Croup Vs Epiglotitis

Croup-Acute Laryngotracheobronchitis: inflammation of the glottic & subglottic region (narrowest part)

1. Viral Croup - parainfluenzae viruses
- occasionally RSV, rhinoviruses, or measles
- coryzal prodrome, low grade fever
- rare < 6/12, consider ? underlying lesion - commonest obstruction at 6/12 to 6 yrs - median age of presentation 18/12 - more common in autumn & winter - <5% require intubation 2. Spasmodic Croup - children with an allergic nature
-? spectrum of asthmatic population
- no coryzal prodrome / fever

3. Bacterial Tracheitis - usually Staph. aureus ± H. influenzae, group A Strep.
- high fever, WCC, purulent secretions
-* risk of sudden obstruction

Varied Clinical Presentation
a. signs of mild croup
- URTI preceding 2-3 days
- loud barking "croupy" cough
- gradual onset inspiratory stridor which is high pitched
- hoarse voice
- no postural preference
- mild fever
- often a past history of croup

b. moderate
- stridor on inspiration & expiration
- tachypnoea
- flaring alar nasae
- suprasternal/intercostal retractions

c. severe - restlessness caused by hypoxia
- exhaustion & listlessness
- deteriorating conscious state
- cyanosis on air

Differential diagnosis
- epiglottitis
- aspiration of foreign body
- bacterial tracheitis
- retropharyngeal abscess
- peritonsillar abscess

Diagnosis
i. history and examination * mainstay of diagnosis
ii. radiology of the larynx (ESS or ICU) ®
"steeple" sign - AP view
widened hypopharynx - lat. view, only ~ 40-50% of cases
iii. direct laryngoscopy under GA

Management
a. minimal disturbance - VM & VO2,nursed by parent
b. adequate hydration,but propensity for pulmonary oedema; hypo-Na+ & convulsions have occurred 2° to SIADH with airway obstruction
c. oxygen therapy ® SpO2 > 90%- hypoxia from parenchymal infection ± increased interstitial water
d. humidification - mainstay for years but studies showing efficacy are lacking now abandoned by many centres but anecdotal evidence ? otherwise
e. steroids - dexamethasone ~ 0.6 mg/kg (= 12 mg) stat., then 0.15 mg/kg q6h.
Given on admission - decreases intubation rate & duration of stay
Failed extubation rate - administer 24 hrs pre & 12 hrs post-extubation
May also be of use in spasmodic croup
f. nebulized adrenaline - 1:1,000 ~ 0.5 ml/kg £ 5 ml of 0.1% solution, nebulised 2 hrly, this dose is effective, has little systemic effect, and is less than the recommended dose for the racemic solution -subsequent doses ® less effective. The obstruction may be more severe after the effect has worn-off ® rebound phenomenon ? progression of the disease process.
-In Acute LTB - lasts ~ 1-2 hrs,doesn't alter course but may allow secretion expectoration and prior to intubation, enhances induction
-In spasmodic croup - may obviate need for intubation
- Post ETT / endoscopy oedema where effect is often dramatic
- prior to transfer if not for intubation
- prior to anaesthesia & intubation if tolerated
g. Antibiotics - only for proven bacterial infection
h. Intubation ~ 2-5% of cases, nasotracheal,use 1 mm less than "size for age"

Indications for Intubation NB: essentially subjective assessment
a. ­ respiratory rate, HR, and chest wall retractions
b. cyanosis not responsive to oxygen
c. exhaustion and/or confusion
d. increased use of, and failure to respond to, nebulised adrenaline
e. need for transport to another hospital

Method
-spontaneously breathing,
-inhalational anaesthetic induction is prolonged
-ETT ~ 1 size smaller for age to minimise trauma
-most safely passed orally, then changed to a nasal
-small tubes are shorter and may be difficult to secure
-sedation ± arm splints to prevent self extubation
-stomach should be emptied with a nasogastric tube
-CPAP or IPPV with PEEP to maintain oxygenation
- size limited to > 3.0 mm, due to requirement to pass a suction catheter to clear secretions

Extubation
-can be attempted when a leak is present with positive pressure or coughing,
- or when the disease has run its course at 5 to 7 days
Reintubation may be required, but the incidence is reduced by administration of steroids prior to extubation ® prednisolone ~ 2 mg/kg/day.
Prior to steroid therapy intubation duration was average 5 days, but now reduced to 2-3 days.

Bacterial Tracheitis
-results in purulent secretions, pseudomembranes and ulceration of epithelium within the trachea
-death can result from upper airway obstruction, endotracheal tube blockage, and toxic shock
-either a primary bacterial infection or a superinfection on primary viral illness
-the causative organisms are,
a. Staphylococcus aureus
b. Haemophilus influenza type B
c. Streptococcus pneumoniae
d. Branhamella catarrhalis

Clinical Presentation
a. fever & toxaemia
b. respiratory distress
c. similar to epiglottitis except for
- the presence of a cough
- a subjective difference in quality of the stridor

Diagnosis
i. CXR - may show tracheal membranes
- narrowing & "fuzziness" are variable
ii. ETT - absence of epiglotitis
- suction following intubation ® pus and membranes in the trachea

Management - similar to that for epiglottitis (see over)
- if intubation is required, the ETT may block acutely with secretions ® aggressive tracheal suction ± reintubation
- bronchoscopy to clear tracheal pus should be considered where the airway remains compromised after intubation, suction and reintubation
- initially, there may not be a leak around an appropriately sized endotracheal tube
- sputum should be sent for gram stain and culture, and urine for rapid antigen identification
- extubation is best performed when, the fever and secretions have settled, and a leak is present around the endotracheal tube
- initial antibiotic therapy ® cefotaxime ~ 50 mg/kg q6h for 10/7, then by MC&S

Epiglottitis: supraglottic, infective inflammatory lesion, caused almost exclusively by Haemophilus influenzae - type B ± occasionally streptococci, staphlococci, or pneumococci
a. acute onset - short history (hrs) with no preceding URTI
b. high fever & toxaemia
c. stridor - low pitched, inspiratory ± expiratory snore, usually constant in nature
d. absence of cough and reluctance to talk
e. characteristic posture - sitting forward,mouth open, drooling & dysphagia
f. diagnosis
- direct laryngoscopy
- urine latex antigen agglutination
- ~ 80% blood culture (+)'ve
- lateral XRay ® "thumb print"

Most commonly children from 2 to 7 years but the disease can involve adults and infants due to septicaemia. The severity of the illness is often out of proportion to the airway obstruction.Children less than 2 years of age may present with airway obstruction atypically accompanied by apnoea, URTI, low grade fever, and/or cough and sudden total obstruction may be precipitated by,
a. instrumentation of the pharynx
b. painful stimuli - eg. IV insertion
c. supine posture

Management
a. minimal disturbance - nurse in mothers arms, etc.
b. ready access to intubation equipment
c. oxygenation - mask or nasal cannulae, if obstructs ® CPAP/assist by bag
d. antibiotics
- cefotaxime ~ 50 mg/kg q6h ± chloramphenacol ~ 25 mg/kg q6h or
- ampicillin was used but high percentage of resistant strains
e. intubation - all but the mildest cases, average duration ~ 18 hours but may be required for longer in cases with,
- pulmonary oedema
- pneumonia
- cerebral hypoxia
f. racemic adrenaline is of no use in this condition and can precipitate obstruction

Epiglottitis - Intubation Indications
1. severe or progressive respiratory distress
2. prior to transportation to a tertiary centre
3. following diagnosis by direct laryngoscopy under GA

- Patients can be managed without intubation if they remain in an area where appropriate personnel, equipment and supervision is available. Such patients are generally older, co-operative and are seen early in the day with minimal signs of obstruction. Diagnosis in these cases is made by lateral neck XRay
- An IV line can be inserted before anaesthesia, but should be delayed until after induction when the patient is distressed or obstruction is severe in order to avoid sudden obstruction.
- In spontaneously breathing, inhalational GA is best tolerated in the sitting position.
- Agitation and distress at induction may be due to acute hypoxia.
- The patient can be laid flat on loss of awareness, and airway obstruction overcome by application of CPAP or assisted ventilation.
- Laryngospasm may be precipitated if laryngeal stimulation occurs prior to surgical anaesthesia being achieved.
- Copious and persistent pulmonary oedema fluid may obscure the larynx, making intubation difficult.
- An ETT of normal size for age or one size smaller should be inserted orally then changed to the nasal route once the child has settled
- Positive pressure should demonstrate a leak around the tube.
- The patient can be sedated ± restrained to prevent self-extubation.
- Muscle relaxants are not routinely required unless IPPV/PEEP is required to overcome hypoxia and hypoventilation from pulmonary oedema.

Complications
a. respiratory failure / obstruction
b. pulmonary oedema ~ 7-10% of cases and is precipitated by intubation
- hypoxia & SNS discharge - ­ PAP
- vascular - endothelial injury & capillary permeability
- decreased intrathoracic pressure after intubation, augmenting venous return, and increasing transmural pulmonary vascular hydrostatic pressure gradients
c. barotrauma
- pulmonary interstitial emphysema (PIE)
- pneumothorax
- pneumomediastinum
d. septicaemia / pneumonia

Extubation Criteria
a. when the fever has settled
b. signs of inflammation subside ® usually ~ 18 hours
- pain subsided
- able to swallow
- free movement of the larynx

NB: exceptions are where hypoxia and reduced lung compliance persist direct laryngoscopy prior to extubation is not required

Thanks to Dr Anuj Clerk for this wonderful article.

Perioperative management of the patient with pheochromocytoma

The KEY: Communication between surgeon, anesthesiologist, and internist.

Background:
Pheochromocytoma is an uncommon neuroendocrine tumor of the chromaffin cell.
The most common sign of the tumor is hypertension, which can be paroxysmal.
The tumor’s intermittent catecholamine surges can cause a variety of symptoms,including headache, chest pain, palpitations, diaphoresis, dyspnea, anxiety,and dizziness.

Surgical excision can prevent the life-threatening complications of hypertensive crises, stroke, arrhythmias, and myocardial infarction.Before 1961,surgical mortality ranged from 24–45%. With appropriate medical preparation and an experienced anesthesiologist and surgical team, survival of excision of a pheochromocytoma is 93.3–100%

Preoperative preparation
Catecholamine excess causes --vasoconstriction that leads to both hypertension and hypovolemia.
Pheochromocytoma patients can die intraoperatively from--severe hypertensive crisis or hypotension that leads to cardiovascular collapse.

When tumor veins are ligated during surgery, the sudden drop in circulating catecholamines can lead to vasodilatation. The catecholamine output of the contralateral adrenal may be suppressed from previous catecholamine excess. In the hypovolemic patient, this can lead to hypotension, shock, and death.

Alpha adrenergic blockade is the cornerstone of preoperative preparation
-it treats both hypertension and vasoconstriction
-improves circulating plasma volume prior to surgery.

Phenoxybenzamine[Non selective, non competitive]-start 2 weeks prior to Sx 5-10 mg BID, step up to control BP~140/90 with max. 300 mg per day. Caution Postural hypotension, nasal stuffiness, reflex tachycardia.

Selective Alfa 1 blockers[Prazosin SR 2-20 mg BD ,doxazosin 1-16 mg OD]- do not block NA re uptake- less reflex tachycardia and orthostatic hypotension so better tolerated.

Liberalization of salt in the diet along with alpha blockade should expand plasma volume.

Beta blockade: Propanolol/Atenolol/metoprolol few days after Alfa Blockade[once reflex tachycardia noted] but few days before srgery.[if not contraindicated by heart failure or asthma]. Beta-blockers may also prevent perioperative arrhythmias and cardiac complications.

As calcium ion transport is essential for release of catecholamines from chromaffin cells, calcium channel blockers are used for control of blood pressure and preoperative preparation at some centers Less periop fluid requirement and post op hypotension in one French study.

Metyrosin [(alpha-methyl-p-tyrosine)Tyrosin hydroxylase inhibitor] reserved for refractory cases at doses of 1–4 mg per day -Very Toxic no longer used

Preoperative evaluation of myocardial function MUST.[left ventricular hypertrophy and dysfunction, but chronic catecholamine excess induced cardiomyopathy.]

Pre op Target:
24 BP monitoring, all readings <160/90, HR <100/min, Postural drop in BP with compensatory tachy as sign of adequate alfa blockade. Intraoperative Management:
-Avoid Histamine release causing agents during induction eg. Morphine
-Adrenaline followed by noradrenaline infusion for fluid refractory hypotension [CVP~10-15mmHg].
-Terlipressin 1 mg followed by vasopressin infused can be used.
-Na.nitroprusside infusion better then Phentolamine boluses [due to shorter duration of action] for hypertensive episodes.
-IV Nicardipine and Magnesium can be used to control hypertensive spikes.
-Betablockers for tachyarrhythmia.

Postoperative Management
-12-24 hours HDU/ICU care must.
-patient may remain hypertensive up to 2 weeks after excision.
-urinary catecholamines should be checked to ensure no additional tumor remains.
-hypoglycemia may develop and persist into the postoperative period once the tumor is removed[Catecholamine withdrawal + Beta blockade induced limit to compensation and unawareness]. Glucose should be included in perioperative fluids, and blood sugars should be monitored frequently intraoperatively and postoperatively.
-patients who undergo bilateral adrenalectomy [some with unilateral surgery as well] will need steroid[Hydrocortisone + Fludrocaortisone] replacement.

If catecholamines are normal, the patient may be one of about 25% of pheochromocytoma patients whose hypertension persists after surgical excision caused by other concomitant disease, such as essential or renal hypertension.

Thanks to Dr Anuj Clerk for contributing this wonderful article.

Compare and contrast persistent vegetative state, locked-in state & akinetic mutism

Persistent vegetative state
* Loss of cognitive neurological function but retains non cognitive functions- respiration,BP, cardiac function etc.
* Lack of consistency in neuro examination; eg.pt may blink, respiration may quicken to stimulation, lack of constant visual following of objects
* EEG- minimal/no change in EEG activity during & after stimulating the patient(i.e no desynchronization)
* Lesion- diffuse cerebral injury, thalamic injury(medial and ventromedian nuclei) & caudal midbrain lesions

Locked-in state
* De-efferented state- patient is alert & aware of environment + quadriplegia+ lower cranial nerve palsy. The only way the patient responds is by vertical gaze & blinking.
* Lesion- involves motor pathways- CS tract, corticobulbar & cortico pontine pathways with sparing of somatosensory pathways & ARAS. The most common site is the ventral pons

Akinetic mutism
* It is a state of altered behaviour where alert appearing patients are silent, inert & profoundly apathetic. They lack psychiatric drive or impulse to action & are doubly incontinent. They usually lie with eyes opened and retain cycles of self-sustained arousal
* Lesion- B/L anterior frontal lobe- this leaves intact motor & sensory pathways

Thanks to Dr Ishaq M for contributing this wonderful article.

Management of Acute Variceal Bleeding

* Gastroesophageal variceal bleeding accounts for 10-30% of upper gastrointestinal haemorrhage and is a major cause of death in patients with cirrhosis.
* The prevalence of oesophageal varices in patients with cirrhosis varies from 24-81%.
* At the time of diagnosis of cirrhosis, oesophageal varices are present in about 60% of decompensated and 30% of compensated patients.
* Despite the high occurrence of varices in cirrhotic patients, only 30% of patients with varices will experience variceal haemorrhage.
* The risk of bleeding appears to be greatest within the first year after diagnosis.
* Mortality of the first bleeding episode is high and ranges between 30% and 50% within 6 weeks; mortality from uncontrolled bleeding in the first instance is between 5-8%.
* Risk factors for the 1st episode of variceal bleeding in cirrhotic patients include - the severity of the liver dysfunction,
- the size of the varices (large greater than small), and
- the presence of endoscopic red wale signs.
- the hepatic venous pressure gradient (HVPG).
* Gastric varices account for approximately 20-30% of cases of variceal bleeding. The prevalence of gastric varices in patients with portal hypertension varies from 6-78% and approximately 25% of gastric varices bleed during lifetime.


General management of bleeding
Patients are usually managed in a high-dependency or intensive therapy unit with facilities for central venous pressure and arterial monitoring.
Therapy is aimed at - correcting hypovolumic shock and resuscitation
- achieving haemostasis at the bleeding site.

This include ABC & resuscitation, initially with plasma expanders and subsequently with blood. If coagulation is defective, replace coagulation factors with fresh frozen plasma. Platelet transfusions may also be required for thrombocytopenia.


Local Haemostasis
An emergency endoscopy should be performed to confirm that varices are the source of bleeding, since peptic ulcer disease is also common in cirrhosis. If possible, endoscopic treatment of varices should be undertaken by endoscopic variceal ligation (banding). Where banding is not possible, sclerotherapy may be useful, adverse events such as oesophageal ulceration and stricture were significantly more severe with sclerotherapy. The most commonly used sclerosants are sodium tetradecyl sulphate (thrombovar) and ethanolamine oleate.


Pharmacotherapy
Octreotide: Decrease portal pressure, 50 micrograms IV, immediately, then 25 to 50 micrograms per hour by IV infusion for 5 days.
While control of initial bleeding has been demonstrated with octreotide, no effect on mortality has been shown. Its transient effect is due to tachyphylaxis.
Terlipressin: 2 mg IV, 6-hourly for 2 to 3 days. It reduces splanchnic blood flow and portal pressure. A meta-analysis demonstrated that terlipressin was associated with a 34% relative risk reduction in mortality compared to placebo.
If endoscopic treatment fails/unavailable and bleeding persists despite octreotide or terlipressin, blood loss can usually be controlled with a Sengstaken-Blakemore–type tube for 24 hours. Balloon tamponade is known to have a high re-bleeding rate when the balloon is decompressed and is associated with serious complications such as ulceration, perforation and aspiration pneumonia. Thus, this should only be considered if facilities for endoscopy are not available prior to transfer to a tertiary centre or as a temporary ‘bridge’ for a maximum of 24 hours until definitive treatment can be instituted.

Antibiotics in Acute Variceal Bleeding
Bacterial infections are seen in about 20% of cirrhotics presenting with upper gastrointestinal bleeding within 48 hours. The incidence of sepsis increases to almost 66% at two weeks. Development of bacterial infection is associated with high mortality and variceal re-bleeding. Antibiotic prophylaxis has been shown to reduce the rate of infection, spontaneous bacterial peritonitis and rebleeding. In addition, antibiotic prophylaxis was clearly proven in a meta-analysis to significantly increase the survival rate. Short-term antibiotic prophylaxis for 7 days should be considered the standard of care in cirrhotic patients with upper gastrointestinal bleeding, irrespective of the type of haemorrhage (variceal or nonvariceal) or the presence or absence of ascites. As to the choice of antibiotic, either third generation cephalosporins given intravenously or oral quinolones (norfloxacin/ciprofloxacin) are generally recommended.

Continued bleeding
Continued bleeding is associated with a high mortality. A second course of endoscopic treatment may be undertaken with continued use of a Sengstaken-Blakemore–type tube for up to 24 hours. Adjunctive infusion of octreotide can be given. An emergency transjugular intrahepatic portosystemic shunt (TIPS) or an emergency portosystemic shunt may be considered, depending on available local expertise.
Transjugular intrahepatic portosystemic shunts (TIPS) is effective in the treatment of acute variceal bleeding with a success rate of over 90% in arresting haemorrhage. The main limiting factors to the use of TIPS are the high morbidity and mortality: the 30-day mortality approaches 100% in patients with advanced liver disease, ongoing sepsis and multi-organ failure. Therefore, the most widely accepted indication for TIPS is as a rescue therapy for uncontrolled variceal bleeding after combined pharmacological and endoscopic therapy.

Surgical Therapy
Surgical options include oesophageal transection with or without devascularisation, portosystemic shunts and liver transplantation. Regardless of the choice of the surgical technique, morbidity and mortality are high: the 30-day mortality associated with emergency surgical procedures is nearly 80%. Similar to TIPS, the role of surgical therapy in the management of acute variceal bleed has been relegated to salvage haemostatic therapy. Liver transplantation is probably only appropriate for liver transplant candidates who bleed while on the waiting list.

Prevention of rebleeding
In patients with cirrhosis who have bled from oesophageal varices, the risk of rebleeding within 12 months is about 60%. Measures to reduce this risk include regular endoscopic banding until varices have largely disappeared. In the longer term, varices recur and may need further banding. In a meta-analysis of clinical trials, therapy with propranolol has been shown to reduce recurrent variceal bleeding and improve survival. In those who rebleed despite the above therapy, TIPS, portosystemic shunt or transplantation should be considered.