Pulmonology USMLE WORLDCOPD The most common bacteria responsible
for acute exacerbation of COPD are S.pneumonia, H.inf, and M
catarrhalis PFTs are the most useful tool to determine if a patient
can benefit from the lung resection surgery Predicted postoperative
FEV1 is very helpful for this purpose can be derived from
preoperative value and the fractional function of the lung tissue
to be resected Current ABG do not provide any useful information in
this regard They are more useful in determining the level of
respiratory compromise and appropriate ventilator settings for
patients undergoing lung resection surgery Doubtful benefit of
resection after 1- FEV12- split function quantitative lung scans
& exercise testing A bronchodilator response test is used to
demonstrate reversibility of airway obstruction It helps to
differentiate between COPD and asthma, although a subset of
patients with COPD may also demonstrate airway reactivity\Acute
exacerbation Case:pt with chronic COPD , develop acute exacerbation
, failed to respond to steroid and Beta agonist , ipratropium and
O2what to do ? DoNIPPV (Noninvasive positive pressure ventilation
)>> then intubate if no response. BUT WHY ? NIPPV :associated
with complications that are a hallmark of intubation, which
includes infections) NIPPV is recommended in a patient of
respiratory distress with : RR>25 per min. pH45 mmHg There is
better alveolar ventilation and less fatigue of respiratory muscles
by using NIPPV Contraindication to NIPPV: septic, Hypotensive,
dysrhythmic patients The patient is already on oxygen therapy, but
she is hypercapnic as well as acidoticNote: In COPD patients, PCO2
is elevated at baseline and it does not stimulate the respiratory
center, unlike in normal individuals. Their only drive to increase
the respiratory rate is hypoxia If you just provide oxygen, it, in
fact, worsens the situation You should provide NIPPV to provide
more oxygen and to wash out the CO2 Caution It is always better to
avoid intubation, if possible, because of various complications
associated with intubation incidence of nosocomial infections,
long-term mortality in these patients However, if the patient does
not respond to NIPPV, then intubation should be considered Systemic
steroids are the first line therapy of the acute exacerbation of
COPD but are relatively ineffective for chronic maintenance therapy
The only two modalities that can decrease mortality in patients
with COPD are: home oxygen therapy smoking cessationThis patient
has complete left lung collapse (complete opacity), possibly from
mucus plugging and obstruction He also has symptoms of respiratory
failure like confusion and sweating He needs urgent bronchoscopy
and removal of the mucus plugs The removal of secretions or plugs
is associated with rapid improvement in Pa02
Please try to understand the various Tx used for COPD It is a
very high yield topic in board exams
Tx of COPD
1st line Anticholinergic drugs (Ipratropium bromide) 2nd
lineBeta-2 agonists like albuterol Inhaled steroids like
beclomethasone MDl are not useful 3rd 4th Aminophylline or oral
Theophylline the diaphragmatic contraction and help
breathingSystemic steroids are the first line therapy of the acute
exacerbation of COPD but are relatively ineffective for chronic
maintenance therapyAntibiotics therapy should be used empirically
for acute exacerbation of COPD and should cover Streptococcus
pneurnonae, Haemophilus influenza, and Moraxella catarrhalis The
only two modalities that can decrease mortality in patients with
COPD are: home oxygen therapy smoking cessation
LTOT( Long-term supplemental oxygen therapy) Once the patient
qualifies for long-term oxygen therapy, it is continued for life
The criteria for initiating long-term oxygen therapy in COPD
patients are as follows1- All COPD patients with PaO2 < 55 mmHg
or SaO2 < 88% on room air2- Patient with cor pulmonale, evidence
of pulmonary HTN or hematocrit> 55% should be started on home
oxygen therapy even when PaO2 is 56-59 mmHg with SaO2 > 89%3-
Home oxygen may also be used in patients who has resting awake PaO2
> 60 mmHg with Sa02 > 90% if they become hypoxic during
exercise or sleep (noctumal hypoxia)The dose of oxygen should be
titrated such that SaO2 is maintained at > 90% during sleep,
normal waking, and at rest. Survival benefits of home oxygen are
significant when it is used for a minimum of 15 hours a dayNote:In
any case of COPD the biggest contributor to mortality is Hypoxia
pulmonary vasoconstriction pulmonary artery pressure Pulmonary
Arterial Hypertension progressive right heart enlargement right
heart failure death. After quitting smoking, home oxygen therapy is
the only modality known to prolong survival in COPDEmphesemaalpha-
1 anti-trypsin deficiency :Any emphysema in a non-smoker, emphysema
presenting in the 3-rd decade any emphesematous changes in the
lower lobesAnother diagnostic clue in this patient is the episode
of neonatal jaundice, which occurs in 26 % of the patients Open
lung biopsy or video assisted lung biopsy is not needed in this
patient, as diagnosis can be made by Dx serum alpha-I anti-trypsin
levels High resolution CT scan should be considered only after the
assessment of alpha-I anti-trypsin levelsASTHMA Indicators of sever
attack: N- PCO2 values indicates CO2 retention because of severe
airway obstruction (air trapping) and or respiratory muscle fatigue
Speech difficulty, Diaphoresis, Altered sensorium, Cyanosis, Silent
lungsExercise induced asthma Beta agonists and mast cell
stabilizers both play an important role in the management of
exercise-induced asthma It should be noted that aerobic exercise
and cold air are more likely to predispose to exercise induced
asthma Exercise induced asthma should not be confused with post
exercise fatigue and seasonal asthma Patient with exercise induced
asthma experiences chest discomfort, wheezing, cough,
breathlessness, fatigue, and abdominal discomfort in some cases The
symptoms may be underreported in some cases due to fear of loosing
position in the team Treadmill exercise challenges with pre
exercise and post exercise PFTs may help in the diagnosisAcute
bronchopulmonary aspergillosis Characterized by worsening asthma;
fleeting pulmonary infiltrates; IgE; peripheral eosinophilia;
immediate skin hypersensitivity reaction to aspergillus antigen;
precipitating antibodies against aspergillus in serum coughing
brownish mucous plugs Oral prednisolone is the Tx of choice for
ABPA which is a hypersensitivity reaction to inhaled aspergillus
antigens Oral itraconazole steroid requirement in patients with
ABPA and improves pulmonary function BUT the mainstay of Tx is oral
prednisolone CXR typically shows a solid mass surrounded by a
radiolucent crescent (crescent sign, Monod's sign) Any case of
bronchial asthma + eosinophils >10 %==>should the suspicion
for parasitic infestations or Hypersensitivity to fungal antigens
Central bronchiectasis
The common diagnostic features of ABPA include
1. Asthma like symptoms2. IgE3. HypereosinophiIia4. Central
bronchiectasis5. Positive Aspergillus Skin testWhenever a patient
with asthma is suspected of having ABPA, skin testing with A
antigen is the first diagnostic step negative, Dx of ABPA is ruled
out positive, serum precipitins against Aspergillus fumigatus and
IgE level are checked ABPA is excluded if IgE levels are 40%
suggestive of chronic eosinophilic pneumonia Glucocorticoid therapy
results in rapid resolution of symptoms and radiographic clearing
CEP who presents with systemic symptoms of fever, malaise, anorexia
and weight loss for several weeks or months you should suspect
Cherg Strauce S Some times the presenting symptom of CCS is CEP
However, CEP usually does not have granulomas on biopsy and
generally does not involve organs other than the lung
Glucocorticoid therapy results in rapid resolution of symptoms and
radiographic clearing
Lung CA A lung mass with cartilage is most likely a hamartoma
and can be observed Most common benign tumor of the
lunghamartoma.SVC syndrome Today, the most common cause of superior
vena cava obstruction is bronchogenic CA. Lung abscess and
pneumonia Never. TB & aspergillosis rarely. In the past various
surgical procedures were devised to relieve the symptoms of SVC
obstruction, but today, angioplasty with stenting is the standard
of care.Pancoast Preoperative radiation is administered before
resection of this tumor. Pancoast tumors may be of any histology
but the majority are either SCC or adenocarcinomas When the tumor
invades the lower brachial plexus, it can cause severe pain in the
arm along the ulnar nerve In a smoker with arm pain, cough and
weight loss, a mass in the lung apex is a Pancoast tumor untiI
otherwise provenNote: Carcinoid tumors are slow growing and have
the best prognosis of all lung cancers NoteAny chronic smoker with
HPO(Hypertrophic osteoarthropathy) should have a CXR to rule out
malignancy HPO is associated with chronic proliferative periostitis
of the long bones, clubbing, and synovitis HPOSCC & AdenoCA Due
to high incidence of lung cancer among smokers, it should be
suspected in any smoker presenting with recurrent pneumonia order
HRCTIncidental Lung nodule ASx + lung mass, the first step is to
get previous chest x rays for comparison The things that you need
to remember are1- Lesions >3 cm are more likely to be
malignant2- Lesions with irregular borders are likely to be
malignant where as smooth borders indicate benign nature3- Presence
of eccentric" calcification indicates malignancyPneumonia Any
patient with fever, night sweats and copious foul smelling sputum
has anyone of these three conditions:1- Bronchiectasis2- Lung
abscess 3- Anaerobic pneumonia Sputum gram stain a specimen that
contains >25 PMN & no abnormality most common abnormality
unilateral infiltrate with hilar adenopathy on the same side A lung
cavity may bepresent in some cases Sometimes there is evidence for
a parapneumonic effusion
Histoplasmosis is the most common fungal infection in theUSA
Note:G-negative bacilli accounts for < 2% of CAP, but account
for most of the nosocomial infection and have high mortality rates
GNB pneumonias are rare in healthy individuals and usually occur in
infants, the elderly. alcoholics, and an immunocompromised host,
especially with neutropenia The usual pathophysiological mechanism
is colonization of the oropharynx, followed by micro aspiration of
upper airway secretionsTB reactivation in HIV+ chronic cough,
weight loss, fever and malaise + bilateral apical consolidation
typical for reactivation tuberculosis Mycobacterial infection
occurs earty in the course of disease with CD4 counts
>200/microLHistoplasma capsulatum on HIV + Disseminated fungal
infection takes place when HIV infection is advanced and
radiography usually shows a miliary patternHHV-8 Kaposi us sarcoma,
which usually has cutaneous findings and pulmonary involvement,
which may be asymptomatic or mildCXRusually shows a pulmonary
nodule or pleural effusionsPCP immunocompromised CD460 mEqil) is
the gold standard preferred over direct mutation analysis as more
than 1,250 mutations in CFTR can lead to cystic fibrosis So gene
testing confirmatory.Lung Abscess Most cases of primary lung
abscess are due to aspiration, periodontal disease or gingivitis
Common causes of altered consciousness are alcoholism, general
anesthesia, drug overdose, stroke, seizures, diabetic coma, shock
or other serious illnesses Secondary lung abscess (obstructive) is
most commonly seen in patients with lung malignancy The location of
lung abscess depends on the etiology In case of aspiration, the
primary site of abscess is the posterior segment of right upper
lobe or apical segment of right lower lobe especially in recumbent
position This is because these segments are in direct continuation
of right bronchus Same segments on left side are less likely to
develop post aspiration lung abscess because right bronchus has
relatively more straight course than the left oneNote: Basal
segment of the right lower lobe abscess might be seen in case of
transdiaphragmatic infection from amebic/pyogenic liver
abscessPneumothoraxCXRno bronchovascular markings on the half of
the right lung Pleural blebs small, CXR commonly seen in severe
asthmatics presents as crepitus over the neck and chest. It may
appear very frightening, but does not produce any respiratory
distress However, a CXR is a must to ensure that there is no
pneumothorax One may also have a tracheobronchial rupture and this
may present with subcutaneous emphysema However, this is more
common in trauma and bronchoscopy may be required Once the CXR is
done, and if no pneumothorax is seen, the patient can be observed.
Subcutaneous emphysema does not require any formal treatment , save
for observation Note: Endotracheal intubation is not required for
SC emphysema Even though they may appear with significant facial
swelling, the majority of these patients are in no respiratory
distress Criteria for mechanical ventilation is based on physical
appearance of the patient, blood gas, acidosis and oxygen
saturation Hyperparic O2 no role. CT if suspected
bronchial,esophageal tear.
"Extremely high yield question for USMLE
Pulmonary Effusion
the first step is Diagnostic thoracentesis (except in patients
with classic signs and symptoms of CHF)Bronchoscopy is a close
alternative when suspect CA ; however, this requires sedation and
is considered to be a relatively invasive procedure This will be
the next step if the pleural fluid cytology is non-diagnostic and
the patient has lung mass If cytology is positive for lung cancer,
then the patient does not require a bronchoscopy
Actually.CHF is the most common cause of pleural effusion (right
side) The determination of pH is important in parapneumonic
effusions in which a value of < 7.2 requires a chest tube
aspiration to prevent empyema Normal pleural fluid pH is
approximately 7.64 . Pleural fluid pH < 7.3 indicates pleural
inflammation . pH of 7.35 is consistent with transudative pleural
effusion .SepticEmboli Drug abuser Tricuspid valve endocarditis
S.aureus PC: acute endocarditis +pulmonary infarction and abscess
Sx fever, pleuritic chest pain, hemoptysis and malaise CXR
peripheral well-circumscribed lesions with cavitation Surgery is
required in the majority of these patients( Valve repair or
replacement is therapeutic) Note:Atelectasis may be seen in
patients with endocarditis but is a result of the infection and not
the cause of endocarditis. Note: Pleural effusions in a drug abuser
may occur from a parapneumonic effusion ClueIn a drug abuser,
presence of well-circumscribed lung opacity is most likely due to
embolism of infected vegetation causing a pulmonary infarct' This
concept is extremely important for the USMLE exams
Proximal (above knee veins) DVT of lower extremities is the most
frequent source of PE.Proximal veins of lower extremity are iliac,
femoral and popliteal
Pulmonary Embolisim Pulmonary infarction after a pulmonary
thromboembolism is very rare. Death of lung tissue is very rarely
seen after embolism because of the copious oxygen supply The lung
receives oxygen from the pulmonary arteries, the bronchial arteries
and from the airways Thus infarction occurs rarely and its
appearance usually is associated with compromise of bronchial
arterial blood flow and/or airways to the involved area Such
compromise is promoted by existence of other cardiac or pulmonary
pathology, such as left ventricular failure, mitral stenosis or
COPD When the x-ray is normal and suspicion is still high, the next
step is obtain a V/Q scan If the via scan is of low probability
with a normal x-ray, one can exclude the diagnosis of PE Hampton
hump-cone shaped area of opacification Westermark sign-dilated
pulmonary artery with distal oligemia Factor V Leiden is the most
common inherited disorder causing hypercoagulability and
predisposition to thromboses, especially DVT of lower extremities
Therapeutic INR for most clinical indications of warfarin is 2 to 3
These conditions include VTE , VHD, and AFib . A higher INR of 3.0
to 4.5 is required only in ceratin clinical settings like
prosthetic heart valves Patients with suspected PE should have a
CXR and ABG, followed by EKG and V/Q scan. Note: V/Q scan is the
most helpful initial evaluation to rule out PE after CXR, ABG and
EKG are obtained Spiral CT scan of the Chest is helpful if the
emboli are large and in the proximal pulmonary artery Spiral CT
will be the answer (instead of V/Q scan) if the baseline chest-x
ray is abnormal (eg destroyed lung) Note:Whenever there is Hypoxia,
oxygen is ordered as a Tx Try noninvasive ventilation such a 100%
non-rebreather mask or BiPAP machine If the ABG shows sever hypoxia
despite being on 100% oxygen the intubation is considered The most
typical findings of a PE on ABG sampling are hypoxemia and
hypocarbia Suspected PE
Notethe problem with CT angiogram is that it can Dx only large
emboli, Small emboli can be easity missed
Suspect choriocarcinoma in any postpartum women who presents
with SOB and hemoptysis The next step chest x-ray, pelvic exam, and
beta-hCGDVT Patients with DVT in whom anticoagulation is
contraindicated require placement of IVC filter for the prevention
of pulmonary embolism Compression stockings do NOT have any role in
the prevention of PE in patients with DVT. They reduce the
incidence of venous thrombosis in postsurgical patients by venous
stasis Once the Dx of DVT is made by diagnostic testing,next step
is to start treatment with anticoagulants unless they are
contraindicated. DVT is not a clinical diagnosis and therefore all
suspected cases of DVT should be evaluted with noninvasive testing
and the test of choice for this purpose is compression US. Dont
start Tx till prove Dx(because we have only DVT not PE). Impedence
plethysmography is the study of choice for recurrent DVT(more
specific) It becomes normal faster than compression US after an
episode of DVT that makes it superior to compression US for
recurrent DVTNocturnal sleep apnea Noctunal pulse oximetryis used
for diagnosing nocturnal desaturation, especially in patients with
sleep apnea Patients with sleep apnea will have episodes of apnea
with resultant desaturation These patients wiII benefit from
nocturnal oxygen administration in the form of CPAPARDS The
earliest sign is often tachypnea followed by dyspnea The physical
exam and chest x-ray are usually normal initially In ARDS, it is
best to keep the patient on the dry side and avoid fluid overload
Therefore, most ARDS patients receive diuretics to help decrease
the fluid overload All patients with ARDS have daily chest x-rays
and are weighed daily to monitor the fluid balance TV beyond the
recommended 8-10 ml/kg does not help with oxygenation and may in
fact respiratory compliance Know the three major complications of
too high a PEEP : Alveolar damage, Tension pneumothorax Ventricular
failure Pulmonary HTN is very common in ARDS and it occurs as a
result of hypoxemic vasoconstriction of pulmonary vasculature PCWP
is normal in ARDS and it is the most important differentiating
point between ARDS and cardiogenic pulmonary edema .It is usually
18 mmHg in cardiogenic pulmonary edemaCriteria for ARDS diagnosis
is1- PCWP< 18 mmHg favors ARDS over cardiogenic pulmonary
edema2- PaO2 to FiO2 ratio of 200 mmHg or less, regardless of the
level of PEEP3- Diffuse, bilateral infiltrates on chest-X ray
This question is based on simple physiology It is expected in
USMLE
When PEEP is increased, its major drawback is a decrease in
cardiac outputPatients who are maintained on PEEP should be
monitored with a Swan-Ganz catheter. To counteract the effects of
PEEP on cardiac output, some physicians may elect to use inotropic
agents or more fluids
Because PEEP increases the intrathoracic pressure, it does
slightly increase the central venous pressure This has no
significant affect on the patientPostoperative patient who presents
with dyspnea and tachypnea. one has to exclude: a. MI, b. PE, c.
pneumonia d. ARDS Goodpasture and hemisiderosis Both patients with
IPH(Idiopathic pulmonary hemosiderosis) and Goodpastures have
hemoptysis (more copious in IPH), iron deficiency anemia and signs
of respiratory compromise In both cases sputum stain may show iron
in the form of hemosiderin and CXR may be abnormal IPH is more
common in young children Serologic assays for measurement of
AGBMAbs further help in confirming the Dx and monitoring treatment
Wagner Note:Fiberoptic bronchoscopy with transbronchial biopsy is
not useful in the Dx , however a thoracoscopic lung biopsy will
reveal the full range of pathology of the condition but is not
favored as a diagnostic procedure. Skin biopsy findings are usually
non-specific hence not useful in the diagnosis A deep punch or
incisional biopsy demonstrates vasculitis and granulomas
Alveolar proteinosis characterized by accumulation of
phospholipid rich material in the alveoli probably due to impaired
clearance Its cause is unknown and it presents with dyspnea and dry
cough CXRshows bilateral alveolar infilterates PFTRLD Lung Bx wiII
confirm the diagnosis by showing PAS positive material Total lung
bronchoalveolar lavage is effective treatment of this disoroer.
(suck them up ) Corticosteroids are of no benefit in this
diseaseHemoptysis A case of massive hemoptysis is a medical
emergency Massive hemoptysis is defined as hemoptysis of >600 ml
of blood per 24 hrs Most of the times the volume is not measured;
therefore any suspicion of massive hemoptysis based up on history
needs to be treated as an emergency. RIGID BRONCHOSCOPY is the
initial intervention of choice in massive hemoptysis because it
allows for rapid visualization of the bleeding site and it allows
for control of bleeding through laser cautery or other
interventions Flexible bronchoscopy is used in the diagnostic
aspects of hemoptysis and it is not a good choice for emergency
management of hemoptysis Because of its small lumen it cannot
provide much scope for interventions Chest X-ray and CT scan are
not ideal choices because of the emergency of the
situationMediastinal mass Ant. mediastinal mass + AFP & HCG
indicates Nonseminomatous tumor Txcan be started even without a
tissue biopsy. Non-seminomas can be Tx with cis platinum based
multi agent chemotherapy These tumors are very aggressive and in
the majority of patients grow to very large sizePrevention is
better than the cureAlways remember the right time when a common
vaccine is given whether it is a child or an adult.This is big in
USMLE
People above 65 years of age should receive pneumococcal
vaccine
Idiopathic Interstitial Fibrosis IPF is a Dx of exclusion best
treated with steroids Most patients will have a positive response
in the first six months but they fail to have sustained response
Bilateral lung transplant is required and it is the rare patient
who can get bilateral transplants The shortage of donors has almost
eliminated the majority of these patients from transplantation in
diffusing capacity does not relate very well with the severity of
disease Alveolar fibrosis causes elastic recoil and as a result
FEV1/FVC ratio may be (fibrosis) A-a gradient is a useful measure
of oxygenation It is increased in interstitial lung diseases due to
poor oxygenationSystemic sclerosisNote:diffuse SSc Pulmonary HTN
and Lung Fibrosis (they have renal a. involvement)BUTLimited SSc
(crest synd) Pulmonary HTN only. NO Interstitial lung dz. (no renal
a. involvement) The most common underlying mechanism of pulmonary
complications is interstitial fibrosis It develops in about 40%
patients with diffuse disease Pulmonary vascular lesions can
develop concornitantty with interstitial fibrosis, but isolated
pulmonary HTN without interstitial fibrosis occurs in < 10% of
patients Aspiration of gastric content with resultant pneumonia due
to esophageal dysmotility. is less common than interstitial
fibrosis The risk of bronchogenic carcinoma is in patients with
systemic sclerosis, but it is not the most common cause of
pulmonary complications. Restriction of chest movements due to
extensive thoracic skin fibrosis is rare NoteTx of interstitial
lung dz cyclophosphamide.Pulmonary HTNIt can be classified as
follows1- Pulmonary HTN associated with disorders of the
respiratory system, hypoxemia, or both2- Pulmonary HTN due to
pulmonary venous hypertension (left ventricular heart disease,
mitral valve disease, or pulmonary veno-occlusive disease)3-
Pulmonary HTN following chronic thromboembolic disease4- Pulmonary
arterial HTN (primary pulmonary hypertension, pulmonary
hypertension associated with vasculopathy)5- Pulmonary HTN due to
disorders directly affecting the pulmonary vasculature (pulmonary
capillary hemangiomatosis)Chronic cough : nassar Cough can be a
presenting symptom of GERD postnasal drip, is the number one cause
of chronic cough in nonsmokers note endoscopy is the most sensitive
investigation for establishing the Dx of GERD The next best step
patient is a 24-hour pH recording Occupational lung Disease Bird
Fanciers lung a form of EAA caused by inhalation of birds antigens
initiated and worsened by exposure to organic antigens or haptens.
avoidance of antigen exposure the most effective Tx (sell your
pigons jerk) repeated exposure will cause progressive lung damage
Systemic corticosteroids severe acute symptoms or significant lung
dysfunction significant improvement clinically and functionally
Long-term outcome unchanged Inhaled steroids may prove to be useful
for prevention or treatment of recurrent disease, but they are
usually not used for this purpose Inhaled cromolyn No role in the
treatment used for prevention of acute bronchoconstriction
resulting from an acute challenge like in cases of exercise-induced
asthma, seasonal asthma long-term maintenance therapy in patients
of asthmaBerylliosis Granulamtous pulmonary disease high tech
industries like aerospace technology, ceramics,
electronicsAsbestosis DxHx of significant exposure + clinical Sx, +
radiographic and physiological findings A radiographic finding of
pleural plaques is the hallmark of asbestos exposureObstructive
sleep apnea OSA The treatment of a mild to moderate disorder
usually starts with weight reduction, avoidance of sedatives and
alcohol, and avoidance of supine posture during sleep Other
treatment modalities include uvulopalatopharyngoplasty and nasal
continuous positive airway pressure (CPAP) during sleep
Tracheostomy is used in patients with a severe disorder, and when
all the other treatment modalities have failed The clinical clues
for diagnosis of this condition are1) Habitual nighttime snoring2)
Day time somnolence3) Hypertension In severe cases, the patient may
develop pulmonary HTN due to chronic hypoxia and 2nd right heart
failure Once OSA is suspected the investigation of choice is
Nocturnal Polysomnography documenting episodes of apnea Lateral
cephalometry is indicated only.when the patient is scheduled for
surgery to relieve the airway obstruction Similarly. MRI is used
only in the presurgical evaluation of the patient. Multiple Sleep
Latency Test is used only when the diagnosis is not clear after
nocturnal polysomnography. It is usually done the day after an
inconclusive Polysomnography
Drugs NoteBeta agonist MAT (multifocal atrial
tachycardia)Ipratropium has low potential for toxicityKnow
Theophylline toxicity
manifests as CNS stimulation (headache, insomnia), GI
disturbances (nausea,vomiting), and cardiac toxicity
(arrhythmia)
Factors that influence the metabolism of theophylline. (eg ,
ciprofloxacin and erythromycin decreases its clearance and raises
plasma concentration)
The exact mechanism responsible for the theophylline toxicity is
debated, but may include PDE inhibition, adenosine antagonism, and
stimulation of epinephrine release
Beta-agonists may cause arrhythmia. nervousness, and tremor, but
CNS and GI effects are not typical Patients who are on high doses
of beta-2 agonists may develop hypokalemia and patient should be
monitored with daily electrolytes The other side affects of beta-2
agonists are tachycardia . tremor, and peripheral edema"Extremely
high yield question for USMLE
Steroids
eosinophils Lymphocyte arrest neutrophils the bone marrow
release mobilizing the marginated neutrophil pool
Note::Hypersensitivity reaction is a potential cause of
leukocytosis due to hypersensitivity-induced inflammation, but the
leukocyte differential neutrophiIia+ eosinophila
Steroids In adults, the adverse effect of low- dose inhaled
corticosteroid are limited to topical problems such as dysphonia,
which occurs in 50 % of patients oral candidiasis; symptomatic in
less than 5 percent High doses of inhaled corticosteroids systemic
absorption and can produce adrenal suppression, cataract formation,
growth in chiIdren, interference with bone metabolism purpura
Steroids cause worsening of the GERD symptoms Even if you use
steroids in the treatment of bronchial asthma, inhaled steroids are
more efficacious and have less systemic effectsExtremely high yield
question for USMLEIII
ACEi
The pathogenesis of the cough is related to an accumulation of
the inflammatory or proinflammatory mediators bradykinin, substance
P, thromboxanes, and prostaglandins
If the cough is disturbing, ACE inhibitor therapy should be
discontinued.
Only if the cough persists after the discontinuation of ACE
inhibitor therapy,CXR
Kinins are degraded by ACE
It is caused by an accumulation of kinins, and possibly by the
activation of the arachidonic acid pathway
N-acetylcysteine Anti sitamol is used to treat patients who have
very viscous secretions The agent reduces the viscosity and
prevents airway plugging N-acetylcysteine is a mucolytic agent,
which is no longer used in exacerbation of COPD, as they are even
implicated in worsening bronchospasm
Hyperbaric oxygenation has a few indications like CO poisoning,
treatment of bends after deep sea diving, few chronic infections
ASAAspirin Sensitivity Syndrome
High yield Q
Clues to correct DxASA ingestion , Persistant nasal blockage
,and episodes of bronchoconstriction.PathogenesisPseudoAllergic
Reaction. an exaggerated release of vasoactive and inflammatory
mediators in susceptible individual .ASA is COX1-2 inhibitor
5-lipoxygenase pathway leukotrines and change PG/LT balance trigger
characteristic reaction ( bronchoconstriction , polyp formation )
in susceptible individual.LT inhibitors are gaining popularity in
the Tx of this condition. (DOC)Other commonly used Tx modalities
include topical steroid and ASA desensitization Tx.
Miscellaneous Shift of the endotracheal tube or into a main
bronchus or mucous plugging could cause a collapsed lung However,
in that case, the main problem is with oxygenation and the
circulatory findings are secondary
BAL is > 90% effective in Dx PCP in HIV positive patients,
especially when CD4 count is