Acid - Base, LFTs, Porphyrias Flashcards Preview

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Flashcards in Acid - Base, LFTs, Porphyrias Deck (30)
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1

Normal Ranges - pH

7.35-7.45

2

Normal Ranges - Co2

4.7-6 kPa

3

Normal Ranges - Bicarbonate

22-30 mmol/l

4

Normal Ranges - O2

10 -13 kPa

5

Steps to solve simple problems - Look at the case in this step by step way to determine the cause

1) pH - acidic or alkali?
2) CO2 - does it fit with the pH?
3) Bicarbonate - does it fit with the pH?
4) Compensation - is there any? Partial or Complete?

6

Metabolic Acidosis
-pH?
-Bicarbonate?
-CO2?
-Causes?

-pH - low
-Bicarbonate - low
-CO2 - normal or low (if compensated)
-Causes - Lactate build up, DKA, Renal tubular

7

Metabolic Alkalosis
-pH?
-Bicarbonate?
-CO2?
-Causes?

-pH - High
-Bicarbonate - High
-CO2 -normal/ High (If compensated)
-Causes - Pyloric Stenosis, Hypokalamia

8

Respiratory Acidosis
-pH?
-Bicarbonate?
-CO2?
-Causes?

-pH - Low
-Bicarbonate - Normal/High (if compensated)
-CO2 - High
-Causes - Lung Injury - pneumonia, COPD, Decreased Ventilation

9

Respiratory Alkalosis
-pH?
-Bicarbonate?
-CO2?
-Causes?

-pH - High
-Bicarbonate - Normal/ Low (if compensated)
-CO2 - Low
-Causes - Mechanical Ventilation, Anxiety/Panic attack

10

what is compensation?

Return of pH towards normal at the expense of other values

11

What is the Anion Gap?

(Na + K) - (Cl + HCO3)

Difference between total concentration of principal cations and principal anions = Concentration of unmeasured anions in the plasma

12

What is the biggest contributor to the Anion Gap?

Almost entirely contributed by Albumin (beware in hypoalbuminaemia)

13

Normal Range for the Anion Gap?

14-18 mmol/l

14

Mnemonic for elevated anion gap metabolic acidosis?
KULT

K etoacidosis (DKA, alcoholic, starvation)
U raemia (renal failure)
L actic Acidosis
T oxins (ethylene glycol, methanol, paraldehyde, salicylate)

15

Osmolar Gap- what is a normal osmolar gap?

Osmolality (measured) - Osmolarity (calculated)

Normal osmolar gap = less than 10

16

What does an elevated osmolar gap suggest?

What does it differentiate?

An elevated osmolar gap provides indirect evidence for the presence of an abnormal solute.
it is increased by extra solutes in the plasma ( e.g. ethylene glycol, ethanol, methanol, mannitol)

Helpful in differentiating the cause of an elevated anion in metabolic acidosis

17

Liver Function Tests - Markers of Liver Cell Damage

ALT
AST
ALK phos
GGT
Bilirubin

18

Liver Function Tests - Markers of Synthetic Function

Clotting (INR)
Albumin
Glucose

19

Aminotransferases - AST/ALT
-normal range?
-causes of high levels?
-ratio in Alcoholic liver disease?
-ratio in Viral liver disease?

- less than 40
- raised when hepatocytes die
-Alcoholic liver disease - 2:1
-Viral liver disease 1:1

20

Alkaline Phosphatase (ALP)
-normal range?
-raised when?

-30-150 iu/L
- Raised with cholestasis (either intrahepatic or extra hepatic) and bone disease, High in pregnancy

21

Gamma GT (GGT)
-Normal range?
-When is it Elevated?

- 30-150 iu/L
- Elevated in chronic alcohol use
- Also bile duct disease and metastases. Used to confirm hepatic source of increased ALP

22

What is Porphyrias?

7 Disorders caused by deficiency in enzymes, involved in haem biosynthesis, leading to build up of toxic haem precursors

23

Acute Intermittent Porphyria (AIP)
- inheritance?
- deficiency?

Autosomal dominant inheritance
HMB (Hydroxymethybilane) synthase deficiency

24

Acute Intermittent Porphyria (AIP)
- Symptoms?

Neuro-visceral only
- abdo pain, seizures, psych disturbances, nausea and vomiting, tachycardia, hypertension, sensory loss, muscle weakness, constipation, urinary incontinence,

NO cutaneous manifestations due to absence of porphyrinogens

25

Acute Intermittent Porphyria (AIP)
- Diagnosis?

ALA + PBG in urine (Port wine urine)

26

Acute Intermittent Porphyria (AIP)
- Precipitating Factors?

ALA synthase inducers (steroids, ethanol, barbiturates)
Stress (infection, surgery)
Reduced caloric intake and endocrine factors (eg premenstrual)

27

Acute Intermittent Porphyria (AIP)
- Treatment?

Avoid precipitating factors, analgesia, IV carbohydrate/ haem arginate

28

Acute porphyrias with skin lesions
- 2 types?
- inheritance?
- Symptoms and clinical signs?

-Hereditary coproporphyria (HCP) and Variegate porphyria (VP)
(these are 2 subtypes of porphyrias, have googled them and they both have the same sort of symptoms and signs, both have no treatment, although liver transplantation has been suggested)

-Autosomal dominant

-Neurovisceral + skin lesions

- Raised porhyrins in faeces or urine

29

Non-Acute porphyrias

Skin lesions ONLY
-Congenital Erythopoietic porphyria (CEP)
-Erythropoietic protoporphyria (EPP)
- -Photosensitivity, burning, itching, oedema following sun exposure
-Porphyria Cutanea Tarda (PCT)

30

Porphyria Cutanea Tarda
-inheritance?
-deficiency?
-symptoms?
-diagnosis?
-treatment?

-inherited/ acquired
-Uroporphyrinogen decarboxylase deficiency
- Cutaneous symptoms - Vesicles (crusitng, pigmented, superficial scarring) on sun exposed sites
-Diagnosis - increased urinary uroporphyrins + coproporphyrins + increased ferritin
- Treatment - avoid precipitants (alcohol, hepatic compromise), phlebotomy