MD

Food Poisoning

Common pathogens attributed to food poisoning include Norovirus, Salmonella, Clostridium perfringens, Campylobacter jejuni, Staphylococcus aureus, and Escherichia coli.

Incubation periods depend on the cause, and range from a few hours to days. The clinical presentation associated with food poisoning varies, but typical symptoms include diarrhea, nausea, vomiting, and abdominal cramping.

Staphylococcal food poisoning

Pathogen: Staphylococcus aureus
Gram-positive bacterium
Some strains produce heat-stable enterotoxins that cause staphylococcal food poisoning.  
Transmission: ingestion of preformed toxins in contaminated food

Characteristics

Typically involves a short latency period; resolution of symptoms after 24–48 hours
Bacteria proliferate in inadequately refrigerated food (canned meats, mayonnaise/potato salad, custards).

Incubation period: 1–4 hours

Clinical findings: nausea, vomiting, abdominal discomfort, diarrhea
 

Bacillus cereus infection


Pathogen: Bacillus cereus, a heat-stable, spore-forming  bacterium that produces two different enterotoxins

Transmission: The bacterium grows in heated food that cools down too slowly or is improperly refrigerated. Reheated rice is a common source of infection.

Incubation period and clinical findings

Enterotoxin I (emetic form): 30 min to 6 h after ingestion → nausea and vomiting
Enterotoxin II (diarrheal form): 6–15 h after ingestion → watery diarrhea for 24–48 h
 
Food poisoning from reheated rice - (B. cereus).

Cavernous Sinus

Each cavernous sinus is a large venous space situated in the middle cranial fossa on either side of the body of the sphenoid bone. Its interior is divided into a number of trabeculae or caverns. The floor of the sinus is formed by the endosteal dura mater. The lateral wall, roof and medial wall are formed by the meningeal dura mater.

Structures in the lateral wall of the sinus from above downwards:

  1. Oculomotor nerve
  2. Trochlear nerve
  3. Ophthalmic nerve - in the anterior part of the sinus, it divides into the lacrimal, frontal and nasociliary nerves.
  4. Maxillary nerve - it leaves the sinus by passing through the foramen rotundum on its way to the pterygopalatine fossa.
  5. Trigeminal ganglion - the ganglion and its dural cave project into the posterior part of the lateral wall of the sinus.

Structures passing through the centre of the sinus:

  1. Internal carotid artery with the venous and sympathetic plexus around it.
  2. Abducent nerve, inferolateral to the internal carotid artery.

Tributaries (incoming channels) of cavernous sinus

  1. Superior ophthalmic vein.
  2. A branch of inferior ophthalmic vein or sometimes vein itself.
  3. Central vein of retina (it may also drain into superior ophthalmic vein).
  4. Superficial middle cerebral vein.
  5. Inferior cerebral vein.
  6. Sphenoparietal sinus.
  7. Frontal trunk of middle meningeal vein (it may also drain into pterygoid plexus or into sphenoparietal sinus).

Draining channels (communications) of cavernous sinus

  1. Into transverse sinus through superior petrosal sinus.
  2. Into internal jugular vein through inferior petrosal sinusand through a plexus around the ICA
  3. Into pterygoid plexus of veinsthrough emissary veins.
  4. Into facial vein through superior ophthalmic vein.
  5. Right and left cavernous sinus communicates with each other by anterior and posterior intercavernous sinuses and through basilar plexus of veins.

 

TYPES OF TRACHEOSTOMY TUBE

  • A tracheostomy tube may be metallic or nonmetallic

Metallic Tracheostomy Tube

  • Metallic tubes are formed from the alloy of silver, copper and phosphorus
  • Example Jackson’s Tracheostomy tube.
  • Has an inner and an outer tube.The inner tube is longer than the outer one so that secretions and crusts formed in it can be removed and the tube reinserted after cleaning without difficulty. However, they do not have a cuff and cannot produce an airtight seal.
  • Advantages of a double lumen tracheostomy tube are easy to remove,clean and replace inner cannula.
  • Inner cannula should be removed and cleaned as and when indicated for the first 3 days. Outer tube, unless blocked or displaced, should not be removed for 3-4 days to allow a track to be formed when tube placement will be easy.

Nonmetallic Tracheostomy Tube

  • Can be of cuffed or noncuffed variety, e.g. rubber and PVC tubes.

Cuffed Tracheostomy Tubes

  • Pediatric tubes do not have a cuff.
  • Cuffed tubes are used in situation where positive pressure ventilation is required, or when the airway is at risk from aspiration. (In unconscious patient or when patient is on respiration).
  • The cuff should be deflated every 2 hours for 5 mins to present pressure damage to the trachea.

Uncuffed Tracheostomy Tubes

  • It is suitable for a patient who has returned to the ward from a prolonged stay in intensive care and requires physiotherapy and suction via trachea.
  • This type of tube is not suitable for patients who are unable to swallow due to incompetent laryngeal reflexes, and aspiration of oral or gastric con­tents is likely to occur.
  • An uncuffed tube is advantageous in that it allows the patient to breathe around it in the event of the tube becoming blocked. Patients can also speak with an uncuffed tube.

Important

Nonmetallic Tracheostomy Tube - Cuffed tubes are used in situation where positive pressure ventilation is required, or when the airway is at risk from aspiration. (In unconscious patient or when patient is on respiration).

Metallic Tracheostomy Tube -Metallic tubes are formed from the alloy of silver, copper and phosphorus .

  • Example Jackson’s Tracheostomy tube.
  • Advantages of a double lumen tracheostomy tube are easy to remove,clean and replace inner cannula.

Alport’s Sd (most cases): "hereditary nephritis", type IV collagen deficit, mutation of COL4A5 ("colaas" - alpha-5 chain, type 4 collagen), hearing loss, ocular abnormalities (lens & cornea), hematuria since childhood (gross, micro)

Charcot Marie Tooth: loss of motor & sensory innervation, distal weakness & sensory loss, wasting in the legs, decreased deep tendon reflexes, tremor, foot deformity with a high arch is common (pes cavus), legs look like inverted champagne bottles. Most accurate test: electromyography. No tx.

Focal Dermal Hypoplasia: skin abnormalities and a wide variety of defects in eyes; teeth; and skeletal, urinary, gastrointestinal, cardiovascular, and central nervous systems.

Fragile X Syndrome: CGG trinucleotid repeat, FMR 1 gene mutation, mental retardation, large ears and jaw, post-pubertal macro-orchidism (males), attention deficit disorder (females)

Hypophosphatemic rickets: infants may show growth retardation, widened joint spaces and flaring at the knees at age 1 (> boys), bowing of the weight-bearing long bones, young children-dentition absent or delayed, older children-multiple dental abscesses.

Incontinentia pigmenti: skin abnormalities (blister--> warts--> hyperpigmentation--> hypopigmentation), alopecia, hypodontia, cerebral atrophy, slow motor development, mental retardation, seizures, skeletal & structural anomalies. Letal >males.

Orofaciodigital Sd: OFD1 gene mutation, malformations of face, oral cavity, digits with polycystic kidney disease and variable involvement of the central nervous system.

RETT’s Sd: sporadic mutation of MECP2 gene, onset 2yo, acquired microcephaly, stopped development, motor & speech regression, autism-like behavior, self-mutilating behavior, inconsolable crying/screaming fits, emotional inversion, hypotonia, dystonia, chorea, bruxism, scholiosis, long QT