Lightning Injury

Types of human lightning strikes

Lightning may injure an individual in 6 ways.^{[5, 32, 33, 34]}

• Direct strike (approximately 3-5% of injuries)
• Side splash from another object (approximately 30% of injuries)
• Contact voltage from touching an object that is struck (approximately 1-2% of injuries)
• Ground current effect as the energy spreads out across the surface of the earth when lightning hits a distance away from the person (approximately 40-50% of injuries)
• Upward leader that does not connect with the downward leader to complete a lightning channel (approximately 20-25% of injuries)
• Blunt trauma if a person is thrown and barotrauma from being close enough to experience the explosive force of lightning^[31]
  
  
  
  

  Complications

  Although rare, serious lightning injuries are likely to primarily cause cardiac and neurologic injury.^{[15, 16, 17]} Otologic injury and cutaneous burns have also been noted as frequent sequelae of these events.^{[16, 18, 19, 20, 21]} Cataract formation resulting from lightning injury typically occurs within days to weeks of injury. This complication has been reported as late as 2 years afterward but commonly occurs within the first week. (See Prognosis, Presentation, Treatment, and Medication.)

  Major complications are rare in mild and moderate lightning injuries, although musculoskeletal discomfort and subjective sensations of paresthesias, irritability, and other nonspecific neurologic sequelae may be present, depending on the location and intensity of the strike. In severe lightning injury with cardiopulmonary resuscitation (CPR) required in the field, permanent neurologic deficit and hypoxic injury are common.

  Complications of being struck by lightning include the following:

  • Chronic pain syndromes
  • Neuromuscular pain
  • Neurocognitive deficits including short-term memory loss, difficulty accessing or processing new information, attention deficit, personality change, distractibility, or loss of ability to multitask
  • Isolation or depression
  • Sympathetic nervous system dysfunction
  • Dizziness
  • Sleep disorders
  • Symptoms similar to postconcussion syndrome (eg, headaches, nausea, confusion)
  • Atypical seizure disorders

  Cardiopulmonary complications include the following:

  • Transient hypertension
  • Electrocardiographic changes
  • Myocardial injury
  • Congestive heart failure
  • Dysrhythmia
  • Transient asystole
  • Atrial fibrillation
  • Ventricular fibrillation
  • Frequent premature ventricular contractions
  • Respiratory complications
  • Apnea
  • Hypoxemia

  Damage to the central nervous system (CNS) is the second most debilitating group of lightning injuries.^[22] Neurologic complications include the following:

  • Immediate loss of consciousness
  • Amnesia and confusion
  • Retrograde amnesia
  • Hemiplegia, aphasia
  • Coma
  • Seizures
  • Intraventricular hemorrhage
  • Hematomas
  • Keraunoparalysis

  Vascular complications include the following:

  • Vasomotor instability
  • Arterial spasm
  • Vasoconstriction
  • Vasodilatation

  Ophthalmic complications include the following:

  • Cataracts
  • Macular holes
  • Corneal lesions
  • Hyphema
  • Iritis
  • Vitreous hemorrhage
  • Retinal detachment
  • Optic nerve injury

  Otologic complications include the following^[18] :

  • Ruptured tympanic membrane
  • Temporary hearing loss

  Gastrointestinal (GI) complications of lightning injuries are similar to those following any major trauma.^{[23, 24]} Most common is gastric atony with gastric dilatation, for which placement of a sump nasogastric tube is mandatory to decompress the stomach and remove swallowed air. Another complication seen in victims of lightning injury is GI bleeding, albeit a very rare complication. GI perforation is another rare complication of lightning injury.^{[24, 25]} Buffering the gastric secretions with antacids and administering cimetidine may prevent this. In 2 unusual fatal cases of lightning strike, autopsy findings showed hemorrhage and necrosis in the pancreas.
  
  
  (Source:http://emedicine.medscape.com/article/770642-overview#aw2aab6b2b2 )

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Croup-Westley score

Epidemiology

Croup is the most common pediatric illness that causes acute stridor, accounting for approximately 15% of clinic and emergency department visits for pediatric respiratory tract infections. It is primarily a disease of infants and toddlers, with a peak incidence from age 6 months to 36 months (3 years). In North America, incidence peaks in the second year of life, at 5-6 cases per 100 children. Although the disease is rare after age 6 years, it may be seen as late as ages 12-15 years.

The male-to-female ratio for croup is approximately 1.4:1. The disease is most common in late fall and early winter but may be seen at any time of year. Approximately 5% of children experience more than 1 episode.

Westley score

Croup scores have been developed to assist the clinician in assessing the degree of respiratory compromise. One of the most commonly cited is the Westley score. Although widely used to evaluate treatment protocols, its clinical efficacy has not been extensively studied. The score evaluates the severity of croup by assessing the following 5 factors, with a score range of 0 to 17:

• Inspiratory stridor: None - 0 points, Upon agitation - 1 point, At rest - 2 points
• Retractions: None - 0 points, Mild - 1 point, Moderate - 2 points, Severe - 3 points
• Air entry: Normal - 0 points, Mild decrease - 1 point, Marked decrease - 2 points
• Cyanosis: None - 0 points, Upon agitation - 4 points, At rest - 5 points
• Level of consciousness: Normal, including sleep - 0 points, Depressed - 5 points

According to the Westley score, a score of less than 3 represents mild disease; a score of 3-6 represents moderate disease; and a score greater than 6 represents severe disease.(Source: Emedicine )

Severity

The most commonly used system for classifying the severity of croup is the Westley score. It is primarily used for research purposes rather than in clinical practice.^[2] It is the sum of points assigned for five factors: level of consciousness, cyanosis, stridor, air entry, and retractions.^[2] The points given for each factor is listed in the table to the right, and the final score ranges from 0 to 17.^[6]

• A total score of ≤ 2 indicates mild croup. The characteristic barking cough and hoarseness may be present, but there is no stridor at rest.^[5]
• A total score of 3–5 is classified as moderate croup. It presents with easily heard stridor, but with few other signs.^[5]
• A total score of 6–11 is severe croup. It also presents with obvious stridor, but also features marked chest wall indrawing.^[5]
• A total score of ≥ 12 indicates impending respiratory failure. The barking cough and stridor may no longer be prominent at this stage.^[5]

85% of children presenting to the emergency department have mild disease; severe croup is rare (<1%).^{[5] (Source:Wikipedia)}

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DKA vs HHS

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Effect of Cardiac Glycosides on Contractility

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Sgarbossa Criteria ECG

Source:http://clinicalmedicineupdate.blogspot.com/2006/04/ecg-zone-sgarbossas-criteria-not-just.html

The presence of left bundlebranch block on the electrocardiogram may conceal the changes of acute myocardial infarction, which can delay both its recognition and thrombolytic treatment.

Elena.B.Sgarbossa et al tested electrocardiographic criteria for the diagnosis of acute infarction in the presence of left bundle-branch block in patients enrolled in the GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) trial who had left bundle-branch block and acute myocardial infarction confirmed by enzyme studies were blindly compared with the electrocardiograms of control patients who had chronic coronary artery disease and left bundle-branch block. The criteria studied is given in the table below.

They found that ST-segment deviation was the only electrocardiographic finding that was useful in the diagnosis of acute myocardial infarction in the presence of left bundle-branch block. Previously proposed electrocardiographic signs involving the QRS complex were not useful.

 The ST changes that were significant are: 
1.ST elevation > or = 1mm and concordant with QRS.
2.ST depression > or = 1mm in v1,v2 or v3.
3.ST elevation > or = 5mm and discordant with QRS. ---

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PALS-Tachycardia

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PALS-Bradycardia

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Continuous Infusions

Source:http://academiclifeinem.blogspot.com/2012/03/paucis-verbis-continuous-infusions.html

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PALS-Medication

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Wellens' syndrome

Source: Wiki


Wellens' syndrome (or sign, or occasionally warning) is an electrocardiographic manifestation of critical proximal left anterior descending(LAD) coronary artery stenosis in patients with unstable angina.

It is characterized by symmetrical, often deep >2mm, T wave inversions in the anterior precordial leads. A less common variant is biphasic T wave inversions in the same leads.

  First described by Hein J. J. Wellens and colleagues in 1982 in a subgroup of patients with unstable angina it does not seem to be rare, appearing in 18% of patients in his original study. A subsequent prospective study identified this syndrome in 14% of patients at presentation and 60% of patients within the first 24 hours. 


The presence of Wellens' syndrome carries significant diagnostic and prognostic value. All patients in the De Zwann's study with characteristic findings had more than 50% stenosis of the left anterior descending artery (mean=85% stenosis) with complete or near-complete occlusion in 59%.


In the original Wellens' study group 75% of those with the typical syndrome manifestations had an anterior myocardial infarction.


Sensitivity and specificity for significant (more or equal to 70%) stenosis of the LAD artery was found to be 69% and 89% respectively with positive predictive value 86%. Wellens' sign has also been seen as a rare presentation of Takotsubo or stress cardiomyopathy.


Diagnostic criteria
 Progressive symmetrical deep T wave inversion in leads V2 and V3
 Slope of inverted T waves generally at 60°-90°
 Little or no cardiac marker elevation  Discrete or no ST segment elevation
 No loss of precordial R waves.
 Pattern abnormal during chest-pain free periods


Further Reading :http://emedicine.medscape.com/article/1512230-overview

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