Endocrine__parathyroid gland

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					In Capsule Series
                             Endocrine


                       Parathyroid gland
                        Ca metabolism

 Normal Ca level : 9 – 11 mg%.
 A. Ionized :              50%                 ( active )
 B. Non-ionized :          50%                ( reserve )
        1)      40% bound to albumin.
        2)      10% any other bond ( Ca carbonate, phosphate ….).

       N.B. :
                  Liver cirrhosis    → ↓ alb.       → hypocalcaemia         but
                  no tetany because ionized         → normal.
                  Nephrotic syndrome                → i same.

       N.B. :
                  Ca level is closely affected & related to P [n. 3 - 4.5 mg%]
                  Notice that Ca-P solubility product = constant [ 40 ].
                  Serum Ca & P levels are controlled by certain hormones :
                       • Parathormone.
                       • Calcitonin.
                       • Active vitamin D.
                  Ca regulation involves 3 sites : bone, intestine & kidney.

                   Parathormone          vitamin D           Calcitonin

  Absorption        ↑ Ca      ↓P       ↑ Ca        ↑P          ↓ Ca
  ( intestine )
Reabsorption        ↑ Ca      ↓P       ↑ Ca        ↑P       ↓ Ca    ↓P
   ( kidney )
  Resorption        ↑ Ca      ↓P       ↑ Ca        ↑P       ↓ Ca    ↓P
    ( bone )
      Blood         ↑ Ca      ↓P       ↑ Ca       ↑P        ↓ Ca    ↓P
 ( net result )

       N.B. :
                  PTH acts directly on nbone & kidney & indirectly on
                  intestine ( through activation of vit.D ).
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              Endocrine




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In Capsule Series
                              Endocrine


               Hyperparathyroidism
  1. Physiology :
       a. Hormone :       Parathormone ( PTH ).
       b. Gland :            Parathyroid gland.
       c. Function of the hormone :        ↑ Ca. level
                 i. GIT          : ↑↑   absorption of Ca.
                ii. Kidney       : ↑↑   reabsorption of Ca.
               iii. Bone         : ↑↑   resorption of Ca.
       d. Regulation of this hormone :
                   i. Ca. level ( hypo    →      ↑ PTH ).
                  ii. P. level  ( hyper   →      ↑ PTH ).
    N.B. :         The main stimulatory of PTH is hyperphosphatemia.

  2. Etiology :
       a. 1ry :
                 i. Adenoma of i parathyroid gland.
                ii. Hyperplasia of i parathyroid gland.
               iii. As a part of multiple endocrine neoplasia
                         ( MEN -1 ) → 3 p :
                       1. hyper-parathyrodisim.
                       2. pituitary tumor.
                       3. pancreatic tumor.
       b. 2ry :
                  i. Due to prolonged hypocalcaemia as in CRF which
                    leads to hyperplasia of i parathyroid gland.
       c. 3ry :
                   i. Pathological extension of 2ry.
                  ii. Prolonged hyperplasia      → autonomous
                    adenoma ( the gland continue to release PTH
                    even after correction of i cause ),e.g:end stage CRF
       d. Ectopic :
                    Paramalignant syndrome (oat cell carcinoma).
  3. C / P :                            50% →      asymptomatic.
       a. C / p of i cause :
                   i. Tumor.
                  ii. CRF.
       b. C / p of i hormone : disease of bone & renal stone
                  i. Bone :             (2p)
                       1.      pain.
                       2.      pathological fracture.
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                           Endocrine


                 ii. Renal :          ( 3 )
                       1. repeated stones.
                       2. polyuria ( Ca diabetes ) &         polydepsia.
                       3. nephrocalcinosis é renal failure may occur.
                iii. Others :         (4х2)
                       1. CNS :
                              a. drowsiness.
                              b. depression.
                       2. GIT :
                              a. peptic ulcer.
                              b. pancreatitis ( abdominal pain ).
                       3. CVS :
                              a. ECG : short Q-T interval & arrhythmia.
                              b. HTN.
                       4. Skin :
                              a. dry.
                              b. itching.

       N.B. :
                  Clinical manifestations of Ca  → Ca > 11mg%.
                  Renal impairment               → Ca > 13mg%.
                  Coma & cardiac arrest          → Ca > 14 mg%.
                         → endocrinal emergency.

  4.     D. D. of hypercalcemia :                    (4Х 3 )

          a. Endocrine :
                  i. Hyperparathyroidism ( 1ry & 3ry ).
                 ii. Hyperthyroidism.
                iii. Addison’s disease   (Cortisone → --- vit.D).
          b. Malignancy :
                  i. 2ries.
                 ii. Multiple myeloma.
                iii. Lymphoma.
          c. Bone :
                  i. T.B.
                 ii. Sarcoidosis.
                iii. Immobilization.
          d. Others :
                  i. Hypervitaminosis.
                 ii. Drugs thiazide.
                iii. Familial hypercalcemia hypocalceuria.


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                                 Endocrine




    5. Investigation :
          a. Inv. for i cause :
                   i. Imaging for i gland :
                        1. C.T.
                        2. M.R.I.
          b. Assay of i hormone level :
                   i. In blood :
                                 parathormone : ↑↑ ed [ n. 0.5 - 1ngm/ml ].
          c. Inv. of i function of i hormone :
                   i. Blood :
                                      1ry           2ry         3ry
1. Ca     ( n : 9 - 11 mg% )           ↑             ↓           ↑
2. P      ( n : 3 - 4.5 mg% )          ↓             ↑           ↑
3. Alk.ph. ( n : 3 - 13 KAU )          ↑            ↑↑          ↑↑↑
                   ii. Urine :
                            1. ↑ Ca       [ n. 150 mg / day ]
                            2. ↑ P        [ n. 1 gm / day ]
                            3. ↑ hydroxyproline          → bone resorption.
                            4. ↑ c-AMP                   → bone resorption.
                   iii. X- ray :
                            1. bone :                        ‫ت‬     ٥
                                 a. loss of lamina dura of i teeth.
                                          ( i earliest sign)
                                 b. sub-periosteal erosions in i middle
                                    phalanges.
                                 c. ground glass appearance.
                                 d. skull        → punshed out lesions.
                                          (paper pot skull).            ‫و‬
                                 e. spine        → code fish spine.
                            2. renal :
                                 a. urinary stones.
                                 b. nephrocalcinosis.
                  iv. Bone biopsy : osteomalacia é excess osteoclasts.
          d. Suppression test :
                      Suppression test →     for Hyperfunction.
                                material   :      steroid.
                    i. Normal : steroid    → ↓ vit.D. → ↓ Ca.
                   ii. In hyperparathyrodism      → –ve response.


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In Capsule Series
                            Endocrine


  6. Treatment :
      a. Surgery :
                  i. Removal of i parathyroid glands.
                 ii. Ca & vit.D. supply to avoid tetany.
      b. Medical :
                i. ↓ intake           &     ↑↑ fluid intake.
               ii. ↓ absorption       :     by oral phosphate.
              iii. ↑ loss of Ca       :     excess saline then fursemide
                                      or    even dialysis in sever cases.
             iv.     Calcitonin       →     ppt Ca in bone.
              v.     β-blocker        →     protect heart       e.g. Inderal.
             vi.     Cortisone is effective in some cases
                         ( myeloma, vit.D excess & sarcoidosis).
             vii.    Alendronate (Osteomax) :↓↓ osteoclstic activity.
                                   ‫آ ة‬           ‫ب‬     ‫رو‬     ‫ا‬        ‫ص وا‬



    Hypercalcemic crisis :            ( serum Ca level > 14 mg % )
      a. Manifestations ( non secific ) :
                i.   Nausea & vomiting.
               ii.   Polyuria.
              iii.   Drowsiness & altered consciousness.
             iv.     Arrythmia.
      b. TTT :
                i. IV normal sline : 4-6 L/day may be nessary.
               ii. Lasix ; but be sure that i patient is adequatly
                   hydrated.
              iii. IV pamidronate ( Aredia ) it's drug of choice in
                   hypercalcemic crisis.
             iv. Calcitonin.
              v. Cortisone.
             vi. Dialysis.




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              Endocrine




                          - 41 -
In Capsule Series
                            Endocrine


                 Hypoparathyroidism
                      (Tetany)
   Def.     :     state of ↑↑ neuro-muscular irritability due to   :
                  ↓↓ ionized Ca , ↓↓ Mg or alkalosis.

  1. Physiology :
           Refer to hyperparathyroidism.
  2. Etiology :       ( ↓ Ca   ,     ↓ Mg             or     alkalosis ).
        a. Hypocalcaemia :
                 i. Hypoparathyroidism :
                       1. surgery : removal of i parathyroid glands
                       2.   irradiation.
                       3.   Di-george syndrome :
                               a. absent parathyroid → ↓ PTH.
                               b. absent thymus     → ↓ T-lymphocyte.
                 ii. ↓ Ca intake :
                            starvation.
                iii. ↓ Ca absorption :
                        1. malabsorption syndrome.
                        2. ↓ vit.D. rickets & osteomalacia.
               iv. Precipitation of Ca :
                        1. in tissues → acute pancreatitis.
                        2. in bone → hunger bone syndrome.
                v. ↑ Ca excretion :
                            CRF ( most common cause of hypocalcemia).
            N.B. teyany rarely occurs inRF because of acidosis which
            convert non ionized Ca into ionized Ca.
          b. Hypomagnesaemia :
                  i. Excess diuretis.
                 ii. Malabsorption syndrome.
          c. Alkalosis :       ( Ionized Ca → non ioized Ca ).
                  i. Respiratory :
                               hyperventilation :     - hysterical.
                                                      - high attitude.
                 ii. Metabolic :
                       1. loss of HCl      :     - repeated vomiting.
                                                 - gastritis.
                                                 - gasterectomy.
                       2. milk alkali syndrome.
                       3. hypokalemia e.g. Conn’s syndrome.
                                                                   - 41 -
In Capsule Series
                          Endocrine


    N.B.        :     Mg Tetany :
                ↓↓ Mg → neuro-muscular irritability é i following
                differences :
                 •    Cramps           →     don’t occur.
                 •    Trausseau’s sign →      –ve.
                Diagnosed by     →     refractory hypokalemia.

  3. C / P :
       a. C / p of i cause :
                i. Surgery of i parathyroid glands.
               ii. Gastritis or gasterectomy.

       b. C / p of i hormone :
               i. Latent tetany :
                     1.   serum Ca = 7 – 9 mg%.
                     2.   manifestation of tetany →      –ve.
                     3.   needs provocative tests to show tetany :
                           a. Chvostek’s test :
                                    tapping over i facial nerve
                                    → contraction of i facial muscles.
                           b. Trousseau’s test :
                                   ↑ Bl.P. slight above systolic Bl.P.
                                   → carpal spasm.
                           c. Erb’s test :
                                   electric current < 4m.ampers
                                   → muscle contraction.
               ii. Manifest tetany :
                               serum Ca < 7 mg%.
                     1.   irritability : restlessness & parastheia around
                          mouth & fingers.
                     2.   convulsions & muscle twitches.
                     3.   spasm :
                             a. eye muscles.
                             b. mouth          :   trismus of jaw.
                             c. larynx         :   stridor & dyspnea.
                             d. carpo-pedal spasm.
                             e. diaphragm :        Hiccough.
                             f. GIT            :   colic.
                             g. bladder        :   retention.
                             h. back ms :          opithotonus.



                                                                         - 42 -
In Capsule Series
                          Endocrine

                    4.    on ectodermal structures :
                           a. skin    :      roughness
                                      &      fall of hair.
                           b. nail    :      brittle.
                           c. lens    :      cataract.
                           d. Teeth   :      hypoplastic.

  4. Investigation :
       a. In hypoparathyrodism:
                i. ↓↓ serum Ca.
               ii. ↑ P.
              iii. ↓ PTH.
          N.B. :
                    PTH is ↑↑ ed in all cases of tetany except in
                    hypoparathyrodism & hypomagnesamia.
       b. In hypomagnesaemia :
               i. Refractory hypokalemia.
       c. In alkaosis :
                i. Normal Ca.
               ii. Normal P.
              iii. PH :      ↑↑ ed.

  5. Treatment :
       a. TTT of i attack : ( emergency ttt )
                i. IV Ca gluconate 10 ml 10% very slowly.
               ii. Patent airway.
       b. TTT of i cause :
               i. Hypocalemia :
                      1.   oral Ca.
                      2. vit.D
               ii. Hypomagnesemia :
                               oral Mg.
              iii. Alkalosis :
                      1. ttt of i cause.
                      2. acidifying drugs.




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