C) Trastorno Depresivo Mayor.
3. Indicaciones dudosas o muy dudosas de psicofármacos
36 of the 55 pups examined (65%) had gross lesions that were indicators of possible traumatic brain injury. As noted in previous years (see Chapter Three), there were two peaks of traumatic brain injury lesions, with eight pups affected in week four of the observation period (30th January to 5th February), and 11 in week nine (2nd – 8th
February) (Figure 4.11). Spinal haemorrhage and intracranial subdural haemorrhage had a less pronounced first peak, instead showing an increase in prevalence over time, with peak occurrence in the last full week of the visit.
0 2 4 6 8 10 12 1 2 3 4 5 6 7 8 9
No. pups affected
Week
SDH SAH Fracture Spinal cord haem Head bruise Severe neck injury Puncture wound Any TBI lesion
Figure 4.11. Frequency of lesions of traumatic brain injury (TBI) over time. SDH = subdural haemor-
rhage, SAH = subarachnoid haemorrhage. Dotted line in week 3 indicates mean pupping date; dashed line at end of week 7 indicates date at which most adult males have left the harem.
Figure 4.12 depicts the frequency of various traumatic brain injury lesions. The most frequent lesion was bruising of the head, which was present in 25/55 (45%) of necropsied pups. Examples of traumatic brain injury-like lesions, including head bruising, are shown in Figure 4.13. The majority of bruises (13/23 (57%)) were over the dorsal aspect of the neurocranium, but bruising was also noted over the nasal bones as well as lateral aspects of the parietal, temporal and occipital areas. In six cases the bruises were less than 20mm in diameter (likely bite wounds), but in the remainder they were more extensive. Six pups with head bruises had bite wounds in the overlying skin, but in the remainder there was no cutaneous damage.
Spinal haemorrhage was the second most frequent lesion, occurring in 18/55 (33%) of pups. Fourteen of these cases (78%) occurred after 25th January (‘late’ season).
Examination of the fixed spinal cords showed that 16 pups had haemorrhage under the dura mater and two pups (E07/08-44Ph and 45Ph) had epidural haemorrhage. Fifteen cases of intracranial subdural haemorrhage were found, with six occurring before January 25th (‘early’ season), and nine in the later part of the season. Figure 4.8
shows the frequency of subdural haemorrhages during the observation period. Subdural haemorrhages consisted of a thin (2-4mm) layer of blood, usually clotted (14/15; 93%),
coating the inner aspect of the dura once the brain had been removed from the cranium. In individual pups, subdural blood films were present in the cerebral or cerebellar compartments, or both. In seven pups the haemorrhage was bilateral. One pup had unilateral haemorrhage in the left cerebellar compartment, which extended into the inter-hemispheric fissure, three had haemorrhage in one cerebellar compartment only, and in four the location of the subdural haemorrhage was not recorded.
Ten pups had haemorrhage of the brain surface at gross necropsy examination. Eight of these occurred in the second half of the season; hence fixed tissues were available for further assessment. While examination of the cut surfaces did not show parenchymal haemorrhage or discolouration suggestive of contusion, microscopic examination confirmed contusion in five cases (E07/08-21, -22, -23, -29 and -34Ph) and subarachnoid haemorrhage in the remaining three (E07/08-30, -37 and -42Ph).
Eight pups (15%) had skull fractures, all of which were in the first half of the season. Two of these were stillborn pups with multiple fractures along suture lines (Figure 4.11) in conjunction with bruising of the soft tissues of the head. In one of these stillborn pups the surface of the brain appeared to be bruised. Of the live-born pups with skull fractures, one had a fracture at the nasal sutures, with bruising of the underlying brain parenchyma. Two pups had single displaced fractures associated with bite wounds. One of these had a cerebral abscess underneath the fracture fragment, and mixed species of bacteria were cultured from this lesion. Of the three remaining cases of skull fracture, one was a single fracture of the zygomatic arch, one was a single fracture ‘near the left orbit’, and the third pup had multiple skull fractures but had sustained extensive scavenging of the brain and other soft tissues of the head, which prevented accurate interpretation of other lesions.
Figure 4.12. Gross lesions seen in pups necropsied at Sandy Bay, Enderby Island in 2007/08 breeding season, which could indicate traumatic brain injury. Figures in brackets at the top of each bar are the percentage of pups affected.
Figure 4.13. (This page and overleaf). Gross lesions consistent with traumatic brain injury (traumatic
brain injury-like lesions) found in pups dying in the 2007/08 breeding season. A. Head bruising. The skin has been removed to show bruising of the subcutaneeous tissues over the dorsal aspect of the neurocranium in an impact type injury. B. Subdural haemorrhage in a pup with meningi- tis. The dura mater is attached to the resected skull bone, and is covered with a layer of clotted blood (right). Image courtesy of Kerri Morgan, Massey University. C. Spinal cord haemorrhage.
B
C
In one pup there was also a vertebral body fracture. All three also had severe bruising to the head, and two had concurrent skull fractures (one with multiple fractures of the neurocranium and mandible, and one with a bite wound involving the neurocranium). These three cases were found between the 2nd and 5th January. None of the pups with
severe neck injuries had concurrent subdural, spinal or retinal haemorrhages.
Several brain lesions that were not identified in the retrospective analysis were also present, including haemorrhage of the cerebellar vermis (nine cases) and cloudy meninges (nine cases).
Twelve pups had eye lesions. Eight had multiple haemorrhages of the sclera without any other eye lesions; one had bilateral retrobulbar haemorrhages as a sole eye lesion; one had scleral haemorrhages plus haemorrhage into the optic sheath; one had retrobulbar haemorrhage with optic sheath haemorrhage; and one had scleral and retinal haemorrhages. The latter pup was the only one with grossly visible retinal haemorrhages. All eye lesions occurred after week four of the season.
Microscopic examination of brain tissue was possible for 36 pups, and showed meningitis in 16 of these (44%). 0 2 4 6 8 10 12 1 2 3 4 5 6 7 8 9
No. pups affected
Week
SDH
Spinal cord haem
Figure 4.14. Number of pups with intracranial subdural haemorrhage or spinal sub-meningeal hae-
morrhage over time. The dashed line indicates the date at which most adult males have left the harem.