Nephro- Nephrolithiasis

What is the 3rd most common affliction of the urinary tract (behind UTIs & prostate issues)?

Urinary calculi

Who is urinary stone disease MC in?

M > F, 3rd or 4th decade

What are the 5 major types of urinary stones?

Calcium oxalate (MC), calcium phosphate, struvite associated with w/ proteus mirablis UTIs, uric acid, cystine

What is the CSS mnemonic for radio-opaque stones?

Calcium, cystine, struvite

What is the MC type of urinary stones & is radiopaque?

Calcium

What geographic factors contribute to stone development?

High humidity, high temp, MC in summer months

What dietary factors contribute to stone development?

Dec calcium intake, poor hydration, inc animal protein & vit C intake, high sodium intake

(Calcium diet must be in normal RDA for balance)

If a patient has a fhx of urinary stones, how much does their risk increase?

2 fold

What meds can crystallize in urine, leading to urinary stones?

Indinavir, acyclovir, triamterene

What other factors put patients at increased risk of urinary stones?

Gastric bypass, HTN, obesity, DM, excessive exercise (marathon runners)

The following presentation is classic of what condition?

• Severe sudden pain localized to flank, may awaken pt

• Pt constantly moving to find comfortable position

• May radiate anteriorly over abdomen then referred to I/L testis or labium as stone moves down ureter

Obstructing stones

What other symptoms can be seen with obstructing stones?

N, V, gross or microscopic hematuria

If a stone becomes lodged at the ureterovesicle junction, what will patients complain of?

Marked urinary urgency & frequency

What does stone size correlate with?

Passage & elimination (not symptom severity)

What labs should eb stone for urinary stones?

UA → hematuria, r/o infx w/ C&S

Serum studies for ca, phosphate, elytes, & uric acid

Give pt urine strainer to analyze retrieved stones

Consider 24 hr urine

How does a purely uric acid stone appear?

Radiolucent

Since most stones have some calcium component, what imaging study will pick them up?

Plain KUB

What is the next best step to use after KUB, and is also used if a patient is pregnant?

Renal US

what is the gold standard for urinary stones, but ONLY if KUB and US are not helpful due to the high radiation content?

Noncontrast helical CT

What imaging modality are all stones visible with?

CT

How is hydration used to treat urinary stones?

Double water intake, drinking during meals, 2 hrs after meals, & at night

What are indications for a urology referral in a patient with stones?

Intractable pain, obstruction, stone size > 10mm, infection, pt w/ single kidney, pregnant, or PMH of severe renal disease

What is the treatment of choice in most cases requiring intervention, mostly smaller radiolucent stones < 10 mm?

Extracorporeal shock wave lithotripsy

What procedure should be done for larger renal stones & proximal ureteral stones > 10 mm?

Percutaneous nephrolithotomy

What procedure should be done for large “staghorn” calculus?

Open stone surgery

What are other procedure options for stones?

Stent placement, stereoscopic stone extraction (>10mm)

How can stones be prevented?

Hydration, diet (dec salt/animal protein intake, inc bran/water, normal RDAs), dont skip meals, climate control

What meds can be used to prevent urinary stones?

Citrates, thiazides, Vit C, D, & co enzyme q10