible for KD were introduced into Japan after World War II and re-emerged in a more virulent form spreading through the industrialized Western world. Advancements in medicine, improvements in healthcare, and, notably, the use of antibiotics reduced the burden of rash and fever illnesses significantly allowing KD to be recognized as a distinct clinical entity.

Nonetheless, the enigma pervades even during the COVID19 pandemic; this time, more pressing as the ever-elusive cause of KD that troubles children’s hearts affects physicians’ sleep and worries parents’ minds. Although the story of Kawasaki disease began decades ago when a young boy’s heart was locked inside a glass specimen, its ending is still being crafted. By the time the heart is found again at the museum, and placed safely for visitors treasuring ancient history, what further knowledge and progress will the scientific community have achieved? How far will humanity have come to find answers to KD and fill in the perplexing missing piece of the puzzle?

For now, there are no answers, but the enigma continues…

Cite this article as: Leah Sarah Peer, Canada, "The Kawasaki Disease Enigma Continues 150 years Later," in International Emergency Medicine Education Project, July 24, 2020, https://iem-student.org/2020/07/24/kawasaki-disease-enigma-continues/, date accessed: September 27, 2020

References and Further Reading

Salter-Harris Fractures

salter harris

Case Presentation

You are a medical student doing your first clinical shift as part of your Emergency Medicine rotation. A 9-year-old boy is brought in by his father after an injury to his left hand approximately 1 hour back. As explained by the father, the child was playing at home with his elder brother when his left index finger became caught in between a door that had quickly slammed shut. Following the injury, the child was reported to be crying due to severe pain, but had no lacerations or other associated injuries. He was rushed to the hospital and presented in the ED as an anxious, weeping boy who held out his left index finger and pointed to the tip as the region of maximal pain. Mild swelling was noted at the distal interphalangeal joint as well as at the tip of the affected finger. After appropriate analgesia was initiated, the child was sent to the Radiology department for X-ray imaging. The images obtained by the department are shown below in Figures 1.1 and 1.2.

Figure 1.1
Figure 1.1
Figure 1.2
Figure 1.2

Findings

Due to the lack of ideal positioning and suboptimal cooperation from the child and his parent, the radiology technician reports back to you stating that the best images they could obtain were the ones displayed above. Although unclear, you can confidently identify a small break in the bone at the base of the distal phalanx. You mention to the father that you see a fracture on the X-ray and report back to your Attending Physician. 

The Attending Physician decides to take a break from his morning coffee and utters the dreaded question: “What kind of fracture is this?” You try to recall a lecture you had about Salter-Harris fractures but cannot recall the classification of these fractures. As if on cue, the father of the patient finds you shuffling your weight in front of the Attending Physician and asks: “You said he has a fracture, will he have to get surgery for his finger?”

“What kind of fracture is this?”

Salter-Harris Fractures

Salter-Harris Fractures refer to fractures that involve the growth plate (physis). Therefore, these fractures are applicable specifically to the pediatric population, occurring most often during periods of rapid growth (growth spurts) when the growth plate is at its weakest, close to age ranges where children tend to participate in high-risk activities (11-12 in girls and 12-14 in boys) [1].

Originally described in 1963 by Dr Robert Salter and Dr Robert Harris [2], the now infamous Salter-Harris fractures are classified by the region of bone that is affected. Figure 2 displays the gross anatomy of a normal distal phalanx similar to the picture we examined in the X-ray, labelled to reflect the different areas of the bone relative to each other. The types of fractures that can occur are outlined below.

SALTER HARRIS ANATOMY
Figure 2
  • Type I Salter-Harris Fractures (Slipped)

    Type I fractures occur when a longitudinal force is applied across the physis, resulting in a displacement (“slip”) of the epiphysis from the metaphysis. Though relatively infrequent (5%), suspicion of this fracture is raised when the epiphysis is seen to either be displaced to the side of its original position relative to the metaphysis or when the gap between the two segments is widened.

Salter-Harris Type I
Salter-Harris Type I
  • Type II Salter-Harris Fractures (Above)

    Type II fractures are the most common (75%) of the Salter-Harris fractures. As with our patient above, this fracture only involves structures “Above” the epiphysis (Metaphysis + Physis/growth plate) with virtually no fracture or displacement of the epiphysis itself. Fortunately, type I and most type II fractures can be managed conservatively with cast immobilization and splinting.

Salter-Harris Type II
Salter-Harris Type II
  • Type III Salter-Harris Fractures (Lower)

    Type III fractures involve both the physis and the epiphysis. Although relatively uncommon (10%), the involvement of the epiphysis and consequent disruption of the growth plate makes this an intra-articular fracture that usually requires surgical fixation.

Salter-Harris Type III
Salter-Harris Type III
  • Type IV Salter-Harris Fractures (Through)

    Continuing the trend of worse outcomes with higher classification types, Type IV fractures involve all three layers (metaphysis, physis and epiphysis) and thus harbor more adverse outcomes and risks, with management primarily consisting of operative internal fixation. Similar to Type III fractures, this is an intra-articular fracture and also occurs at a similar rate of 10%.

Salter-Harris Type IV
Salter-Harris Type IV
  • Type V Salter-Harris Fractures (Rammed/Crushed)

    The rarest of all the Salter-Harris fractures, type V fractures occur due to high impact compression of the growth plate. Potential disruption of the germinal matrix and compromised vascular supply to the growth plate can lead to growth arrest.

Salter-Harris Type V
Salter-Harris Type V

A convenient method to recall the Salter-Harris classifications is outlined below using the mnemonic “SALTR”

Salter-Harris Classification
Salter-Harris Classification

Case Resolution

You ascertain the patient’s fracture to be a type II Salter-Harris fracture, justifying your answer to the Attending Physician by pointing out that the affected region in the X-ray is limited to the metaphysis and physis with no epiphyseal involvement. Recognizing the potential for parental misconceptions surrounding the diagnosis of fractures in pediatric patients [3], you approach the father and explain that, though there is a fracture present, there is likely no need for any surgical intervention. You advise that the left index finger will be immobilized using a splint and further elaborate on the unlikelihood of this injury to manifest any long-term developmental or growth arrest in the affected region.

References and Further Reading

  1. Levine RH, Foris LA, Nezwek TA, et al. Salter Harris Fractures. [Updated 2019 Aug 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan
  2. Salter, Robert B.; Harris, W. Robert: Injuries Involving the Epiphyseal Plate, The Journal of Bone and Joint Surgery (JBJS): April 1963 – Volume 45 – Issue 3 – p 587-622
  3. Sofu H, Gursu S, Kockara N, Issin A, Oner A, Camurcu Y. Pediatric fractures through the eyes of parents: an observational study. Medicine (Baltimore). 2015;94(2):e407. doi:10.1097/MD.0000000000000407
Cite this article as: Mohammad Anzal Rehman, UAE, "Salter-Harris Fractures," in International Emergency Medicine Education Project, December 23, 2019, https://iem-student.org/2019/12/23/salter-harris-fractures/, date accessed: September 27, 2020

A 20-months-old head trauma: CT or Not CT?

by Stacey Chamberlain

A 20-month-old female was going up some wooden stairs, slipped, fell down four stairs, and hit the back of her head on the wooden landing at the bottom of the stairs. She did not lose consciousness and cried immediately. She was consolable after a couple of minutes and is acting normal per her parents. She has not vomited. On exam, she is well-appearing, alert, and has a normal neurologic exam. She is noted to have a left parietal hematoma measuring approximately 4×4 cm.

Should you get CT imaging of this child to rule out clinically significant head injury?

PECARN Pediatric Head Trauma Algorithm

Age < 2

Age ≥ 2

  • GCS < 15, palpable skull fracture, or signs of altered mental status
  • Occipital, parietal or temporal scalp hematoma; History of LOC≥5 sec; Not acting normally per parent or Severe Mechanism of Injury?
  • GCS < 15, palpable skull fracture, or signs of altered mental status
  • History of LOC or history of vomiting or Severe headache or Severe Mechanism of Injury?

The PECARN (Pediatric Emergency Care Applied Research Network) Pediatric Head Trauma Algorithm was developed as a CDR to minimize unnecessary radiation exposure to young children. The estimated risk of lethal malignancy from a single head CT in a 1-year-old is 1 in 1000-1500 and decreases to 1 in 5000 in a 10-year-old. Due to these risks, in addition to costs, length of stay and potential risks of procedural sedation, this CDR is widely employed given the frequency of pediatric head trauma ED visits. This CDR has the practitioner use a prediction tree to determine risk, but unlike some other risk stratification tools, the PECARN group does make recommendations based on what they consider acceptable levels of risk. In the less than 2-year-old group, the rule was found to be 100% sensitive with sensitivities ranging from 96.8%-100% sensitive in the greater than two-year-old group.

This algorithm does have some complexity and ambiguity. It requires the practitioner to know what were considered signs of altered mental status and what were considered severe mechanisms of injury. In addition, certain paths of the decision tree lead to intermediate risk zones. In these cases, the recommendation is “observation versus CT,” allowing for the ED physician to base his/her decision to image or not based on numerous contributory factors including physician experience, multiple versus isolated findings, and parental preference, among others.

Other pediatric head trauma CDRs rules have been derived and validated; however, in comparison trials, PECARN performed better than the other CDRs. Of note, in this study, physician practice (without the use of a specific CDR) performed as well as PECARN with only slightly lower specificity.

Case Discussion

For purposes of the case study, the patient falls into an intermediate risk zone of clinically important brain injury. However, a sub-analysis of patients less than two years old with isolated scalp hematomas suggests that patients were higher risk if they were < 3 months of age, had non-frontal scalp hematomas, large scalp hematomas (> 3cm), and severe mechanism of injury. Given the large hematoma in the case study patient and a severe mechanism of injury (a fall of > 3 feet in the under two age group), one might more strongly consider imaging due to these two additional higher risk factors.

Cite this article as: iEM Education Project Team, "A 20-months-old head trauma: CT or Not CT?," in International Emergency Medicine Education Project, May 15, 2019, https://iem-student.org/2019/05/15/a-20-months-old-head-trauma-ct-or-not-ct/, date accessed: September 27, 2020

Ortho Pearls – Salter-Harris Classification

iEM-Infographic-Pearls-Ortho - Salter Harris

Recommended Chapters

Reduction of Common Fractures and Dislocations

Splinting and Casting

A kid with wrist pain!

In case you didn’t encounter a kid with wrist pain today!

Pediatric fractures affecting growth plate are classified with Salter-Harris classification. It is from I to V. 

What is your opinion about below x-ray? I, II, III, IV or V?

Please give your answer at the comment box below.

428.3 - salter harris 2

iEM Education Project Team uploads many clinical picture and videos to the Flickr and YouTube. These images are free to use in education. You can also support this global EM education initiative by providing your resources. Sharing is caring!

Elbow Pain

In case you didn’t encounter a child with elbow pain today!

iEM Education Project Team uploads many clinical picture and videos to the Flickr and YouTube. These images are free to use in education. You can also support this global EM education initiative by providing your resources. Sharing is caring!