Parapneumonic effusion and Pneumothorax

Pratap Sagar Tiwari, MD, Internal Medicine

Note: This is lecture class slide for MBBS students

Parapneumonic effusion

• Parapneumonic effusion is any pleural effusion secondary topneumonia (bacterial or viral) or lung abscess.

• Empyema is, by definition, pus in the pleural space. Pus is thick, viscidfluid that appears to be purulent.

• A complicated parapneumonic effusion is a parapneumonic pleuraleffusion for which an invasive procedure, such as tube thoracostomy,is necessary for its resolution, or a parapneumonic effusion on whichthe bacterial cultures are positive .

Complicated Pleural effusion

• Positive bacterial studies

• a glucose level < 60 mg/dl

• a pH < 7.20.

• a lactic acid dehydrogenase (LDH) level of >three times the upper normal limit of serum.

Parapneumonic effusion

• Exudative stage

• fibropurulent stage

• Fibrotic stage

Reference: Richard W. Light "Parapneumonic Effusions and Empyema", Proceedings of the

American Thoracic Society, Vol. 3, No. 1 (2006), pp. 75-80.

Parapneumonic effusion: exudative stage

• The first stage is the exudative stage in which there is rapidoutpouring of fluid into the pleural space.

• Most of the fluid is due to increased pulmonary interstitial fluidtraversing the pleura to enter the pleural space but some of this isdue to increased permeability of the capillaries in the pleural space.

• The pleural fluid in this stage is characterized by negative bacterialstudies, a glucose level >60 mg/dl, a pH >7.20, and LDH level of < 3Xthe upper normal limit of serum.

Parapneumonic effusion: fibropurulent stage

• If untreated, the effusion may proceed to the second stage, which isthe fibropurulent stage.

• The pleural fluid in this stage is characterized by positive bacterialstudies, a glucose level <60 mg/dl, a pH <7.20, and a pleural fluid LDH>3 times the upper normal limit for serum.

• In this stage, the pleural fluid becomes infected and progressivelyloculated.

• The pleural fluid needs to be drained in this stage and drainagebecomes progressively difficult as more loculations form.

Parapneumonic effusion: fibrotic stage

• If a stage 2 effusion is not drained, the effusion may progress to the third stage in which fibroblasts grow into the pleural fluid from both the visceral and parietal pleurae, producing a thick pleural peel. The peel over the visceral pleura prevents the lung from expanding.

• Because the pleural space must be eradicated if a pleural infection is going to be eliminated, this peel must be removed if the infection is going to be cured.

Pneumothorax

Pneumothorax

• The term ‘pneumothorax’ was first coined by Itard and then Laennec in1803 and 1819 respectively, (1) and refers to air in the pleural cavity (ie,interspersed between the lung and the chest wall).

• Primary spontaneous pneumothorax (PSP): occurring in absence of knownlung disease.

• Secondary pneumothorax (SSP) is associated with underlying lung diseasemost commonly COPD.

• Subpleural blebs and bullae are found at the lung apices at thoracoscopyand on CT scanning in up to 90% of cases of PSP,(5) and are thought toplay a role.

1. Laennec RTH. Traite´ du diagnostic des maladies des poumons et du coeur. Tome Second, Paris: Brosson and Chaude´, 1819.

2. Donahue DM, Wright CD, Viale G, et al. Resection of pulmonary blebs and pleurodesis for spontaneous pneumothorax. Chest 1993;104:1767e9.

Smoking: a risk factor for pneumothorax

• Smoking has been implicated in this aetiological pathway, thesmoking habit being associated with a 12% risk of developingpneumothorax in healthy smoking men compared with 0.1% innonsmokers. 1

• Ref: 1. Bense L, Eklund G, Odont D, et al. Smoking and the increased risk of contracting pneumothorax. Chest 1987;92:1009e12.

Risks factors for PSP include the following:

1. Smoking

2. Tall, thin stature in a healthy person

3. Marfan syndrome

4. Pregnancy

5. Familial pneumothorax

6. Blebs and bullae

• Typical PSP patients also tend to have a tall and thin body habitus. Whetherheight affects development of subpleural blebs or whether more negative apicalpleural pressures cause preexisting blebs to rupture is unclear.

• Pregnancy is an unrecognized risk factor, as suggested by a 10-year retrospectiveseries in which 5 of 250 spontaneous pneumothorax cases were in pregnantwomen.

Signs and symptoms

• The presentation of patients with pneumothorax varies depending on the following types of pneumothorax and ranges from completely asymptomatic to life-threatening respiratory distress:

• Spontaneous pneumothorax: No clinical signs or symptoms in primary spontaneous pneumothorax until a bleb ruptures and causes pneumothorax; typically, the result is acute onset of chest pain and SOB, particularly with SSP

• Iatrogenic pneumothorax: Symptoms similar to those of spontaneous pneumothorax, depending on patient’s age, presence of underlying lung disease, and extent of pneumothorax

• Tension pneumothorax: Hypotension, hypoxia, chest pain, dyspnea

• Catamenial pneumothorax: Women aged 30-40 years with onset of symptoms within 48 hours of menstruation, right-sided pneumothorax, and recurrence.

Management : SP

• Breathlessness indicates the need for active intervention(needle aspiration or chest tube drainage) as well as supportive treatment (including oxygen).

• Patients with PSP or SSP and significant breathlessness associated with any size of pneumothorax should undergo active intervention.

• The size of the pneumothorax determines the rate of resolution and is a relative indication for active intervention.

• For small PSP: Observation is the treatment of choice if without significant breathlessness.

• All patients with SSP should be admitted to hospital for at least 24 h and receive supplemental oxygen and most will require chest tube drainage.

• For recurrent or persistent air leak : Surgical treatment

• The surgical treatments usually involve pleurodesis (in which the layers of pleura are induced to stick together) or pleurectomy (the surgical removal of pleural membranes).

• Tetracycline used to be recommended as the first-line sclerosant therapy for both PSP and SSP.

Pneumothorax : Chest tube drainage

Source:www.aic.cuhk.edu.hk

Tension Pneumothorax

• This is a medical emergency that can arise in a variety of clinical situationslike Ventilated patients on ICU, Trauma patients, Resuscitation patients(CPR), Lung disease, especially acute presentations of asthma and COPD.

• It arises as a result of the development of a one-way valve system at thesite of the breach in the pleural membrane, permitting air to enter thepleural cavity during inspiration but preventing egress of air duringexpiration, with consequent increase in the intrapleural pressure such thatit exceeds atmospheric pressure for much of the respiratory cycle.

• As a result, impaired venous return and reduced cardiac output results inthe typical features of hypoxaemia and haemodynamic compromise.

Pneumothorax

Source: hubpages.com Source: mddirect.org

Tension Pneumothorax

• Injury acts as one-way valve• Air can enter pleural space• Air cannot exit pleural space

• During inspiration, negative intrapleural pressure sucks additional air into pleural space• Intrathoracic pressure increases

• Sequence of events• Lung collapses

• Vital capacity decreases

• Respiratory exchange decreases

• Venous return decreases• Cardiac output decreases

• As tension pneumo worsens:• Ipsilateral diaphragm is depressed• Mediastinum is pushed into contralateral lung

• Gas exchange further impaired

• SVC / IVC can kink• Worsening venous return / perfusion

• Result: hypotension / shock & death

http://www.fprmed.com/Pages/Trauma/Tension_Pneumothorax.html

Treatment

• Immediate placement of a 14-g catheter into the second intercostal space at the midclavicular line should yield a rush of air and decompression of the pneumothorax.

• All patients require subsequent chest tube placement.

• Immediate Needle decompression• Enter chest

• 2nd or 3rd intercostal space• Mid-clavicular line• Leave plastic sheath on needle• Several needles may need to be placed• Should hear a rush of air through needle

• Usually very obvious

• This is initially diagnostic AND therapeutic• Patient MUST have definitive chest tube place after this

• Regardless of air rush or not

http://www.fprmed.com/Pages/Trauma/Tension_Pneumothorax.html

Chest tube placement

• Can be done initially (before CXR) or after needle thoracostomy• If done before CXR

• Weigh the benefit of a chest tube without CXR against the risk of respiratory distress and hemodynamic compromise

• If uncertain of diagnosis, begin with needle decompression then convert to a chest tube

• Definitive treatment for tension pneumothorax• Tube size selection

• For most trauma cases, use 36-40F tube• May consider smaller thoracostomy tube (24-28F) if non-trauma situation

• Insertion point• Adult:

• 4th-6th intercostal space at mid/ ant axillary line

• Monitor vital signs and ABG

• Tetanus prophylaxis, if penetrating injury• Prophylaxis :Td 0.5 cc IM

• If hypotension persists• Persistent hypotension frequently suggests hypovolemia

End of slides

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