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1. Masterpass > 10.1 Mediastinal Mass > Flashcards

10.1 Mediastinal Mass Flashcards

1
Q

A 16-year-old-girl with 6 weeks’ history of cervical lymphadenopathy
has been added to the end of your list for cervical lymph node biopsy to aid
diagnosis.

She complains of increasing face and neck swelling, exertional dyspnoea,
shortness of breath, and coughing while lying flat. She also has been
complaining of noises when breathing.

Past Medical History She has no other medical condition.
Drugs Nil
on examination Anxious
Comfortable at rest
Chest: Clear

investigations Hb 13.3 g/dL (12–15) APPT 22 sec (21–34 sec)
WCC 17.4 × 109/L (4–11) PT 12 sec (11–13.6 sec)
Neutrophils 4.5 × 109/L (2–7.5) INR 1.0 (0.9–1.2)
Lymphocytes 12.2 × 109/L (1.5–3.5)
Eosinophils 0.1 × 109/L (0.04–0.44) Na 138 mmol/L (137–145)
Basophils 0.1 × 109/L (0.0–0.1) K 4.4 mmol/L (3.6–5.0)
Monocytes 0.5 × 109/L (0.2–0.8) Urea 6 mmol/L (1.7–8.3)
Platelet count 300 × 109/L (150–400) Creat 80 umol/L (62–124)

summarise the case.

A

This is a paediatric patient with no previous medical illness presenting with
possible haematological malignancy for an urgent procedure. There is also a
risk with her airway due to the presence of neck swelling and a mediastinal
mass.

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2
Q

What are the main issues?

A
  • Paediatric case with consent issues
  • Potential difficult airway due to facial and neck swelling
  • Potential difficult airway due to tracheal compression
  • Possible haematological malignancy and its implications
  • Haemodynamic instability due to compression of great vessels
  • Urgent procedure
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3
Q

Can you talk through the investigations?

A

Bloods
Lymphocytic leucocytosis
otherwise normal

Chest X-ray
Asymmetric hilar lymphadenopathy
Lobulated mediastinal widening

CT chest
No level indicated
Large anterior mediastinal mass is seen with hypodense areas representing
necrotic component in the middle. Trachea seems slightly pushed to the
right and is flattened.

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4
Q

What are the causes of lymphocytosis?

A

Lymphocytes make up 20%–40% of leucocytes.

Causes of increased lymphocyte count can be classified as:

Absolute

    • Acute—
      Cytomegalovirus (CMV)
      Epstein-Barr virus (EBV),
      pertussis,
      hepatitis,
      toxoplasmosis
    • Chronic—
      tuberculosis,
      brucellosis
    • Lympho proliferative malignancy
      (CLL, ALL, lymphoma)

Relative

  • Age < 2 yrs
  • Connective tissue diseases
  • Hormonal imbalance—Addison’s disease and thyrotoxicosis
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5
Q

What is the differential diagnosis for lymphadenopathy?

A

Bilateral hilar lymphadenopathy

  • Sarcoidosis
  • Tuberculosis
  • Lymphoma
  • Silicosis
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6
Q

What is the differential diagnosis for generalised lymphadenopathy

A

Generalised Lymphadenopathy

    • Malignant
      ° Lympho proliferative malignancy
      ° Myelo proliferative malignancy
    • Nonmalignant
      °
      Infective
      - Infectious mononucleosis
      - Toxoplasmosis
      - HIV
      - Tuberculosis

° Autoimmune connective tissue disorders
- Rheumatoid arthritis
- SLE

° Drug-induced
- Allopurinol
- Atenolol
- Penicillin
- Gold

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7
Q

How would you assess the patient preoperatively?

History

A

History

  • Severity of dyspnoea:
    factors worsening dyspnoea,
    positional changes,
    functional assessment, etc.
  • Presence of added noises:
    time of onset,
    quality and timing with regards
    to respiratory cycle,
    positional changes
  • Past medical history
  • Anaesthetic history:
    whether the child has had any anaesthetics in the
    past, previous grade of intubation, history of reflux and allergies
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8
Q

examination

A
  • General assessment of extent of facial and neck swelling
  • Airway assessment
  • Signs of Superior Vena Cava Obstruction (SVCO)
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9
Q

investigations

A
  • Imaging: All patients with an anterior mediastinal mass should have a chest radiograph and a CT scan prior to any surgical procedure to plan the airway management.

The CT scan will show the site, severity, and extent of the airway compromise to assess the level and degree of obstruction.

  • Nasal endoscopy to assess the cord function.
  • Lung function tests to look for the extent of intrathoracic or extrathoracic obstruction.
  • ECHO to rule out pericardial effusion and cardiac compression.
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10
Q

Are you concerned about the noise when breathing?

What is ts importance?

A

Yes. The added noise here is called stridor.

Stridor occurs due to turbulence caused by the passage of air through
narrowed airway.

The timing of the stridor with respect to the respiratory cycle indicates the location of the narrowing.

  • Inspiratory stridor (laryngeal)—
    obstruction above the level of glottis
  • Expiratory stridor (tracheobronchial)—
    obstruction in the intrathoracic airways
  • Biphasic stridor—obstruction between glottis and subglottis
    or a critical obstruction at any level
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11
Q

What are the complications due to mass effect of the mediastinal tumour?

A
  • Vascular compromise—SVCO and pulmonary vessel obstruction
  • Laryngeal nerve palsy
  • Dysphagia
  • Stridor and airway compromise
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12
Q

What is superior vena cava obstruction (SVCO)

Causes

A

The thin-walled SVC gets easily compressed by the mediastinal mass

results in obstructive damage of venous flow from the upper half of the body.

causes of SVCO

  • Intrinsic: thrombus
  • Extrinsic: tumours
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13
Q

SVCO Features

A

The disease is characterised by
facial and neck swelling,
head fullness,
nasal stuffiness,
orthopnoea,
dysphagia,
stridor,

and positive Pemberton’s sign (facial plethora and respiratory distress when both arms are elevated,
demonstrating the presence of thoracic inlet obstruction

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14
Q

challenges during anaesthesia

A
  • Need for supplemental oxygen
  • Orthopnoea—induction in the sitting-up position
  • IV cannula in the lower extremity
  • Airway oedema
  • Mucosal bleeding
  • Laryngeal nerve palsy
  • Haemodynamic instability due to decreased venous return
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15
Q

How would you proceed with this case?

A

Preoperative

  • History, examination, and investigations, as discussed earlier
  • Optimisation:
    This is an urgent surgery to aid diagnosis,
    so procedure cannot be delayed.
  • Explain to the child and her parents about her journey in theatre and give
    reassurance.
  • Discussion with patient and family regarding the choice of anaesthetic—
    LA versus GA.
  • Premedication with benzodiazepine in an anxious patient but generally
    avoided if there is risk of airway compromise
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16
Q

intraoperative

A
  • Involving senior surgeon, anaesthetist, and ODP
  • Emergency drugs and equipment

Emergency drugs—
atropine, suxamethonium (controversial), fluids and vasopressors.

Airway equipment—
rigid bronchoscopy and difficult airway trolley,
jet ventilation,
cardiopulmonary bypass (CPB) on standby.

Femoro femoral bypass is the most common setup.

17
Q

Monitoring

Anaesthetic choice

A

Monitoring
* AAGBI monitoring
* Arterial line in case of vascular compromise
* Femoral access for CPB

Anaesthetic choice
* Local anaesthetic infiltration alone
* Superficial and deep cervical plexus blocks
* General anaesthesia

18
Q

LA versus GA

A

Local anaesthesia

Indication
- Symptomatic patients with definite airway obstruction on CT/MRI

  • Tracheal cross-sectional area of ≤ 50% predicted
  • PEFR ≤ 50% predicted

Choice
- Superficial cervical plexus block

  • Deep cervical plexus block

________________________________

General anaesthesia

Indication

  • Patient refusal
  • Contraindication to LA (or a paediatric patient as in this case)

Choice

  • Ketamine
  • Spontaneously breathing patient with LMA
19
Q

Avoid

A
  • General anaesthesia, as it can cause loss of intrinsic muscle tone,
    decreased lung volumes, and decreased transpleural pressure gradient
  • Muscle relaxants
  • Positive pressure ventilation,
    which can precipitate severe hypotension
    and also increases intrathoracic tracheal compression
  • Coughing, as it can cause complete airway obstruction
    by positive pleural pressure,
    increasing intrathoracic tracheal compression
20
Q

Explain the technique of superficial cervical plexus block.

Is it easier to perform in this patient?

A

Superficial and deep cervical plexus blocks are done for superficial neck
surgery such as carotid endarterectomy and cervical lymph node excision.

Both types of blocks have a similar pattern of sensory distribution, but deep
block is associated with greater risk for complications such as vertebral
artery puncture, systemic toxicity, and nerve root injury. So, there is a trend
towards favouring the superficial approach.

Preparation
* Explaining the risks and obtaining informed consent
* Intravenous access
* AAGBI monitoring
* Emergency drugs and equipment

21
Q

Anatomy
The cervical plexus

A

Anatomy
The cervical plexus is formed from the anterior primary rami
of the first four cervical spinal nerves,

C 1–4. It lies deep to the internal jugular vein and the
sternocleidomastoid muscle and

superficial to the transverse process of cervical vertebrae

and the scalene muscles and spreads into four cutaneous branches:

the greater auricular nerve,
lesser occipital nerve,
supraclavicular nerve,
the transverse cervical nerve.

22
Q

Position

Landmarks

Superficial cervical plexus block

A

Position
Supine or semi-sitting position with the head facing away from the side to be blocked

Landmarks

Neck and facial swelling can make the procedure difficult and risky and can
potentiate airway and vascular compromise.

23
Q

Ultrasound guidance may be helpful in this case.

A

Technique

  • Sterile technique
  • Skin infiltration with local anaesthetic solution
  • 25 G needle with flexible tubing attached to a 20 mL syringe of
    marcaine—0.25% to 0.5%
  • Needle insertion site behind the posterior border of the
    sternocleidomastoid muscle at its midpoint between the mastoid
    and the clavicle
  • Injection made in a fan-wise fashion at a depth of approximately 1 cm
24
Q

the anxious patient has refused to have surgery under local infiltration or nerve blocks.

How would you proceed with general anaesthetic?

Induction

A

Aim to prevent cardiac compression, airway occlusion, and SVC obstruction.

Induction

  • IV cannula in the lower extremity
  • Induction in sitting position (semi Fowler’s position)
  • Inhalational (preferred choice) or IV induction agent titrated to effect
  • Choose spontaneous ventilation with LMA
  • Awake fibreoptic technique if intubation is necessary with a reinforced
    smaller calibre and longer endotracheal tube
25
Q

How would you proceed with general anaesthetic?

Maintenance

Emergence

A

Maintenance

  • Maintenance with gas in spontaneously breathing patient
  • TIVA with short-acting drugs for quick emergence

Emergence

Postoperative airway obstruction due to airway oedema,
tracheomalacia, and bleeding warrant the need for awake extubation in ITU.

The following steps would aid in an uneventful extubation:

  • Test for leak around the endotracheal tube cuff.
  • Administer dexamethasone or chemo radiotherapy in sensitive tumours
    to shrink size of tumour.
  • Use adrenaline nebulisers.
  • Extubate over airway exchange catheters.
26
Q

Following gas induction, the patient stops breathing and you are unable to ventilate her. What would you do now?

simple measure

A

Follow difficult or failed intubation guidelines.

But cricoid puncture and emergency tracheostomy are futile
if the level of airway obstruction is at the
intrathoracic tracheobronchial tree.

simple measures
* Change in position—
lateral, sitting up, or prone—to decrease the mechanical effect of the tumour.

  • Avoid positive pressure ventilation for fear of luminal closure.
  • Administer high-dose steroids for tumour shrinkage.
  • Direct laryngoscopy and endobronchial intubation down the least
    obstructed lumen.
  • Awake fibreoptic intubation with difficult airway.
27
Q

Following gas induction, the patient stops breathing and you are unable to ventilate her. What would you do now?

Other measures

A

other measures

  • Rigid bronchoscopy—
    dilatation of stenosis,
    laser, and electro cautery to
    debulk the tumour and stenting to bypass
  • Low-frequency jet ventilation with Sander’s injector
    or high-frequency translaryngeal jet ventilation with Hunsaker’s catheter
  • CPB bypass and ECMO to restore oxygenation when other measures fail
28
Q

You have managed to intubate the patient with a 6 mm microlaryngoscopy
tube (MLT). You have transferred the patient after biopsy to ITU for
monitoring and extubation when ready.

How can you reduce the tumour size in the postoperative setting?

A
  • High-dose steroids—dexamethasone
  • Chemotherapy or radiotherapy depending upon the type of tumour
  • Endoscopic debulking of the tumour
29
Q

What is the chemotherapy choice for lymphoma?

A

non-Hodgkin’s Lymphoma

  • CHOP: Cyclophosphamide, Hydroxydaunomycin (Doxorubicin), Oncovin (Vincristine), Prednisone
  • COPP: Cyclophosphamide, Oncovin, Procarbazine, Prednisone

Hodgkin’s Lymphoma

  • ABVD: Adriamycin, Bleomycin, Vinblastine, Dacarbazine
  • BEACOPP: Bleomycin, Etoposide, Adriamycin, Cyclophosphamide,
    oncovin, Procarbazine, Prednisone
30
Q

Following chemotherapy in itU, the blood test showed serum potassium of 6.9 mmol/L. What
are the possible causes?

A

Normal serum potassium 3.5–5.5 mmol/L

Mild hyperkalemia 5.5–6.0 mmol/L

Moderate hyperkalemia 6.1–7.0 mmol/L

Severe hyperkalemia > 7.0 mmol/L

causes of hyperkalemia in this case

  • Decreased excretion—
    renal failure
  • Redistribution—
    metabolic acidosis,
    tumour lysis syndrome secondary to chemotherapy or the tumour itself
31
Q

How do you treat high K?

A

Treatment is necessary if K+ is > 7 mmol/L

or

if patient is symptomatic with ECG changes

  1. Stop further accumulation of potassium.
    * Stopping drugs that increase potassium
    * Low-potassium diet
  2. Protect cardiac cells
    * 10% Calcium gluconate—10 mL intravenously over 2 min.
    Repeat as necessary.
  3. Redistribution
    * Salbutamol nebulisers: 2.5–5 mg
    * Insulin infusion: 10 U actrapid + 50 mL 50% glucose as an IV infusion
  4. Removal of potassium from the body
    * Haemodialysis
    * Calcium resonium enema

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