Week 7 - Lung Cancer and GI dealing with toxins Flashcards Preview

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Flashcards in Week 7 - Lung Cancer and GI dealing with toxins Deck (65)
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1
Q

Describe the incidence of lung cancer amongst socio-economic groups

A

-Most affluent have least incidence -> education and access to healthcare

2
Q

What age group is predominantly affected by lung cancer?

A

-People aged 60-80

3
Q

List some risk factors for lung cancer

A
  • Smoking
  • Asbestos
  • Radon
  • Occupational carcinogens
  • Genetic/familial factors
4
Q

Where do lung cancers commonly metastasise?

A
  • Draining LNs
  • Brain
  • Bone
  • Adrenals
  • Pericardium
5
Q

What type of staging is used in lung ca.? Describe this system

A
  • TNM staging

- Tumour size, lymph node involvement and metastases

6
Q

What diagnostic imaging techniques are used in lung cancer?

A
  • CXR
  • CT and staging CT (includes abdo and pelvis)
  • PET scan for distant metastases
7
Q

What diagnostic techniques are used for tissue sampling in lung ca?

A

It is location dependant

  • bronchoscopy bx
  • ultrasound bx (neck/chest wall)
  • CT Bx
  • Surgical Bx
8
Q

What are the clinical features of a primary lung tumour?

A
  • Often asymptomatic

- Cough, wheeze, dyspnoea, haemoptysis, weight loss and malaise

9
Q

What are the classical symptoms of regional metastases of lung cancer?

A
  • Bloated face due to SVC obstruction
  • Hoarseness due to left recurrent laryngeal nerve palsy
  • Dysphagia due to oesophageal compression
10
Q

What are the classical symptoms of distant metastases of lung cancer?

A
  • Bone pain/fractures

- CNS symptoms including headache and visual distrubances

11
Q

What are the metabolic presentations of lung cancer?

A
  • Thirst and constipation due to hypercalcaemia

- seizures due to hyponatraemia

12
Q

What signs of lung cancer may be present on examination?

A
  • Clubbing
  • Cachexia
  • Pale conjunctiva
  • Cervical lymphadenopathy
  • Liver enlargement
  • Bloated face
13
Q

What paraneoplastic syndromes can occur with lung cancer?

A
  • Endocrine ->Cushings, Hypercalcaemia
  • Haematological -> anaemia
  • Neurological -> encephalopathy
14
Q

List the pathological types of lung cancer

A
  • Non-small cell -> squamous, adenocarcinoma and large cell
  • Small cell
  • Carcinoid (rare)
15
Q

What tumour markers are sometimes present in lung cancers?

A

-EGFR mutations

16
Q

Which lung cancer can cause hypercalcaemia?

A

-Squamous cell carcinoma by secreting PTHrp

17
Q

Which lung cancer can produce cushings or SIADH?

A

-Small cell carcinoma by secreting ACTH or ADH

18
Q

How is small cell carcinoma primarily treated?

A

-Radiotherapy

19
Q

List some important features of small cell carcinoma

A
  • Shorter doubling time than other lung cancers
  • Earlier development of metastases
  • 18-24 month survival
20
Q

List some important features of squamous cell carcinoma

A
  • More common in men
  • Highly associated with smoking
  • Local mets occur with dissemination being late stage
  • Histology shows keratin pearls
21
Q

List some important features of adenocarcinoma of the lung

A
  • Contains ducts and glands which secrete mucus
  • Found peripherally in the lung
  • Grows slower and is smaller
  • Metastasise early
22
Q

Which lung cancers are primarily treated by surgery?

A
  • Squamous

- Adenocarcinoma

23
Q

Describe the incidence of lung cancer

A

-Most common male cancer and exceeds breast cancer as a cause of death in women

24
Q

How many people die of lung cancer each year in UK?

A

-40,000

25
Q

Why is biopsy particularly important in cancer?

A

-Not only for a diagnosis but for guidance on prognosis and treatment too

26
Q

Describe the 5 year survival rate in general for luncg cancer in UK

A

-10%

27
Q

List the different catagories of possible toxins

A

-Chemical, bacterial, viruses, protozoa, helminth

28
Q

What physical defences do with have to ingestion of toxins?

A
  • Senses (Sight/smell/memory)
  • Saliva
  • Gastric acid
  • Small intestine secretions
  • Colonic mucus
  • Anaerobic environment
  • Peristalsis/segmentation
29
Q

How is saliva a physical defence to toxins?

A
  • Contains lysozyme and lactoperoxidase, complement, IgA and polymorphs
  • Washes toxins down to stomach
30
Q

What is xerostomia and its consequences regarding toxins?

A
  • Reduced salivary flow

- Microbial over growth in mouth and dental caries can lead to hairy tongue and parotitis

31
Q

What is the most common causative organism of parotitis?

A

-S.aureus

32
Q

What is black hairy tongue?

A

-Infection of the mouth caused by aspergillus

33
Q

How does the stomach act as a defence to toxins?

A

-Lots of gastric acid produced each day with a pH as low as 0.87 which kills the majority of bacteria and viruses

34
Q

What is achlorhydria and its clinical relevance to toxins?

A
  • Decreased acid production

- Patients are more susceptble to shigellosis, cholera, salmonella

35
Q

Why are patients taking a PPI in hospital more prone to c.diff infections?

A

-Decreased gastric acid production increases susceptibility to infection

36
Q

Why can gastric aspirates be used as a diagnostic tool for TB?

A

-Swallow sputum in the night and TB is resistant to gastric acid

37
Q

List 2 bacteria which are resistant to gastric acid

A
  • Helicobacter pylori

- Mycobacterium tuberculosis

38
Q

Name 2 viruses which are resistant to gastric acid

A
  • Hepatitis A

- Norovirus

39
Q

What defences does the small intestine have which help to keep it sterile?

A
  • Bile
  • Proteolytic enzymes
  • Lack of nutrients
  • Anaerobic environment
  • Shedding of epithelia
  • Peristalsis
40
Q

What is the main protective mechanism in the colon?

A

-Colonic mucus

41
Q

Which conditions are associated with eosinophilia?

A
  • Asthma
  • Parasitic infections
  • Allergy
42
Q

Explain the mechanism of the guinae worm (dracunculiasis)

A

Worm egg is ingested and passes through duodenum to retroperitoneum -> emerges and makes its way to the feet -> when person stands in water will burrow out into water -> becomes an adult worm in the foot and needs to be pulled out bit by bit daily

43
Q

What is the association between gut infections and mast cells? What is the consequence of this

A
  • Gut infection which activate complement recruit mast cells which release histamine
  • This causes vasodilation and increased capillary permeability
  • Water moves into the gut and is passed in faeces (rice-water stool)
44
Q

What is the main mechanism to remove toxins from the blood in the GI tract?

A

-Hepatic-portal system

45
Q

List some causes of liver failure

A
  • Alcohol
  • Viral hepatitis
  • Drugs
  • Autoimmune
46
Q

Why does hepatic encephalopathy occur in liver failure?

A

-Increased blood ammonia due to failure to clear ammonia via urea cycle

47
Q

How does liver cirrhosis lead to portosystemic shunting? What are the clinical manifestations of this?

A
  • Hepatic fibrosis leads to portal hypertension
  • > Increased pressure causes backflow of venous blood and shunting into the systemic circulation
  • Oesophageal varices, haemorrhoids and caput medusae
48
Q

How come you can get anal bleeding with cirrhosis?

A

-Cirrhosis -> portal hypertension -> Submucosal veins have more blood in at anorectal junction due to portosystemic shunting -> during a rise in intrasbdominal pressure these veins normally swell -> Increased blood can lead to bursting and bleeding

49
Q

Why can you get haemorrhoids in portosystemic shunting?

A

-Increased anorectal vein pressure causes veins to swell and appear as haemorrhoids

50
Q

What is caput medusae?

A

-Dilation and filling of veins in anterior abdominal wall

51
Q

What is the difference between the appearance of caput medusae and IVC obstruction?

A

-Caput medusae veins run in all direction whereas in IVC obstruction veins only run towards the heart

52
Q

What adaptive defences are there against toxins?

A

-T and B lymphocytes

53
Q

What innate defences is there against toxins?

A

-Macrophage, neutrophil, basophil, eosinophil, mast cell and complement

54
Q

What is GALT?

A

-Gut associated lymphatic tissue eg tonsils, peyers patches, appendix

55
Q

What is walders ring of fire?

A

-Palatine tonsil, lingual tonsil and nasopharengeal tonsil

56
Q

Where do tonsils drain?

A

-Cervical lymph nodes

57
Q

What are the most common causes of sore throat with cervical lymphadeopathy?

A
  • Adenovirus
  • Viridans strep
  • Strep pyogenes
58
Q

What is the relationship between ileoceal valve and peyers patches?

A
  • Peyer’s patches are located in the terminal ileum beneath the mucosa
  • Incompetent ileocecal valve results in reflux of bacteria when ther eis a rise in intraabdominal pressure
  • Peyer’s patches prevent bacteria accessing the body
59
Q

What is mesenteric adenitis? Why is its clinical presentation important?

A
  • Inflammaiton of the mesenteric lymph nodes commonly caused by adenovirus
  • Presents as right iliac fossa pain which is easily mistaken for appendicitis
60
Q

What is the relationship between peyers patches and typhoid fever?

A

-Inflammation of peyer’s patches can perforate and kill patients

61
Q

Name a few chemical toxins

A

-Lead, aluminium, mercury, arsenic

62
Q

List some causes of gut ischaemia

A
  • Arterial disease
  • Systemic hypotension
  • Intestinal venous thrombosis
63
Q

How does the colon protect itself from toxins?

A
  • Colonic mucus

- Epithelial shedding

64
Q

Where are kuppfer cells? What role do they perform?

A
  • Lining the hepatic sinusoids

- Phagocytosis and detoxifcation of blood which passes through from portal vein

65
Q

In general, What is the prognosis like for lung cancers?

A

-Poor (highest ca related deaths)