Vasovagal syncope (Vasovagal reaction, episode or attack)

Condition related to stimulation of the vagus nerve.

Vagus nerve:

• a mixed nerve that innervates the pharynx and larynx and lungs and heart and esophagus and stomach and most of the abdominal viscera.
• it is the tenth cranial nerve.
• originates at brainstem

Many vasovagal syncope conditions fall under this condition – they are differ in their mechanism.

Some common mechanisms:

Standing up very quickly

Stress

Any painful or unpleasant stimuli, such as:

• Having blood drawn
• Experiencing intense pain
• Experiencing medical procedures with local anesthesia
•  Venipuncture
• Giving or receiving a needle immunization.
• Watching someone give blood
• Watching someone experience pain
• Watching or experiencing medical procedures
• Sight of blood
• Occasions of slight discomfort, such as dental and eye examinations
• Hyperthermia, a prolonged exposure to heat
• High temperature, either in the environment or due to exercise

Arousal or stimulants e.g. sex

Sudden onset of extreme emotions

Hunger

Nausea or vomiting

dehydration

Micourination syncope or defecation syncope

Abdominal straining or ‘bearing down’

Swallowing (‘swallowing syncope’) or coughing (‘cough syncope’)

Pressing upon certain places on the throat, sinuses, and eyes, also known as vagal reflex stimulation when performed clinically.

Water colder than 10 Celsius (50° F), or ice that comes in contact with the face, that stimulates the mammalian diving reflex

High altitude

Use of certain drugs that affect blood pressure, such as amphetamines 

Intense laughter

Pathophysiology:

In people with vasovagal episodes, the episodes are typically recurrent, usually happening when the person is exposed to a specific trigger.

The initial episode often occurs when the person is a teenager, then recurs in clusters throughout his or her life.

Prior to losing consciousness, the individual frequently experiences a prodrome of symptoms such as lightheadedness, nausea, sweating, ringing in the ears (tinnitus), uncomfortable feeling in the heart, weakness and visual disturbances such as lights seeming too bright, fuzzy or tunnel vision.

These symptoms last for at least a few seconds before consciousness is lost (if it is lost), which typically happens when the person is sitting up or standing.

When sufferers pass out, they fall down (unless this is impeded); and when in this position, effective blood flow to the brain is immediately restored, allowing the person to wake up.

The autonomic nervous system’s physiologic state  leading to loss of consciousness may persist for several minutes, so:

1. If sufferers try to sit or stand when they wake up, they may pass out again;
2. The person may be nauseated, pale, and sweaty for several minutes.

resulting in simultaneous enhancement of parasympathetic nervous system (vagal) tone and withdrawal of sympathetic nervous system tone.

This results in a spectrum of hemodynamic responses:

1. On one end of the spectrum is the cardioinhibitory response, characterized by a drop in heart rate (negative chronotropic effect) and in contractility (negative inotropic effect) leading to a decrease in cardiac output that is significant enough to result in a loss of consciousness. It is thought that this response results primarily from enhancement in parasympathetic tone.
2. On the other end of the spectrum is the vasodepressor response, caused by a drop in blood pressure without much change in heart rate. This phenomenon occurs due to vasodilation, probably as a result of withdrawal of sympathetic nervous system tone.
3. The majority of people with vasovagal syncope have a mixed response somewhere between these two ends of the spectrum

Central Lines

  

Types of Central Lines: 

 

1. Peripherally Inserted Central Catheter – PICC

• typically used in patients receiving antibiotics for an extended time period
• inserted in the antecubital fossa
• central catheter is inserted and threaded through the peripheral catheter
• distal catheter tip lies in the superior vena cava
• have positive, negative pressure valves preventing the inflow of air or outflow of blood.

Does not require heparin flushing 

• flush with NS after each use
• use 12ml or larger syringe
• 

 2. Port- A- Cath 

• A catheter connects the port to a vein.
• Implanted venous access device
• resembles small pacemaker in size
• implanted in upper chest
• tip lies in the superior vena cava
• Huber needle access only
• no external devices emerge from skin
• heparin flushed
• 

 3. Hickman aka Broviac  

• a central line that is tunneled under the skin so that the exit site is away from where the catheter enters the blood vessel
• has free-hanging line
• does not have antireflux valve like PICC

4.Tunneled catheter. 

• A vascular access device whose proximal end is tunneled subcutaneously from the insertion site and brought out through the skin at an exit site
• Passing the catheter under the skin helps keep it in place better, lets you move around easier, and makes it less visible.

 5.Implanted port. 

• similar to a tunneled catheter but is left entirely under the skin.
• Medications are injected through the skin into the catheter.
• Some implanted ports contain a small reservoir that can be refilled in the same way.
• After being filled, the reservoir slowly releases the medicine into the bloodstream.
• An implanted port is less obvious than a tunneled catheter and requires very little daily care.
• It has less impact on a person’s activities than a PICC line or a tunneled catheter

  

Chest Ausculatation

Cardiac Auscultation Landmarking

Lung Auscultation Landmaring:

Medical Fun and Games

Like a flower waiting to bloom
Like a lightbulb in a dark room
I’m just sitting here waiting for you
To come home and turn me on

Like the desert waiting for the rain
Like a school kid waiting for the spring
I’m just sitting here waiting …

 - Norah Jones

Antiemetics

 

• treat nausea and vomiting
• act by inhibiting dopamine or serotonin receptors in the brain
• act to block various pathways preventing signals from reaching the VC or CTZ

 

Physiologic vomiting triggers

1. Stimulus of the vomiting center – VC
2. Stimulus of the chemoreceptor trigger zone – CTZ

 

Secondary to nausea and vomiting is dehydration

• excessive fluid loss can lead to acid-base disturbances

 

Types of antiemetics

1. anticholinergics
2. Antihistamines
3. Benzodiazepines
4. Cannabinoids
5. Glucocorticoids
6. Phenothiazines
7. Serotonin Receptor Antagonists

 

Acholinergics (Scopalamine)

• block Ach receptors in the vestibular nuclei and reticular formation
• prevent stimuli from these areas being transmitted to VC or Chemoreceptor trigger zone

 

Antihistamines (Gravol or dimenhydrinate)

• bind histamine receptors inhibiting the binding of Ach to vestibular nuclei and reticular formation

 

Neuroleptic agents (Phenothiazines)

• block dopamine receptors in the chemoreceptor trigger zone
• meds also relieve vertilago
• use in chemo tx of nausea and vomiting

 

Prokinetic agents (Maxeran)

• blocks dopamine in the CTZ and stimulates GI peristalsis
• acts to tighten gastroesophageal sphincter preventing GERD
• aids in gastric emptying – used for tube feed pts
• Maxeran must be reduced if diarrhea develops
• SE – drowsiness

 

Serotonin blockers (Odancetron aka Zofran)

• blocks serotonin receptors in the GI, VC and CTZ
• often effective when gravol is not

Benzodiazepines (Ativan)

• decreases response in VC and CTZ
• used as a adjunct to treat nausea and vomiting, not alone
• uncommon in the tx of nausea and vomiting

 

Glucocorticoids

• action in N and V tx unclear
• used in adjunct with other antiemetics
• used in chemo related N and V
• not a first line antiemetic due to it being a steroid, decreasing immunity and elevating the WBC count

 

Antiemetic considerations:

• liver and kidney Fx
• Fluid and electrolyte balance (dehydration risk)
• BP & P – hypovolemia risk

 

Antiemetic choice considerations

1. if vomiting occurs after a meal, administer prior to meal
2. If gravol is ineffective use Serotonin blockers (Odancetron)

The Common Cold

 

Viral infection of the upper respiratory tract

Etiology:
1.rhinovirus
2.parainfluenza virus
3.respiratory syncytial virus
4.coronaviruses
5.adenovirus

Modes of transmission/spread
1.Direct contact: person to person
most contagious in first 3 days of symptom onset
incubation period of 5 days

2.Indirect contact: viruses can survive more than 5 hours on the following:
fomites
skin
fingers touching contaminated surfaces then mucous membranes

3.Aerosoled
coughing
sneezing

Manifestations:
nasopharyngeal dryness and stuffiness
excessive nasal secretions
tearing at the eyes
typically clear and watery secretions
inflammation and erythmatous upper respiratory tract mucus membranes
sore throat
hoarseness
headache
generalized malaise
chills
fever
exhaustion

duration – 7 days

Diagnosis

Hx
symptoms, onset, duration

Treatment: OTC remedies

1.Antihistamines
used to dry nasal secretions
may act to dry bronchial secretions
may worsen cough
may cause dizziness, drowsiness and impaired judgment

2.Decongestants – sympathomimetic agents
constrict blood vessels to decrease swelling
may result in systemic vasoconstriction
may elevate blood pressure
should be avoided in those with HTN, heart disease, hyperthyroidism, diabetes

3.Vitamin C
studies show contradictory results
4.Zinc Lozenges – studies also show variable results

Inflammatory Bowel Disease

 

Two chronic disorders:

1.Crohn`s disease
2.Ulcerative Colitis

Etiology:

Genetic susceptibility (no gene yet identified): Intolerance of normal gut flora by the body`s immune system.
Immune response is unregulated.

1. Ulcerative Colitis

• Chronic inflammation of the colon that produces ulcers in its lining
• region of affected gut is continuous

 2. Crohn`s Disease

• A chronic form of inflammatory bowel disease that usually affects the lower small intestine (called the ileum) or the colon
• skip lesions in small and large intestine

 

Differentiating Characteristics of Crohn`s Disease and Ulcerative Colitis

Characteristics	Crohn`s Disease	Ulcerative Colitis
Type of inflammation	Granulomatous	Ulcerative and exudative:
Level of involvement	submucosa	mucosa
Area of involvement	Ileum, colon	Rectum and left colon
Extent of Involvement	skip lesions in small and large intestine	region of affected gut is continuous
Diarrhea	common	common
Rectal bleeding	rare	common
Fistuals	common	rare
Stricture	common	rare
Perianal abscesses	Common	Rare
Development of cancer	Uncommon	Relatively Common

 

Martin, Glenn and Porth, Carol, Mattson. 2009. Pathophysiology Concepts of Altered Health States. 8th ed. Lippincott Williams and Wilkins. Philadelphia

Rhabdomyolysis

Rhabdomyolysis is the rapid breakdown (lysis) of skeletal muscle tissue (rhabdomyo) due to injury to muscle tissue. The muscle damage may be caused by physical (e.g., crush injury), chemical, or biological factors. This condition may lead to renal failure.

Etiology:

The Mind

The mind has exactly the same power as the hands:
not merely to grasp the world, but to change it.
- Colin Wilson

Anticoagulants

 

• anticoagulant
• reduces risk of thrombus formation

 

Heparin Hemorrhage Risk Indicators

• bleeding gums
• hemotemesis
• hematuria
• melena

 

Diagnostics

• aPTT = activated partial thromboplastin time or PTT = partial thromboplastin time
• allows therapeutic heparin range to be monitored

 

Preexisting conditions that contraindicate heparin use:

• threatened abortion
• cerebral of aortic aneurysm
• cerebrovascular hemorrhage
• severe hypertension
• blood dyscrasia
• recent opthalmic surgery
• recent neurosurgery

 

Preexisting conditions indicative of increased hemorrhage risk

1. recent childbirth
2. severe diabetes
3. severe retanopathy
4. hepatopathy
5. severe trauma
6. vasculitis
7. active ulcer or GI lesion
8. GU or Respiratory tract lesion

 

Over the counter medications which increase hemorrhage risk

1. aspirin
2. nonsteroidal antiinflammatories
3. cephalosporins
4. antithyroid agents
5. probenecid
6. thrombolytics
7. garlic
8. ginger
9. ginkgo
10. horse chestnut
11. feverfew