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1

A gram negative intracellular diplococcus that causes meningitis

Neisseria or Neisseria Meningitidis

2

A gram positive diplococcus that causes pneumonia

Pneumococcus or streptococcus pneumoniae

3

A gram positive organism that grows in bunches and causes abscesses

Staphylococcus Aureus

Staphylococcus comes from the greek, and means 'grape-cluster berry'

4

The organism that causes tetanus

Clostridium tetanae

Clostridium species tend to be soil dwelling and form spores. This includes the causative organisms of Botulinum toxin, Gas gangrene and tetanus. 

5

A gram negative rod that commonly causes urinary tract infections

E-coli

The most common enteric bacterium that causes pathology.

6

Cystic dilatation of duct during lactation caused by obstruction

  • duct ectasia
  • mammary duct ectasia
  • fibroadenoma
  • mastitis
  • fibrocystic change
  • galactocoele
  • galactorrhoea
  • gynaecomastia
  • intraductal papilloma
  • lactating
  • adenoma

galactocoele

this is caused by a proteinaceous blockage of the lactiferous duct and the accumulation of milk, producing a cyst. 

The milk within the cyst is sterile and there is no point of ingress for bacteria so they don't become infected. It will resolve when lactation ceases. A simple needle drainage won't resolve the cyst as the plug remains and milk will continue to be produced. 

If management is needed then the cyst should be surgically excised. 

7

Infection of the breast that occurs during lactation

  • duct ectasia
  • mammary duct ectasia
  • fibroadenoma
  • mastitis
  • fibrocystic change
  • galactocoele
  • galactorrhoea
  • gynaecomastia
  • intraductal papilloma
  • lactating
  • adenoma

mastitis

the suffix '-itis' tells you that of the options this is the only infective/inflammatory process. 

The symptoms include a red, swollen area of the breast that is often tender. There can also be nipple discharge, sometimes streaked with blood, a firm tender lump, or a burning pain in the breast. 

8

Occurs in males with liver disease 

  • duct ectasia
  • mammary duct ectasia
  • fibroadenoma
  • mastitis
  • fibrocystic change
  • galactocoele
  • galactorrhoea
  • gynaecomastia
  • intraductal papilloma
  • lactating
  • adenoma

gynaecomastia

Due to build up of oestrogen seen in liver disease, results in development of breasts. 

9

Occurs in the presence of a high prolactin

  • duct ectasia
  • mammary duct ectasia
  • fibroadenoma
  • mastitis
  • fibrocystic change
  • galactocoele
  • galactorrhoea
  • gynaecomastia
  • intraductal papilloma
  • lactating
  • adenoma

galactorrhoea

Galactorrhoea is the abnormal prodction of milk, as opossed to lactation which is physiological. 

It is often seen with pituitary tumours such as prolactinomas. 

10

The commonest benign tumour of the female breast

  • duct ectasia
  • mammary duct ectasia
  • fibroadenoma
  • mastitis
  • fibrocystic change
  • galactocoele
  • galactorrhoea
  • gynaecomastia
  • intraductal papilloma
  • lactating
  • adenoma

fibroadenoma

A fibroadenoma is a benign lump of the female breast, it is colloquially known as a 'breast mouse'. They are well defined and very mobile within the tissue, this distinguishes them from malignant lumps. They tend to be solitary and found in women of childbearing age. 

11

Causes an increased loss of HCO3-

  • Diabetic ketoacidosis
  • Intestinal fistula
  • Metabolic acidosis
  • Metabolic alkalosis
  • Poor lung perfusion
  • Pyloric stenosis
  • Renal failure
  • Respiratory acidosis
  • Respiratory alkalosis

Intestinal fistula

There is an increased loss of bicarbonate if there is an intestianal fistula

12

Causes increased H+ production

  • Diabetic ketoacidosis
  • Intestinal fistula
  • Metabolic acidosis
  • Metabolic alkalosis
  • Poor lung perfusion
  • Pyloric stenosis
  • Renal failure
  • Respiratory acidosis
  • Respiratory alkalosis

Diabetic ketoacidosis

In diabetic ketoacidosis there is an ionic shift due to the accumulation of ketones in the body. this leads to a shift of potassium into the intracellular compartment. THis in turn increases the H+ production to mantain the ionic gap. 

13

Causes increased H+ loss 

  • Diabetic ketoacidosis
  • Intestinal fistula
  • Metabolic acidosis
  • Metabolic alkalosis
  • Poor lung perfusion
  • Pyloric stenosis
  • Renal failure
  • Respiratory acidosis
  • Respiratory alkalosis

Pyloric stenosis

In pyloric stenosis there is a delay in emptying the stomach contents and there is an increase in vomiting, this is the source of lost H+ ions. 

14

Can be compensated by increased renal excretion of H+

  • Diabetic ketoacidosis
  • Intestinal fistula
  • Metabolic acidosis
  • Metabolic alkalosis
  • Poor lung perfusion
  • Pyloric stenosis
  • Renal failure
  • Respiratory acidosis
  • Respiratory alkalosis

Metabolic acidosis

Be aware that compensation for a metabolic acidosis is with hyperventilation. Renal excretion (question 4) of acid is not really compensation, but just correcting the problem.

15

5. Can be compensated by hypoventilation

  • Diabetic ketoacidosis
  • Intestinal fistula
  • Metabolic acidosis
  • Metabolic alkalosis
  • Poor lung perfusion
  • Pyloric stenosis
  • Renal failure
  • Respiratory acidosis
  • Respiratory alkalosis

Metabolic alkalosis

Also although hypoventilation would compensate for a metabolic alkalosis, that effect is minimised in humans by hypoxia.

16

Gain in bicarbonate ions or loss of H+ ions resulting in raised pH. 

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Metabolic Acidosis with Respiratory Compensation
  • Metabolic Alkalosis with Respiratory Compensation
  • Respiratory Acidosis with Metabolic Compensation
  • Respiratory Alkalosis with Metabolic Compensation

a. Metabolic Alkalosis

This is by definiton a metabolic acidosis. 

17

24 year old female presents at A&E with a broken ankle. The interpretation of her blood gas results (pH 7.62, PCO2 3.59, PO2 14.1, HCO3 23, Base Excess 0) demonstrates a ____.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Metabolic Acidosis with Respiratory Compensation
  • Metabolic Alkalosis with Respiratory Compensation
  • Respiratory Acidosis with Metabolic Compensation
  • Respiratory Alkalosis with Metabolic Compensation

a. Respiratory Alkalosis

In true EMQ style this young woman is having a panic attack due to the broken ankle and is hyperventilating. This is resulting in the off-gassing of her CO2 resulting in a respritory alkolosis. 

18

3. 22 year old model is admitted to A&E with weakness and tingling sensations in both hands and feet, and “poor balance”. Patient denies pill ingestion but admits she has been on a strict diet regimen to meet her agency’s expectations. Her ABG results (pH 7.55, PCO2 6.67, PO2 12.0, HCO3 45) demonstrate ____.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Metabolic Acidosis with Respiratory Compensation
  • Metabolic Alkalosis with Respiratory Compensation
  • Respiratory Acidosis with Metabolic Compensation
  • Respiratory Alkalosis with Metabolic Compensation

a. Metabolic Alkalosis

The patient has an alkalotic pH with a high bicarbonate. She has a degree of hypercapnia, but not enough to compensate. 

In this case we see that this patient is having symptoms of metabolic alkolosis, with the parastesia and poor balance. It is likely that in EMQ land this fashion model has been frequently vomitinf. 

19

4. A 40 year old lady with severe chronic back pain (treated aggressively with OTC NSAIDs) for several years was found to have BP 155/95 at her routine GP visit. Her urine dipstick demonstrated ++ protein and increased white blood cells. Her ABG results (pH 7.30, PCO2 4.27, HCO3 15) demonstrate _____.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Metabolic Acidosis with Respiratory Compensation
  • Metabolic Alkalosis with Respiratory Compensation
  • Respiratory Acidosis with Metabolic Compensation
  • Respiratory Alkalosis with Metabolic Compensation

 

a. Metabolic Acidosis with Respiratory Compensation

This case demonstrates only a partial compensation, she is still acidotic at pH7.30

 

20

5. A 45 year old man with a history of solvent (inhalant) abuse presents to A&E complaining of dyspnoea (SPO2 99% on room air). He is tachypnoeic on examination and demonstrates Kussmaul breathing. His ABG (pH 6.95, PCO2 1.20, PO2 17.0, HCO3- 2) demonstrates ___.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Metabolic Acidosis with Respiratory Compensation
  • Metabolic Alkalosis with Respiratory Compensation
  • Respiratory Acidosis with Metabolic Compensation
  • Respiratory Alkalosis with Metabolic Compensation

a. Metabolic acidosis with respiratory compensation

He's been huffing so much glue he's put himself in metabolic acidosis. This is due to the metabolism of the volitaile compounds leading to increased secretion of sodium and potassium in the urine. 

His Kussmaul breathing is a physiologic response to blow off more CO2, but it hasn't come close to correcting this acidosis. 

21

An elderly patient on the ward has RR 16, HR 65, temp 37.5 degrees C. His blood gases are pH 7.35 (7.35-7.45), pCO2 9.0 (4.7-6 kPa), pO2 8.1(10.0-13.3 kPa), HCO3 45 (22-30). Rank the underlying diseases below in order of likelihood, going from most to least likely:

  • Pulmonary embolism
  • Tension pneumothorax
  • COPD
  • Hyperventilation
  • Pneumonia

Answer: 1. COPD 2. Pneumonia 3. Pulmonary embolism 4. Tension pneumothorax  5. Hyperventilation 

 

This is a picture of respiratory acidosis with metabolic compensation. Hyperventilation would cause alkalosis so is least likely.

A tension pneumothorax would not have time to establish compensation so is next least likely.

The carbon dioxide is high and the oxygen is low so this is type 2 respiratory failure with no v/q mismatch. while a number of small PEs might result in compensation over time they would give a type 1 picture with low oxygen and normal carbon dioxide.

Both pneumonia and COPD might give this blood gas picture but this patient's vital measurements show no sign of infection so COPD is most likely.

22

1. A 42 year old man with heartburn presents with the following blood gases: pH 7.51, pCO2 5.2kPa, bicarbonate = 30 mmol/l.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Compensated Respiratory Alkalosis
  • Compensated Respiratory Acidosis
  • Compensated Metabolic Alkalosis
  • Compensated Metabolic Acidosis
  • Type I Respiratory Failure
  • Type II Respiratory Failure

a. Metabolic Alkalosis

He's been eating antacid tablets like sweeties

We see an alkalotic pH combined with a normal CO2, combined with the history, and we know it's metabolic with no compensation. 

23

2. 65 year old long- term smoker is admitted with drowsiness and confusion. ABG reveals pH 7.36, pO2 7kPa, pCO2 8kPa, bicarbonate 24 mmol/l.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Compensated Respiratory Alkalosis
  • Compensated Respiratory Acidosis
  • Compensated Metabolic Alkalosis
  • Compensated Metabolic Acidosis
  • Type I Respiratory Failure
  • Type II Respiratory Failure

a. Type II Respiratory Failure

The pH here is normal but there is a low O2 and high CO2, which is a type II respiratory failure, by definition. 

24

3. Treat with IV sodium bicarbonate

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Compensated Respiratory Alkalosis
  • Compensated Respiratory Acidosis
  • Compensated Metabolic Alkalosis
  • Compensated Metabolic Acidosis
  • Type I Respiratory Failure
  • Type II Respiratory Failure

a. Metabolic Acidosis

Sodium Bicarbonate is going to make the blood more alkali, as such it could only plausibly be a treatment for acidosis, respiratory acidosi is caused by hypoventialtion, the treatment for which is ventilation support.

Metabolic acidosis is caused by increased H+ ions or increased loss of bicarbonate ions, so it stands to reason that it is treated with IV bicarbonate. 

25

4. 24 year old female presents with an aspirin overdose. She appears to be breathing heavily. pH 7.38, pO2 12kPa, pCO2 2.5kPa, bicarbonate 16 mmol/l.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Compensated Respiratory Alkalosis
  • Compensated Respiratory Acidosis
  • Compensated Metabolic Alkalosis
  • Compensated Metabolic Acidosis
  • Type I Respiratory Failure
  • Type II Respiratory Failure

a. Compensated Metabolic Acidosis

We know that a Salicylate poisining causes a metabolic acidosis, but in this case the blood gas shows a normal pH and a low CO2, we also have the observation that she is breathing heavily. This is therefore a compensated metabolic acidosis. 

26

5. 55 year old male with difficulty breathing is diagnosed with Guillain- Barre syndrome. pH 7.25, pO2 12kPa, pCO2 9kPa, bicarbonate 25 mmol/l.

  • Metabolic Acidosis
  • Metabolic Alkalosis
  • Respiratory Acidosis
  • Respiratory Alkalosis
  • Compensated Respiratory Alkalosis
  • Compensated Respiratory Acidosis
  • Compensated Metabolic Alkalosis
  • Compensated Metabolic Acidosis

Type I Respiratory Failure
Type II Respiratory Failure

a. Respiratory Acidosis

We see here an acidic pH with a high CO2. 

Guillain-Barre can affect the muscles of respiration, as we see here. This has resulted in hypoventilation and an accumulation of CO2. 

27

22 year old man presents with a painless, red ulcer on his penis. Microscopy reveals spiral shaped organisms.

  • Benzylpenicillin
  • Ceftriaxone
  • Chloramphenicol
  • Clarithromycin
  • Colistin
  • Gentamicin
  • Intravenous 
  • Meropenem
  • Moxifloxacin
  • Orally
  • Rifampicin
  • Trimethoprim
  • Vancomycin
  • Rectally

a. Benzylpenicillin

What is being described here is the classic chancre ulcer that is the harbinger of primary syphilis infection. The microscopy describes the causative organism of Treponema pallidum. 

Syphilis is simply treated with a single dose of IM Benzylpenicillin

28

2. On a routine swab for a pre-op patient, the lab is able to culture Staphylococcus aureus. The lab also reports that this particular strain is not sensitive to Penicillins.

  • Benzylpenicillin
  • Ceftriaxone
  • Chloramphenicol
  • Clarithromycin
  • Colistin
  • Gentamicin
  • Intravenous 
  • Meropenem
  • Moxifloxacin
  • Orally
  • Rifampicin
  • Trimethoprim
  • Vancomycin
  • Rectally

a. Vancomycin

Vancomycin is recommended for use on gram-positve bacteria where resistance to penicillins is known or suspected. 

29

3. The route of administration when administering Vancomycin to treat serious C.difficile infection.

  • Benzylpenicillin
  • Ceftriaxone
  • Chloramphenicol
  • Clarithromycin
  • Colistin
  • Gentamicin
  • Intravenous 
  • Meropenem
  • Moxifloxacin
  • Orally
  • Rifampicin
  • Trimethoprim
  • Vancomycin
  • Rectally

a. Orally

C.difficile is an infection of the digestive system so the most effective method of administration is into the digestive system. IV administration would be more effective if this were an organism presenting as a bacteraemia. 

30

4. This antibiotic which is usually administered as eye drops, can cause grey baby syndrome in neonates, because of an inability to metabolise the drug.

  • Benzylpenicillin
  • Ceftriaxone
  • Chloramphenicol
  • Clarithromycin
  • Colistin
  • Gentamicin
  • Intravenous 
  • Meropenem
  • Moxifloxacin
  • Orally
  • Rifampicin
  • Trimethoprim
  • Vancomycin
  • Rectally

a. Chloramphenicol

Grey baby syndrome occurs due to insufficient enzyme activity and kidney excretion of the drug in neonates. This allows Chloamphenicol to build up to toxic levels, resulting in the life threatening Grey baby syndrome.