Hyponatraemia a. Addison’s disease b. Compulsive water drinking c. Treatment with diuretics d. Syndrome of inappropriate antidiuresis A 54-year-old male smoker complaining of weight loss and haemoptysis, who is found to have a plasma sodium concentration of 114 mmol/L. What is most likely diagnosis?
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Hyponatraemia
a. Addison’s diseaseb. Compulsive water drinkingc. Treatment with diureticsd. Syndrome of inappropriate antidiuresis
A 54-year-old male smoker complaining of weight loss and haemoptysis, who is found to have a plasma sodium concentration of 114 mmol/L.
What is most likely diagnosis?
Answer
d. Syndrome of inappropriate antidiuresis
How do you prove ?
Paired serum / urine for:SodiumOsmolality
Hypo – ‘rhubarb’
• Serum rhubarb• Serum renal function and electrolytes• Urine creatinine, sodium and rhubarb• Urine and plasma osmolality• ALL SHOULD BE PAIRED
• What is the single most important clinical assessment to make in a patient with hyponatraemia ?
A middle-aged woman with a long history of rheumatoid disease complains of fainting episodes.
Plasma sodium concentration is 128 mmol/L.
The sodium concentration of a random urine sample is 80 mmol/L.
Postural hypotension is demonstrable.
What diagnoses are compatible with these findings?
Answer
Adrenal failureAnalgesic nephropathyOver treatment with diuretics
LEARNING POINT:
You must know the volume status of your patient.
CAUSES OF HYPONATRAEMIA:– Depletion of sodium – eg Adrenocortical insufficiency– Water excess – eg SIADH, iatrogenic (excess administration
of hypotonic fluids such as 5% dextrose– Combined water and sodium excess – eg CCF.
KEY INVESTIGATION OFTEN OVERLOOKED
• Urine electrolytes
• Assess urine at same time as plasma, and when plasma abnormalities still present.
• If in ‘reasonable’ steady state, then 24 hour collections may be required.
• If serum ‘analyte’ sufficiently abnormal then comparison to random urine may be possible (is urine chemistry appropriate to plasma chemistry). Will need to look for patterns (eg high / low Na and K)
SODIUM• In hyponatraemia, the kidney should conserve sodium to
less than 20 mmol/L
• Urine concentration can be influenced by water reabsorption – thus use FeNA
• Distinguish inappropriate renal loss (typically ATN) from volume depletion
• Dividing line often stated as 1% (much higher in neonates) but can vary in states effecting amount of sodium filtered.
URINE CHEMISTRY• Parameter
Sodium
Chloride
Potassium
Osmolality
pH
• Uses• Assessment of volume status• Diagnosis of hypoNa and ARF• Evaluation of calcium and urate
excretion in stone formers
• Diagnosis of metabolic alkalosis• Urine anion gap
• Diagnosis of hypokaleamia, ratio to sodium in neonatal supplementation
• HypoNa, hyperNa, ARF, DI, concentrating ability
• Diagnosis of RTA• Volume status
• HYPOKALEAMIA:
What clinical observation is most important to drive investigations ?
A 40yr old patient has a plasma potassium concentration of 2.8 mmol/L; plasma bicarbonate is 34 mmol/L.
What clinical observation is required to help drive investigations ?
BLOOD PRESSURE – this patient is hypertensive
What are the possible diagnoses/ explanations which explain all these findings?
Answer
Conn’sRenal artery stenosis bp with thiazides
Mrs D B age 35Aug 02 Referred by GP for management of
hypercholesterolaemia
Chol = 9.8 mmol/lTG = 1.2 mmol/l
FH Father uco DBF for FHC2 brothers – normal cholesterolGrandfather – DM
• Hypernatraemia Uosmol should be > 600 mosmol/Kg. If less than plasma omso then primary renal water loss
• Urine osmo > 750 makes DI unlikely
• Urine osmolality– In children old enough to stay dry overnight
(with low index of clinical suspicion), consider early morning (first urine passed) osmo – value above 750 mosmol/Kg excludes DI. Do not attempt if urine volumes > 30 ml/Kg body weight, or high index of suspicion to avoid hypertonic states.
56yr male
PC: Moderate increase in sweating; ? Some weight loss.
• 60 year old female, generally unwell, abdominal pain.
• U+E = NAD• LFT = NAD• Calcium = 2.9 mmol/L
• PTH = 5.9 pmol/L [1.5 – 7.7]
CHOL = 8.4 mmol/LHDL = 2.2 mmol/LTG = 0.9 mmol/L
What tests would you request next:a. Fasting glucoseb. 9 am Cortisolc. Bone profiled. FT4 TSH
e. LFTs
51-year-old female on routine vascular risk programme was found to have following blood test results
Answer
d. TFTse. LFTs
Case (cont)FT4 TSH normalALB = 38 gl/LAST = 40 u/LALP = 280 iu/L [<120]Bil = 28 µmol/L? What test/s nexta. 24 hour urine proteinb. Immunoglobulinsc. Auto antibodiesd. FBC
(p.133)
Answer
b. Immunogloblins ( 1 gM)c. Auto antibodies (antimitochondrial dbs)
2A 18-year-old man is noticed by a friend to be jaundiced immediately following a mild ‘flu-like’ illness. He has otherwise been well. His serum biochemical results are: bilirubin 80 µmol/L, aspartate aminotransferase 42 IU/L, alkaline phosphatase 82 IU/L, albumin 44 g/L. His urine tests negative for bilirubin.
What is the most likely Dx?
(p.133)
Answer
GilbertsHaemolysisUnconjugated bilirubin
17 yr girl – known anorexia. Recently commenced monitored re-feeding regime.
Sodium = 138 mmol/L Potassium = 4.1 mmol/L
Urea = 3.3 mmol/L Creatinine = 48 umol/L
Albumin = 37 g/L Bili = 11 umol/L
ALP = 83 IU/L ALT = 534 IU/L
? Cause of raised ALT
? What other tests required
? Follow-up
4
A fit, elderly man has biochemical tests performed as part of a ‘well-man’ screen. The only abnormality is a serum alkaline phosphatase activity of 200 iu/L.
A 40-year-old journalist with a history of excessive alcohol ingestion undergoes an ‘executive health screen’. Which of the following biochemical results from analysis of serum suggest the presence of an additional problem?
(p.134)
Answer
c. Cholesterol 9.6 mmol/L
a. Chronic osteomyelitisb. Multiple myelomac. Osteoarthritisd. Paget’s disease of bonee. Renal osteodystrophy
An elderly woman complains of back pain: serum total protein concentration 85 g/L; albumin, 30 g/L. The presence of the following condition could explain these abnormalities
Answer
a. Osteomyelitisb. Myeloma
The following results are found in an adult patient presenting with weight loss, diarrhoea and abdominal discomfort: serum calcium concentration 1.95 mmol/L, phosphate 0.6 mmol/L, albumin 32 g/L, alkaline phosphatase 230 iu/L.
What further biochemical investigations would you request?
Answer
25-0H vitamin D PTHCaMalabsorption of fat
• 14 yr old female, hirsute, lack of secondary sexual characteristics, primary amenorrhoea
• Which one of the following findings in a patient with primary hypothyroidism could not be explained by this condition ?
• a). Hyponatraemia• b). Increased mean red cell volume• c). Plasma cholesterol of 7.2 mmol/L• d). Plasma ALP 2x the ULN• e). Plasma CK 2x the ULN
• d). Plasma ALP 2x the ULN
• Elderly female with weight loss and abdo pain radiating to the back.– Bilirubin = 225 µmol/L– Albumin = 36 g/L– Protein = 68 g/L– AST = 42 U/L– ALP = 455 U/L– Gamma-GT = 72 U/l– Urine positive for bilirubin
• What is the provisional diagnosis ?• a). Hepatic mets form ca colon• b). Primary biliary cirrhosis• c). Carcinoma of the head of pancreas• d). Autoimmune chronic hepatitis• e). Sclerosing cholangitis
• c). Carcinoma of the head of pancreas
Male infant.
Born at term. At approx 45 mins age noted to have no cardiac output. Resuscitated, RIP few days later.
Troponin = 2.9 ng/ml
Interpret ?
83 year old female admitted with confusion and mobility
underestimated (bag leaking) / underreplaced. Clinically no concerns re volume status.
PLASMASodium = 144
Potassium = 5.2
Urea = 3.5
Creatinine 19
Phosphate = 1.54
URINESodium = < 10
Potassium = 111
Osmolality = 776
pH = 5.0
Phosphate = 106
PTH = 94
• 24yr old female• Presented for asthma check. But
reported generalised headache and ‘off colour’ 2-3/7.
• PMH:– Depression 2-3 years previous, now
resolved and much better, some some ‘stress’ over financial debt
– TOP 3-4 years previous.
U+E from GP shows potassium of 1.9mmol/L
Lab add phosphate, Mg and Ca2+ - all normal
Patient referred to AAU for O/C medical team
Lab D/W O/C medical SpR – advises admission urine for electrolytes and store for laxative / diuretic screening
Medical review:
No reported diarrhoaea, vomiting or other GI symptoms. No dysuria or polyuria
Patient currently fasting for Ramadan, but normally eats poorly – usually skips breakfast and often lunch also. Denies laxative or diuretic abuse.
BP 93/65 PR 78 and RR 22 and sats 99%
No organomegaly
Well perfused with no oedema
Hint of u wave in II, V3 – V5
Weight 42 Kg
Venous gas confirms potassium of 1.9mmol/L with significant alkalosis (pH 7.53, bicarb 44 mmol/L, BE +19.2)
No documented assessment of nutritional status and risk
Imp:
? Laxative abuse, ? Vomiting after feeds, ? anorexia
Rx:
1L saline + 40 mmol potassium (x 2)
Ward round:
Imp as above, but no obvious evidence of anorexia noted
Despite no evidence of cortisol excess, only investigation for hypokalemia was 9am cortisol and 24hr UFC. Only urine studies were from lab adding onto UFC sample.
Urine electrolytes results (K+ = <10mmol/L) noted in record but not interpreted and significance not documented.
9am cortisol result interpreted incorrectly
Following admission, significant hypophosphataemia (0.35 mmol/L) occurred, but no intervention, no discussion in record and no repeat testing.