MCQs IN FLUID AND ELECTROLYTE DISORDERS

A two year-old boy was admitted to the Emergency Department after having a witnessed tonic clonic seizure lasting for less than 5 minutes at home. The child is normally fit and well with no previous history of febrile or afebrile seizure or family history of epilepsy. Prior to the seizure, there were no respiratory or coryzal symptoms. No definitive history eliciting head trauma was mentioned. However, the parent noticed that he had been drinking excessively (estimated 2e3 litres) throughout the course of the day.

On examination, the child was post-ictal, drowsy and lethargic. There was no rash. The rest of his examination was unremarkable. His blood results showed a sodium level of 125 mmol/litres with normal renal function. He was fluid restricted and observed overnight. His sodium levels normalized to 135 mmol/litres with good recovery. He was referred to the Endocrinology team for follow up.

1. The child had a hyponatraemic seizure. Which ONE of the following conditions does NOT cause low serum sodium levels?

a. Syndrome of Inappropriate Antidiuretic Hormone
Secretion (SIADH).
b. Diabetes Insipidus
c. Diarrhoea
d. Hypertriglyceridaemia
e. Cirrhosis

2. Which ONE of the following statements in regards to hyponatraemia is false?

a. In hospitalized children, hypotonic fluid use for maintenance hydration is potential risk factor.
b. Acute hyponatraemia can cause brain cell swelling and cerebral oedema.
c. The emergency treatment of hyponatraemia is fluid restriction and 0.9% sodium chloride solution.
d. The recommended rate of correcting low sodium levels should not be faster than 10 mmol/litres a       day.
e. In the treatment of SIADH, Intravenous furosemide may be needed.

3. Select ONE true answer about SIADH
a. Urine osmolality is usually low
b. Urine sodium can be high
c. Serum osmolality is high
d. Occurs commonly with nephrotic syndrome
e. SIADH does not cause hyponatraemia


Answers :

(1. b, 2. c, 3. b).

Hyponatraemia is a serum sodium level less than 135 mmol/litres. The causes of hyponatraemia can be classified according to the patient’s volume status:
1) Hypovolaemic hyponatraemia (seen in diarrhoea secondary to gastroenteritis or cerebral salt wasting
syndrome).
2) Hypervolaemic hyponatraemia (seen in congestive heart failure, cirrhosis or nephrotic syndrome).
3) Normovolaemic hyponatraemia (seen in SIADH or water intoxication).

Pseudohyponatraemia is a laboratory artefact that presents when the plasma contains very high concentrations of protein (Multiple myeloma) or lipid (hypertriglycerideamia).
The treatment of hyponatraemia is based on the specific aetiology. However, it is important to avoid overly rapid correction that might lead to central pontine myelinolysis or osmotic demyelination syndrome. The current recommendation, according to the British National Formulary (BNF),
is to correct sodium levels by a rate not faster than 10 mmol/litres in 24 hours. However, acute hyponatraemia with severe neurological symptoms, requires urgent correction of sodium levels in order to reduce the incidence of cerebral oedema. Intravenous hypertonic saline (4e6
ml/kg of 3% sodium chloride) is the recommended treatment. Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) is characterized by hyponatraemia, inappropriately concentrated urine, high urine osmolality, low plasma osmolality and normal-to-high urine sodium. It
is an uncommon condition in children. It can be caused by CNS disorders (trauma, infection, tumour, haemorrhage), pneumonia, hypothalamic-pituitary surgery and excessive administration of Vasopressin in the treatment of Diabetes Insipidus. Drugs, such as Carbamazepine and some tricyclic
antidepressants can increase vasopressin secretion or mimic vasopressin action. The recommended treatment is fluid restriction, usually to two-thirds of oral intake or less and diuresis to remove excessive free water.

Pediatric Course Review For 6 year medical Students

1- Hypocalcemia is characterized by all of the following features except :

A- Numbness and tingling of circumoral regions.

B- Hyperactivity tendon reflexes.

C- Carpopedal Spasm

D- Shortening of QT interval in ECG.

2- The first evidence of pubertal development in female is :

A- Appearance of breast buds.

B- Onset of menarche

C- Appearance of axillary hair.

D- Appearance of pubic hair.

3- Boner age is normal in :

A- Hypothyroidism.

B- Genetic short stature.

C- Hypopitutarism.

D- Emotional deprivation.

4- Retardation of skeletal maturity can be caused by all except :

A- Chronic renal failure.

B- Hypothyroidism.

C- Protein energy malnutrition.

D- Congenital adrenal hyperplasia.

5- When the child is not able to perform skipping, walking, on heels, hopping in place or going forward in tandem gait, his motor development is considered to be below :

A- 3 years.

B- 6 years.

C- 4 years.

D- 7 Years

6- The following is a delayed milestone development :

A- Head elevation at 12 week.

B- Pincer grasp at 9 months.

C- Bisyllable at 12 months.

D- Stand with support at 10 months,

7- Vocabulary of 11/2 year old is :

A- 5 words.

B- 10-20 words.

C- 20- 30 words.

D- 30-40 words.

Answers :

1- D

2- A

3- B

4- D

5- B

Skipping - 4 years           Walk on toe-tip - 2.5 years

heel-to--to- walks and jumps on foot - 5 years                       Hopping in a place - 4 year

6- C

Delayed development if :

   - Absence of pincer grip by 10-11 month

   - not able to say ba or da by 8-9 months

   - not able to stand holding on by 9-10 months.7- 

7 - B

          By 12 months - can use 2 words with meaning   

          By 18 months use  10 –25 words

CASES OF HYPOCALCEMIA

An 8-year-old boy has been admitted with cramping of his hands and feet that began with a recent illness. He has been healthy except for a chronic infection of his skin and nails for which he sees a dermatologist. Your physical exam of this normal appearing boy includes Chvostek’s and Trousseau’s signs, both of which are positive. Labs come back with a normal CBC, normal renal function, and electrolytes but a total serum calcium

of 7.2 mg/dL, phosphorus of 7.9 mg/dL, and an albumin of 3.9 g/dL.

What is the most likely diagnosis and what studies would you like to perform next? 

What should your initial treatment be? What other illnesses do you need to be monitoring?

Answer :

Hypocalcemia in a school aged child. This child has symptomatic

hypocalcemia with a low serum calcium and high serum phosphorus. The high phosphorus

points to likely dysfunction of PTH secretion or function but the normal body habitus suggests that he does not have Albright’s Hereditary Osteodystrophy (AHO) as with pseudohypoparathyroidism. He does not have renal failure and the normal CBC makes tumor lysis less likely. 

You look for hypomagnesemia that could cause this picture

but the magnesium level is normal and an EKG shows prolonged QT interval. Other studies that are sent off with the initial labs are PTH and 25(OH)D levels. 

Because he is not having serious manifestations like seizures or tetany, you choose to start treatment with oral calcium to both raise the serum calcium and to act as a phosphate binder. You

choose a dose of 500 mg of elemental calcium four times daily as calcium carbonate and you place the patient on a low phosphate diet of 800 mg/day or less. 

As soon as the phosphorus level starts to come down you start active 1,25(OH)2D at a “physiologic” dose of 0.5 mcg daily.

 The PTH level comes back in the low normal range, which is

inappropriate for the level of calcium consistent with hypocalcemia and the 25(OH)D level is normal. 

The rash turns out to be chronic Candida infection and the diagnosis of polyglandular autoimmune syndrome (PGA) type 1 is strongly suggested. Since a high percentage of PGA type 1 patients will go on to develop Addison’s disease, you must

carefully monitor for this potentially life-threatening condition, which can present with electrolyte abnormalities such as hyponatremia, hypokalemia, and acidosis. 

A random cortisol of less than 18 μg/dL is suggestive of adrenal insufficiency but a cortisol stimulation test may be required. In addition to Addison’s disease, other disorders associated

with PGA 1 should be suspected if other clinical abnormalities develop.

An Approach to a Neonate with Cholestatic Jaundice

There is a broad differential diagnosis for conjugated hyperbilirubinemia in the newborn period. If the patient appears

sick, the differential diagnosis includes sepsis, galactosemia,

and hypopituitarism. If the patient appears well, obstructive, infectious, and metabolic etiologies should be considered. 

Obstructive conditions include extrahepatic biliary

atresia, choledochal cyst, idiopathic neonatal hepatitis,

Alagille syndrome, gallstone, and cystic fibrosis. 

Biliary atresia must be evaluated with a liver ultrasound and liver biopsy quickly as long-term outcomes are better for infants who

undergo a Kasai procedure at age less than 60 days. 

Infants with biliary atresia typically are feeding and growing well and subsequently develop clay-colored stools as the bile flow

decreases. 

The abdominal ultrasound is also helpful in diagnosing other causes of cholestasis including a choledochal cyst or gallstones.

 Alagille syndrome is a genetic disorder with symptoms that include conjugated hyperbilirubinemia due to a lack of bile ducts, peripheral pulmonary stenosis, butterfly vertebrae, triangular facies, and eye abnormalities (posterior embryotoxon). Cystic fibrosis can also cause neonatal cholestasis.

Infectious causes of conjugated hyperbilirubinemia include

TORCHinfections, most commonly cytomegalovirus, urinary

tract infections, and sepsis due to Gram-negative bacteria.

Head ultrasound and eye examination are useful in identifying

TORCH infections.

 There are many metabolic causes of  conjugated hyperbilirubinemia including galactosemia and tyrosinemia, which are tested for on the newborn screen.

Urine reducing substances and succinylacetone are positive

in patients with galactosemia and tyrosinemia, respectively.

Hypothyroidism and panhypopituitarism can also lead to

cholestasis and can be diagnosed with appropriate hormonal

studies.

 Alpha-1-antitrypsin (A1AT) deficiency leads to accumulation of A1AT in the hepatocytes, which leads to abnormal bile secretion and cholestasis. Total parenteral nutrition and medication use are other important causes of cholestasis.

Medications that more commonly lead to conjugated hyperbilirubinemia include amoxicillinclavulanate, trimethoprimsulfamethoxazole, erythromycin, naproxen, and rifampin.

An infant with conjugated hyperbilirubinemia who otherwise

appears well should have a laboratory evaluation, which should include a basicmetabolic panel, AST, ALT,GGT, CBC with differential, ammonia, albumin, and coagulation studies.

 AST, ALT, and GGT levels are often elevated with

cholestasis due to liver cell or bile duct injury. 

The GGT level is normal or low in patients with bile acid synthesis defects and progressive familial intrahepatic cholestasis (PFIC). 

Prolonged prothrombin time, low albumin, and elevated ammonia

can be seen with cholestasis if there is advanced liver

injury.

 The newborn screening test results should be confirmed to be normal to rule out galactosemia and tyrosinemia.

Urine should be sent for urinalysis, urine culture and sensitivity,

and reducing substances to look for urinary tract infection

and galactosemia.

 An abdominal ultrasound should be performed early in the evaluation process to assess for biliary atresia, choledochal cyst, or other anatomic causes for cholestasis.

 While awaiting the test results, the parents should be counseled to have their infant evaluated if he develops fever, acholic stools, worsening jaundice, or easy bleeding.

Clinical case 2

An 11-day-old baby girl presents to her pediatrician with new

onset jaundice. She is a full term infant born via a spontaneous

vaginal delivery without any complications during the

pregnancy or delivery. Her total bilirubin at the time of

discharge from the full term nursery on day of life 2 was

6.5 mg/dL. The mother’s blood type is Oþ, and the infant’s

blood type is Bþ with the direct antibody test negative.

Maternal hepatitis B surface antigen is negative. She is breastfeeding every 2–3 hours with good weight gain.

She is afebrile without acholic stools, vomiting, irritability,

or bleeding. There is no family history of hyperbilirubinemia,

Alagille syndrome, or alpha-1-antirypsin deficiency.

Her vital signs are stable. Physical examination is normal

except for icterus. There is no dysmorphic facies, nystagmus,

heart murmur, or hepatosplenomegaly. Stool is yellow in

color.

Laboratory evaluation performed during the clinic visit shows a total bilirubin 8.5 mg/dL, conjugated bilirubin 3.5 mg/dL, aspartate aminotransferase 20 IU/L, alanine aminotransferase 46 IU/L, gamma-glutamyl transpeptidase (GGT) 288 IU/L, and alkaline phosphatase 163 IU/L.

 A complete blood count (CBC) shows white blood cell count

12.3 x 109/L, hemoglobin 17.7 g/dL, and platelets 248 x 109/L

with a differential of 26% segmented neutrophils, 58%

lymphocytes, 11% monocytes, and 5% eosinophils. Newborn

screening result is normal. The prothrombin time is 9.3 seconds.

 A liver ultrasound shows a normal appearing liver without intrahepatic or extrahepatic biliary dilatation.

Further evaluation included an alpha-1-antirypsin phenotype,

and toxoplasma IgM, which were normal. Urine was

negative for cytomegalovirus. TSH is normal.

Further evaluation reveals the cause of her conjugated

hyperbilirubinemia.

What do you think that investigation?

what was the diagnosis?


Answer


A catheterized urine sample was positive for nitrites and leukocyte esterase and showed 25–50 white blood cells and 5–50 bacteria/ high powered field.

 A urine culture subsequently grew >100,000 colonies/ mL of Escherichia coli. The infant was treated with 14 days of amoxicillin clavulanate. On day 5 of antibiotic treatment, the infant’s conjugated bilirubin decreased to 1.3 mg/dL, and two weeks after completing the course of antibiotics, the total bilirubin was 1.0 mg/dL and conjugated bilirubin was 0.4 mg/dL. As part of the evaluation for her urinary tract infection, she underwent a voiding
cystourethrogram and renal ultrasound that showed bilateral
grade 3 vesicoureteral reflux and bilateral Society for

Fetal Urology (SFU) grade 2 hydronephrosis, respectively


Lessons for the Clinician

• For neonates with jaundice, check a serum level of
conjugated bilirubin with the total bilirubin.

• A direct bilirubin may overestimate the conjugated
bilirubin.

• When evaluating a well-appearing infant with conjugated
hyperbilirubinemia, include a urinalysis and urine
culture.

• For full term, well-appearing infants<8 weeks of age with
jaundice, the risk of having a UTI is 5.5–7.5%. In these
cases, the hyperbilirubinemia will resolve with treatment

of the UTI.

clinical case

A 6-year-old girl presents with bilateral lower leg swelling, progressive fatigue,and ultimately, refusal to walk secondary to severe pain, which began a month ago.

She had a respiratory illness along with mouth sores one month prior to development of these symptoms. There is no history of fever, rash, travel or sick contacts. Family history is significant for leukemia, breast cancer, colon cancer, and osteoarthritis.

She is afebrile and has normal vital signs.Her lower extremity examination shows non-pitting edema over both ankles and knees. There is no tenderness or crepitus on palpation of her lower extremities. She moves her lower extremities spontaneously when lying in bed and has normal strength. She has pain with full extension of knees as well as with dorsiflexion of feet. There is no spinal tenderness, or limitation in range ofmotion of her back and hips. Sensations and deep tendon reflexes are intact bilaterally. She has significant apprehension when asked to walk, and bears weight briefly on her toes. In addition, she demonstrates marked emotional lability.

Laboratory results are as follows: WBC count 18.7K/mL (71% neutrophils, 0%

Bands), Hgb 10.4 g/dL, a platelet count 611 K/mL, and a normal peripheral smear.

Serum electrolytes, BUN, creatinine, liver enzymes, LDH, uric acid, creatinine kinase, aldolase and antineutrophil cytoplasmic antibodies (ANCA) are within normal limits. Her erythrocyte sedimentation rate is 127 mm/hr (0–10 mm/hr) and C-reactive protein is 5.8 mg/dL (0.0–0.9 mg/dL).MRI of the lower extremities reveals normal osseous structures with edema within the popliteal fossae and patchy muscular and fascial edema bilaterally . 

Evaluation for infectious processes, including bacterial cultures of blood and stool, respiratory viral panel, PPD, and serologic evaluation for Bartonella,

Parvovirus B19, Coccidiomycosis, EBV, CMV and mycoplasma

were negative. A bone scan was normal. An MRI of the brain and spine performed, after consultation with neurology because of behavioral changes, to rule out secondary CNS involvement, were normal.

She remains nonambulatory during first few days of hospitalization, until further evaluations reveal the diagnosis.

What do you think this investigation which was requested?

What is the diagnosis?

What is the treatment?


Because of markedly elevated inflammatory markers and inability to ambulate, our differential diagnosis included infectious, post-infectious, rheumatologic, and oncologic processes.

some of these have been excluded by the above mentioned investigation.

the test which reveal the diagnosis : ASO and DNAse B titers results came back at 447 IU/mL (0–99 IU/mL) and 340 (</ ¼ 170),

respectively. Thus a diagnosis of post streptococcal myositis
and fasciitis was made.

She was started on oral amoxicillin and non-steroidal antiinflammatory medications. In addition, physical therapy
was initiated, and within three days she showed marked
improvement. She was discharged home to complete a tenday
course of amoxicillin. At her one month follow up, she was back to her baseline activity level without pain, and her ASO titer and ESR had normalized.

Lessons for the Clinician:

• It is important to consider post-streptococcal related myalgia/myositis in the differential diagnosis of children presenting with diffuse muscle and fascial inflammation.

• Post-streptococcal related myalgia/myositis can have atypical
presentations, such as isolated myalgia and can mimic other serious diseases.

• Serum levels of muscle enzymes are normal in patients with post-streptococcal myositis.


Remember :

Post-streptococcal myositis has been reported in patients ranging is ages from 6 to 39 years and there has been a slight female predominance. All patients have presented with severe, debilitating myalgia, generally affecting the proximal muscles of the upper and lower extremities.


Patients generally have a neutrophil predominant leukocytosis,
mild anemia, thrombocytosis, elevated inflammatory markers, normal muscle enzymes and elevated ASO titer.

MRI would remain the modality of choice for establishing
diagnosis, and in our case indeed revealed inflammation
of both muscle and fascia without any bony involvement.

Imaging studies were not performed in the previously reported cases.

Treatment strategies have been variable, but generally included use of anti-inflammatory medications, antibiotics against group A Streptococcus and occasionally steroids for
refractory cases. 

Response to treatment is generally good, with most patients returning to baseline along with resolution of serologic evidence of inflammation.