Differentiating restrictive lung disease

Hello!

Let's talk about restrictive lung diseases today.

We know that an increased FEV1 / FVC ratio is suggestive of a restrictive lung disease.

However, you want to get lung volumes and confirm it by looking at the reduced TLC.

There are two types of restrictive lung diseases that you want to differentiate - pulmonary and extrapulmonary.

In pulmonary restrictive lung disease, all lung volumes are reduced due to fibrosis.

In extrapulmonary restrictive lung disease, the residual volume will be normal or even increased.

Why? Because in neuromuscular diseases, the muscles don't have the strength to blow air out.

DLCO is another way you can differentiate the two.

In pulmonary restrictive lung disease, the surface of alveolar membrane that participates in gas exchange is reduced and the DLCO is low.

In extrapulmonary restrictive lung disease, the DLCO is normal.

That's all!

-IkaN

Transient Tachypnea of Newborn notes

Hello!

What is Transient Tachypnea of Newborn (TTN)?

Foreign body aspiration - Flexible or rigid bronchoscopy?

Foreign body aspiration (FBA) - Which bronchoscopy should you do? Flexible or rigid?

#TLDR:
Life threatening - Rigid bronchoscopy
Diagnosis not clear - Flexible bronchoscopy

Children - Rigid bronchoscopy
Adults - Flexible bronchoscopy

Mnemonic: childRen thReatening - Rigid bronchoscopy

So first ask - is this a life threatening FBA? Yes - Rigid bronchoscopy (after airway stabilization of course)

Then ask - Is the diagnosis clear? No - Flexible bronchoscopy

If the diagnosis is clear and the FBA is not life threatening - See the age.

If it is a child - Rigid bronchoscopy
If it is an adult - Flexible bronchoscopy

Here's a looooong copy paste explanation from UpToDate:

Post - intubation Cardiac Arrest : possible mechanisms

Hey Awesomites

Early post - intubation Cardiac Arrest ( within 10 minutes ) is a serious major complication of emergency intratracheal intubation associated with high in - hospital mortality, and occurs with approximately 2% frequency in the ED.

Various retrospective and case- control studies have been well designed to establish the connection and factors associated in the causation. One of the studies by Heffner et al. found that a higher pre - intubation shock index ( PISI ), that is defined as heart rate divided by systolic BP, and a higher weight of the patient are independently associated with post - intubation CA.

Systolic hypotension ( BP less than 90 mmHg ) is independently associated with post - intubation CA.

Emergency intubation can cause hypotension potentially as a consequence of actual intubation acting as a sympatholytic stimulus, mechanical ventilation ( positive pressure ventilation with subsequent fall in venous return ), and/ or the induction agents used.

Also important to note is that the association between pre - intubation hypotension and post - intubation progressive decline in BP and subsequently pulseless electrical activity arrest raises the question of whether treatment of hypotension before intubating by fluid resuscitation and vasopressors can decrease the rate of post - intubation CA.

That's all
- Jaskunwar Singh

Clubbing

CLUBBING:

Bulbous enlargement of the distal portion of the digits due to increased subungual soft tissue.
It is also known as the "Hippocratic fingers", as it is believed that perhaps Hippocrates was the first to document clubbing as a sign of disease.

Grades of clubbing-
Grade I- presence of fluctuation test °
Grade II- obliteration of Lovibond angle*
Grade III- parrot beak or drumstick appearance
Grade IV- hypertrophic osteoarthropathy (HOA)

*Refer the diagram
°Refer the video clipping

Theories of clubbing-
1. Neurogenic theory- vagal stimulation via neural reflexes can lead to proliferation of connective tissue at the distal extremities resulting in clubbing.

2.Humoral theory- Normally lungs throws out all the soluble substances by inactivation. But in case of lung problems, these systems reach the systemic circulation in active state and stimulate the changes seen in HOA (growth hormone, PTH, bradikynin, prostaglandin, ferritin)

3.Hypoxic theory- Hypoxia is suggested to be a stimulus for HOA. It leads to opening of deep arteriovenous shunts and fistulae which increase blood flow to the extremities and leads to hypertrophy.

4.Platelets derived growth factor- Normally megakaryocytes and large platelets get destroyed in the lungs. But in lung pathology they escape the lung and reach the distal extremities. Here they interact with the endothelial cells and release platelet derives growth factor (PDGF) post activation. PDGF and other mediators then activate the fibroblasts and transforming growth factor beta which lead to collagen production and connective tissue laying down ultimately giving rise to clubbing and HOA.
This is the latest accepted theory.

Causes of clubbing-

'CLUBBING'

C - cyanotic heart diseases, chron's disease
L - lung causes (lung abscess, emphysema, interstitial lung disease, bronchogenic carcinoma, tuberculosis)
U - ulcerative colitis
B - biliary cirrhosis
B - benign mesothelioma
I - infective endocarditis, idiopathic, inherited
N - neurogenic tumors
G - graves disease

Shivani Mangalgi
Medicowesome 2017

Courtesy YouTube

Pulmonary Alveolar Proteinosis: High yield points

Pulmonary Alveolar Proteinosis (PAP)

a. Lipoproteinaceous material(like surfactant) accumulates within alveoli.
b. There is susceptibility to pulmonary infections, sometimes with opportunistic organisms.
c. In the congenital form, there is mutation in the gene for surfactant protein B or C or the Bc chain of the receptor for GM-CSF.
d. It can be secondary to Hematologic cancers, pharmacologic immunosuppression, inhalation of organic dust (eg., silica) or toxic fumes and certain infections.
e. Acquired PAP is an autoimmune disease targeting GM-CSF.
f. 72 percent patients have a history of smoking.
g. Most patients present with progressive exertional dyspnea of insidious onset and cough. If there is secondary infection, there can also be fever, chest pain, hemoptysis.
h. Physical examination: Some patients have cyanosis, clubbing, inspiratory crackles.
i. Chest X ray: Bilateral air-space disease with an ill-defined nodular or confluent pattern.
j. HRCT: Patchy, ground glass opacifications with superimposed interlobular septal and intralobular thickening, a pattern called "Crazy Paving".
k. The lavage fluid in patients with this disorder has an opaque, milky appearance. It is PAS positive.
l. Electron Microscopy shows that the intraalveolar material consists of amorphous, granular debris containing numerous osmiophilic, fused membrane structures resembling lamellar bodies and tubular myelin. 
m. Acquired PAP has been treated successfully by Whole-lung lavage. 

-VM

Asthma + Eosinophilia

Let us suppose that a patient has the classic signs & symptoms of Asthma and with that she has eosinophilia ( Absolute eosinophil count above 500/mm3).

The next step should be to look at the serum IgE levels.

If it is also elevated-

1. Do a stool examination and serological testing for strongyloidiasis.

2. Do Aspergillus-skin testing and check for aspergillus specific IgE.

If you have got a positive result for one of the above two, you have your diagnosis.

But what if both of the above results come out to be negative.

Then consider Churg Strauss syndrome or Eosinophilic granulomatosis with polyangiitis.

That's it!

-VM

Subpleural opacities and Ground Glass Opacities

Hey guys!

I saw a patient today, a 37 year old female patient with chief complaints of cough and shortness of breath. She has a history of allergic rhinitis and migraine. She is also obese with an BMI of 31.

As you must have guessed already she was diagnosed with Bronchial asthma. On the spirometry report done 4 months back,  there was an obstructive pattern and after giving bronchodilators her FEV1 increased by 22% (>12%) and FEV1 vol increased by 300ml (>200ml). These findings also strongly support the diagnosis of asthma.

She was started on Albuterol as needed and Salmeterol-fluticasone MDI. She didn't show good response in the first 4 weeks, so she was also started on Montelukast and Tiotropium inhaler.

Now after 4 months, she still had cough and shortness of breath. She had bilateral polyphonic wheezes. A chest X Ray was done which came out to be normal. On pulse oximetry, SaO2 was 97% while breathing ambient air. On chest CT we found two attributes:
Subpleural opacities and Ground glass opacities.

So based on the CT scan findings, differential diagnosis:

Subpleural opacities:
1. Eosinophilic granulomatosis with polyangiitis( previously called Churg Strauss).

2. Organizing pneumonia

3. Pulmonary embolism with resultant subpleural pulmonary infarction

4. Allergic bronchopulmonary aspergillosis ( well, not really, actually in this case, there is peripheral air space opacification which looks identical to subpleural opacities)

Now Ground glass opacities:

1. Atypical pneumonia

2. Hypersensitivity pneumonia

3. Several ILDs

4. Sarcoidosis

5. Pulm Edema

6. Pulm Haemorrhage

That's all!

-VM

Lung Cancer Subtypes

Subtypes of lung cancer:-
1. Squamous cell cancer-
Most common variant in India.
Smoking is a risk factor.
Central in location.
Local growth is surgically resectable.
Cavity formation is seen.

2. Adenocarcinoma-
Most common variant of lung cancer overall.
Most common lung cancer among non smokers.
Peripheral in location.
Transbronchial spread i.e. it arises at one lobe and spreads to the another lobe.

3. Small cell carcinoma/Oat cell carcinoma-
Most aggressive variant.
Smoking is a risk factor.
Central  in location.
It exhibits micrometastasis.
It has worst prognosis.

4. Large cell carcinoma-
Observed in Non smokers.
Peripheral in location.
This is associated with Estrogen production which manifests as Gynecomastia.

I hope this will help you to distinguish between the various subtypes.

Thank you
-Md Mobarak Hussain (Maahii)

Settings for mechanical ventilation

These are my quick and dirty notes to help ventilator settings related questions on the USMLE.

Postural variations in pulmonary edema and embolism

Hey Awesomites

Patients with pulmonary edema prefer to be in an upright position, while those with pulmonary embolism prefer flat position.


This is because in cases of edema, there is excess fluid accumulation in lungs, which limits respiratory movements. In upright position, the fluid will settle down and thus it lowers the pressure in pulmonary vessels which makes it easier to breathe.

On the other hand, in case of pulmonary embolism, the patient  is placed in left lateral decubitus (durant maneouver) and Trendelenburg position immediately. The air embolus moves through the right side of heart to enter into the lungs. But in Durant's maneouvre and Trendelenburg position, the embolus gets trapped in the apex of the heart and so does not get transported through pulm arteries to enter the lungs.
Check this link for more detail on venous emboli management


Thats all
- Jaskunwar Singh

Answer is not always antibiotics!

Clinical vignette:
Young, non smoker, female comes with complaints of sore throath, dry cough, nasal congestion for 10 days. Now, she feels better however she coughs out yellowish expectoration.
There are scattered wheezes and crackles that clear with coughing.
You've ordered relevant labs and meanwhile the patient asks you if she would need antibiotics. What would your next step be?

Answer: Symptomatic management.
Reason: Since there is a history of preceding viral infection and her current situation indicated Acute Bronchitis, the expectant management would be fairly Symptomatic!
Infact, there are articles that state that giving antibiotics could worsen the patient condition! Also, judicious use of antibiotics can help prevent antibiotic resistance.

Let's fight antibiotic resistance!

Stay awesome!
-Rippie

FENO in asthma: routine clinical testing

Hey Awesomites

One of the additional tests for determining the present status of airways in asthmatics is the measurement of Fraction of Nitric Oxide in Expired air (FENO).

The levels of Nitric oxide are elevated in the presence of inflammation in the airways, that is eosinophilic in nature.

In children <12 years, normal FENO is usually less than 36 ppb. However, in case of allergic inflammation of airways, the levels rise to >50 ppb.

Note that FENO is not diagnostic, but a test for independent prediction of exacerbations in asthmatic patients and is now done routinely in clinical practice, as approved by US- FDA.

Thats all
- Jaskunwar Singh

Croup : Review of key points

Here's a short Mnemonic/Review of Important facts about Croup - Acute Tracheobronchitis !

Remember :
CROUPS

C - Common respiratory disease
R - Respiratory viruses like Parainfluenza
O - Oxygen Treatment (Humidified)
U - Ugly Cough - Barking / Seal like cough
P - Prodrome of illness followed by Inspiratory Stridor
S - Steeple sign on X Ray

It's helpful to remember Acute EPIGLOTTITIS as the complete opposite of CROUPS using similar ideas.

- Not as common.
- Caused by Bacteria generally (Strep , Hib)
- Oxygen Therapy + AntiBiotics
- Ugly - Sniffing dog like position + Drooling
- Prodrome not particularly, but Stormy acute onset.
- Shows Thumb print appearance on X Ray.

Hope this helped !
Happy Studying !
Stay awesome.

~ A.P.Burkholderia

Contraindications for Noninvasive Ventilation Mnemonic

Hey guys

This is one of my rare mnemonic posts. I don't post much on this coz most of my mnemonics are kinda personal if not socially inappropriate :p

So Noninvasive ventilation, imagine having a mask on ur face, all air tight, almost strangulating and as if this isn't enough, with multiple tiny outlets giving jets of air which are titillating your highly itchable nasal area.

Unpleasant, right?

Talking of unpleasant, you do remember Hitler, right?
He GAAASED the Jews, since that's not a possibility for us since we all love Zuckerberg let's think about something on a similar note.

"GAAAS the HOEs"

G- GI bleeding
A- Aspiration
A- Angina( including MI)
A- Arrest( Cardiac and Respiratory)
S- Surgery on ur face

H- Haemodynamic instability
O- Obstruction ( in upper airway)
E- Encephalopathy ( Severe)
S- _____

I've left the last one blank for the reader to fill up. Hint: It has something to do with​ obstruction of the lower airways.

Hope this is helpful!

-VM

Fact of the day : Pinenes for refreshing your Airways

Hello

Did you know? One of the reasons your lungs feel refreshed ( increased mental focus and energy ) when you walk through the shades of beautiful pine forest is because of an anti - inflammatory compound called alpha -Pinene, that is found in conifers. It is used as a bronchodilator in the treatment of asthma and is abundantly present in marijuana.

- Jaskunwar Singh

Coccidioidomycosis mnemonic

Coccidioidomycosis is caused by Coccidioides immitis!

Chest x-ray - Left Lung.

Hello everybody!

Let's see the image correlations of the left lung today.

The left lung has an apical lobe ,lingula and a basal lobe.

Apical lobe has 2 segments: Anterior and posterior.
Lingula : The tongue like extension and the alleged counterpart of the middle lobe has 2 parts to it : Superior and Inferior.
Basal lobe has 4 segments namely : Superior, Posterior, Medial, Lateral.

Carefully observe how the identification of these segments differs while seeing an X-ray.

Apical lobe:

Basal Lobe:

So that's it with the interpretation of lung fields on X-rays!

Hope this is helpful!

-Medha.

Flow volume loop notes and mnemonics

Here are my notes on the flow volume loops!

Flow volume loop explanation video and mnemonic

Hello!

I explain the flow volume loops seen in obstructive lung diseases, restrictive lung diseases, intrathoracic and extrathoracic - fixed variable obstruction in this video with mnemonics! :)