2 min read - Acute kidney injury

A 54 years old previously well patient admitted with progressively worsening shortness of breath for 2 days duration. He had low grade fever for the same duration. There was no history of cough, wheezing or chest pain. He had facial and leg swelling. 4 days back he had taken medications from the local hospital for a back pain he developed after lifting a cupboard.


What are the differential diagnoses?

• Like in any patient with acute SOB, respiratory and cardiac causes should be considered first.

On examination he was ill, tachypnoeic and had generalized edema. There was a erythematous rash all over the body. Blood pressure was 180/100mmHg. There was no cardiomegaly or murmurs. Lungs had few basal crepirations and occasional wheezing. Abdomen was soft.

• In patients who are tachypnoeic, few lung signs can always be present. Correlate the degree of SOB with the lung signs. If the SOB is disproportionately severe compared to the signs, consider following differentials.
• Pulmonary embolism
• Acidosis

What other differential diagnoses will you consider?

What are you going to do now?

• ECG

What is the abnormality?
What is the cause for that abnormality?
What are the other ECG findings associated with this condition?

• One of the most informative investigations that will help you come to a diagnosis in this scenario would be an ARTERIAL BLOOD GAS (ABG).

ABG was done, 

• pH - 7.1
• pO2 - 95 mmHg
• pCO2 - 28 mmHg
• HCO3 - 10 mmol/l
• Na - 143 mmol/l
• K - 5.8 mmol/l
• Cl - 98 mmol/l

What is the interpretation of this ABG?

• There is acidosis
• It is a metabolic acidosis
• It is a high anion gap metabolic acidosis
• If you are not sure how this conclusion was made, you will have to read ABG analysis again!

With this ABG and ECG findings, what could be the most likely diagnosis?

• ACUTE RENAL FAILURE

What are the principals of management of acute renal failure?

• EXCLUDE OBSTRUCTION!
• Catheter maight be the only thing required for the treatment of some patients if you picked up the distended bladder in your abdominal examination!

• Fluid balance
• Patients will be fluid depleted in pre-renal renal failure - Give fluid
• In other conditions the patient will be fluid overloaded - Get rid of fluid

This is where the house officer has his role! The urine output should me accurately measured and the urine output per hour should be calculated. NEVER EVER TELL - 'sir, the patient/ bystander has not measured'. Its your job to make sure that it's measured and documented!

• Correction of electrolyte abnormalities
• Correct hyperkalemia
• Read about other electrolyte abnormalities associated with ARF

Never miss hyperkalemia on the ECG.

ALWAYS ASK PATIENT AVOID POTASSIUM CONTAINING FOOD AND BEVERAGES as much as possible. Read about to what they can take and what they cant take!

Many medications contain a lot of potassium. eg: A single dose of IV Co-amoxyclav (Amoxycillin with potassium clavulanate) can kill a patient with established ARF.

• Correction of acidosis
• Bicarbonate might help/ it might make things worse! Why?
• If acidosis is mild and you are can treat the underlying cause - Wait and see.
• If acidosis is severe, or the renal problem will take time to recover - Dialysis

What are the other complications associated with ARF?

This patient had acute renal failure secondary to acute interstitial nephritis caused by NSAIDS given for his back pain.

He required several sessions of dialysis.

He made a complete recovery.

• Read about other causes of acute renal failure.
• Read a bit about acute interstitial nephritis.