Week 7 Lecture 2 Flashcards
What is atelectasis?
Atelectasis is a medical condition characterized by the collapse or incomplete expansion of a part or all of the lung.
What can cause atelectasis?
Various reasons including blockage of the airways, pressure from outside the lung, or weakened lung tissue.
What is resorption atelectasis?
Resorption atelectasis occurs when the airway leading to a portion of the lung is blocked, preventing air from reaching the alveoli.
What are the major causes of resorption atelectasis?
- Aspiration of a foreign body blocking a conducting airway
- Tumor or other growth
- A mucous plug
What is compression atelectasis?
Compression atelectasis happens when there is external pressure on the lung, preventing it from expanding fully.
What are common causes of compression atelectasis?
- Tumor
- Enlarged lymph nodes
- Fluid accumulation in the pleural cavity
- Pneumothorax
What is the role of the pleura?
The pleura provides protection, lubrication, and support to the lungs during breathing.
What are the two layers of the pleura?
- Visceral Pleura
- Parietal Pleura
What is pleural effusion?
Pleural effusion is an abnormal collection of fluid in the pleural space.
What are the two major types of pleural effusions?
- Transudative
- Exudative
What characterizes transudative pleural effusion?
Transudate is protein- and cell-poor fluid that accumulates due to an imbalance of Starling forces.
What are common causes of exudative pleural effusions?
- Malignant diseases
- Inflammatory conditions
- Infectious diseases
- Vascular issues
What is a parapneumonic effusion?
Parapneumonic effusion is an accumulation of fluid in the pleural space that occurs as a complication of pneumonia.
What are the stages of a parapneumonic effusion?
- Exudative phase
- Fibrinopurulent stage
- Organization stage
What is empyema?
Empyema is a collection of pus within the pleural cavity.
What are the clinical features of pleural effusions?
- Dyspnea
- Chest pain
True or False: Transudates tend to be bilateral.
True
What is the normal intrapleural pressure?
Normal intrapleural pressure is around -10 cm water at the lung bases.
What can cause a pneumothorax?
Trauma and obstructive lung disease can cause a pneumothorax.
What is the primary function of mesothelium?
To provide a smooth, protective surface that allows organs to move against one another with minimal friction.
What is the typical volume of pleural fluid present in the pleural cavity?
Normally, between 10 – 25 ml of pleural fluid.
What happens to pleural fluid production in certain medical conditions?
Conditions can disrupt the balance of pleural fluid production and absorption, leading to pleural effusion.
What is the function of the pleural fluid?
The pleural fluid acts as a lubricant, allowing smooth movement of the lungs during breathing.
What is the significance of the phrase ‘the sun cannot set on a parapneumonic effusion’?
It emphasizes the urgency of diagnosing and treating parapneumonic effusions promptly.
What are the two main types of influenza viruses?
- Influenza A
- Influenza B
What type of virus is influenza?
Influenza viruses are negative-sense single-stranded RNA viruses.
What role does hemagglutinin play in influenza?
Hemagglutinin allows the virus to bind to and invade the host cell.
What is the function of neuraminidase in influenza?
Neuraminidase allows the virus to disengage from the cell and spread.
What characterizes uncomplicated infectious pleural effusions?
Exudate with neutrophils, no microbes found on thoracocentesis.
What indicates a complicated parapneumonic effusion?
Bacteria invade but are cleared rapidly, with more neutrophils and protein.
What is the treatment for empyema?
Empyema may require drainage or more invasive therapy.
What do hemagglutinin and neuraminidase do in the influenza virus life cycle?
Binding and budding of the virus
Hemagglutinin binds to sialic acid-containing glycolipids or glycoproteins on respiratory cells, while neuraminidase allows the virus to disengage from the cell.
What is the function of PB protein in influenza viruses?
RNA-dependent RNA polymerase
This protein is responsible for synthesizing viral mRNAs.
What are the two types of proteins that act as ion channels in influenza?
- Influenza A – M2
- Influenza B – NB
What is the primary site of infection for influenza viruses?
Respiratory epithelium
This includes the cells lining the nose, throat, and lungs.
How does the influenza virus enter the host’s respiratory tract?
Through inhalation of respiratory droplets, direct contact, or contact with contaminated surfaces.
What happens once the influenza virus is inside the host cell?
Viral RNA is released and serves as a template for replication.
What immune responses are activated in response to influenza infection?
- Innate immune response
- Adaptive immune response
What is a cytokine storm in the context of influenza?
Excessive inflammation and cytokine release contributing to severe symptoms.
What are the potential severe complications of influenza infection?
- Bacterial pneumonia
- Exacerbation of chronic respiratory conditions
- Systemic complications
What is antigenic shift?
A sudden and major change in the antigenic properties of the influenza virus due to genetic reassortment.
What is antigenic drift?
Gradual changes in the antigenic properties of the influenza virus due to mutations.
What does the ‘H’ and ‘N’ in influenza virus naming refer to?
- H refers to hemagglutinin type
- N refers to neuraminidase type
What are the most common influenza subtypes in humans?
- H1
- H2
- H3
- N1
- N2
What is the typical transmission method for influenza?
Direct droplet transmission, usually through coughing.
What are the clinical features of influenza?
- Cough
- Sore throat
- Rhinorrhea
- Systemic symptoms like fatigue and myalgias
What is a common complication of influenza in children?
Reye syndrome
This can occur due to the administration of salicylate drugs.
What is the role of neuraminidase inhibitors in influenza treatment?
They are beneficial for severe disease if given within 48 hours of onset.
What is the R0 rate for SARS-CoV-2 compared to influenza?
R0 for SARS-CoV-2 is between 5 and 6, while for influenza it is between 1 and 2.
What structural proteins are encoded by the SARS-CoV-2 genome?
- S (spike)
- E (envelope)
- M (membrane)
- N (nucleocapsid)
How does SARS-CoV-2 enter host cells?
By binding to the ACE2 enzyme after cleavage of the spike protein by TMPRSS2.
What is the consequence of the cytokine storm in COVID-19?
Acute respiratory distress syndrome (ARDS) and multi-organ system stimulation.
What is the primary mechanism of viral replication for SARS-CoV-2?
Translation in the cytoplasm followed by cleavage by host and viral proteases.
What is a significant difference between antigenic shift and drift?
Antigenic shift involves major changes through gene swapping, while drift involves minor mutations.
What are the common respiratory symptoms of influenza?
Cough, sore throat, and nasal congestion.
What is the incubation period for influenza symptoms?
Typically averages 2 days (1-4 days).
What promotes viral uptake by cleaving ACE2 and activating the SARS-CoV-2 S-protein?
The serine protease TMPRSS2
During early infection, where can viral copy numbers be high?
In the lower respiratory tract
Which types of cells release inflammatory signaling molecules during infection?
- Infected cells
- Alveolar macrophages
- Recruited T lymphocytes
- Monocytes
- Neutrophils
What activates kinin receptors on the lung endothelium during late lung inflammation?
Plasma and tissue kallikreins release kinins
What effect do kinins have on vascular smooth muscle?
Leads to vascular smooth muscle relaxation and increased vascular permeability
Which receptor controls the process of vascular leakage in the lungs?
ACE2 receptor
What are the consequences of dysregulated proinflammatory cytokine release?
- Pulmonary edema fills the alveolar spaces
- Hyaline membrane formation
- Compatible with early-phase acute respiratory distress syndrome
What can anomalous coagulation result in during COVID-19?
Formation of microthrombi and subsequent thrombotic sequelae
What types of immunity play important roles in acute SARS-CoV-2 infection?
- Cell-mediated immunity
- Humoral immunity
Which immune response is thought to be more important in controlling infection during COVID-19?
T cell responses
What is observed about T cell responses in mild COVID-19 patients compared to moderate to severe patients?
T cell responses were higher in mild COVID-19 patients
What do studies suggest about antibody responses in moderate to severe COVID-19 patients?
More robust antibody responses compared to mild disease patients
What is the incubation period for COVID-19?
2 to 14 days (median 5-6 days)
What percentage of COVID-19 patients remain asymptomatic?
Approximately 30%
What are some mild to moderate symptoms of COVID-19?
- Fever or chills
- Cough (can be productive)
- Shortness of breath
- Fatigue
- Muscle or body aches
- Headache
- Loss of taste or smell (10%)
- Sore throat
- Congestion or runny nose
- Conjunctivitis
- Nausea or vomiting
- Diarrhea
What are some severe symptoms of COVID-19?
- Dyspnea (severe)
- Cyanosis
- Chest pain (could be angina)
- Confusion
- Inability to wake or stay awake
What percentage of COVID-19 patients may require oxygen support due to lower respiratory symptoms?
15%
What unique condition can develop in COVID-19 patients regarding hypoxemia?
Significant hypoxemia (oxygen saturation < 90%) but limited dyspnea and respiratory discomfort
What is the estimated mortality rate of COVID-19?
Just over 2%
What are some risk factors for severe complications and viral pneumonia in COVID-19 patients?
- Advanced age (>80% of deaths occur in people over age 65)
- Male sex
- Racial and ethnic minorities
- Chronic conditions (cardiovascular disease, chronic kidney disease, diabetes, obesity, malignancy)
- Immunocompromised individuals
What are some complications associated with COVID-19?
- Death
- Heart attack & myocarditis
- Cerebrovascular disease
- Ischemic stroke due to hypercoagulability
- Acute kidney injury (acute renal failure)
What do the kidneys produce that is conveyed by the ureters?
Urine
Urine is conveyed to the urinary bladder.
What aspect of each kidney normally contacts a suprarenal gland?
Superomedial aspect
The suprarenal glands are part of the endocrine system.
What separates the suprarenal glands from the kidneys?
A weak fascial septum
This means the glands are not actually attached to the kidneys.
What type of structures are the superior urinary organs (kidneys and ureters)?
Primary retroperitoneal structures
They were originally formed as and remain retroperitoneal viscera.
What surrounds the kidneys and their vessels?
Perinephric fat
This fat extends into the renal sinuses.
What is the renal hilum?
The entrance to the renal sinus
It allows structures that serve the kidneys to enter and exit.
Where does the hilum of the left kidney lie in relation to the transpyloric plane?
Near the transpyloric plane, approximately 5 cm from the median plane
The transpyloric plane passes through the superior pole of the right kidney.
At what level do the renal arteries arise?
At the level of the IV disc between the L1 and L2 vertebrae
The right renal artery passes posterior to the IVC.
How many segmental arteries do the renal arteries typically divide into?
Five segmental arteries
These are end arteries that do not anastomose significantly.
What supplies the superior segment of the kidney?
The superior segmental artery
Other segments are supplied by their respective segmental arteries.
What is the function of the right renal vein?
It receives blood from the right kidney
The left renal vein is longer and receives additional veins.
What type of fibers make up the renal nerve plexus?
Sympathetic and parasympathetic fibers
The plexus is supplied by fibers from the abdominopelvic splanchnic nerves.
Where do visceral afferent fibers conveying pain sensation from the kidneys follow?
Sympathetic fibers retrograde to spinal ganglia and cord segments T11–L2
Ureteric pain is referred to the ipsilateral lower quadrant.
What type of fibers are conveyed from the inferior thoracic and upper lumbar spinal cord levels to the vesical plexuses?
Sympathetic fibers
Parasympathetic fibers are from sacral spinal cord levels.
What is the effect of parasympathetic fibers on the detrusor muscle?
They are motor to the detrusor muscle
They inhibit the internal urethral sphincter in males.
What happens during bladder stretching?
The bladder contracts reflexively and the internal urethral sphincter relaxes
This allows urine to flow into the urethra.
What controls involuntary urine flow from the bladder to the urethra?
The internal urethral sphincter
The external urethral sphincter controls voluntary urine flow.
What additional function does the internal urethral sphincter have in males?
It prevents the flow of semen into the male bladder during ejaculation
Damage to these muscles can lead to urinary incontinence.
What is the length and diameter of the female urethra?
Approximately 4 cm long and 6 mm in diameter
It passes antero-inferiorly from the bladder to the external urethral orifice.
Where is the external urethral orifice located in females?
In the vestibule of the vagina
It is directly anterior to the vaginal orifice.
What does the musculature surrounding the internal urethral orifice of the female bladder lack?
An internal sphincter
This differentiates it from the male anatomy.
What are the main nerves that supply the female urethra?
Vesical nerve plexus and pudendal nerve
Which nerves carry visceral afferents from most of the urethra?
Pelvic splanchnic nerves
What type of afferents does the pudendal nerve provide to the urethra?
Somatic afferents
From which spinal ganglia do both visceral and somatic afferent fibers extend?
S2–S4 spinal ganglia
What is the primary goal of lower urinary tract (LUT) function?
Maintaining a low-pressure bladder during filling and periodic voluntary bladder emptying
What neural mechanisms mediate the contraction of the internal and external urethral sphincters during bladder filling?
Sympathetic (hypogastric nerve) and somatic (pudendal nerve)
What occurs when the pontine micturition center (PMC) is released from tonic inhibitory control?
Initiation of the voiding process
What role does the periaqueductal gray (PAG) play in LUT function?
Switching circuitry between storage and voiding phases
True or False: Frontal, Midcingulate, and Subcortical areas of the brain contribute to LUT regulation.
True
What are umbrella cells?
Specialized epithelial cells found in the lining of the urinary tract, particularly in the bladder
What is the primary function of umbrella cells?
Maintain bladder integrity and prevent leakage of urine
Fill in the blank: Umbrella cells are resistant to _______.
Urine
What are the key characteristics of umbrella cells?
Large size, flattened shape, extensive apical membrane folds (plaques or ridges)
What do tight junctions in umbrella cells regulate?
Movement of ions, water, and solutes across the epithelium
What specialized transport mechanisms do umbrella cells possess?
Aquaporin water channels for water reabsorption
What is the vesicoureteric junction?
The junction between the urinary bladder and the ureter
What condition does a defective valve mechanism at the vesicoureteric junction lead to?
Vesicoureteral reflux (VUR)
How is vesicoureteral reflux (VUR) classified?
Into grades I (mildest) to V (most severe)
What are potential complications of untreated vesicoureteral reflux?
Recurrent urinary tract infections, urinary incontinence, kidney damage
What does the term urinary tract infection encompass?
Asymptomatic bacteriuria, cystitis, prostatitis, pyelonephritis
What distinguishes asymptomatic bacteriuria (ASB) from a urinary tract infection (UTI)?
ASB occurs without symptoms, while UTI is symptomatic and requires treatment
What is the primary pathway for bacteria in urinary tract infections (UTIs)?
Bacteria establish infection by ascending from the urethra to the bladder
Continuing ascent up the ureter to the kidney is the pathway for most renal parenchymal infections.
What are the typical symptoms of uncomplicated cystitis?
- Dysuria
- Urinary frequency
- Urgency
- Nocturia
- Hesitancy
- Suprapubic discomfort
- Gross hematuria
Symptoms may vary in individual cases.
True or False: The introduction of bacteria into the bladder always leads to a symptomatic infection.
False
Normal voiding and innate host defense mechanisms can eliminate bacteria.
What is asymptomatic bacteriuria (ASB)?
Bacteriuria detected incidentally without local or systemic symptoms referable to the urinary tract
Diagnosis of ASB is considered when there are no symptoms.
What distinguishes mild pyelonephritis from severe pyelonephritis?
Mild pyelonephritis can present as low-grade fever, while severe pyelonephritis can manifest as high fever, rigours, nausea, vomiting, and flank pain
Symptoms of cystitis may not be present in severe cases.
What is the main feature distinguishing cystitis from pyelonephritis?
Fever
The fever of pyelonephritis typically exhibits a high spiking ‘picket-fence’ pattern.
What is urosepsis?
A systemic inflammatory response due to bacteria from the urinary tract entering the bloodstream
Can lead to organ dysfunction and septic shock.
What is the predominant microorganism in the normal vaginal microbiota?
Lactobacillus species
Specific species include L. crispatus, L. gasseri, L. jensenii, and L. iners.
What are common risk factors for urinary tract infections (UTIs)?
- Obstruction
- Short urethra length
- Catheterization
- Vaginal area colonization
Women are at higher risk due to shorter urethra.
What is the most frequent pathogen causing UTIs?
E. coli
Followed by Klebsiella and Proteus.
What role do P fimbriae play in E. coli infections?
Mediates binding to specific receptors on the surface of uroepithelial cells
Important in the pathogenesis of pyelonephritis.
What is the effect of urease production by Proteus mirabilis?
Raises urine pH above 7, enhancing bacterial growth and increasing likelihood of renal stones
Urease production is significant in pyelonephritis development.
What are the characteristics of Klebsiella bacteria in healthcare settings?
- Adhere to mucosal surfaces
- Form biofilms
- Develop antibiotic resistance
These traits make treatment challenging.
What is interstitial cystitis?
A chronic condition associated with bladder inflammation and pain
Symptoms occur alongside lower urinary tract symptoms (LUTS).
Fill in the blank: The clinical presentation of interstitial cystitis often includes pain perceived to be attributable to the _______.
bladder
Pain may also occur outside the bladder.
What are the common symptoms of urosepsis?
- Fever
- Chills
- Rapid heart rate
- Rapid breathing
- Confusion
- Decreased urine output
Prompt diagnosis and treatment are essential.
What can cause papillary necrosis in patients with diabetes?
Obstructive uropathy associated with acute papillary necrosis
Sloughed papillae obstruct the ureter.
What is the relationship between Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) and autoimmune disorders?
There is a significant prevalence of autoimmune disorders in IC/BPS patients.
What have historical studies identified in the bladder mucosa of IC/BPS patients?
Anti-urothelial antibodies.
What are the recognizable patterns of inflammatory infiltration in the bladder mucosa of IC/BPS patients?
- Lymphoplasmacytic infiltrates
- Stromal edema and fibrosis
- Urothelial denudation
- Detrusor mastocytosis
What is the significance of Hunner lesions in patients with IC/BPS?
They are discrete inflammatory lesions with a well-characterized inflammatory profile.
How can bladder inflammation in IC/BPS patients be characterized?
By infiltration of acute and chronic inflammatory cells and mast cells.
What is the primary function of the urothelium in the bladder?
To provide a robust barrier layer.
What are glycosaminoglycans (GAGs) in relation to the urothelium?
They are dense layers on the luminal surface that protect the underlying bladder interstitium.
Fill in the blank: Defects in the barrier function of the urothelium may lead to ______ in IC/BPS patients.
bladder pain
What are common clinical manifestations of IC/BPS?
- Discomfort and/or pain related to the bladder
- Daytime and nighttime urinary frequency
- Urinary urgency
What tools are most reliable for diagnosing IC/BPS?
History and physical examination, along with simple laboratory testing.
What are some complications associated with IC/BPS?
- Significant disability
- Decreased quality of life
- Significant mental health morbidity
What is the reported prevalence of suicidal ideation in IC/BPS patients?
11–23%
What is the median age for bladder cancer occurrence?
65 years
True or False: Bladder tumors are more common in women than in men.
False
What percentage of bladder tumors are urothelial malignant neoplasms?
90%
What are common risk factors for bladder cancer?
- Cigarette smoking
- Industrial exposure to azo dyes
- Infection with S. haematobium
- Drugs like cyclophosphamide
- Radiation therapy
What type of tumors account for approximately 2% and 7% of bladder cancers, respectively?
- Adenocarcinomas (2%)
- Squamous cell cancers (7%)
Fill in the blank: Urothelial papillomas are usually discovered incidentally during cystoscopy for _______.
an unrelated condition or for painless hematuria
What characterizes exophytic papillomas?
Papillary fronds lined by transitional epithelium.
What is the typical clinical presentation of inverted papillomas?
Nodular mucosal lesions, usually in the trigone area.
What defines Urothelial Carcinoma In Situ?
Full-thickness lesions with malignant changes confined to the bladder mucosa.
What is the significance of carcinoma in situ in bladder cancer?
One third are associated with subsequent invasive carcinoma.
What are the clinical presentations of urothelial carcinoma of the bladder?
- Sudden hematuria
- Dysuria
What does the TNM system classify?
Bladder cancers.
What laboratory tests are useful in bladder cancer diagnosis?
- Urinalysis
- Imaging studies (Ultrasound, CT, MRI)
- Urine cytology
What is the purpose of Transurethral resection of bladder tumor (TURBT)?
Resection is done down to muscular elements of the bladder.
