A site for medical students - Practical,Theory,Osce Notes

Hypertrichosis -clinical significance

Hypertrichosis is a condition where there is excessive growth of hair in generalized or localized pattern but this is not of male pattern of distribution.
Congenital hypertrichosis is seen in porphyria cutanea tarda, 
Hurler's syndrome, 
Giant pigmented naevus also called as [bathing suit naevus]
Acquired hypertrichosis is seen in the following conditions
  • Malignancy-bronchogenic carcinoma
  • Drugs-phenytoin, steroids,minoxidil, diazoxide, streptomycin.
  • Endocrine causes
  • Sexual precocity
  • Hypothyroidism
  • Adrenal hyperplasia or neoplasm

What is hypertelorism?

Hypertelorism means the presence of wide spaced eyes. This is diagnosed when the inter inner canthal distance between the two eyes is more than half of the inter pupillary distance
Causes of hypertelorism
Hypertelorism is a feature that can have many underlying etiology
  • This may be due to a mass pushing the two orbits apart
  • A cleft in the bone between the eyes 
  • As part of a syndrome.

What is Rocker Bottom Feet ?

This is a severe type of flat foot with a protuberant heel.
It is characterised by a prominent calcaneus/heel and a convex rounded sole.
It has Persian slipper appearance
  • Calcaneus in fixed equinus
  • Achilles tendon is very tight
  • The hindfoot is in valgus
  • The head of the talus is found medially in the sole
  • The forefoot is abducted and dorsiflexed.
It is also known as a congenital vertical talus
What is the pathology of Rocker bottom feet?
It occur from a dorsal and lateral dislocation of the talonavicular joint.
Seen in the following conditions
Aneuploidic syndromic
  • Trisomy 13- Patau syndrome
  • Trisomy 18 also called Edward's syndrome, which may be associated with PDA
  • 18q deletion syndrome
  • Spina bifida
  • Arthrogryposis
What are the differential diagnosis ?
In the antenatal/neonatal period clubfoot is an important differential diagnosis
In the adult period differentail diagnosis considered is acquired rocker bottom deformity occurring secondary to:
Underlying neuromuscular disorder
diabetic foot (Charcot joint)

Causes of Miosis

Miosis is defined as Pupil size is < 2 mm
Following are the common causes of miosis
  • Old age
  • Homer's syndrome
  • Drugs or toxins
  • Neostigmine
  • Morphine
  • Organophosphorous poisoning
  • Pontine haemorrhage.

Unilateral miosis causes
  • Homer’s syndrome• Paralysis of cervical sympathetic - Horner's syndrome
  • Drugs
  • Irritation of parasympathetic system
  • Drugs - Morphine, organophosphate poisoning, levodopa
  • Deep coma, increased-OLpontine hemorrhage
  • Rowland Payne syndrome - Consists of Horner's syndrome, phrenic nerve and recurrent laryngeal nerve involvement. It is caused in metastatic tumor at neck from malignancy like carcinoma breast.
  • Old age.
  • Argyll Robertson pupil.
  • Application of pilocarpine drops : overdose of neostigmine.
  • Iritis.

Bilateral miosis causes
Pin-point pupil.

  • Morphine or barbiturate poisoning, 
  • heat stroke (hyperpyrexia)

How to differentiate between patients with pin point pupil
  • Pontine haemorrhage—There is coma, hyperpyrexia and long tract signs (ie. sings ol pyramidal tract lesion).
  • Organophosphorus poisoning— It is diagnosed by history, absense of long tract signs, and sign of respiratory depression. The patient may be unconscious but there is absense of pyrexia.

Irregular pupils are due to 
  • Coloboma.
  • Neurosyphilis
  • followlng eye operation.
  • Sometimes, it is seen in normal healthy subjects.

Dilatation (mydriasis) of pupil

Mydriasis is defined as Pupil size > 5 mm
Constrictors ol the pupil are supplied by parasympathetics via the oculomotor nerve while the dilator are controlled by sympathetic nervous system. Changes in the size of the pupil do not affect the vision

Unilateral mydriasis causes
  • Drugs—-anticholinergics -
  • Acute ciliary ganglionitis—following several days after infection/ trauma
  • 3rd nerve palsy.
  • Holmes-Adies pupil or myotonic pupil.
  • Blindness due to Optic atrophy 
  • Acute congestive glaucoma.
  • Head injury-Uncal herniation Unilateral pupillary dilatation is the most important physical sign in the unconscious patient, and until proved otherwise a dilated pupil indicates that a herniated temporal lobe is compressing-the ipsilatcral oculomotor nerve, and that immediate surgical action is required.
Bilateral mydriasis causes
  • Anxiety
  • Myopic eyes
  • Infancy 
  • Thyrotoxicosis 
  • Drug poisoning-antihistamine, phenolhiazinc, anticholinergics, Datura poisoning,Drugs like atropine and pethidine
  • Application of mydriatics(atropine)
  • Postictal state 
  • Parinaud’s syndrome
  • Coma.
  • Severe raised intracranial tension.
  • Cerebral anoxia.

Size of Pupils and clinical significance

Normal size of pupil varies from 3 to 5 mm. 
Pupils < 3mm size in average condition of illumination are called miotic and pupils > 5 mm are called mydriatic. Pin point pupil is said to be present when the pupillary size is less than or equal to 1 mm.
  • Normal—3-5 mm 
  • Mydriasis > 6 mm
  • Miosis < 2 mm
  • Pin point pupil < I mm
  • A difference of 0.5 mm between the two pupils is abnormal

Anatomical peculiarities of 3,4,6th cranial nerve

The 3rd cranial nerve-oculomotornerve
The oculomotor nuclear complex is located in the the middbrain at the level of superior colliculus. This has one unpaired and four paired nuclear columns.
The unpaired column constitute
  • Edinger-Westphal nucleus
  • Subnucleus for levator palpebrae superioris. 
The paired nuclei constitutes
  • Subnuclei for superior, inferior and medial recti and inferior oblique.
4th cranial nerve-Trochlear nerve
  • Trochlear nerve passes posteriorly and the fibres from the right and left trochlear nuclei decussate on the dorsum of mid brain. 
  • This is the only cranial nerve that emerges dorsally from the brainstem. 
  • The left trochlear nucleus sends fibres to the right superior oblique muscle and vice versa.

6th cranial nerve-Abducent nerve 
  • Abducent nerve has a very long intracranial course and supplies the lateral rectus muscle..
  • Because of its long intracranial course, this  nerve  is affected in conditions producing raised intracranial tension, hence producing a false localizing sign.