CASE PRESENTATION

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CASE PRESENTATION

• BY DR K MOODLEY
• SpR Paediatrics

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CASE HISTORY

• NAME- CT
• DOB- 31/07/05
• BIRTH HISTORY Born in CGH,born at 38 weeks
  gestation.Delivered by caesarian section for
  maternal cholestasis.No antenatal or postnatal
  concerns.No dysmorphic features noted at birth.

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HISTORY -CONTINUED

• Immunisations-up to date
• SOCIAL HISTORY- Lives with her parents and older
  brother.No family history of metabolic bone
  disease.
• DIETARY HISTORY-She was bottlefed on SMA gold
  since birth and was weaned at 4/12 of age.Diet
  has been mixed varied consisting of
  vegetables/pasta/cereals.

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• She had normal exposure to sunlight
• DEVELOPMENT-
• -Late crawling
• -walked at 17 months of age
• -Fine motor skills-nad
• -Speech-nad
• -vision and hearing-nad
• -

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EXAMINATION

• AUXOLOGY
• -Height -97.4cm(below expected mid parental
  height)
• -Weight-16.5 kg

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• CHEST-clear
• CVS-HS were normal,no murmurs heard
• ABDOMEN- soft, non tender,with no palpable masses
• CNS-nad

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• MUSCULOSKELETAL
• -Bilateral bowed legs
• -slight rickety rosary
• -No frontal bossing
• -No swollen joints noted

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INVESTIGATIONS

• Electrolytes nad
• FBC nad
• LFT-
• ALT-13 Cor Ca-2.35 PTH-6.3
• GGT-10 Phosp- 0.68
• BILI-6 TP- 70
• ALP-570 ALB-48
• Ca-2.43 25(OH) vit D3- 35

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URINE
CREATININE- 616
Ca- lt0.5
Cacreat ratio-lt0.82
Phosphcreat ratio-3.33
Total protein-0.02
Proteincreat ratio-32.5
Tubular reabsorption of phsosphate- low(lt60)
Urine organic acids- pending
Urine amino acids -negative
Urine glucose-negative
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• GENETIC TESTS
• Negative for mutation in either PHEX gene or
  FGF23 gene.
• Ongoing genetic tests to look for DMP1 gene.

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• RADIOLOGY
• Xray of left wrist displayed degree of fraying
  and splaying at metaphysis ,consistent with
  rickets.
• Subsequent xrays showed coarsened and trabecular
  appearance of bones consistent with a diagnosis
  of Hypophosphataemic rickets.

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DIAGNOSIS

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TREATMENT

• Initially started on cholecalciferol 3000units
  daily for 3 months.
• No improvement after correcting Vitamin D
  levels,subsequently started on alfacalcidiol
  500ng/day
• Phosphate sandoz
• Calcium-1-2 mmol/kg/day

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• HYPOPHOSPHATAEMIC RICKETS

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PATHOPHYSIOLOGY

• Mutation on PHEX 1 gene
• Leads to loss of function mutation
• FG23 acts on kidney to cause increased phosphate
  excretion and decreased alpha hydroxylase
  activity.
• Phosphate wasting at level of proximal tubule
  which leads to inability to establish normal
  ossification.

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CLINICAL SIGNS

• Slowed growth rate in first year of life
• Short stature
• Reluctance to weightbear
• Late dentition and multiple dental abscesses
• Intellectual development is unaffected
• Widened joint spaces and flaring and bowing at
  the knees

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DIFFERENTIAL DIAGNOSES

• Cystinosis
• Fanconis syndrome
• Tyrosinaemia
• RTA
• Hereditary hypophosphataemic rickets with
  hypocalcaemia
• Vitamin D dependent rickets
• Vitamin D deficient rickets

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INVESTIGATIONS

• Ca/Phosp/ALP
• PTH
• 25 OH vitaminD
• Urinary loss of phosphate

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• Renal tubular phosphate reabsorption
• Early morning urine should be used.
• The TRP in X linked hypophosphataemic rickets is
  60
• Repeated early measurement of ALP and renal
  phosphate handling allows early diagnosis in
  children

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• Tubular phosphate wasting in X linked
  hypophosphataemic rickets can be evident as early
  as 6 weeks,however there is very little evidence
  that early treatment in these patients improve
  outcome.

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IMAGING

• Radiography of wrists ,knees ,ankles and long
  bones
• In children receiving treatment ,periodic renal
  ultrasound to monitor for the development of
  nephrocalcinosis

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TREATMENT

• Outpatient
• Serial Ca and Phosphate measurements
• Calcitriol
• Alfacalcidiol
• Calcium and phosphate supplements

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• Thank you