Nephrology: Challenging Cases

UPDATE IN INTERNAL

MEDICINE - 2019

Robert S. Brown, M.D.

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Conflict of Interest Disclosure

I disclose the following relevant financial relationship:

Börm Bruckmeier Publishing LLC −− Author

“Nephrology Pocket” and “Acid Base Electrolytes Pocket” book & apps

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Acid Base & Electrolyte

Disorders

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1) A 51 yo woman with relapsed acute

myelogenous leukemia (AML) and an IV line

infection is seen for hyperkalemia.

She was noted to lose weight (52→50 Kg) and

have orthostasis and tachycardia despite omission

of all antihypertensive Rx.

Medications: Daptomycin, cefepime, allopurinol,

megestrol, odansetron (decitabine & hydrea for ↑

blasts 10 days ago)

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Laboratory studies reveal the following:

Sodium (mEq/L) 131

Potassium (mEq/L) 6.2

Chloride (mEq/L) 103

Bicarbonate (mEq/L) 20

BUN (mg/dL) 34 (12 mmol/L)

Creatinine (mg/dL) 0.8 (71 µmol/L)

Uric acid (mg/dL) 1.8 (107 µmol/L)

UNa+ (mEq/L) 77

UK+ (mEq/L) 33

Ucreat (mg/dL) 72 (6.36 mmol/L)

UOsm (mOsm/L) 664

Px exam: Cachectic, BP 120/72 →100/60, T 35° C

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The hyperkalemia is likely secondary to

A. Volume depletion from hydrea

B. Sepsis

C. Salt-wasting renal disease from AML

D. Decitabine toxicity

E. Megestrol toxicityCOPYRIGHT

2) Hyperkalemia may be exacerbated

by all of the following drugs except:

A. ACE inhibitors

B. Heparin

C. Amphotericin B

D. Trimethoprim

E. Succinylcholine

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3) A 35 year old woman is noted by her family to

develop confusion shortly after a birthday

party. Less severe similar episodes have

occurred in the past when she told friends that

she felt temporarily “drunk”.

Past Hx is positive for depression, morbid

obesity and some form of abdominal surgery

for weight loss.

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You should suspect that her illness may be

caused by:

A. Salicylate ingestion

B. Acetaminophen ingestion

C. Isopropyl alcohol ingestion

D. Carbohydrate ingestion

E. Toluene ingestion (glue sniffing toxicity)

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Laboratory studies reveal the following:

Urinalysis: SG 1.002, pH 6.5, trace glucose, trace protein.

The 24 hour urine output is 6 liters.

Sodium (mEq/L) 146

Potassium (mEq/L) 3.5

Chloride (mEq/L) 112

Bicarbonate (mEq/L) 18

BUN (mg/dL) 10 (3.6 mmol/L)

Creatinine (mg/dL) 0.6 (53 µmol/L)

Calcium (mg/dL) 9.0 (2.3 mmol/L)

Glucose (mg/dL) 145 (8.0 mmol/L)

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This patient most probably:

A. has renal tubular acidosis

B. has gestational diabetes mellitus

C. has primary polydipsia

D. will respond to DDAVP for diabetes insipidus

E. should not be given DDAVPCOPYRIGHT

Kidney Stones

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5) An otherwise healthy 44-year-old man has recurrent calcium oxalate stones. He is on no medications and has no history of gastrointestinal or urinary tract disease.

Serum electrolytes are normal. Serum calcium and phosphate are repeatedly normal.

Urinalysis is normal with pH of 5.5.

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Urinary evaluation (24 hr) reveals:

Calcium 350 mg/day (8.73 mmol)

Oxalate 47 mg/day ( 520 µmol)

Citrate 200 mg/day (1041 µmol)

Urate 860 mg/day (5116 µmol)

Sodium 237 mEq/day

Volume 1,900 ml/day

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All of the following therapies could beuseful except:

A. Hydrochlorothiazide

B. Potassium citrate

C. Low sodium diet

D. Low calcium diet

E. Allopurinol COPYRIGHT

6) The previous patient has developed colicky

flank pain and is noted to have a 5 mm stone

in the distal left ureter.

At this time, you advise:

A. Tamsulosin

B. Nifedipine

C. Shock wave lithotripsy

D. Ureteroscopy with stent placement

E. More sex

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Renal Disorders

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7) A 68 year old woman has noted leg edema

and fatigue. Laboratory studies reveal:

Hgb 9.9 Na 138

BUN 37 K 4.2

Creatinine 1.7 Cl 116

Glucose 96 CO2 17

Calcium 10.1 pH 7.34

Phosphate 1.8 Albumin 2.6

Urinalysis: pH 7.0, 1+ protein, 1+ glucose,

5-15 RBC/hpf, 5-10 WBC/hpf, rare waxy cast

Urine protein/ urine creatinine: 2.7

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The most likely diagnosis is:

A. Nephrocalcinosis due to RTA

B. Sjogren’s syndrome with nephropathy

C. Membranous nephropathy associated

with a carcinoma

D. HIV nephropathy

E. Light chain deposition nephropathyCOPYRIGHT

8) A 69 year old man complains of 2 weeks

of cough. Exam is normal as are blood

tests except the creatinine is 1.7 mg/dL

(150 µmol/L). He is treated with 5 days of

levofloxacin.

He returns 2 weeks later (bad followup!!),

now with hemoptysis and a petechial rash

on the lower extremities.

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Physical examination shows an ill-appearing

man with blood pressure of 150/98 mmHg.

The lungs reveal bilateral crackles. The rest

of the physical exam is unremarkable except

for raised, non-blanching papules over the

lower extremities. COPYRIGHT

Urinalysis reveals 3+ protein, 3+ hemoglobin

with numerous RBC’s, 5-10 WBC’s, and RBC

and WBC casts.

Serum creatinine is 6.4 mg/dL (566 µmol/L).

Complement levels are normal.

Chest X-ray reveals bilateral pulmonary

infiltrates.

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The procedure most likely to yield a useful

diagnosis is:

A. Renal biopsy

B. Bronchoscopy

C. Thoracoscopic lung biopsy

D. Renal arteriogram

E. Serum tests for anti-glomerular basement

antibody (anti-GBM) and anti-neutrophil

cytoplasmic antibodies (ANCA)

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9) The most likely diagnosis in the foregoing

patient is:

A. Cryoglobulinemic vasculitis

B. Goodpasture's syndrome

C. Systemic vasculitis associated with an

anti-neutrophil cytoplasmic antibody

D. Henoch-Schonlein purpura

E. Systemic lupus erythematosus

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10) A previously healthy 26-year-old man

becomes ill with fever, malaise, back pain,

and sore throat. One day later he notices

gross hematuria.

Urinalysis shows 2+ protein, 3+ blood,

30-40 RBC/hpf with acanthocytes.

The serum creatinine is 0.9.

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The most likely cause of the urine findings is:

A. Acute post-streptococcal glomerulonephritis

B. Nephrolithiasis

C. IgA nephropathy

D. Lupus nephritis

E. Granulomatosis with polyangiitis (formerly

Wegener’s granulomatosis)

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11) A 48 yo woman returns from 2

months in Brazil with muscle twitching,

cramps, weakness and polyuria.

PMHx: Hypertension on HCTZ;

GERD on omeprazole.

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She had received numerous mosquito bites and

testing for zika virus is positive.

Evaluation is also notable for hypokalemia,

hypocalcemia, and widening of her QRS on

ECG.

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At this time, you suspect that her new

symptoms have been caused by:

A. Hypokalemia

B. Hypoparathyroidism

C. Hypomagnesemia

D. Guillain Barre syndrome

E. Anxiety about zika virus & pregnancy

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12) A 45 year old man who is HIV positive has

had headache, weakness, generalized

aching, nausea and vomiting for one week.

He has a history of hypertension for 3 years

and has been on hydrochlorothiazide for 3

months. He drinks 3-5 alcoholic beverages

a day and admits to past use of intravenous

cocaine and heroin.

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On exam, he appears lethargic with a BP of

170/115 mmHg, P of 100/min and T 980 (36.70).

Fundi show arteriolar narrowing. There is mild

jugular venous distension and basilar crackles.

There is 3+ pitting edema of the legs and

generalized tenderness.

Neurologic exam shows weakness, more marked

proximally than distally.

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Laboratory tests:

BUN 60 mg/dL (21.4 mmol/L)

Creatinine 9 mg/dL (796 µmol/L)

Sodium 136 mEq/L

Potassium 6.8 mEq/L

Chloride 100 mEq/L

Bicarbonate 14 mEq/L

Calcium 6.4 mg/dL (1.6 mmol/L)

Phosphorus 12.5 mg/dL (4.0 mmol/L)

Uric acid 21 mg/dL (1249 µmol/L)

Bilirubin 0.6 mg/dL (10 µmol/L)

Hematocrit 35 %

WBC 14,000/cu mm

Platelets 125,000/cu mm

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Peripheral blood smear shows normal

differential and morphology

Urinalysis: 1+ protein, 4+ heme by dipstick.

Sediment: 3-5 RBC/hpf, 1-3 WBC/hpf;

several coarse granular casts/lpf.

Renal ultrasound: normal kidney size

without evidence for obstruction

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Evaluation of the renal failure would most

likely reveal:

A. hypertensive nephrosclerosis

B. allergic interstitial nephritis secondary to

thiazide therapy

C. systemic vasculitis with a crescentic

glomerulonephritis

D. acute tubular necrosis

E. focal glomerular sclerosis with

collapsing glomerulopathy

F. urate nephropathy

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13) A 26 year old woman is admitted to the

hospital following a one to two week diarrheal

illness. She has been febrile and confused at

home.

On exam, she is delirious with a BP 140/90,

P 110/min, T 103ºF (39.4ºC). There is no clear

source of fever. Stool is green and bloody.

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Laboratory studies show a hematocrit of 24%,

WBC of 8,200 without band forms and

platelet count of 62,000. The peripheral blood

smear reveals numerous schistocytes.

The BUN is 78 mg/dL (27.8 mmol/L).

The creatinine is 4.2 mg/dL (371 µmol/L).

The urinalysis reveals 2+ protein, 10-20

RBC/hpf and granular casts.

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You would start :

A. Treatment only after special tests return

B. Antibiotics targeted against Gram-negative

organisms

C. Supportive care

D. Corticosteroids and cyclophosphamide

E. Plasma exchange therapy + FFPCOPYRIGHT

14) A 52-year-old woman with known

polycystic kidney disease develops low

grade fever and mild left flank pain.

Urinalysis reveals numerous white blood

cells, red blood cells and bacteria. The

urine gram stain reveals gram-negative

rods.

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The best treatment option for this patient is:

A. Intravenous gentamicin for presumed Gram-negative

bacterial urinary tract infection

B. Begin both gentamicin and cephalothin therapy to

achieve synergy of two antibiotics in the urine and

fluid of an infected cyst

C. Begin either oral ciprofloxacin or sulfa-trimethoprim

D. Obtain an US or CT to look for an infected cyst

E. Both C and D

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Extra Credit Question

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15) A 25 yo man develops fever, myalgias,

headache and cough 10 days after his return from

a kayaking vacation in Hawaii.

Physical exam

shows T 100.5° F

(38°C), no distress,

a tender enlarged

liver and ‘classic’

head exam as

shown.

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Laboratory studies reveal the following:

Sodium (mEq/L) 132

Potassium (mEq/L) 3.3

Chloride (mEq/L) 101

Bicarbonate (mEq/L) 24

BUN (mg/dL) 54 (19 mmol/L)

Creatinine (mg/dL) 2.6 (230 µmol/L)

ALT (U/L) 340 (5.7 µkat/L)

Total bilirubin (mg/dL) 12 (205 µmol/L)

Hgb 11.4/µL, WBC 9,800/µL (82% polys), Platelets 90,000/µL

Urinalysis: Nonoliguric, SG 1.008, pH 5.0, 1+ protein,

3-5 RBC/hpf, 15 WBC/hpf, few coarse granular casts

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At this time, you would

A. Suspect hepatitis B with renal disease

B. Start high dose corticosteroids

C. Start steroids & immunosuppressive Rx

D. Start antibiotic Rx

E. Supportive Rx alone with IV fluids, etc. COPYRIGHT