Diabetes CPC Flashcards
Give 2 diagnostic results of diabetes
Fasting plasma glucose > 7.0mM
HbA1c > 6.5% (48mmol/mol)
48F unconscious
Vomiting, polyuria + polydipsia, SOB, dehydrated
Poorly controlled HTN + Obese
BP 80/40
Why is she unconscious?
A. Diabetic ketoacidosis
B. Hyperosmolar non-ketotic coma
C. Severe hypotension
D. Stroke
E. Renal failure
Low blood flow to brain
A or B - need tests to distinguish
48F unconscious
Vomiting, polyuria + polydipsia, SOB, dehydrated
Poorly controlled HTN + Obese
BP 80/40
What test should we do?
A. ABG
B. CT brain
C. CXR
D. FBC
E. ECG
A. ABG
pH 7.65
PCO2 6.1 kPa
PO2 15 kPa
What is the acid/base abnormality?
Metabolic alkalosis
High pH: alkalosis
High CO2: not hyperventilating
Label the diagram A-D
A: Metabolic acidosis
B: Respiratory acidosis
C: Respiratory alkalosis
D: Metabolic alkalosis
Give 3 causes of metabolic alkalosis
H+ loss e.g. vomiting
Hypokalaemia
Ingestion of bicarbonate
Describe the process of respiratory compensation in metabolic alkalosis
Metabolic alkalosis inhibits ventilation
CO2 increases (though hypoxia prevents significant hypoventilation)
Improvement of pH at expense of making CO2 worse
Describe compensatory mechanisms in renal disease
Acidosis: Lungs hyperventilate
Alkalosis: Underbreathing is blocked by hypoxia- CO2 won’t rise much as it should as brain forces breathing
In a patient with high pH and high CO2 that is not hyperventilating, what will the bicarbonate be?
High
What equation can be used to calculate osmolality?
2 (Na + K) + Urea + Glucose
What equation is used to calculate the anion gap?
Na + K
- Cl -Bicarbonate
How do ketones influence the anion gap?
Ketones are anions
Result in high anion gap
Give 3 sources of potassium loss in hypokalaemia
Intestinal: D+V, fistula
Renal: Mineralocorticoid excess, diuretics, renal tubular disease
Redistribution: Insulin, alkalosis
What effect does hypokalaemia have on cells?
- Low K+
- More H+ shifts into cells instead of K+
- Extracellular alkalosis
- Hypokalaemic alkalosis
What effect does alkalosis have on cells?
- Low H+
- More K+ shifts into cells instead of H+
- Hypokalaemia-
Hypokalaemic alkalosis
What effect does hypokalaemia have in the kidney?
Lack of intracellular K+ leads to increased excretion of H+ in exchange for Na+
Production of acid urine
Generation of bicarbonate
48F unconscious
Vomiting, polyuria + polydipsia, SOB, dehydrated
Poorly controlled HTN + Obese + DM
Previous fractured hip
Wound on shin not healing properly
BP 80/40
What is the diagnosis?
A. Cystic fibrosis
B. SLE
C. Cushing’s syndrome
D. Sjogren’s
E. Osteoporosis
C. Cushing’s syndrome
Patient has Cushing’s syndrome.
ACTH: 250
Cortisol: 3120
Dexamethasone failed to suppress
Low dose dex: Cortisol= 3100
High dose dex: Cortisol= 2990
What is the cause?
A. Pituitary Cushing’s
B. Ectopic ACTH
C. Adrenal tumour
B. Ectopic ACTH
Adrenal tumour would suppress ACTH
Due to low K+, likely ectopic ACTH
as really high Cortisol starts binding Aldosterone receptor
Examination: Reduced expansion on right
Percussion: dull on right
Vocal resonance: increased on right
What is indicated by these findings?
A. Pleural effusion
B. Pneumothorax
C. Collapse and consolidation
D. COPD
E. Bronchiectasis
C. Collapse + consolidation
Patient very hypokalaemic and hypotensive.
Osmolality: 380 mosm/kg
What management is required?
Rehydrate cautiously
Replace K+ with caution
Despite rehydration and potassium replacement, patient does not pass urine.
Na: 145
K: 5.2
U: 50
Creat: 500
Glucose: 34.0
What is the differential?
How can these be distinguished?
Acute renal failure (ATN due to dehydration)
Chronic renal failure (diabetic renal disease)
Renal biopsy
What cardiac consequences arise from potassium disturbance>
Hypokalaemia: Ventricular fibrillation
Hyperkalaemia: Asystole
If acute tubular necrosis is found on biopsy, what treatment is necessary?
Dialysis for 3w
(complete recovery)
If diabetic glomerular kidney disease is found on biopsy, what treatment is necessary?
Lifelong dialysis (is End stage renal failure)
