Management of septicaemia in neurosurgical patients

Risk mitigation & management of neurosurgical complications

The common risk in neurosurgical procedure if occurrence of neurological deficit, bleeding during surgery, oedema due to retraction of the brain tissue, CSF leak, surgical site infection, inadequate decompression of the tumour, brain herniation, etc.

A proper preoperative surgical planning is an important step for risk mitigation.

Mastering Neurosurgery Operative Skills

 The neurosurgery operative skill can be mastered by learning 2 basic steps

1. Starts with making Burr hole & craniotomy, corticectomy 

2. Suboccipital craniectomy

2. Laminectomy

4. Laminectomy, durotomy , myelotomy

For operating all supratentorial lesions, craniotomy is done. 

For operating midline posterior fossa or infra tentorial lesions, sub occipital craniotomy is performed.

For operating spinal lesions, laminectomy is very commonly performed. This is basic neurosurgical skill.

The surface marking and understanding of the applied neuroanatomy is important. Once you reach the brain surface after craniotomy and opening of the dura, all he cortical surface looks similar, i.e., clci, gyri, CSF in subarachnoid space, and cortical vessels. So, there is only one way of identifying intracranial cerebral structures, like frontal lobe, parietal lobe , temporal lobe or occipital lobe is by surface marking of the skull, before start of the surgery. Similar principle is applied for identifying motor strip, speech area, hearing area, visual area or any other eloquent area of cerebral cortex, is by surface marking. So, before draping of the surgical area, a marking is made over the scalp.

Majority of the neurosurgical procedures are done through non eloquent area of the brain, especially, right middle frontal gyrus or right superior parietal lobule.

Respiratory System, Pneumonia, Chronic Pulmoary Obstructive Disease (COPD)- Emhysema, Chronic Brochitis, Brochiectasis, Asthtma, Carcinoma of lung

Respiratory system is very important in clinical setting. Every doctor must be aware about this system. As oxygen is important for life, similarly understanding of the respiratory system is essential for sustaining the medical practice of any doctor. Good aspect of this fact is that anybody can learn the entire respiratory system in a very simple way and theory of the respiratory system can be understood in one page and its usual practice in clinical setting makes every doctor confident in understanding of the respiratory system.

Common symptoms of diseases of the respiratory system are dyspnea, cough, fever, hemoptysis, chest pain, weight loss. So, just knowing the details about each symptom can help in making a provisional diagnosis of diseases of the respiratory system.

History-

Dyspnea or Dyspnoea is difficulty in breathing which may be in the form of breathlessness.

Cough may be dry of with sputum ( Expectoration).

Dry cough is commonly seen in Legionella.

Purulent Sputum- Klebsiella ( Thick Red Currant Jelly like sputum )

So, the history taking is important in making a diagnosis of respiratory system. History of tubercular contact is common in Tuberculosis. History of smoking is common in COPD and lung carcinoma. History of significant weight loss is common in Tuberculosis and lung carcinoma.

Clinical Examination of patients should be done in a systematic manner. Start with

Inspection- 

On inspection alone certain diagnosis of respiratory system can be made. Measure respiratory rate, observe the pattern of the breathing ( abdominothoracic or thoracoabdominal), Dyspnea, use of accessory muscles of respiration, movement of the chest, any structural abnormality of the chest wall, curvature of the spine ( kyphosis, scoliosis ), any tumor of the chest, e.g., chondroma.

Palpation-

Extent of chest expansion can be measured by placing both palm across the spine and asking the patient to take deep breath.

On palpation of the chest wall cutaneous emhysema can be detected. Cutaneous emphysema is the air in the subcutaneous tissue of the chest and it feels like crepitations while compressing sknn over the chest wall. 

Vocal fremitus is examined by placing the ulnar aspect of the hand over different areas of the chest wall feeling the vibration of the sound with and while patients produces repetitive words like one, one , one. Vocal fremitus is decreased in pleural effusion but it is increased in pneumonia.

Extent of any bony tumor like chondroma of the ribs or costochondral junction can be felt by palpation.

Fracture of the ribs can be detected on palpation. Tenderness of the chest wall can be detected on palpation. Any paraspinal collection or cold abscess can also be detected on palpation which is very common in Tuberculosis.

Percussion-

Placing the middle finger of of one hand over the chest wall and tapping with index finger of other hand will commonly elicit tympanic or dull percussion over the chest wall. The normal percussion sound over the lungs is tympanic. In hemothorax the percussion will be dull. In hydropneuomathorax it will dull below and tympanic in upper part of pneumothorax. In Pneumonia ( Consolidation of the lungs ) it is dull but this is stony dull in case of pleural effusion. Tympanic sound is increased in case of emphysema of the lungs. In pneumothorax the percussion is hyperresonant.

Auscultation-

Auscultation is done with stethoscope and all doctors should own a stethoscope. The usual breath sound are either vesicular or amphoric. The breath sounds are inreased in consolidation ,i.e., in pneumonia. The breath sounds are decreased, i.e., muffled, in pleural effusion. Breath sounds will be decreased in hemothorax.

Crepts are heard in lung infection,  pulmonary edema.

Ronchi or whistle like sounds are heard in bronchoconstriction and in asthma.

So, the with clinical examination will be sufficient to make the diagnosis of  tension pneumothorax.

Pleural effusion, pneumothorax, hydropneumothorax, pneumonia, emphysema can be provisionally diagnosed on clinical examination itself. It can further be clearly diagnosed with chest X ray.

Investigations-

Chest X-Ray Postero-anterior view (PA) is very common radiological investigation. It helps in diagnosis of rib fracture, flail chest, pneumothorax, hydropneumorax, COPD, brochiectasis,  pleural effusion, Cor pulmonale, cardiomegaly, mediastinal widening, carcinoma ung, Tuberculosis, chest metastasis.

In Pnumonia, cosolidation or cavitation is seen on chest  ray depending upon type of pneumonia

       In consolidation, the lungs shadow appear radiopaque on chest x ray. 

                       Lobar consolidation is seen in pneumococcal pneumonia.

                       Bibasal consolidation is seen in Legionella pneumonia.

                       Patchy shadows- Chlamydia psittaci. If Bilateral then Mycoplasma.

     In cavitation, pneumonia is due to

                      Bilateral cavitation- Staphylococcal

                      Upper lobe cavitation- Klebsiella

    Bilateral perihilar interstitial shadowing is seen in Pneumocystis carnii pneumonia.

Tram line ang ring shadows are seen in brochiectasis. 

Spirometry can diagnose the restrictive and obstructive disease of the lungs. 

      FEV1 is helpful in the diagnosis of asthma.

V/Q scan ( Ventilation perfusion scan) 

CT scan or HRCT ( High resolution CT scan)  of the chest helps in the diagnosis of brochiectasis, and lung carcinoma.

Pulmonary angiography- clot in the 5th order pulmonary artery can be seen in Pulmoary embolism which usually occurs on 10th post operative day. 

Bronchoscopy and biopsy

Montoux test, sputum culture and sensitivity test is useful in diagnosis of Tuberculosis.

Legionella serology

Treatment of respiratory diseases

Tension pneumothorax- Tension pneumothorax is a medical emergency. Tracheal deviation is noticed in a patient who complaints of sudden shortness of breaths and neck veins are distended. Patient becomes cyanosed. So, needle thoracocentesis is done immediately.

Pneumororax oxygen, needle aspiration, chest tube drain. 

Hemothorax- chest tube drainage

Bronchogenic carcinoma- It can present with fever if there is secondary pneumonia and it requires antibiotic therapy. Surgery is for Non small cell lung cancer. Radiotherapy is treatment of choice if patient's age is more than 65 years. 

Bronchiectasis- steroid inhaler, antibiotics if there is associated infection. Postural drainage.

Pneumonia-

          Streptococcus pneumoniae- Ampicillin or cefuroxime

          Legionella- Erythromycin

          Staphylococcus- Flucloxacillin

          Pneumocystis carnii pneumonia- high dose co-trimoxazole, or pentomidine

          

Pulmonary embolism-Anticoagulant

Acute pulmonary edema- Patient develops acute breathlessness and cough productive of frothy and pink sputum. Patient cannot lie flat & on examination crackles are present both mid zones with scattered wheezes. Treat it with IV Frusemide.

Acute astham attack- young patient presents with breathlessness and becomes too breathless to speak. There is tachycardia. Chest x ray may be normal.  Treat with nebulized salbutamol.

Foreign body obstructing bronchial airway, patient is choked-Heimlich manoeuvre. Commonly observed that a person becomes suddenly breathless while eating. Person develos marked stridor, develops choking and drooling.

Pneumothorax and Pleural effusion- Needle aspiration. if recur, chest drain.

In PLAB examination, the common themes on which the questions are framed comprise of

1. Pneumonia- types of pneumonia, investigations, treatment of pnemonia

2. Hemoptysis- causes, investigations

3. Asthma- presentation, dignosis, treatment

4. Chest pain- causes, investigations, treatment

5. Breathlessness- causes, investigations

6. Pulmonary oedema- presentation, investigations, treatment

7, Cough- presentation, causes

8.Wheeze- investigation, treatment

9. Pleural effusion- presentation, investigations and treatment

     

                                                         Summary of Respiratory system 

Mechanical Ventilation ( Modes of Ventilators ) in Intensive Care Unit (ICU)

Start your understanding about the setting of ventilators. The respiratory support to a patient by mechanical means, i.e., through machines ( Ventilators) is known as Mechanical Ventilation ). There are basically 3 modes of ventilation, i.e., CMV, SIMV and CPAP. Once youunderstand this, then it is very easy to know all about mechanical ventilation in ICU.

 

ABG ( Arterial Blood Gas ) Interpretation

Doctors, Nursing staff and Paramedical staff working in emergency & ICU setting need to know the value of ABG. It helps in the diagnosis of the conditions where a patient may require a correction of the electrolyte imbalance, respirtory problems and certaion metabolic conditions and there may be requirement of mechanical ventilation.

Interpretation of ABG is very easy and one just need one page notes for interpretation of ABG. This image will make you confident of diagnosis of a patient who is on ventilator and may require some modification in the ventilator setting. 

  

 

Glioblastoma or Glioblastoma Multiforme (GBM)

Glioblastoma is most malignant and most frequent primary brain tumor. Glioblastoma Multiforme ( GBM) is also called WHO grade IV astrocytoma and it is the most malignant of the astrocytomas.
Incidence
 It accounts for 12-15% of all intracranial neoplasms and 60-75% of all astrocytic tumors.
Age 
It may manifest at any age, but preferentially affects adults, with a peak incidence at between 45 and 75 years of age. About 1% of patients are younger than 20 years old. primary GBM is more common in older adults between 60-75 years.
Secondary GBMs which constitute about 5% of all GBMs , usually occur about a decade or two decade earlier.
 Location
Cerebral hemispheres are the most common site in adults. Glioblastoma occurs most often in the subcortical white matter and deep periventricular white matter of the cerebral hemispheres. Most affectected sites are temporal, parietal frontal and occipital lobes. Combined fronto-temporal location is particularly typical.
Tumor infiltration often extends into the adjacent cortex and through the corpus callosum into the contralateral cerebral hemisphere. Glioblastoma is notorious for its rapid invasion of neighbouring brain structures. A very common feature is extension of the tumor through the corpus callosum into the contralateral hemisphere, creating the image of a bilateral, symmentrical lesion ( Butterfly glioma).
Glioblastoma of the basal ganglia and thalamus is not uncommon, especially in children. Glioblastoma of the brain stem( malignant brain stem glioma)is infrequent and often affects children.
20% of GBM are multifocal and of which 2-5% are synchronous.
Types of Glioblastoma and clinical features
Two forms of GBM are currently recognized: Primary ("de novo") GBM and secondary glioblastoma. Primary glioblastoma constitute majority, about more than 90%, , which arise de novo.
Secondary glioblastoma arise from a previously pre-existing lower grade glioma. While the two types share similar histology, they differ genetically. Neurofibromatosis type 1 ( NF1), Li Fraumeni and Turcot syndrome demonstrate an enhanced propensity to develop GBM.
The clinical history of the disease is usually short ( less than 3 months in more than 50% of cases). Unless the neoplasm has developed from a lower grade astrocytoma ( secondary glioblastoma).
Symptoms and signs of raised intracranial pressure ( headache, vomiting, papilledema) are common. Seizures , focal neurological deficits  are common. Sometimes patients may present with sudden stroke like features due to acute intratumoral hemorrhage ( in about 2% patients).
Histopathology
Glioblastoma on gross appearance look like Reddish-gray " rind of tumor, with necrotic core with marked peritumoral edema. It shows increased vascularity, and intra-tumoral hemorrhage.
The histopathological features include nuclear atypia, cellular pleomorphism, mitotic activity, vascular thrombosis, microvascular proliferation, and necrosis.
As the term glioblastoma " multiforme " suggests , the histopathology is extremely variable.  The varied tumor cells include: pleomorphic fibrillary astrocytes, gemistocytes, bipolar bland appearing but mitotically active small cells ( including " microglia")and large bizzare multinucleated giant cells. While some lesions show a high degree of cellular and nuclear polymorphism with numerous multinucleated giant cells, others are highly cellular, but rather monotonous.
GBMs generally have a high proliferation index (MIB-1), usually exceeding 10%.
Immunohistochemistry shows GFAP and olig 2 positivity. IDH-1 is very helpful in distingushing secondary GBM (positive) from primary GBM ( negative).
Radiology of Glioblastoma
At least 90 -95% of GBM demonstrate a thick, irregular, enhancing "rind" of tumor surrounding a necrotic core.
CT scan of brain: Most GBMs demonstrate a hypodense central mass surrounded by an iso-to moderately hyperdense rim on non-enhanced CT scan. Hemorrhage is common but calcification are rare. marked mass effect and significant hypodense peritumoral edema are typical ancillary findings.
Contrast Enhanced Computerized Tomography (CECT) of Brain reveals strong but heterogenous irregular rim enhancement. In highly vascular GBMs prominant vessels are seen as linear enhancing foci adjacent to the mass.
MRI of Brain: T1W1 image shows poorly marginated mass with mixed signal intensity . Subacute hemorrhage is common. T2/FLAIR image shows heterogenous intensity with extensive vasogenic edema. Necrosis, cysts, hemorrhage at various stages of evolution are seen. Fluid-debris level is seen in some cases.
Contrast Enhanced magnetic Resonance Imaging ( CE MRI) of brain shows strong but irregular contrast enhancement with central non-enhancing core.
DWI MR : most GBMs do not restrict on diffusion weighted imaging.
DTI may show increased fractional anisotropy and disrupted white matter tracts from tumor invasion.
MR spectroscopy (MRS) may show elevated choline peak and decreased NAA.
On imaging the differential diagnosis of GBM is usually Metastasis and Abscess. Metastasis is usually multiple and occur at gray-white matter junction and non-infiltrating. Intracranial abscess is usually thinner with more regular rim which usually restrict on DWI.

Treatment of Glioblastoma
Neurosurgery and Radiation Oncology intervention: Craniotomy and tumor decpmpression. The cytoreductive surgery followed by chemo and radiotherapy.

Sources:
1. WHO classification of Tumours of the central nervous system Edited by David N.Louis, Hiroko Ohgaki, Otmar D. Wiestler , Webster K.Cavene
2. Handbook of Neurosurgery by Mark S. Greenberg