Kidneys

First posted online on 4 January 2010

Updated online on 24 January 2019

Kidney disease can take a long time to develop and suddenly show an acute crisis when conditions are severe.

Chronic kidney disease (CKD) occurs in otherwise apparently healthy-looking individuals. It is sometimes at a clinic appointment for hypertension that such a CKD patient is picked up for Acute Kidney Injury (AKI) with mild to severe hydronephrosis. 

Investigations are BUSE (blood urea, serum electrolytes) or RFT (renal function test - Na+, K+, urea, creatinine, Cl-, PO43-), VBG (venous blood gas), FBC (full blood count, HbA1c, Hb), sputum C&S, urine C&S, etc. TRO TB, tumour, cancer, etc. BUSE is done 2x a day initially and then once daily.

The renal system comprises the 2 kidneys, the 2 ureters, a urinary bladder and the urethra.

Normal kidney structure is available from online image libraries.

Imaging techniques to view the kidneys are:

1. Ultrasound (Ultrasound KUB) and 
2. CT scan (CT scan KUB). KUB = Kidney, Ureters, Bladder.
3. CT Urology

A Toshiba Prime Aquilion CT scanner
(each unit is approx. RM640k)
HUSM has 2 CT scanners, the other unit is a Siemens.

In CT scan, contrast media is used to view better details. A base scan is first performed and then an iodine contrast media injected intravenously (pink cap line) and images captured for viewing. The blue cap is used for children and is not appropriate for use in CT scan with contrast media in adults.

After the CT scan and use of contrast media, the patient needs to take AEN for 3 days (2 tablets per day). This is a smelly tablet and smells of scrap rubber or burnt Japanese slippers. When dissolved in some water, it forms an orange-flavoured fizzy drink.

Pink cap

Smelly tablets dissolving in water.
Stenac Effervescent Tablets, 600 mg
(Acetylcysteine 600mg)
Reg. No. : MAL09011475X
Synmosa Biopharma Corporation 

In CT Urology, phase contrast will show how urine is filtered by the various sections of the kidney. It will provide evidence as to where a blockage is located, if any.

A blockage in the renal system may not necessarily arise from a renal stone but a soft tissue mass which grows around the ureters, thus constricting the ureters and causing urine to flow back into the kidneys, and over a long time. causing hydronephrosis of the kidneys and ureters. The kidneys appear inflammed and smaller then normal size, while the ureters have a thick proximal or distal surrounding soft tissue mass, covering at least 3 cm to 4 cm of the 25 cm normal length of the ureters. These tissue masses surrounding the ureters can be visualised on CT scan.

Hydronephrosis can be detected by ultrasound and CT scan.

Hydronephrosis is an inflammed condition of the kidney. The central region of the kidney is filled with urine for long periods, and the kidney becomes damaged in this process. As more regions of the kidney is inflammed and affected by hydronephrosis, kidney function begins to go down. The kidney can barely cope to secrete waste products in urine even though it may still produce sufficient urine.

The kidney is an encapsulated organ. The renal capsule is normally thin. However, in hydronephrosis, the renal capsule can be thicker than normal. The cause of this thickening is unknown.

Both ultrasound and CT scan will show hydronephrosis and hydroureter(s). In hydroureter, the ureter may be affected proximally, leaving the remainder of the ureter normal (unaffected).

Hydronephrosis of both kidneys plus hydronephrosis of the promixal right ureter may not give any renal colic, back pain or flank pain. So it is difficult to rapidly pick up patient with CKD, AKI and hydronephrosis at a hypertension clinic.

Whether upper respiratory tract infection (URTI) or the common sore throat will affect kidneys and renal function remains unknown. But in susceptible individuals, frequent sore throats may affect the kidneys and lead to hydronephrosis in the long run.

So a history of common colds, severe flu and URTI with and without renal involvement should be looked into for possible causes of CKD, AKI and hydronephrosis in individuals who have hypertension and are on long term anti-hypertensive treatment (eg Twynsta or Amlodipine alone).

Elective surgery to place a ureteral stent in a thickened pelvic junction may not be a good thing if urine output is not affected. The stent may not be able to correct the high urea and creatinine levels in hypertensive individuals who have URTI and AKI with hydronephrosis.

Such patients may first show increasing urea and creatinine levels, which suddenly jump to high levels, mimicking uremia and creatininemia, which are toxic to brain, liver and heart. This condition is worsened by high potassium levels (hyperkalemia). Venous blood gas (VBG) will show Metabolic Acidosis.

Severe dehydration will give a dry wrinkled skin in the elderly. This is corrected by intravenous saline drip and adequate fluid intake (eg 1 litre water intake + 2 litres drip and 3 litres urine output). One week is sufficient for rehydration and continuing for another week minus iv drip works fine. In the second week, water intake can be increased to 2 litres (minus iv saline drip) and urine output 2 litres. Monitoring input and output for 1-2 weeks is fine.

Re-purposed saline bottle, graduated, to collect urine

Metabolic acidosis is treated with a cocktail (one by one) dextrose, lactate and actimed? Calcium carbonate tablet (500mg) is taken orally.

Hyperkalemia is treated with Kalimate (calcium polystyrene  sulfonate, 5g per sachet; Japan). 3 sachets of total 15g white powder is mixed in little water and consumed.

Kalimate, 5g per sachet

URTI is treated with iv Augmentin, and then continued with oral intake for 1 week.

Anemia develops in CKD, AKI and hydronephrosis as the kidney fails to produce erythropoietin (EPO) which is needed for erythropoiesis. Iron supplement (ferrous fumarate, 200mg x 2 tablets) will help to overcome anemia. Reduce to 1 tablet and alternate days as needed. Obimin is a better alternative for some elderly women.

Folate is needed for rbc.

Amlodipine (5 or 10 mg) can be switched wtih Felodipine (5 or 10 mg) as appropriate and then switched back if headaches develop while on Felodipine. Amlodipine (5 mg) usually works fine in patients who have taken Twynsta for a long time.

Loratadine is only needed temporarily for 1-2 days to reduce runny nose in URTI.

Vit C?

Vit B?

External links:

Renal ultrasound - Hydronephrosis
https://youtu.be/N750NAEmEso

Radiology Assistant
http://www.radiologyassistant.nl/en/p5a3056eebe646/normal-values-ultrasound.html

Distal Renal Tubular Acidosis (distal RTA)
https://www.ncbi.nlm.nih.gov/m/pubmed/6807085/?i=5&from=/8558697/related

Hydronephrosis
https://en.m.wikipedia.org/wiki/Hydronephrosis
https://www.kidney.org/atoz/content/hydronephrosis

Low Purine Diet
https://www.healthline.com/health/tips-for-following-low-purine-diet#1

Anemia and Chronic Kidney Disease
https://www.kidney.org/atoz/content/what_anemia_ckd

Ureteral Stenting
https://www.radiologyinfo.org/en/info.cfm?pg=ureteralNephro
https://www.mskcc.org/cancer-care/patient-education/ureteral-stent-placement

Patients' comments about Kidney Pain
https://comments.medicinenet.com/kidney_pain/patient-comments-4627.htm