Pulmonary Hypertension
Normal PAP = 10-14
PAH = >25
Idiopathic or Primary PAH
- heritable
- often due to an inactivating mutation in BMPR2 (this gene normally inhibits vascular smooth muscle)
- a mutation in BMPR2 allows for excessive VSM proliferation leading to increased resistance
- associated with HIV and Kaposi sarcoma
Pg 614 Treatments Bosentan and Androsentan - competitively antagonize the endothelin receptor to decrease PVR Prostaglandins Sildenafil Dihydropyridine CCB (nifedipine)
When a lung collapses the intrathoracic volume increases due to chest wall expansion
FRC
- at FRC airway and alveolar pressures are at 0
- and intra pleural pressure is negative (prevents pneumothorax)
- PVR is at minimum
- Compliance = change in lung volume for a given change in pressure, decrease in pulmonary fibrosis, pneumonia, pulmonary edema, increase in emphysema, normal aging.
Cyanide Poisoning
Give patient nitrites
- converts hemoglobin to methemoglobin and allows for increased removal of cyanide by methemoglobin
- methemoglobin has an increased affinity for cyanide
Methemoglobinemia
- nitrites and nitrates
- anti malarial drugs
- dapsone
- sulfonamides
- local anesthetic
- metoclopramide
Treatments
- methylene blue
- vitamin C
- Cimetidine gradually lowers methemoglobin levels
Clinical presentation
- cyanosis
- chocolate colored blood
Carboxyhemoglobin
Hemoglobin bound to CO in place of O2
- causes a decrease in oxygen binding capacity with a left shit in the oxygen dissociation curve which decreases O2 unloading in tissues
Treatment = hyperbaric O2 and 100% O2
Oxygen Content of Blood
Pg 605
COPD
- decreased arterial PO2
- physiologic shunt –> decreased O2 extraction ratio
- decreased blood O2 content
Excercise/activity
- No change in arterial O2 content
- decreased venous PO2 due to increased O2 demand and increased oxygen extraction by tissues
Alveolar Gas Equation
606
Normal A-a gradient = 10-15mmHg
PAO2 - PaO2
Anemia can occur due to uterine fibroids = causes excessive uterine bleeding
Cyanosis occurs when deoxygenated Hb is >5g/dL
See Picture
High Altitude
- Barometric pressure is decreased
- decreased PaO2 and PAO2
Compensation
- acute increase in ventilation ==> causes you to blow off more CO2 ==> increased bicarbonate excretion
- respiratory alkalosis with metabolic acidosis compensation
- increase Erythropoietin => Increase Hb and hematocrit (RBC)
- increased 2,3-BPG ==> to allow unloading of oxygen to tissues
- increased mitochondria, increased O2 efficiency
- Treatment = Acetozolamide to help with altitude sickness
Pg 607
Acute mountain sickness symptoms
- headache
- fatigue
- acute cerebral edema due to hypoxia induced vasodilation
- acute pulmonary edema = hypoxia induced local vasoconstriction which increases capillary pressure which forces fluid out the vasculature and into the lungs
Chronic mountain sickness
- Increased RBC mass and hematocrit
- increased blood viscosity and decreased tissue blood flow
- elevated PAP
- Right heart enlargement
- Peripheral artery pressure
- Congestive Heart failure
Aviation and Space Flight
The effect of gravitational force on the body on a flight
- G-force moves blood
- Positive G (pushes you into chair) = Head–> Feet
Visual blackouts occur at about 4-6Gs because there insufficient blood return to the heart and insufficient pumping go blood to brain
- Negative G = Feet –> Head
Space G-force
- G-force that is achieved during a spacecraft liftoff = 8-9Gs
How is the body affected at 0 gravity?
- decreased blood volume
- decreased RBC mass
- decreased muscle strength/work capacity
- decreased maximum cardiac output
- loss of calcium and phosphate resulting in loss of bone mass
Deep Sea and Hyperbaric Medicine
Nitrogen Narcosis
- Nitrogen dissolves into neural membranes which causes reduced neuronal excitability
- diver becomes jovial/careless and become drowsy and lose strength coordination
Decompression sickness = the bends = caisson disease
- when you are underwater nitrogen disolves in the blood
- when you come up to sea level to quickly the gases begin to escape the dissolve state and form actual bubbles that can occlude the blood vessels
- symptoms = pain in joints and muscles of arms and legs, neurological problems (dizziness, paralysis, syncope) , chokes (air bubbles occlude lung capillaries resulting shortness of breath, pulmonary edema, death)
- Treatment = hyperbaric therapy
Hyperbaric oxygen uses
- decompression sickness
- arterial gas emboli
- carbon monoxide poisoning
- Gas gangrene
- osteomyelitis
Asthma
Curshmanns Spiral = shed epithelium forms whirled mucus plugs
Charcot Leyden crystals = eosinophilic, hexagonal, double pointed, needle like crystals formed from breakdown of eosinophils in sputum
Lines of Zahn
- interdigiting areas of pink
- platelets, fibrin and red RBCs found only in thrombi formed before death
- help distinguish pre and postmortem thrombi
READ STEP BOOK
611-613
And DRUGS of Respiratory
Sarcoidosis
- bilateral hilar lymphadenopathy
- noncaseating granulomatous
- increased ACE and Vitamin D due to increased 1-alpha hydroxylase
Drugs that can cause Restrictive Lung Disease
Bleomycin
Busulfan
Amiodarone
Methotrexate
Lung Cancer
Small Cell (oat cell) lung carcinoma
Non-Small cell carcinoma
- adenocarcinoma - most common type of lung cancer. Usually found on pre-existing lesions. Most common lung cancer found in non smokers and females. CEA positive
- squamous cell carcinoma
- large cell lung cancer
617-619
Pneumonia
Pg 616
Common cause of pneumonia in immunocompromised = Pneumocystis jiroveci
Most common cause of atypical/walking pneumonia = Mycoplasma pneumonia
Common cause in alcoholics = Klebsiella pneumoniae = aspirational
Interstitial pneumonia in bird handlers = Chlamydia psittaci
See Pictures
Lung Abscess
Pg 617
- always treat with clindamycin
Pleural Effusion
Pg 615
- Exudative effusions must be drained as soon as possible for risk of infection
Restrictive Lung Diseases
Sarcoidosis
- 10x more common in blacks in US
- non-caseating granuloma = epithelioid histiocytes
- can see asteroid body = giant cell configuration
- peripheral adenopathy
- cutaneous rash = pretrial
- hypercalcemia = due to increased Vit D. (increased 1-alph hydroxylase enzyme)
- BILATERAL HILAR ADENOPATHY
Hypersensitivity Pneumonitis
- noncaseating granulomas in upper portions of lungs
Silicosis
- glass maker, sand blasting
- impairs the phagolysosome formation which causes increased TB risk
- eggshell calcification of hilar lymph nodes
- increased incidence of TB
- nodules coalesce and pull lungs inwards
Berylliosis
- non-caseating granulomas in lungs, hilar lymph nodes (looks like sarcoidosis)
- increased risk for lung cancer
- systemic disease with granulomas in all organs possible
Coal Workers Pneumoconiosis
- with Rheumatoid Arthritis = Caplan syndrome
- build up of carbon inside macrophages = anthracosis
Idiopathic Pulmonary Fibrosis
- TGF-beta from injured pneumocytes induces fibrosis
- must exclude radiation therapy
- lung transplant is only treatment
ANY NONCASEATING GRANULOMA CAN CAUSE HYPERCALCEMIA
ARDS
There is decreased lung compliance due to loss of surfactant and damaged alveoli
- deflating lung is easier than inflating
- lung damage allows neutrophils to get into alveoli and produce cytokines that damage type 1 pneumocytes
- hyaline membranes are formed due to protein exudation
- Type 2 pneumocytes proliferate to fix damaged type 1
Be careful with Ventilator
- high tidal volume ventilation may lead to acute lung injury
Pots Puffy Tumor
- Sinusitis in which there is pus collection under periosteum of frontal bone ==> can cause meningitis
Influenza Virus
- Single Stranded RNA virus
- has nucleocapsid surrounded by matrix
Matrix - Hemagglutinin = required for attachment to cells (decreased infectivity with antibody to this)
- Neuraminidase = required for release of virus from infected cells (antibody correlates with viral shedding and illness severity) => Zanamivir and Oseltamivir
Antigenic drift
- point mutations
- cause epidemics
- occurs in influenza A and B
- reason we get flu shots every year
Antigenic Shift
- major change due to exchange of gene segments
- genetic reassortment
- occurs in A subtypes only
- can cause a pandemic
very bad BODY ACHES
Cyanosis
Patients with normal Hgb manifest cyanosis at higher SaO2 values than patients with anemia
